WO2018034308A1 - Polishing method, polishing device, and recording medium with computer program recorded thereon - Google Patents
Polishing method, polishing device, and recording medium with computer program recorded thereon Download PDFInfo
- Publication number
- WO2018034308A1 WO2018034308A1 PCT/JP2017/029453 JP2017029453W WO2018034308A1 WO 2018034308 A1 WO2018034308 A1 WO 2018034308A1 JP 2017029453 W JP2017029453 W JP 2017029453W WO 2018034308 A1 WO2018034308 A1 WO 2018034308A1
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- Prior art keywords
- polishing
- pad
- temperature
- polishing pad
- surface temperature
- Prior art date
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- 238000005498 polishing Methods 0.000 title claims abstract description 348
- 238000000034 method Methods 0.000 title claims abstract description 64
- 238000004590 computer program Methods 0.000 title description 3
- 239000012530 fluid Substances 0.000 claims abstract description 78
- 239000000758 substrate Substances 0.000 claims abstract description 40
- 230000008859 change Effects 0.000 claims abstract description 22
- 238000003825 pressing Methods 0.000 claims abstract description 6
- 239000012809 cooling fluid Substances 0.000 claims description 54
- 238000010438 heat treatment Methods 0.000 claims description 47
- 238000001816 cooling Methods 0.000 claims description 25
- 238000004088 simulation Methods 0.000 claims description 17
- 230000035945 sensitivity Effects 0.000 claims description 14
- 230000004044 response Effects 0.000 claims description 10
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- 239000007788 liquid Substances 0.000 description 13
- 238000003860 storage Methods 0.000 description 13
- 238000010586 diagram Methods 0.000 description 12
- 230000007246 mechanism Effects 0.000 description 8
- 238000007517 polishing process Methods 0.000 description 8
- 238000009529 body temperature measurement Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 7
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- 229920002545 silicone oil Polymers 0.000 description 6
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- 238000005259 measurement Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
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- 239000000126 substance Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000006061 abrasive grain Substances 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
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- 239000000112 cooling gas Substances 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
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- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
- B24B37/015—Temperature control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/34—Accessories
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/14—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the temperature during grinding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
Definitions
- the present invention relates to a polishing method for polishing a substrate such as a wafer, a polishing apparatus, and a recording medium on which a computer program for controlling the surface temperature of a polishing pad of the polishing apparatus is recorded.
- a CMP (Chemical Mechanical Polishing) apparatus is used in a process of polishing a surface of a substrate in the manufacture of a semiconductor device.
- the CMP apparatus holds a substrate with a polishing head, rotates the substrate, and presses the substrate against a polishing pad on a rotating polishing table to polish the surface of the substrate.
- a polishing liquid slurry
- the surface of the substrate is planarized by the chemical action of the polishing liquid and the mechanical action of abrasive grains contained in the polishing liquid.
- the polishing rate of the substrate depends not only on the polishing load on the polishing pad of the substrate but also on the surface temperature of the polishing pad. This is because the chemical action of the polishing liquid on the substrate and the hardness of the polishing pad depend on the temperature. Therefore, in the manufacture of semiconductor devices, it is important to keep the surface temperature of the polishing pad during polishing of the substrate at an optimal value in order to increase the polishing rate of the substrate and keep it constant.
- the PID parameter determination method often depends on a skilled person having special knowledge, experience, and know-how. Therefore, a lot of time is required to determine the PID parameter, and the cost is increased.
- an object of the present invention is to provide a polishing method and a polishing apparatus that do not require special knowledge, experience, and know-how, and that calculate PID parameters efficiently in a short time.
- Another object of the present invention is to provide a recording medium on which a program for controlling the surface temperature of the polishing pad is recorded.
- a substrate is pressed against a surface of a polishing pad to polish the substrate, and a flow rate of a fluid flowing through the pad temperature adjusting member is controlled during the polishing of the substrate.
- the flow control valve is operated according to the operation amount.
- the step of measuring the surface temperature of the polishing pad includes a step of measuring a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
- the pad temperature adjusting member in the step of changing the surface temperature of the polishing pad, is brought into contact with or close to the surface of the polishing pad during polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a flow rate control valve for controlling the flow rate of the flowing fluid.
- the step of changing the surface temperature of the polishing pad is a flow rate for controlling the flow rate of the fluid supplied from the pad temperature adjusting member onto the surface of the polishing pad during the polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a control valve.
- the fluid is a heating fluid and a cooling fluid.
- the step of calculating the PID parameter uses a limit cycle method, a step response method, or a Ziegler-Nichols limit sensitivity method to change the surface temperature of the polishing pad over time. It is a process of calculating a PID parameter based on it.
- a simulation of the surface temperature of the polishing pad expected as a result of operating the flow control valve with an operation amount calculated using the PID arithmetic expression is performed.
- a simulation is further executed to show a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed.
- Another aspect of the present invention includes a polishing table that supports a polishing pad, a polishing head that presses a substrate against the polishing pad, and a pad temperature adjustment system that adjusts a surface temperature of the polishing pad, and the pad temperature adjustment system.
- a pad temperature adjusting member having a flow path through which a fluid flows, a fluid supply pipe connected to the flow path, a flow control valve attached to the fluid supply pipe, and a surface temperature of the polishing pad
- a PID control unit for operating the flow rate control valve, and the PID control unit operates the flow rate control valve during polishing of the substrate to control the surface of the polishing pad.
- the polishing apparatus is characterized in that the flow control valve is operated according to the operation amount.
- the pad temperature measuring device is at least one temperature measuring device selected from an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile.
- the pad temperature measuring device is configured to measure a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
- the pad temperature adjustment system further includes a temperature indicator that displays a surface temperature of the polishing pad measured by the pad temperature measuring device.
- the pad temperature adjusting member is a cooling nozzle that sprays a cooling fluid onto the surface of the polishing pad.
- the pad temperature adjusting member has a pad contact surface capable of contacting the surface of the polishing pad.
- the PID control unit calculates the PID parameter using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method.
- the PID control unit executes a simulation of a surface temperature of the polishing pad that is expected as a result of operating the flow rate control valve with an operation amount calculated using the PID arithmetic expression. It is configured.
- the PID control unit is configured to further execute a simulation showing a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed.
- a command is given to the polishing head to cause the polishing head to perform an operation of pressing the substrate against the surface of the polishing pad to polish the substrate, and the fluid flowing through the pad temperature adjusting member.
- a step of changing a surface temperature of the polishing pad by operating a flow rate control valve provided to control a flow rate; a step of obtaining a measured value of the surface temperature of the polishing pad; and a surface of the polishing pad In order to minimize the deviation between the target temperature value and the measured value of the surface temperature of the polishing pad, using the step of calculating the PID parameter based on the time change of the temperature and the PID arithmetic expression having the PID parameter. Calculating a manipulated variable of the flow rate control valve and operating the flow rate control valve according to the manipulated value in a computer It is a non-transitory computer-readable recording medium recording a program for causing the row.
- the PID parameter can be automatically calculated based on the time change of the surface temperature of the polishing pad during the polishing of the substrate, an experiment by trial and error for determining the PID parameter, special knowledge No experience, know-how is required, and there is no need to rely on skilled workers. Therefore, the PID parameter can be determined in a short time and efficiently.
- FIG. 1 is a schematic view showing a polishing apparatus.
- the polishing apparatus includes a polishing head 1 that holds and rotates a wafer W that is an example of a substrate, a polishing table 2 that supports a polishing pad 3, and a polishing liquid (for example, A polishing liquid supply nozzle 4 for supplying a slurry) and a pad temperature adjusting system 5 for adjusting the surface temperature of the polishing pad 3.
- the surface (upper surface) of the polishing pad 3 constitutes a polishing surface for polishing the wafer W.
- the polishing head 1 can move in the vertical direction, and can rotate in the direction indicated by the arrow about its axis.
- the wafer W is held on the lower surface of the polishing head 1 by vacuum suction or the like.
- a motor (not shown) is connected to the polishing table 2 and is rotatable in the direction indicated by the arrow. As shown in FIG. 1, the polishing head 1 and the polishing table 2 rotate in the same direction.
- the polishing pad 3 is affixed to the upper surface of the polishing table 2.
- the polishing apparatus further includes a dresser 20 for dressing the polishing pad 3 on the polishing table 2.
- the dresser 20 is configured to swing on the surface of the polishing pad 3 in the radial direction of the polishing pad 3.
- the lower surface of the dresser 20 constitutes a dressing surface composed of a large number of abrasive grains such as diamond particles.
- the dresser 20 rotates while swinging on the polishing surface of the polishing pad 3, and dresses the surface of the polishing pad 3 by slightly scraping the polishing pad 3.
- the polishing of the wafer W is performed as follows.
- the wafer W to be polished is held by the polishing head 1 and further rotated by the polishing head 1.
- the polishing pad 3 is rotated together with the polishing table 2.
- the polishing liquid is supplied from the polishing liquid supply nozzle 4 to the surface of the polishing pad 3, and the surface of the wafer W is pressed against the surface of the polishing pad 3 (ie, the polishing surface) by the polishing head 1.
- the surface of the wafer W is polished by sliding contact with the polishing pad 3 in the presence of the polishing liquid.
- the surface of the wafer W is flattened by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid.
- the pad temperature adjusting system 5 includes a pad temperature adjusting member 11 in which a flow path for flowing a fluid for adjusting the surface temperature of the polishing pad 3 is formed, and the temperature adjusted heating fluid and cooling fluid are supplied to the pad temperature adjusting member. 11 and a fluid supply system 30 for supplying the fluid to the vehicle 11.
- the pad temperature adjusting member 11 can be in direct contact with the surface of the polishing pad 3 or close to the surface of the polishing pad 3.
- the pad temperature adjustment system 5 further includes a vertical movement mechanism (vertical movement mechanism) 71 that moves the pad temperature adjustment member 11 perpendicularly to the surface of the polishing pad 3.
- the pad temperature adjusting member 11 is held by the vertical movement mechanism 71.
- the vertical movement mechanism 71 is configured to be able to move the pad temperature adjusting member 11 in the vertical direction with respect to the surface of the polishing pad 3. With such a configuration, the pad temperature adjusting member 11 can be in direct contact with the surface of the polishing pad 3 or close to the surface of the polishing pad 3.
- the vertical movement mechanism 71 includes a combination of a servo motor and a ball screw mechanism, or an air cylinder.
- the pad temperature adjusting member 11 is configured to move perpendicularly to the surface of the polishing pad 3 to maintain a constant temperature in a region on the surface of the polishing pad 3 (a radial position of the polishing pad 3). ing.
- the pad temperature adjusting member 11 is perpendicular to the surface of the polishing pad 3 so as to maintain the temperature at the radial position of the polishing pad 3 at a distance of 100 mm from the center CL of the polishing pad 3 at 60 degrees. Move in the direction. The user can arbitrarily determine (change) the surface temperature of the polishing pad 3 controlled by the pad temperature adjusting member 11 and the radial position of the polishing pad 3.
- the user may change the distance from the center CL of the polishing pad 3 from 100 mm to 200 mm as the radial position of the polishing pad 3, and change the surface temperature of the polishing pad 3 from 60 degrees to 70 degrees. May be.
- the pad temperature adjusting member 11 is set against the surface of the polishing pad 3 so as to maintain the temperature at the radial position of the polishing pad 3 at a distance of 200 mm from the center CL of the polishing pad 3 at 70 degrees. Move up and down.
- the fluid supply system 30 includes a fluid supply tank 31 as a fluid supply source that stores a temperature-adjusted fluid, a heating fluid supply pipe 32 that connects the fluid supply tank 31 and the pad temperature adjustment member 11, and a heating fluid return pipe 33. And. One end of the heating fluid supply pipe 32 and the heating fluid return pipe 33 is connected to the fluid supply tank 31, and the other end is connected to the pad temperature adjusting member 11.
- the heated fluid whose temperature is adjusted is supplied from the fluid supply tank 31 to the pad temperature adjusting member 11 through the heated fluid supply pipe 32, flows in the pad temperature adjusting member 11, and passes from the pad temperature adjusting member 11 to the heated fluid return pipe 33. Returned to the fluid supply tank 31.
- the heating fluid circulates between the fluid supply tank 31 and the pad temperature adjusting member 11.
- the fluid supply tank 31 has a heater (not shown), and the heated fluid is heated to a predetermined temperature by the heater.
- a first open / close valve 41 and a first flow control valve 42 are attached to the heated fluid supply pipe 32.
- the first flow rate control valve 42 is disposed between the pad temperature adjusting member 11 and the first opening / closing valve 41.
- the first on-off valve 41 is a valve that does not have a flow rate adjustment function, while the first flow rate control valve 42 is a valve that has a flow rate adjustment function.
- the fluid supply system 30 further includes a cooling fluid supply pipe 51 and a cooling fluid discharge pipe 52 connected to the pad temperature adjusting member 11.
- the cooling fluid supply pipe 51 is connected to a cooling fluid supply source (for example, a cold water supply source) provided in a factory where the polishing apparatus is installed.
- the cooling fluid is supplied to the pad temperature adjusting member 11 through the cooling fluid supply pipe 51, flows through the pad temperature adjusting member 11, and is discharged from the pad temperature adjusting member 11 through the cooling fluid discharge pipe 52.
- a second opening / closing valve 55 and a second flow rate control valve 56 are attached to the cooling fluid supply pipe 51.
- the second flow rate control valve 56 is disposed between the pad temperature adjusting member 11 and the second opening / closing valve 55.
- the second on-off valve 55 is a valve that does not have a flow rate adjustment function, whereas the second flow rate control valve 56 is a valve that has a flow rate adjustment function.
- FIG. 2 is a schematic view showing another embodiment of the polishing apparatus.
- one end of the cooling fluid supply pipe 51 and the cooling fluid discharge pipe 52 may be connected to the fluid supply tank 31, and the other end may be connected to the pad temperature adjusting member 11.
- the cooling fluid that circulates between the fluid supply tank 31 and the pad temperature adjusting member 11 is cooled in the fluid supply tank 31.
- the heating fluid circulating between the fluid supply tank 31 and the pad temperature adjusting member 11 is heated in the fluid supply tank 31.
- the cooling fluid discharge pipe 52 is a cooling fluid return pipe.
- the pad temperature adjustment system 5 includes a pad temperature measuring device 39 that measures the surface temperature of the polishing pad 3 (hereinafter, also referred to as pad surface temperature), and the pad surface measured by the pad temperature measuring device 39.
- a PID control unit 40 that operates the first flow control valve 42 and the second flow control valve 56 based on the temperature is further provided.
- the first opening / closing valve 41 and the second opening / closing valve 55 are normally opened.
- the pad temperature measuring device 39 is disposed above the surface of the polishing pad 3 and is configured to measure the surface temperature of the polishing pad 3 in a non-contact manner.
- the pad temperature measuring device 39 is connected to the PID control unit 40, and further connected to the temperature indicator 45 via the PID control unit 40.
- the pad temperature measuring device 39 may be an infrared radiation thermometer or a thermocouple thermometer that measures the surface temperature of the polishing pad 3, measures the surface temperature of the polishing pad 3, and acquires the temperature distribution of the polishing pad 3. It may be a thermography or a thermopile.
- the pad temperature measuring device 39 is at least one temperature measuring device among an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile.
- the pad temperature measuring device 39 may not be able to accurately measure the surface temperature of the polishing pad 3. Therefore, the pad temperature measuring device 39 is disposed at a sufficiently high position from the surface of the polishing pad 3.
- FIG. 3 is a view of the temperature measurement region of the pad temperature measurement device 39 as viewed from above
- FIG. 4 is a view of the temperature measurement region of the pad temperature measurement device 39 as viewed from the side.
- the pad temperature measuring device 39 is configured to measure the surface temperature of the polishing pad 3 in a region including the center CL of the polishing pad 3 and the outer peripheral portion 3 a of the polishing pad 3. (See dotted lines in FIGS. 3 and 4).
- the pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 in a non-contact manner, and sends the measured value of the surface temperature to the PID control unit 40.
- the pad temperature measuring device 39 may measure the surface temperature of the polishing pad 3 every predetermined time.
- the PID control unit 40 operates the first flow rate control valve 42 and the second flow rate control valve 56 based on the measured pad surface temperature so that the pad surface temperature is maintained at a preset target temperature. .
- the first flow rate control valve 42 and the second flow rate control valve 56 operate according to the control signal from the PID control unit 40 and adjust the flow rate of the heating fluid and the cooling fluid supplied to the pad temperature adjustment member 11. Heat exchange is performed between the heating fluid and the cooling fluid flowing through the pad temperature adjusting member 11 and the polishing pad 3, thereby changing the pad surface temperature.
- Warm water is used as the heating fluid supplied to the pad temperature adjusting member 11.
- the hot water is heated to, for example, about 80 ° C. by the heater of the fluid supply tank 31.
- silicone oil may be used as a heating fluid.
- the silicone oil is heated to 100 ° C. or higher (for example, about 120 ° C.) by the heater of the fluid supply tank 31.
- the cooling fluid supplied to the pad temperature adjusting member 11 cold water or silicone oil is used.
- silicone oil is used as a cooling fluid, the polishing pad 3 can be quickly cooled by connecting a chiller as a cooling fluid supply source to the cooling fluid supply pipe 51 and cooling the silicone oil to 0 ° C. or lower. it can.
- the heating fluid supply pipe 32 and the cooling fluid supply pipe 51 are completely independent pipes. Therefore, the heating fluid and the cooling fluid are simultaneously supplied to the pad temperature adjusting member 11 without being mixed.
- the heating fluid return pipe 33 and the cooling fluid discharge pipe 52 are also completely independent pipes. Therefore, the heating fluid is returned to the fluid supply tank 31 without being mixed with the cooling fluid, and the cooling fluid is discharged without being mixed with the heating fluid.
- FIG. 5 is a horizontal sectional view showing the pad temperature adjusting member 11.
- the pad temperature adjustment member 11 is a heat exchange member having a heating channel 61 and a cooling channel 62 formed therein.
- the heating channel 61 and the cooling channel 62 extend adjacent to each other and extend in a spiral shape. In the present embodiment, the heating channel 61 is shorter than the cooling channel 62.
- the heating fluid supply pipe 32 is connected to the inlet 61 a of the heating channel 61, and the heating fluid return pipe 33 is connected to the outlet 61 b of the heating channel 61.
- the cooling fluid supply pipe 51 is connected to the inlet 62 a of the cooling flow path 62, and the cooling fluid discharge pipe 52 is connected to the outlet 62 b of the cooling flow path 62.
- the inlets 61a and 62a of the heating channel 61 and the cooling channel 62 are located at the peripheral edge of the pad temperature adjusting member 11, and the outlets 61b and 62b of the heating channel 61 and the cooling channel 62 are pad temperature adjusting members. 11 is located in the center.
- the heating fluid and the cooling fluid flow spirally from the peripheral portion of the pad temperature adjusting member 11 toward the central portion.
- the heating channel 61 and the cooling channel 62 are completely separated, and the heating fluid and the cooling fluid are not mixed in the pad temperature adjusting member 11.
- the shapes of the heating channel 61 and the cooling channel 62 are not limited to the embodiment shown in FIG. 5, and the pad temperature adjusting member 11 may have a zigzag heating channel and a cooling channel.
- FIG. 6 is a plan view showing the positional relationship between the pad temperature adjusting member 11 on the polishing pad 3 and the polishing head 1.
- the pad temperature adjusting member 11 is circular when viewed from above, and the diameter of the pad temperature adjusting member 11 is smaller than the diameter of the polishing head 1.
- the distance from the center CL of the polishing pad 3 to the center of the pad temperature adjusting member 11 is the same as the distance from the center CL of the polishing pad 3 to the center of the polishing head 1. Since the heating channel 61 and the cooling channel 62 are adjacent to each other, the heating channel 61 and the cooling channel 62 are arranged not only in the radial direction of the polishing pad 3 but also in the circumferential direction of the polishing pad 3. Yes. Therefore, while the polishing table 2 and the polishing pad 3 are rotating, the pad temperature adjusting member 11 in contact with or close to the polishing pad 3 exchanges heat with both the heating fluid and the cooling fluid.
- FIG. 7 is a schematic diagram showing the temperature indicator 45.
- the pad temperature adjustment system 5 further includes a temperature indicator 45 that displays the surface temperature of the polishing pad 3 measured by the pad temperature measuring device 39.
- the PID control unit 40 is connected to the pad temperature measuring device 39 and the temperature indicator 45.
- the pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 in the temperature measurement region, and the measured surface temperature of the polishing pad 3 is displayed on the temperature display 45.
- the temperature of each surface position of the polishing pad 3 (that is, the surface position of the polishing pad 3 expressed in an orthogonal coordinate system) is displayed in a color and is easily displayed. For example, the surface position of the polishing pad 3 having a high temperature is represented in red, and the surface position of the polishing pad 3 having a low temperature is represented in blue.
- the temperature display 45 displays the surface temperature distribution of the polishing pad 3 as a color distribution.
- the user may specify the measurement position of the polishing pad 3 on the temperature indicator 45, or may specify the measurement position of the polishing pad 3 by inputting coordinates.
- the temperature display 45 measures the temperature at the current measurement position of the specified polishing pad 3, the temperature at an arbitrary time, the time transition of the temperature, the temperature distribution of the polishing pad 3, the maximum temperature, the minimum temperature, and the average temperature. The time integral value of the selected temperature is displayed.
- the PID control unit 40 operates the first flow control valve 42 and the second flow control valve 56 in order to eliminate the difference between the preset target temperature and the measured surface temperature of the polishing pad 3. Configured to calculate quantity.
- the operation amount of the first flow control valve 42 and the operation amount of the second flow control valve 56 are, in other words, the valve opening.
- the operation amount of the first flow rate control valve 42 is proportional to the flow rate of the heating fluid
- the operation amount of the second flow rate control valve 56 is proportional to the flow rate of the cooling fluid.
- the PID control unit 40 sets the operation amount of the first flow control valve 42 to 100.
- the operation amount of the second flow control valve 56 is determined by subtracting from%.
- the PID control unit 40 may determine the operation amount of the first flow control valve 42 by subtracting the operation amount of the second flow control valve 56 from 100%.
- the operation amount of the first flow control valve 42 being 100% indicates that the first flow control valve 42 is fully open, and the operation amount of the first flow control valve 42 is 0%. It shows that the flow control valve 42 is completely closed.
- the operation amount of the second flow rate control valve 56 being 100% indicates that the second flow rate control valve 56 is fully open, and the operation amount of the second flow rate control valve 56 is 0%. , Indicating that the second flow control valve 56 is completely closed.
- the flow rate of the heating fluid when the operation amount of the first flow control valve 42 is 100% is the same as the flow rate of the cooling fluid when the operation amount of the second flow control valve 56 is 100%. Therefore, the sum of the flow rate of the heating fluid passing through the first flow rate control valve 42 and the flow rate of the cooling fluid passing through the second flow rate control valve 56 is always constant.
- the PID control unit 40 includes the first flow control valve 42 and the second flow control valve 56 so that the sum of the operation amount of the first flow control valve 42 and the operation amount of the second flow control valve 56 becomes 100%. To operate.
- the heating fluid flows in the heating flow path 61 of the pad temperature adjusting member 11, and only the cooling fluid flows in the cooling flow path 62.
- the respective flow rates of the heating fluid and the cooling fluid are controlled based on the surface temperature of the polishing pad 3. That is, the first flow rate control valve 42 and the second flow rate control valve 56 are operated by the PID control unit 40 based on the difference between the surface temperature of the polishing pad 3 and the target temperature. Therefore, the surface temperature of the polishing pad 3 can be stably maintained at the target temperature.
- FIG. 8 is a view showing another embodiment of the pad temperature adjusting member 11. Since the configuration and operation of the present embodiment that are not particularly described are the same as those of the above-described embodiment, redundant description thereof is omitted.
- the pad temperature adjusting member 11 is a cooling nozzle that sprays a cooling fluid onto the surface of the polishing pad 3.
- a cooling gas such as air or an inert gas (for example, nitrogen gas) is used as the cooling fluid.
- a cooling channel 12 through which a cooling fluid flows is formed inside the pad temperature adjusting member 11 that is a cooling nozzle.
- the cooling flow path 12 is connected to the cooling fluid supply pipe 51 and the injection port of the pad temperature adjusting member 11.
- the cooling fluid When the cooling fluid is supplied to the pad temperature adjusting member 11 through the cooling fluid supply pipe 51, the cooling fluid is supplied from the ejection port of the pad temperature adjusting member 11 onto the surface of the polishing pad 3.
- a flow rate control valve 56 for controlling the flow rate of the cooling fluid supplied from the pad temperature adjusting member 11 onto the surface of the polishing pad 3 is attached to the cooling fluid supply pipe 51. In this embodiment, no heating fluid is used.
- the PID control unit 40 When the pad temperature adjusting member 11 is a heat exchange member (see FIG. 5), the PID control unit 40 operates the flow rate control valves 42 and 56 during polishing of the wafer W, thereby adjusting the surface temperature of the polishing pad 3. Can be changed.
- the pad temperature adjusting member 11 is a cooling nozzle (see FIG. 8)
- the PID control unit 40 changes the surface temperature of the polishing pad 3 by operating the flow rate control valve 56 during polishing of the wafer W. Can do.
- the pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 when the wafer W is being polished, and sends the measured value of the surface temperature to the PID control unit 40.
- the PID control unit 40 is configured to acquire a measured value of the surface temperature of the polishing pad 3 from the pad temperature measuring device 39 and calculate a PID parameter based on a temporal change in the surface temperature of the polishing pad 3.
- the PID parameter is calculated based on the time change of the surface temperature of the polishing pad 3 using any one of the limit cycle method, the step response method, and the limit sensitivity method of Ziegler Nichols. PID parameters calculated by these methods may be adjusted based on fuzzy inference, and PID parameters are calculated using a two-degree-of-freedom PID method that can optimize both target value tracking and disturbance suppression. May be.
- the PID control unit 40 uses a PID arithmetic expression (described later) having a PID parameter calculated by the above method to minimize the deviation between the temperature target value of the polishing pad 3 and the measured value of the surface temperature.
- the operation amounts of the flow control valves 42 and 56 are calculated.
- the PID control unit 40 operates the flow rate control valves 42 and 56 according to the calculated operation amount during polishing of the wafer W.
- the PID control unit 40 is configured to automatically calculate PID parameters during polishing of the wafer W.
- a limit cycle method which is an example of a method for calculating PID parameters, will be described with reference to the drawings.
- FIG. 9 is a diagram for explaining the limit cycle method.
- symbol PV indicates a measured value of the surface temperature of the polishing pad 3
- symbol MV indicates an operation amount of the flow rate control valves 42 and 56
- symbol SV indicates a temperature target of the surface temperature of the polishing pad 3.
- the value is shown.
- the vertical axis indicates the measured value PV
- the horizontal axis indicates time.
- the vertical axis shows the operation amount MV of the flow control valves 42 and 56.
- the horizontal axis indicates time.
- the operation amount of the flow control valves 42 and 56 is determined so that the flow control valves 42 and 56 are fully opened and fully closed. More specifically, when the first flow control valve 42 is fully open (operation amount 100%), the second flow control valve 56 is fully closed (operation amount 0%). Further, when the second flow control valve 56 is fully opened (operation amount 100%), the first flow control valve 42 is fully closed (operation amount 0%). As described above, the operation in which the flow control valves 42 and 56 are repeatedly fully opened and fully closed is called a two-position operation of the flow control valves 42 and 56.
- FIG. 10 is a view showing the two-position operation of the flow control valves 42 and 56.
- the vertical axis represents the operation amount MV of the flow control valves 42 and 56
- the horizontal axis represents the deviation e.
- the PID control unit 40 when the measured value PV is higher than the temperature target value SV, the PID control unit 40 fully closes the first flow rate control valve 42 with an operation amount of 0% and sets the second flow rate control valve 56. The surface temperature of the polishing pad 3 is lowered by fully opening at an operation amount of 100%.
- the PID control unit 40 When the measured value PV is lower than the temperature target value SV, the PID control unit 40 fully opens the first flow rate control valve 42 with an operation amount of 100% and fully closes the second flow rate control valve 56 with an operation amount of 0%. Thus, the surface temperature of the polishing pad 3 is raised.
- the PID control unit 40 when the measured value PV is higher than the temperature target value SV, the PID control unit 40 outputs the cooling side operation amount ⁇ M, and when the measured value PV is lower than the temperature target value SV, the PID control unit 40 operates the heating side. Output amount + M.
- the PID control unit 40 repeatedly opens and closes the flow rate control valves 42 and 56 to periodically change the surface temperature of the polishing pad 3. Such a periodic temperature change is called a limit cycle waveform.
- the cycle of the limit cycle waveform to be generated may be 2 to 3 cycles.
- the PID control unit 40 can also repeat opening and closing the flow control valve 56 with the first opening and closing valve 41 closed. Limit cycle waveforms can be generated. That is, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 fully opens the flow control valve 56 at an operation amount of 100%, and when the measured value PV is lower than the temperature target value SV, the flow control valve 56. May be fully closed with an operation amount of 0%.
- the PID control unit 40 can generate a limit cycle waveform by controlling the flow rate of the cooling fluid supplied onto the surface of the polishing pad 3. That is, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 opens the flow rate control valve 56 and supplies the cooling fluid onto the surface of the polishing pad 3. When the measured value PV is lower than the temperature target value SV, the PID control unit 40 fully closes the flow rate control valve 56 and stops the supply of the cooling fluid to the surface of the polishing pad 3.
- the PID control unit 40 determines the surface temperature amplitude X and the dead time Lt of the polishing pad 3 based on the generated limit cycle waveform.
- the PID control unit 40 calculates the limit sensitivity Kc and the limit period Tc using the amplitude M of the manipulated variable of the flow control valves 42 and 56, the amplitude X of the surface temperature of the polishing pad 3, and the dead time Lt, respectively.
- the limit sensitivity Kc is obtained by using the following formula (3)
- the limit period Tc is obtained by using the following formula (4).
- Kc 4 ⁇ M / ( ⁇ ⁇ X) (3)
- Tc 4 ⁇ Lt (4)
- the PID control unit 40 calculates PID parameters from the calculated limit sensitivity Kc and limit period Tc.
- the PID parameter is a parameter necessary for PID control of the flow rate control valves 42 and 56, and includes a proportional gain Kp, an integration time Ti, and a differentiation time Td.
- a method for calculating the PID parameter will be described.
- FIG. 11 is a diagram showing an example of coefficients used for calculating PID parameters.
- FIG. 11 shows coefficients used for calculation of PID parameters (and PI parameters) in the control rules of the fixed value control direction (Ziegler and Nichols) and the follow-up control direction (Chien, Herones, and Rewick). Note that the coefficient for calculating the PID parameter is not limited to the numerical values shown in FIG. These coefficients are determined in advance according to the polishing conditions of the wafer W.
- a PID parameter (that is, proportional gain Kp, integration time Ti, and differentiation time Td) can be calculated by multiplying the predetermined coefficient, the limit sensitivity Kc, and the limit period Tc, respectively.
- the PID control unit 40 uses the PID arithmetic expression including the calculated PID parameter to minimize the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3.
- the operation amounts of the flow control valves 42 and 56 are calculated.
- the PID formula is It can be expressed as.
- FIG. 12 is a diagram showing a feedback control system when calculating PID parameters.
- the two-position operation of the flow rate control valves 42 and 56 is performed based on the deviation e as the non-linear element N (X).
- An input to the control object P (j ⁇ ) for minimizing the deviation e, that is, an operation amount MV of the flow control valves 42 and 56 is calculated.
- the PID control unit 40 operates the flow rate control valves 42 and 56 to maintain the surface temperature of the polishing pad 3 at a desired target temperature.
- the PID control unit 40 is configured by a dedicated computer or a general-purpose computer.
- FIG. 13 is a schematic diagram illustrating a configuration of the PID control unit 40.
- the PID control unit 40 includes a storage device 110 that stores programs and data, a processing device 120 such as a CPU (central processing unit) that performs operations according to programs stored in the storage device 110, data, programs, and An input device 130 for inputting various information to the storage device 110, an output device 140 for outputting processing results and processed data, and a communication device 150 for connecting to a network such as the Internet are provided.
- a processing device 120 such as a CPU (central processing unit) that performs operations according to programs stored in the storage device 110, data, programs, and
- An input device 130 for inputting various information to the storage device 110
- an output device 140 for outputting processing results and processed data
- a communication device 150 for connecting to a network such as the Internet are provided.
- the storage device 110 includes a main storage device 111 accessible by the processing device 120 and an auxiliary storage device 112 that stores data and programs.
- the main storage device 111 is, for example, a random access memory (RAM)
- the auxiliary storage device 112 is a storage device such as a hard disk drive (HDD) or a solid state drive (SSD).
- the input device 130 includes a keyboard and a mouse, and further includes a recording medium reading device 132 for reading data from the recording medium and a recording medium port 134 to which the recording medium is connected.
- the recording medium is a non-transitory tangible computer-readable recording medium, such as an optical disc (eg, CD-ROM, DVD-ROM) or semiconductor memory (eg, USB flash drive, memory card). is there.
- Examples of the recording medium reading device 132 include an optical drive such as a CD drive and a DVD drive, and a card reader.
- An example of the recording medium port 134 is a USB terminal.
- the program and / or data recorded on the recording medium is introduced into the PID control unit 40 via the input device 130 and stored in the auxiliary storage device 112 of the storage device 110.
- the output device 140 includes a display device 141 and a printing device 142.
- the printing device 142 may be omitted.
- the temperature indicator 45 described above may be used as a display device for the PID control unit 40. In this case, the display device 141 may be omitted.
- the PID control unit 40 operates according to a program electrically stored in the storage device 110.
- FIG. 14 is a flowchart showing the operation steps of the PID control unit 40 that operates according to a program.
- the PID control unit 40 instructs the polishing head 1 to cause the polishing head 1 to perform an operation of pressing the wafer W against the surface of the polishing pad 3 to polish the wafer W (see Step 1 in FIG. 14).
- the step of changing the surface temperature of the polishing pad 3 by operating the flow rate control valves 42 and 56 see step 2 of FIG. 14
- the operation of measuring the surface temperature of the polishing pad 3 are performed.
- Steps 3 and 4 in FIG. 14 Based on the step of causing the pad temperature measuring device 39 to execute the measurement of the surface temperature of the polishing pad 3 (see Steps 3 and 4 in FIG. 14) and the time variation of the surface temperature of the polishing pad 3, Using the step of calculating (see step 5 in FIG. 14) and the PID calculation formula including the PID parameter, the temperature target value SV and the surface temperature of the polishing pad 3 A step of calculating an operation amount of the flow control valves 42 and 56 for minimizing a deviation from the constant value PV (see step 6 in FIG. 14), and a step of operating the flow control valves 42 and 56 based on the operation amount (See step 7 in FIG. 14).
- the program for causing the PID control unit 40 to execute these steps is recorded on a computer-readable recording medium that is a non-temporary tangible material and provided to the PID control unit 40 via the recording medium.
- the program may be provided to the PID control unit 40 via a communication network such as the Internet.
- FIG. 15 is a diagram for explaining the step response method.
- symbol PV indicates a measured value of the surface temperature of the polishing pad 3
- symbol MV indicates an operation amount of the flow rate control valves 42 and 56.
- the vertical axis in FIG. 15 indicates the measured value PV and the manipulated variable MV, and the horizontal axis in FIG. 15 indicates time.
- the PID control unit 40 switches the first flow rate control valve 42 from fully closed to fully open, and switches the second flow rate control valve 56 from fully open to fully closed, so that the surface temperature of the polishing pad 3 is increased. Change.
- the pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 at this time and sends it to the PID control unit 40.
- the PID control unit 40 acquires this measurement value from the pad temperature measuring device 39, calculates the slope R of the tangent TL of the curve indicating the time change of the surface temperature of the polishing pad 3, and calculates the slope R of the tangent TL and the dead time Lt. , And a time constant ⁇ .
- the curve of the measured value PV shown in FIG. 15 is called a process reaction curve.
- the PID control unit 40 can also generate a process reaction curve by switching the second flow rate control valve 56 from fully open to fully closed while the first opening / closing valve 41 is closed. Even when the pad temperature adjusting member 11 is a cooling nozzle, the PID control unit 40 can generate a process reaction curve by controlling the flow rate of the cooling fluid supplied onto the surface of the polishing pad 3. That is, the PID control unit 40 can generate a process reaction curve by switching the flow control valve 56 from fully open to fully closed.
- the tangent TL indicates the process reaction when the measured value PV increases to a predetermined value (63% in the present embodiment) when the measured value PV is represented by a value from 0% to 100%. It is a tangent line passing through the point P1 on the curve. The slope R is obtained based on the tangent line TL.
- the dead time Lt is obtained by calculating the time difference from the time when the first flow control valve 42 is fully opened to the time at the intersection P2 between the tangent TL and the horizontal axis.
- the time constant ⁇ is obtained by calculating the time difference from the time at the intersection P2 to the time corresponding to the point P1.
- the integration time Ti can be obtained by using the following formula (7) or the following formula (8).
- Ti b ⁇ Lt (7)
- Ti b ⁇ ⁇ (8)
- the differential time Td can be obtained by using the following formula (9).
- Td c ⁇ Lt (9)
- the coefficients a, b, and c in the above equations (6) to (9) are predetermined numerical values, for example, the coefficient a is 1.2, the coefficient b is 2.0, and the coefficient c is 0. .5.
- the PID control unit 40 minimizes the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3 using the PID calculation formula (see the above formula (5)) having the calculated PID parameter.
- the amount of operation of the flow control valves 42 and 56 is calculated.
- FIG. 16 is a diagram for explaining the limit sensitivity method of Ziegler-Nichols.
- symbol PV indicates a measured value of the surface temperature of the polishing pad 3
- symbol SV indicates a temperature target value of the surface temperature of the polishing pad 3
- symbol Pu indicates a period of a limit gain.
- the curve Kp1 is a control curve of the measured value PV by the first gain
- the curve Kp2 is a control curve of the measured value PV by the second gain larger than the first gain Kp1
- the curve Kp3 is the second gain Kp2.
- It is a control curve of the measured value PV with a larger third gain (Kp1 ⁇ Kp2 ⁇ Kp3).
- the vertical axis in FIG. 16 indicates the measured value PV
- the horizontal axis in FIG. 16 indicates time.
- the PID control unit 40 increases the first gain Kp1, the second gain Kp2, and the third gain Kp3 in this order in a state where the integration time Ti and the differentiation time Td are invalidated, and the temperature target value SV Hunting (waveform of measured value PV) is generated between measured values PV.
- the gain value is increased by ten.
- hunting occurs when the third gain Kp3 is output.
- the third gain Kp3 is determined as the limit gain Ku.
- the PID control unit 40 calculates the period Pu of the limit gain Ku.
- the PID control unit 40 calculates PID parameters (proportional gain Kp, integration time Ti, derivative time Td) using the limit gain Ku and the period Pu. More specifically, the proportional gain Kp can be obtained by using the following equation (10), the integration time Ti can be obtained by using the following equation (11), and the differential time Td can be obtained by the following equation (12). ) Can be used.
- the coefficients a, b, and c in the above equations (10) to (12) are predetermined numerical values, for example, the coefficient a is 0.6, the coefficient b is 0.5, and the coefficient c is 0. .125.
- the PID control unit 40 minimizes the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3 using the PID calculation formula (see the above formula (5)) having the calculated PID parameter.
- the amount of operation of the flow control valves 42 and 56 is calculated.
- the PID control unit 40 can automatically calculate the PID parameter based on the temporal change in the surface temperature of the polishing pad 3 during the polishing of the wafer W, and therefore determines the PID parameter. For this reason, trial and error experiments, special knowledge, experience, and know-how are not necessary, and there is no need to rely on skilled workers. Therefore, the PID parameter can be determined efficiently in a short time. Furthermore, according to the present embodiment, time and personnel can be significantly reduced, and thus costs can be reduced.
- the PID control unit 40 is configured to execute a simulation of the surface temperature of the polishing pad 3 that is expected as a result of operating the flow control valves 42 and 56 with the operation amount calculated using the PID arithmetic expression described above. .
- the surface position of the polishing pad 3 on which the simulation result is displayed is arbitrarily determined by the user, and the PID control unit 40 executes the simulation based on the PID parameter and the temperature target value SV.
- the PID control unit 40 is configured to further execute a simulation showing the time transition of the surface temperature of the polishing pad 3 expected when the temperature target value SV is changed.
- FIG. 17 is a diagram showing simulation results showing the time transition of the surface temperature of the polishing pad 3. As shown in FIG. 17, the simulation result of the time transition of the surface temperature of the polishing pad 3 is displayed on the temperature display 45. The surface position of the polishing pad 3 on which the simulation result is displayed is arbitrarily determined by the user.
- the PID control unit 40 is configured to automatically determine the PID parameter for each polishing process of the wafer W.
- the polishing process of the wafer W is changed depending on, for example, the film thickness of the wafer W, the polishing pad, and the type of slurry.
- FIG. 18 is a flowchart showing how the PID parameters are calculated for each wafer W polishing process.
- one wafer W is polished by using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method (step 1 in FIG. 18). reference).
- the wafer W is polished according to a polishing recipe for calculating PID parameters.
- the limit cycle method is used, the temperature target value SV when polishing one wafer W is the same as the temperature target value when polishing the wafer W in an actual polishing process.
- the most appropriate PID parameter is calculated from the limit cycle method, the step response method, and the Ziegler-Nichols limit sensitivity method (see step 2 in FIG. 18), and polishing of the wafer W reflecting the calculated PID parameter is executed (see FIG. 18). (See Step 3 in FIG. 18).
- the wafer W is polished by a polishing process different from the polishing process at the time of polishing the wafer W, one wafer W is polished again, and the most appropriate PID parameter is calculated (see step 4 in FIG. 18). ).
- the PID control unit 40 may execute a simulation of the expected surface temperature of the polishing pad 3 (see Step 5 in FIG. 18).
- the temperature indicator 45 includes the time from the operation of the flow rate control valves 42 and 56 to the change of the surface temperature of the polishing pad 3 and the magnitude of the overshoot caused in the change of the surface temperature of the polishing pad 3.
- the deviation between the temperature target value SV and the measured value PV, and the magnitude of hunting generated in the waveform of the measured value PV of the surface temperature of the polishing pad 3 may be displayed.
- the present invention can be used for a polishing method for polishing a substrate such as a wafer, a polishing apparatus, and a recording medium on which a computer program for controlling the surface temperature of a polishing pad of the polishing apparatus is recorded.
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Abstract
The present invention relates to a polishing method for polishing a substrate such as a wafer. The polishing method comprises: polishing a substrate (W) by pressing the substrate (W) against the surface of a polishing pad (3); changing the surface temperature of the polishing pad (3) by operating flow rate control valves (42, 56) that are for controlling the flow rate of a fluid flowing through a pad temperature adjusting member (11) during the polishing of the substrate (W); measuring the surface temperature of the polishing pad (3); computing a PID parameter on the basis of a change in the surface temperature of the polishing pad (3) over time; calculating operation quantities of the flow rate control valves (42, 56) that are for minimizing the deviation between a target temperature value and a measured value of the surface temperature of the polishing pad by using a PID arithmetic expression that includes the PID parameter; and operating the flow rate control valves (42, 56) in accordance with the operation quantities during the polishing of the substrate (W).
Description
本発明は、ウェーハなどの基板を研磨する研磨方法、研磨装置、および該研磨装置の研磨パッドの表面温度を制御するためのコンピュータプログラムを記録した記録媒体に関するものである。
The present invention relates to a polishing method for polishing a substrate such as a wafer, a polishing apparatus, and a recording medium on which a computer program for controlling the surface temperature of a polishing pad of the polishing apparatus is recorded.
CMP(Chemical Mechanical Polishing)装置は、半導体デバイスの製造において、基板の表面を研磨する工程に使用される。CMP装置は、基板を研磨ヘッドで保持して基板を回転させ、さらに回転する研磨テーブル上の研磨パッドに基板を押し付けて基板の表面を研磨する。研磨中、研磨パッドには研磨液(スラリー)が供給され、基板の表面は、研磨液の化学的作用と研磨液に含まれる砥粒の機械的作用により平坦化される。
A CMP (Chemical Mechanical Polishing) apparatus is used in a process of polishing a surface of a substrate in the manufacture of a semiconductor device. The CMP apparatus holds a substrate with a polishing head, rotates the substrate, and presses the substrate against a polishing pad on a rotating polishing table to polish the surface of the substrate. During polishing, a polishing liquid (slurry) is supplied to the polishing pad, and the surface of the substrate is planarized by the chemical action of the polishing liquid and the mechanical action of abrasive grains contained in the polishing liquid.
基板の研磨レートは、基板の研磨パッドに対する研磨荷重のみならず、研磨パッドの表面温度にも依存する。これは、基板に対する研磨液の化学的作用および研磨パッドの硬さが温度に依存するからである。したがって、半導体デバイスの製造においては、基板の研磨レートを上げて更に一定に保つために、基板研磨中の研磨パッドの表面温度を最適な値に保つことが重要とされる。
The polishing rate of the substrate depends not only on the polishing load on the polishing pad of the substrate but also on the surface temperature of the polishing pad. This is because the chemical action of the polishing liquid on the substrate and the hardness of the polishing pad depend on the temperature. Therefore, in the manufacture of semiconductor devices, it is important to keep the surface temperature of the polishing pad during polishing of the substrate at an optimal value in order to increase the polishing rate of the substrate and keep it constant.
そこで、研磨パッドの表面温度を測定し、測定された研磨パッドの温度情報に基づいてPID制御により研磨パッドの研磨面の温度を調整する研磨装置が提案されている(例えば特許文献1参照)。
Therefore, a polishing apparatus that measures the surface temperature of the polishing pad and adjusts the temperature of the polishing surface of the polishing pad by PID control based on the measured temperature information of the polishing pad has been proposed (for example, see Patent Document 1).
しかしながら、PIDパラメータを決定するための方法については、明確な指針は存在せず、ユーザーは試行錯誤を重ねながらPIDパラメータを決定しなければならない。また、PIDパラメータの決定方法については、特別な知識や経験、ノウハウを有する熟練者に依存している場合も多い。したがって、PIDパラメータを決定するために、多くの時間が必要となり、コストもかかってしまう。
However, there is no clear guideline for the method for determining the PID parameter, and the user must determine the PID parameter through trial and error. In addition, the PID parameter determination method often depends on a skilled person having special knowledge, experience, and know-how. Therefore, a lot of time is required to determine the PID parameter, and the cost is increased.
そこで、本発明は、特別な知識や経験、ノウハウを必要とせず、さらに、短時間で、かつ効率的にPIDパラメータを算定する研磨方法、および研磨装置を提供することを目的とする。また、本発明は、研磨パッドの表面温度を制御するためのプログラムを記録した記録媒体を提供することを目的とする。
Therefore, an object of the present invention is to provide a polishing method and a polishing apparatus that do not require special knowledge, experience, and know-how, and that calculate PID parameters efficiently in a short time. Another object of the present invention is to provide a recording medium on which a program for controlling the surface temperature of the polishing pad is recorded.
上述した目的を達成するために、本発明の一態様は、基板を研磨パッドの表面に押し付けて該基板を研磨し、前記基板の研磨中に、パッド温度調整部材に流れる流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させ、前記研磨パッドの表面温度を測定し、前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定し、前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算し、前記基板の研磨中に、前記操作量に従って前記流量制御バルブを操作することを特徴とする研磨方法である。
In order to achieve the above-described object, according to one embodiment of the present invention, a substrate is pressed against a surface of a polishing pad to polish the substrate, and a flow rate of a fluid flowing through the pad temperature adjusting member is controlled during the polishing of the substrate. Operating the flow control valve for changing the surface temperature of the polishing pad, measuring the surface temperature of the polishing pad, calculating the PID parameter based on the time change of the surface temperature of the polishing pad, The operation amount of the flow rate control valve for minimizing the deviation between the temperature target value and the measured value of the surface temperature of the polishing pad is calculated using a PID arithmetic expression having the PID parameter, and the substrate is polished. In the polishing method, the flow control valve is operated according to the operation amount.
本発明の好ましい態様は、前記研磨パッドの表面温度を測定する工程は、前記研磨パッドの中心と外周部とを含む領域における温度分布を測定する工程を含むことを特徴とする。
本発明の好ましい態様は、前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材を前記研磨パッドの表面に接触させ、または近接させて該パッド温度調整部材に流れる流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする。
本発明の好ましい態様は、前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材から前記研磨パッドの表面上に供給される流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする。
本発明の好ましい態様は、前記流体は、加熱流体および冷却流体であることを特徴とする。 In a preferred aspect of the present invention, the step of measuring the surface temperature of the polishing pad includes a step of measuring a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
In a preferred aspect of the present invention, in the step of changing the surface temperature of the polishing pad, the pad temperature adjusting member is brought into contact with or close to the surface of the polishing pad during polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a flow rate control valve for controlling the flow rate of the flowing fluid.
In a preferred aspect of the present invention, the step of changing the surface temperature of the polishing pad is a flow rate for controlling the flow rate of the fluid supplied from the pad temperature adjusting member onto the surface of the polishing pad during the polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a control valve.
In a preferred aspect of the present invention, the fluid is a heating fluid and a cooling fluid.
本発明の好ましい態様は、前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材を前記研磨パッドの表面に接触させ、または近接させて該パッド温度調整部材に流れる流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする。
本発明の好ましい態様は、前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材から前記研磨パッドの表面上に供給される流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする。
本発明の好ましい態様は、前記流体は、加熱流体および冷却流体であることを特徴とする。 In a preferred aspect of the present invention, the step of measuring the surface temperature of the polishing pad includes a step of measuring a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
In a preferred aspect of the present invention, in the step of changing the surface temperature of the polishing pad, the pad temperature adjusting member is brought into contact with or close to the surface of the polishing pad during polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a flow rate control valve for controlling the flow rate of the flowing fluid.
In a preferred aspect of the present invention, the step of changing the surface temperature of the polishing pad is a flow rate for controlling the flow rate of the fluid supplied from the pad temperature adjusting member onto the surface of the polishing pad during the polishing of the substrate. It is a step of changing the surface temperature of the polishing pad by operating a control valve.
In a preferred aspect of the present invention, the fluid is a heating fluid and a cooling fluid.
本発明の好ましい態様は、前記PIDパラメータを算定する工程は、リミットサイクル法、ステップ応答法、ジーグラ・ニコルスの限界感度法のうちのいずれかを用いて、前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定する工程であることを特徴とする。
本発明の好ましい態様は、前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行することを特徴とする。
本発明の好ましい態様は、前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行することを特徴とする。 In a preferred aspect of the present invention, the step of calculating the PID parameter uses a limit cycle method, a step response method, or a Ziegler-Nichols limit sensitivity method to change the surface temperature of the polishing pad over time. It is a process of calculating a PID parameter based on it.
In a preferred aspect of the present invention, a simulation of the surface temperature of the polishing pad expected as a result of operating the flow control valve with an operation amount calculated using the PID arithmetic expression is performed.
In a preferred aspect of the present invention, a simulation is further executed to show a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed.
本発明の好ましい態様は、前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行することを特徴とする。
本発明の好ましい態様は、前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行することを特徴とする。 In a preferred aspect of the present invention, the step of calculating the PID parameter uses a limit cycle method, a step response method, or a Ziegler-Nichols limit sensitivity method to change the surface temperature of the polishing pad over time. It is a process of calculating a PID parameter based on it.
In a preferred aspect of the present invention, a simulation of the surface temperature of the polishing pad expected as a result of operating the flow control valve with an operation amount calculated using the PID arithmetic expression is performed.
In a preferred aspect of the present invention, a simulation is further executed to show a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed.
本発明の他の態様は、研磨パッドを支持する研磨テーブルと、基板を前記研磨パッドに押し付ける研磨ヘッドと、前記研磨パッドの表面温度を調整するパッド温度調整システムとを備え、前記パッド温度調整システムは、流体が流れる流路が内部に形成されたパッド温度調整部材と、前記流路に接続された流体供給管と、前記流体供給管に取り付けられた流量制御バルブと、前記研磨パッドの表面温度を測定するパッド温度測定器と、前記流量制御バルブを操作するPID制御部とを備え、前記PID制御部は、前記基板の研磨中において、前記流量制御バルブを操作して、前記研磨パッドの表面温度を変化させ、前記研磨パッドの表面温度の測定値を前記パッド温度測定器から取得し、前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定し、前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算し、前記操作量に従って前記流量制御バルブを操作することを特徴とする研磨装置である。
Another aspect of the present invention includes a polishing table that supports a polishing pad, a polishing head that presses a substrate against the polishing pad, and a pad temperature adjustment system that adjusts a surface temperature of the polishing pad, and the pad temperature adjustment system. A pad temperature adjusting member having a flow path through which a fluid flows, a fluid supply pipe connected to the flow path, a flow control valve attached to the fluid supply pipe, and a surface temperature of the polishing pad And a PID control unit for operating the flow rate control valve, and the PID control unit operates the flow rate control valve during polishing of the substrate to control the surface of the polishing pad. Changing the temperature, obtaining a measured value of the surface temperature of the polishing pad from the pad temperature measuring instrument, and based on the time change of the surface temperature of the polishing pad, An ID parameter is calculated, and an operation amount of the flow control valve for minimizing a deviation between a temperature target value and a measured value of the surface temperature of the polishing pad is calculated using a PID arithmetic expression having the PID parameter. The polishing apparatus is characterized in that the flow control valve is operated according to the operation amount.
本発明の好ましい態様は、前記パッド温度測定器は、赤外線放射温度計、熱電対温度計、サーモグラフィ、およびサーモパイルのうち、少なくとも1つの温度測定器であることを特徴とする。
本発明の好ましい態様は、前記パッド温度測定器は、前記研磨パッドの中心と外周部とを含む領域における温度分布を測定するように構成されていることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整システムは、前記パッド温度測定器によって測定された前記研磨パッドの表面温度を表示する温度表示器をさらに備えていることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整部材は、前記研磨パッドの表面に冷却流体を吹きかける冷却ノズルであることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整部材は、前記研磨パッドの表面に接触可能なパッド接触面を有することを特徴とする。 In a preferred aspect of the present invention, the pad temperature measuring device is at least one temperature measuring device selected from an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile.
In a preferred aspect of the present invention, the pad temperature measuring device is configured to measure a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
In a preferred aspect of the present invention, the pad temperature adjustment system further includes a temperature indicator that displays a surface temperature of the polishing pad measured by the pad temperature measuring device.
In a preferred aspect of the present invention, the pad temperature adjusting member is a cooling nozzle that sprays a cooling fluid onto the surface of the polishing pad.
In a preferred aspect of the present invention, the pad temperature adjusting member has a pad contact surface capable of contacting the surface of the polishing pad.
本発明の好ましい態様は、前記パッド温度測定器は、前記研磨パッドの中心と外周部とを含む領域における温度分布を測定するように構成されていることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整システムは、前記パッド温度測定器によって測定された前記研磨パッドの表面温度を表示する温度表示器をさらに備えていることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整部材は、前記研磨パッドの表面に冷却流体を吹きかける冷却ノズルであることを特徴とする。
本発明の好ましい態様は、前記パッド温度調整部材は、前記研磨パッドの表面に接触可能なパッド接触面を有することを特徴とする。 In a preferred aspect of the present invention, the pad temperature measuring device is at least one temperature measuring device selected from an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile.
In a preferred aspect of the present invention, the pad temperature measuring device is configured to measure a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
In a preferred aspect of the present invention, the pad temperature adjustment system further includes a temperature indicator that displays a surface temperature of the polishing pad measured by the pad temperature measuring device.
In a preferred aspect of the present invention, the pad temperature adjusting member is a cooling nozzle that sprays a cooling fluid onto the surface of the polishing pad.
In a preferred aspect of the present invention, the pad temperature adjusting member has a pad contact surface capable of contacting the surface of the polishing pad.
本発明の好ましい態様は、前記PID制御部は、リミットサイクル法、ステップ応答法、ジーグラ・ニコルスの限界感度法のうちのいずれかを用いてPIDパラメータを算定することを特徴とする。
本発明の好ましい態様は、前記PID制御部は、前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行するように構成されていることを特徴とする。
本発明の好ましい態様は、前記PID制御部は、前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行するように構成されていることを特徴とする。 In a preferred aspect of the present invention, the PID control unit calculates the PID parameter using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method.
In a preferred aspect of the present invention, the PID control unit executes a simulation of a surface temperature of the polishing pad that is expected as a result of operating the flow rate control valve with an operation amount calculated using the PID arithmetic expression. It is configured.
In a preferred aspect of the present invention, the PID control unit is configured to further execute a simulation showing a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed. And
本発明の好ましい態様は、前記PID制御部は、前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行するように構成されていることを特徴とする。
本発明の好ましい態様は、前記PID制御部は、前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行するように構成されていることを特徴とする。 In a preferred aspect of the present invention, the PID control unit calculates the PID parameter using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method.
In a preferred aspect of the present invention, the PID control unit executes a simulation of a surface temperature of the polishing pad that is expected as a result of operating the flow rate control valve with an operation amount calculated using the PID arithmetic expression. It is configured.
In a preferred aspect of the present invention, the PID control unit is configured to further execute a simulation showing a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed. And
本発明のさらに他の態様は、研磨ヘッドに指令を与えて、基板を研磨パッドの表面に押し付けて該基板を研磨する動作を前記研磨ヘッドに実行させるステップと、パッド温度調整部材に流れる流体の流量を制御するために設けられた流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させるステップと、前記研磨パッドの表面温度の測定値を取得するステップと、前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定するステップと、前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算するステップと、前記操作量に従って前記流量制御バルブを操作するステップをコンピュータに実行させるためのプログラムを記録した非一時的なコンピュータ読み取り可能な記録媒体である。
According to still another aspect of the present invention, a command is given to the polishing head to cause the polishing head to perform an operation of pressing the substrate against the surface of the polishing pad to polish the substrate, and the fluid flowing through the pad temperature adjusting member. A step of changing a surface temperature of the polishing pad by operating a flow rate control valve provided to control a flow rate; a step of obtaining a measured value of the surface temperature of the polishing pad; and a surface of the polishing pad In order to minimize the deviation between the target temperature value and the measured value of the surface temperature of the polishing pad, using the step of calculating the PID parameter based on the time change of the temperature and the PID arithmetic expression having the PID parameter. Calculating a manipulated variable of the flow rate control valve and operating the flow rate control valve according to the manipulated value in a computer It is a non-transitory computer-readable recording medium recording a program for causing the row.
本発明によれば、基板の研磨中において、研磨パッドの表面温度の時間変化に基づいてPIDパラメータを自動で算定することができるため、PIDパラメータを決定するための試行錯誤による実験、特別な知識や経験、ノウハウは不要であり、熟練者に頼る必要はない。したがって、PIDパラメータを短時間で、かつ効率的に決定することができる。
According to the present invention, since the PID parameter can be automatically calculated based on the time change of the surface temperature of the polishing pad during the polishing of the substrate, an experiment by trial and error for determining the PID parameter, special knowledge No experience, know-how is required, and there is no need to rely on skilled workers. Therefore, the PID parameter can be determined in a short time and efficiently.
以下、本発明の実施形態について図面を参照して説明する。
図1は、研磨装置を示す模式図である。図1に示すように、研磨装置は、基板の一例であるウェーハWを保持して回転させる研磨ヘッド1と、研磨パッド3を支持する研磨テーブル2と、研磨パッド3の表面に研磨液(例えばスラリー)を供給する研磨液供給ノズル4と、研磨パッド3の表面温度を調整するパッド温度調整システム5とを備えている。研磨パッド3の表面(上面)は、ウェーハWを研磨する研磨面を構成する。 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing a polishing apparatus. As shown in FIG. 1, the polishing apparatus includes a polishinghead 1 that holds and rotates a wafer W that is an example of a substrate, a polishing table 2 that supports a polishing pad 3, and a polishing liquid (for example, A polishing liquid supply nozzle 4 for supplying a slurry) and a pad temperature adjusting system 5 for adjusting the surface temperature of the polishing pad 3. The surface (upper surface) of the polishing pad 3 constitutes a polishing surface for polishing the wafer W.
図1は、研磨装置を示す模式図である。図1に示すように、研磨装置は、基板の一例であるウェーハWを保持して回転させる研磨ヘッド1と、研磨パッド3を支持する研磨テーブル2と、研磨パッド3の表面に研磨液(例えばスラリー)を供給する研磨液供給ノズル4と、研磨パッド3の表面温度を調整するパッド温度調整システム5とを備えている。研磨パッド3の表面(上面)は、ウェーハWを研磨する研磨面を構成する。 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing a polishing apparatus. As shown in FIG. 1, the polishing apparatus includes a polishing
研磨ヘッド1は鉛直方向に移動可能であり、かつその軸心を中心として矢印で示す方向に回転可能となっている。ウェーハWは、研磨ヘッド1の下面に真空吸着などによって保持される。研磨テーブル2にはモータ(図示せず)が連結されており、矢印で示す方向に回転可能となっている。図1に示すように、研磨ヘッド1および研磨テーブル2は、同じ方向に回転する。研磨パッド3は、研磨テーブル2の上面に貼り付けられている。
The polishing head 1 can move in the vertical direction, and can rotate in the direction indicated by the arrow about its axis. The wafer W is held on the lower surface of the polishing head 1 by vacuum suction or the like. A motor (not shown) is connected to the polishing table 2 and is rotatable in the direction indicated by the arrow. As shown in FIG. 1, the polishing head 1 and the polishing table 2 rotate in the same direction. The polishing pad 3 is affixed to the upper surface of the polishing table 2.
研磨装置は、研磨テーブル2上の研磨パッド3をドレッシングするドレッサ20をさらに備えている。ドレッサ20は研磨パッド3の表面上を研磨パッド3の半径方向に揺動するように構成されている。ドレッサ20の下面は、ダイヤモンド粒子などの多数の砥粒からなるドレッシング面を構成する。ドレッサ20は、研磨パッド3の研磨面上を揺動しながら回転し、研磨パッド3を僅かに削り取ることにより研磨パッド3の表面をドレッシングする。
The polishing apparatus further includes a dresser 20 for dressing the polishing pad 3 on the polishing table 2. The dresser 20 is configured to swing on the surface of the polishing pad 3 in the radial direction of the polishing pad 3. The lower surface of the dresser 20 constitutes a dressing surface composed of a large number of abrasive grains such as diamond particles. The dresser 20 rotates while swinging on the polishing surface of the polishing pad 3, and dresses the surface of the polishing pad 3 by slightly scraping the polishing pad 3.
ウェーハWの研磨は次のようにして行われる。研磨されるウェーハWは、研磨ヘッド1によって保持され、さらに研磨ヘッド1によって回転される。一方、研磨パッド3は、研磨テーブル2とともに回転される。この状態で、研磨パッド3の表面には研磨液供給ノズル4から研磨液が供給され、さらにウェーハWの表面は、研磨ヘッド1によって研磨パッド3の表面(すなわち研磨面)に対して押し付けられる。ウェーハWの表面は、研磨液の存在下での研磨パッド3との摺接により研磨される。ウェーハWの表面は、研磨液の化学的作用と研磨液に含まれる砥粒の機械的作用により平坦化される。
The polishing of the wafer W is performed as follows. The wafer W to be polished is held by the polishing head 1 and further rotated by the polishing head 1. On the other hand, the polishing pad 3 is rotated together with the polishing table 2. In this state, the polishing liquid is supplied from the polishing liquid supply nozzle 4 to the surface of the polishing pad 3, and the surface of the wafer W is pressed against the surface of the polishing pad 3 (ie, the polishing surface) by the polishing head 1. The surface of the wafer W is polished by sliding contact with the polishing pad 3 in the presence of the polishing liquid. The surface of the wafer W is flattened by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid.
パッド温度調整システム5は、研磨パッド3の表面温度を調整するための流体が流れる流路が内部に形成されたパッド温度調整部材11と、温度調整された加熱流体および冷却流体をパッド温度調整部材11に供給する流体供給システム30とを備えている。パッド温度調整部材11は、研磨パッド3の表面に直接接触し、または研磨パッド3の表面に近接することができる。
The pad temperature adjusting system 5 includes a pad temperature adjusting member 11 in which a flow path for flowing a fluid for adjusting the surface temperature of the polishing pad 3 is formed, and the temperature adjusted heating fluid and cooling fluid are supplied to the pad temperature adjusting member. 11 and a fluid supply system 30 for supplying the fluid to the vehicle 11. The pad temperature adjusting member 11 can be in direct contact with the surface of the polishing pad 3 or close to the surface of the polishing pad 3.
パッド温度調整システム5は、パッド温度調整部材11を研磨パッド3の表面に対して垂直に移動させる上下動機構(垂直移動機構)71をさらに備えている。パッド温度調整部材11は、上下動機構71に保持されている。この上下動機構71は、パッド温度調整部材11を研磨パッド3の表面に対して上下方向に移動させることが可能に構成されている。このような構成により、パッド温度調整部材11は、研磨パッド3の表面に直接接触し、または研磨パッド3の表面に近接することができる。上下動機構71としては、サーボモータとボールねじ機構との組み合わせ、またはエアシリンダなどから構成される。
The pad temperature adjustment system 5 further includes a vertical movement mechanism (vertical movement mechanism) 71 that moves the pad temperature adjustment member 11 perpendicularly to the surface of the polishing pad 3. The pad temperature adjusting member 11 is held by the vertical movement mechanism 71. The vertical movement mechanism 71 is configured to be able to move the pad temperature adjusting member 11 in the vertical direction with respect to the surface of the polishing pad 3. With such a configuration, the pad temperature adjusting member 11 can be in direct contact with the surface of the polishing pad 3 or close to the surface of the polishing pad 3. The vertical movement mechanism 71 includes a combination of a servo motor and a ball screw mechanism, or an air cylinder.
パッド温度調整部材11は、研磨パッド3の表面に対して垂直に移動して、研磨パッド3の表面上の領域(研磨パッド3の半径方向の位置)の温度を一定に維持するように構成されている。例えば、パッド温度調整部材11は、研磨パッド3の中心CLからの距離が100mmである研磨パッド3の半径方向の位置の温度を60度に維持するように、研磨パッド3の表面に対して垂直方向に移動する。ユーザーは、パッド温度調整部材11によって制御される研磨パッド3の表面温度および研磨パッド3の半径方向の位置を任意に決定(変更)することができる。例えば、ユーザーは、研磨パッド3の半径方向の位置として、研磨パッド3の中心CLからの距離を100mmから200mmに変更してもよく、研磨パッド3の表面温度として、60度から70度に変更してもよい。結果として、パッド温度調整部材11は、研磨パッド3の中心CLからの距離が200mmである研磨パッド3の半径方向の位置の温度を70度に維持するように、研磨パッド3の表面に対して上下方向に移動する。
The pad temperature adjusting member 11 is configured to move perpendicularly to the surface of the polishing pad 3 to maintain a constant temperature in a region on the surface of the polishing pad 3 (a radial position of the polishing pad 3). ing. For example, the pad temperature adjusting member 11 is perpendicular to the surface of the polishing pad 3 so as to maintain the temperature at the radial position of the polishing pad 3 at a distance of 100 mm from the center CL of the polishing pad 3 at 60 degrees. Move in the direction. The user can arbitrarily determine (change) the surface temperature of the polishing pad 3 controlled by the pad temperature adjusting member 11 and the radial position of the polishing pad 3. For example, the user may change the distance from the center CL of the polishing pad 3 from 100 mm to 200 mm as the radial position of the polishing pad 3, and change the surface temperature of the polishing pad 3 from 60 degrees to 70 degrees. May be. As a result, the pad temperature adjusting member 11 is set against the surface of the polishing pad 3 so as to maintain the temperature at the radial position of the polishing pad 3 at a distance of 200 mm from the center CL of the polishing pad 3 at 70 degrees. Move up and down.
流体供給システム30は、温度調整された流体を貯留する流体供給源としての流体供給タンク31と、流体供給タンク31とパッド温度調整部材11とを連結する加熱流体供給管32および加熱流体戻り管33とを備えている。加熱流体供給管32および加熱流体戻り管33の一方の端部は流体供給タンク31に接続され、他方の端部はパッド温度調整部材11に接続されている。
The fluid supply system 30 includes a fluid supply tank 31 as a fluid supply source that stores a temperature-adjusted fluid, a heating fluid supply pipe 32 that connects the fluid supply tank 31 and the pad temperature adjustment member 11, and a heating fluid return pipe 33. And. One end of the heating fluid supply pipe 32 and the heating fluid return pipe 33 is connected to the fluid supply tank 31, and the other end is connected to the pad temperature adjusting member 11.
温度調整された加熱流体は、流体供給タンク31から加熱流体供給管32を通じてパッド温度調整部材11に供給され、パッド温度調整部材11内を流れ、そしてパッド温度調整部材11から加熱流体戻り管33を通じて流体供給タンク31に戻される。このように、加熱流体は、流体供給タンク31とパッド温度調整部材11との間を循環する。流体供給タンク31は、ヒータ(図示せず)を有しており、加熱流体はヒータにより所定の温度に加熱される。
The heated fluid whose temperature is adjusted is supplied from the fluid supply tank 31 to the pad temperature adjusting member 11 through the heated fluid supply pipe 32, flows in the pad temperature adjusting member 11, and passes from the pad temperature adjusting member 11 to the heated fluid return pipe 33. Returned to the fluid supply tank 31. Thus, the heating fluid circulates between the fluid supply tank 31 and the pad temperature adjusting member 11. The fluid supply tank 31 has a heater (not shown), and the heated fluid is heated to a predetermined temperature by the heater.
加熱流体供給管32には、第1開閉バルブ41および第1流量制御バルブ42が取り付けられている。第1流量制御バルブ42は、パッド温度調整部材11と第1開閉バルブ41との間に配置されている。第1開閉バルブ41は、流量調整機能を有しないバルブであるのに対し、第1流量制御バルブ42は、流量調整機能を有するバルブである。
A first open / close valve 41 and a first flow control valve 42 are attached to the heated fluid supply pipe 32. The first flow rate control valve 42 is disposed between the pad temperature adjusting member 11 and the first opening / closing valve 41. The first on-off valve 41 is a valve that does not have a flow rate adjustment function, while the first flow rate control valve 42 is a valve that has a flow rate adjustment function.
流体供給システム30は、パッド温度調整部材11に接続された冷却流体供給管51および冷却流体排出管52をさらに備えている。冷却流体供給管51は、研磨装置が設置される工場に設けられている冷却流体供給源(例えば、冷水供給源)に接続されている。冷却流体は、冷却流体供給管51を通じてパッド温度調整部材11に供給され、パッド温度調整部材11内を流れ、そしてパッド温度調整部材11から冷却流体排出管52を通じて排出される。
The fluid supply system 30 further includes a cooling fluid supply pipe 51 and a cooling fluid discharge pipe 52 connected to the pad temperature adjusting member 11. The cooling fluid supply pipe 51 is connected to a cooling fluid supply source (for example, a cold water supply source) provided in a factory where the polishing apparatus is installed. The cooling fluid is supplied to the pad temperature adjusting member 11 through the cooling fluid supply pipe 51, flows through the pad temperature adjusting member 11, and is discharged from the pad temperature adjusting member 11 through the cooling fluid discharge pipe 52.
冷却流体供給管51には、第2開閉バルブ55および第2流量制御バルブ56が取り付けられている。第2流量制御バルブ56は、パッド温度調整部材11と第2開閉バルブ55との間に配置されている。第2開閉バルブ55は、流量調整機能を有しないバルブであるのに対し、第2流量制御バルブ56は、流量調整機能を有するバルブである。
A second opening / closing valve 55 and a second flow rate control valve 56 are attached to the cooling fluid supply pipe 51. The second flow rate control valve 56 is disposed between the pad temperature adjusting member 11 and the second opening / closing valve 55. The second on-off valve 55 is a valve that does not have a flow rate adjustment function, whereas the second flow rate control valve 56 is a valve that has a flow rate adjustment function.
図2は研磨装置の他の実施形態を示す模式図である。図2に示すように、冷却流体供給管51および冷却流体排出管52の一方の端部は流体供給タンク31に接続され、他方の端部はパッド温度調整部材11に接続されてもよい。本実施形態では、流体供給タンク31とパッド温度調整部材11との間を循環する冷却流体は流体供給タンク31内で冷却される。同様に、流体供給タンク31とパッド温度調整部材11との間を循環する加熱流体は流体供給タンク31内で加熱される。図2では、冷却流体排出管52は冷却流体戻り管である。
FIG. 2 is a schematic view showing another embodiment of the polishing apparatus. As shown in FIG. 2, one end of the cooling fluid supply pipe 51 and the cooling fluid discharge pipe 52 may be connected to the fluid supply tank 31, and the other end may be connected to the pad temperature adjusting member 11. In the present embodiment, the cooling fluid that circulates between the fluid supply tank 31 and the pad temperature adjusting member 11 is cooled in the fluid supply tank 31. Similarly, the heating fluid circulating between the fluid supply tank 31 and the pad temperature adjusting member 11 is heated in the fluid supply tank 31. In FIG. 2, the cooling fluid discharge pipe 52 is a cooling fluid return pipe.
図1に戻り、パッド温度調整システム5は、研磨パッド3の表面温度(以下、パッド表面温度ということがある)を測定するパッド温度測定器39と、パッド温度測定器39により測定されたパッド表面温度に基づいて第1流量制御バルブ42および第2流量制御バルブ56を操作するPID制御部40とをさらに備えている。第1開閉バルブ41および第2開閉バルブ55は、通常は開かれている。
Returning to FIG. 1, the pad temperature adjustment system 5 includes a pad temperature measuring device 39 that measures the surface temperature of the polishing pad 3 (hereinafter, also referred to as pad surface temperature), and the pad surface measured by the pad temperature measuring device 39. A PID control unit 40 that operates the first flow control valve 42 and the second flow control valve 56 based on the temperature is further provided. The first opening / closing valve 41 and the second opening / closing valve 55 are normally opened.
パッド温度測定器39は、研磨パッド3の表面の上方に配置されており、非接触で研磨パッド3の表面温度を測定するように構成されている。パッド温度測定器39は、PID制御部40に接続されており、さらにPID制御部40を介して温度表示器45に接続されている。パッド温度測定器39は、研磨パッド3の表面温度を測定する赤外線放射温度計または熱電対温度計であってもよく、研磨パッド3の表面温度を測定し、研磨パッド3の温度分布を取得するサーモグラフィまたはサーモパイルであってもよい。パッド温度測定器39は、赤外線放射温度計、熱電対温度計、サーモグラフィ、およびサーモパイルのうち、少なくとも1つの温度測定器である。パッド温度測定器39に、ウェーハWの研磨によって飛び散った液体(スラリーなど)が付着すると、パッド温度測定器39は、研磨パッド3の表面温度を正確に測定することができないことがある。したがって、パッド温度測定器39は研磨パッド3の表面から十分に高い位置に配置されている。
The pad temperature measuring device 39 is disposed above the surface of the polishing pad 3 and is configured to measure the surface temperature of the polishing pad 3 in a non-contact manner. The pad temperature measuring device 39 is connected to the PID control unit 40, and further connected to the temperature indicator 45 via the PID control unit 40. The pad temperature measuring device 39 may be an infrared radiation thermometer or a thermocouple thermometer that measures the surface temperature of the polishing pad 3, measures the surface temperature of the polishing pad 3, and acquires the temperature distribution of the polishing pad 3. It may be a thermography or a thermopile. The pad temperature measuring device 39 is at least one temperature measuring device among an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile. If liquid (slurry or the like) splashed by polishing the wafer W adheres to the pad temperature measuring device 39, the pad temperature measuring device 39 may not be able to accurately measure the surface temperature of the polishing pad 3. Therefore, the pad temperature measuring device 39 is disposed at a sufficiently high position from the surface of the polishing pad 3.
図3はパッド温度測定器39の温度測定領域を上から見た図であり、図4はパッド温度測定器39の温度測定領域を横から見た図である。図3および図4に示すように、パッド温度測定器39は、研磨パッド3の中心CLと研磨パッド3の外周部3aとを含む領域における研磨パッド3の表面温度を測定するように構成されている(図3および図4の点線参照)。
3 is a view of the temperature measurement region of the pad temperature measurement device 39 as viewed from above, and FIG. 4 is a view of the temperature measurement region of the pad temperature measurement device 39 as viewed from the side. As shown in FIGS. 3 and 4, the pad temperature measuring device 39 is configured to measure the surface temperature of the polishing pad 3 in a region including the center CL of the polishing pad 3 and the outer peripheral portion 3 a of the polishing pad 3. (See dotted lines in FIGS. 3 and 4).
パッド温度測定器39は、非接触で研磨パッド3の表面温度を測定し、表面温度の測定値をPID制御部40に送る。パッド温度測定器39は、所定時間毎に研磨パッド3の表面温度を測定してもよい。PID制御部40は、パッド表面温度が、予め設定された目標温度に維持されるように、測定されたパッド表面温度に基づいて、第1流量制御バルブ42および第2流量制御バルブ56を操作する。第1流量制御バルブ42および第2流量制御バルブ56は、PID制御部40からの制御信号に従って動作し、パッド温度調整部材11に供給される加熱流体の流量および冷却流体の流量を調整する。パッド温度調整部材11を流れる加熱流体および冷却流体と研磨パッド3との間で熱交換が行われ、これによりパッド表面温度が変化する。
The pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 in a non-contact manner, and sends the measured value of the surface temperature to the PID control unit 40. The pad temperature measuring device 39 may measure the surface temperature of the polishing pad 3 every predetermined time. The PID control unit 40 operates the first flow rate control valve 42 and the second flow rate control valve 56 based on the measured pad surface temperature so that the pad surface temperature is maintained at a preset target temperature. . The first flow rate control valve 42 and the second flow rate control valve 56 operate according to the control signal from the PID control unit 40 and adjust the flow rate of the heating fluid and the cooling fluid supplied to the pad temperature adjustment member 11. Heat exchange is performed between the heating fluid and the cooling fluid flowing through the pad temperature adjusting member 11 and the polishing pad 3, thereby changing the pad surface temperature.
パッド温度調整部材11に供給される加熱流体としては、温水が使用される。温水は、流体供給タンク31のヒータにより、例えば約80℃に加熱される。より速やかに研磨パッド3の表面温度を上昇させる場合には、シリコーンオイルを加熱流体として使用してもよい。シリコーンオイルを加熱流体として使用する場合には、シリコーンオイルは流体供給タンク31のヒータにより100℃以上(例えば、約120℃)に加熱される。パッド温度調整部材11に供給される冷却流体としては、冷水またはシリコーンオイルが使用される。シリコーンオイルを冷却流体として使用する場合には、冷却流体供給源としてチラーを冷却流体供給管51に接続し、シリコーンオイルを0℃以下に冷却することで、研磨パッド3を速やかに冷却することができる。
温 Warm water is used as the heating fluid supplied to the pad temperature adjusting member 11. The hot water is heated to, for example, about 80 ° C. by the heater of the fluid supply tank 31. In order to increase the surface temperature of the polishing pad 3 more quickly, silicone oil may be used as a heating fluid. When silicone oil is used as the heating fluid, the silicone oil is heated to 100 ° C. or higher (for example, about 120 ° C.) by the heater of the fluid supply tank 31. As the cooling fluid supplied to the pad temperature adjusting member 11, cold water or silicone oil is used. When silicone oil is used as a cooling fluid, the polishing pad 3 can be quickly cooled by connecting a chiller as a cooling fluid supply source to the cooling fluid supply pipe 51 and cooling the silicone oil to 0 ° C. or lower. it can.
加熱流体供給管32および冷却流体供給管51は、完全に独立した配管である。したがって、加熱流体および冷却流体は、混合されることなく、同時にパッド温度調整部材11に供給される。加熱流体戻り管33および冷却流体排出管52も、完全に独立した配管である。したがって、加熱流体は、冷却流体と混合されることなく流体供給タンク31に戻され、冷却流体は、加熱流体と混合されることなく排出される。
The heating fluid supply pipe 32 and the cooling fluid supply pipe 51 are completely independent pipes. Therefore, the heating fluid and the cooling fluid are simultaneously supplied to the pad temperature adjusting member 11 without being mixed. The heating fluid return pipe 33 and the cooling fluid discharge pipe 52 are also completely independent pipes. Therefore, the heating fluid is returned to the fluid supply tank 31 without being mixed with the cooling fluid, and the cooling fluid is discharged without being mixed with the heating fluid.
次に、パッド温度調整部材11の一例について、図5を参照して説明する。図5は、パッド温度調整部材11を示す水平断面図である。図5に示すように、パッド温度調整部材11は、その内部に形成された加熱流路61および冷却流路62を有する熱交換部材である。加熱流路61および冷却流路62は、互いに隣接して延びており、かつ螺旋状に延びている。本実施形態では、加熱流路61は、冷却流路62よりも短い。
Next, an example of the pad temperature adjusting member 11 will be described with reference to FIG. FIG. 5 is a horizontal sectional view showing the pad temperature adjusting member 11. As shown in FIG. 5, the pad temperature adjustment member 11 is a heat exchange member having a heating channel 61 and a cooling channel 62 formed therein. The heating channel 61 and the cooling channel 62 extend adjacent to each other and extend in a spiral shape. In the present embodiment, the heating channel 61 is shorter than the cooling channel 62.
加熱流体供給管32は、加熱流路61の入口61aに接続されており、加熱流体戻り管33は、加熱流路61の出口61bに接続されている。冷却流体供給管51は、冷却流路62の入口62aに接続されており、冷却流体排出管52は、冷却流路62の出口62bに接続されている。加熱流路61および冷却流路62の入口61a,62aは、パッド温度調整部材11の周縁部に位置しており、加熱流路61および冷却流路62の出口61b,62bは、パッド温度調整部材11の中心部に位置している。したがって、加熱流体および冷却流体は、パッド温度調整部材11の周縁部から中心部に向かって螺旋状に流れる。加熱流路61および冷却流路62は、完全に分離しており、パッド温度調整部材11内で加熱流体および冷却流体が混合されることはない。なお、加熱流路61および冷却流路62の形状は、図5に示す実施形態に限定されず、パッド温度調整部材11は、ジグザグ状の加熱流路および冷却流路を有してもよい。
The heating fluid supply pipe 32 is connected to the inlet 61 a of the heating channel 61, and the heating fluid return pipe 33 is connected to the outlet 61 b of the heating channel 61. The cooling fluid supply pipe 51 is connected to the inlet 62 a of the cooling flow path 62, and the cooling fluid discharge pipe 52 is connected to the outlet 62 b of the cooling flow path 62. The inlets 61a and 62a of the heating channel 61 and the cooling channel 62 are located at the peripheral edge of the pad temperature adjusting member 11, and the outlets 61b and 62b of the heating channel 61 and the cooling channel 62 are pad temperature adjusting members. 11 is located in the center. Therefore, the heating fluid and the cooling fluid flow spirally from the peripheral portion of the pad temperature adjusting member 11 toward the central portion. The heating channel 61 and the cooling channel 62 are completely separated, and the heating fluid and the cooling fluid are not mixed in the pad temperature adjusting member 11. The shapes of the heating channel 61 and the cooling channel 62 are not limited to the embodiment shown in FIG. 5, and the pad temperature adjusting member 11 may have a zigzag heating channel and a cooling channel.
図6は、研磨パッド3上のパッド温度調整部材11と研磨ヘッド1との位置関係を示す平面図である。パッド温度調整部材11は、上から見たときに円形であり、パッド温度調整部材11の直径は研磨ヘッド1の直径よりも小さい。研磨パッド3の中心CLからパッド温度調整部材11の中心までの距離は、研磨パッド3の中心CLから研磨ヘッド1の中心までの距離と同じである。加熱流路61および冷却流路62は、互いに隣接しているので、加熱流路61および冷却流路62は、研磨パッド3の径方向のみならず、研磨パッド3の周方向に沿って並んでいる。したがって、研磨テーブル2および研磨パッド3が回転している間、研磨パッド3に接触または近接するパッド温度調整部材11は、加熱流体および冷却流体の両方と熱交換を行う。
FIG. 6 is a plan view showing the positional relationship between the pad temperature adjusting member 11 on the polishing pad 3 and the polishing head 1. The pad temperature adjusting member 11 is circular when viewed from above, and the diameter of the pad temperature adjusting member 11 is smaller than the diameter of the polishing head 1. The distance from the center CL of the polishing pad 3 to the center of the pad temperature adjusting member 11 is the same as the distance from the center CL of the polishing pad 3 to the center of the polishing head 1. Since the heating channel 61 and the cooling channel 62 are adjacent to each other, the heating channel 61 and the cooling channel 62 are arranged not only in the radial direction of the polishing pad 3 but also in the circumferential direction of the polishing pad 3. Yes. Therefore, while the polishing table 2 and the polishing pad 3 are rotating, the pad temperature adjusting member 11 in contact with or close to the polishing pad 3 exchanges heat with both the heating fluid and the cooling fluid.
図7は温度表示器45を示す模式図である。図7に示すように、パッド温度調整システム5は、パッド温度測定器39によって測定された研磨パッド3の表面温度を表示する温度表示器45をさらに備えている。PID制御部40はパッド温度測定器39および温度表示器45に接続されている。パッド温度測定器39は、その温度測定領域において、研磨パッド3の表面温度を測定し、測定された研磨パッド3の表面温度は温度表示器45に表示される。温度表示器45には、研磨パッド3の各表面位置(つまり、直交座標系で表される研磨パッド3の表面位置)の温度が色で表現されるなど、視覚的にわかりやすく表示される。例えば、温度が高い研磨パッド3の表面位置は赤色で表され、温度が低い研磨パッド3の表面位置は青色で表される。温度表示器45は、研磨パッド3の表面温度の分布を、色分布として表示する。
FIG. 7 is a schematic diagram showing the temperature indicator 45. As shown in FIG. 7, the pad temperature adjustment system 5 further includes a temperature indicator 45 that displays the surface temperature of the polishing pad 3 measured by the pad temperature measuring device 39. The PID control unit 40 is connected to the pad temperature measuring device 39 and the temperature indicator 45. The pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 in the temperature measurement region, and the measured surface temperature of the polishing pad 3 is displayed on the temperature display 45. On the temperature display 45, the temperature of each surface position of the polishing pad 3 (that is, the surface position of the polishing pad 3 expressed in an orthogonal coordinate system) is displayed in a color and is easily displayed. For example, the surface position of the polishing pad 3 having a high temperature is represented in red, and the surface position of the polishing pad 3 having a low temperature is represented in blue. The temperature display 45 displays the surface temperature distribution of the polishing pad 3 as a color distribution.
ユーザーは、研磨パッド3の測定位置を温度表示器45上で指定してもよく、または研磨パッド3の測定位置を座標入力によって指定してもよい。温度表示器45には、指定された研磨パッド3の測定位置の現時刻における温度、任意時刻の温度、温度の時間推移、研磨パッド3の温度分布、最大温度、最小温度、平均温度、測定された温度の時間積分値などが表示される。
The user may specify the measurement position of the polishing pad 3 on the temperature indicator 45, or may specify the measurement position of the polishing pad 3 by inputting coordinates. The temperature display 45 measures the temperature at the current measurement position of the specified polishing pad 3, the temperature at an arbitrary time, the time transition of the temperature, the temperature distribution of the polishing pad 3, the maximum temperature, the minimum temperature, and the average temperature. The time integral value of the selected temperature is displayed.
PID制御部40は、予め設定された目標温度と、測定された研磨パッド3の表面温度との差を無くすために必要な第1流量制御バルブ42の操作量および第2流量制御バルブ56の操作量を計算するように構成されている。第1流量制御バルブ42の操作量および第2流量制御バルブ56の操作量は、言い換えれば、バルブ開度である。第1流量制御バルブ42の操作量は、加熱流体の流量に比例し、第2流量制御バルブ56の操作量は、冷却流体の流量に比例する。
The PID control unit 40 operates the first flow control valve 42 and the second flow control valve 56 in order to eliminate the difference between the preset target temperature and the measured surface temperature of the polishing pad 3. Configured to calculate quantity. The operation amount of the first flow control valve 42 and the operation amount of the second flow control valve 56 are, in other words, the valve opening. The operation amount of the first flow rate control valve 42 is proportional to the flow rate of the heating fluid, and the operation amount of the second flow rate control valve 56 is proportional to the flow rate of the cooling fluid.
第1流量制御バルブ42および第2流量制御バルブ56のそれぞれの操作量を0%から100%までの数値で表したときに、PID制御部40は、第1流量制御バルブ42の操作量を100%から引き算することで、第2流量制御バルブ56の操作量を決定するように構成されている。一実施形態では、PID制御部40は、第2流量制御バルブ56の操作量を100%から引き算することで、第1流量制御バルブ42の操作量を決定してもよい。
When the operation amounts of the first flow control valve 42 and the second flow control valve 56 are expressed by numerical values from 0% to 100%, the PID control unit 40 sets the operation amount of the first flow control valve 42 to 100. The operation amount of the second flow control valve 56 is determined by subtracting from%. In one embodiment, the PID control unit 40 may determine the operation amount of the first flow control valve 42 by subtracting the operation amount of the second flow control valve 56 from 100%.
第1流量制御バルブ42の操作量が100%であることは、第1流量制御バルブ42が全開であることを示し、第1流量制御バルブ42の操作量が0%であることは、第1流量制御バルブ42が完全に閉じられていることを示している。同様に、第2流量制御バルブ56の操作量が100%であることは、第2流量制御バルブ56が全開であることを示し、第2流量制御バルブ56の操作量が0%であることは、第2流量制御バルブ56が完全に閉じられていることを示している。
The operation amount of the first flow control valve 42 being 100% indicates that the first flow control valve 42 is fully open, and the operation amount of the first flow control valve 42 is 0%. It shows that the flow control valve 42 is completely closed. Similarly, the operation amount of the second flow rate control valve 56 being 100% indicates that the second flow rate control valve 56 is fully open, and the operation amount of the second flow rate control valve 56 is 0%. , Indicating that the second flow control valve 56 is completely closed.
第1流量制御バルブ42の操作量が100%であるときの加熱流体の流量は、第2流量制御バルブ56の操作量が100%であるときの冷却流体の流量と同じである。したがって、第1流量制御バルブ42を通過する加熱流体の流量と、第2流量制御バルブ56を通過する冷却流体の流量との合計は、常に一定である。
The flow rate of the heating fluid when the operation amount of the first flow control valve 42 is 100% is the same as the flow rate of the cooling fluid when the operation amount of the second flow control valve 56 is 100%. Therefore, the sum of the flow rate of the heating fluid passing through the first flow rate control valve 42 and the flow rate of the cooling fluid passing through the second flow rate control valve 56 is always constant.
PID制御部40は、第1流量制御バルブ42の操作量と、第2流量制御バルブ56の操作量との総和が100%となるように、第1流量制御バルブ42および第2流量制御バルブ56を操作する。
The PID control unit 40 includes the first flow control valve 42 and the second flow control valve 56 so that the sum of the operation amount of the first flow control valve 42 and the operation amount of the second flow control valve 56 becomes 100%. To operate.
本実施形態によれば、パッド温度調整部材11の加熱流路61には加熱流体のみが流れ、冷却流路62には冷却流体のみが流れる。加熱流体および冷却流体のそれぞれの流量は、研磨パッド3の表面温度に基づいて制御される。つまり、第1流量制御バルブ42および第2流量制御バルブ56は、研磨パッド3の表面温度と目標温度との差に基づいてPID制御部40によって操作される。したがって、研磨パッド3の表面温度を目標温度に安定して維持することができる。
According to the present embodiment, only the heating fluid flows in the heating flow path 61 of the pad temperature adjusting member 11, and only the cooling fluid flows in the cooling flow path 62. The respective flow rates of the heating fluid and the cooling fluid are controlled based on the surface temperature of the polishing pad 3. That is, the first flow rate control valve 42 and the second flow rate control valve 56 are operated by the PID control unit 40 based on the difference between the surface temperature of the polishing pad 3 and the target temperature. Therefore, the surface temperature of the polishing pad 3 can be stably maintained at the target temperature.
図8はパッド温度調整部材11の他の実施形態を示す図である。特に説明しない本実施形態の構成および動作は、上述した実施形態と同じであるので、その重複する説明を省略する。図8に示すように、パッド温度調整部材11は、研磨パッド3の表面に冷却流体を吹きかける冷却ノズルである。本実施形態では、冷却流体として、空気または不活性ガス(例えば窒素ガス)などの冷却気体が使用される。冷却ノズルであるパッド温度調整部材11の内部には、冷却流体が流れる冷却流路12が形成されている。冷却流路12は、冷却流体供給管51およびパッド温度調整部材11の噴射口に接続されている。冷却流体供給管51を通じてパッド温度調整部材11に冷却流体を供給すると、冷却流体はパッド温度調整部材11の噴射口から研磨パッド3の表面上に供給される。冷却流体供給管51には、パッド温度調整部材11から研磨パッド3の表面上に供給される冷却流体の流量を制御するための流量制御バルブ56が取り付けられている。本実施形態では、加熱流体は使用されない。
FIG. 8 is a view showing another embodiment of the pad temperature adjusting member 11. Since the configuration and operation of the present embodiment that are not particularly described are the same as those of the above-described embodiment, redundant description thereof is omitted. As shown in FIG. 8, the pad temperature adjusting member 11 is a cooling nozzle that sprays a cooling fluid onto the surface of the polishing pad 3. In the present embodiment, a cooling gas such as air or an inert gas (for example, nitrogen gas) is used as the cooling fluid. A cooling channel 12 through which a cooling fluid flows is formed inside the pad temperature adjusting member 11 that is a cooling nozzle. The cooling flow path 12 is connected to the cooling fluid supply pipe 51 and the injection port of the pad temperature adjusting member 11. When the cooling fluid is supplied to the pad temperature adjusting member 11 through the cooling fluid supply pipe 51, the cooling fluid is supplied from the ejection port of the pad temperature adjusting member 11 onto the surface of the polishing pad 3. A flow rate control valve 56 for controlling the flow rate of the cooling fluid supplied from the pad temperature adjusting member 11 onto the surface of the polishing pad 3 is attached to the cooling fluid supply pipe 51. In this embodiment, no heating fluid is used.
パッド温度調整部材11が熱交換部材(図5参照)である場合、PID制御部40は、ウェーハWの研磨中に、流量制御バルブ42,56を操作することで、研磨パッド3の表面温度を変化させることができる。パッド温度調整部材11が冷却ノズル(図8参照)である場合、PID制御部40は、ウェーハWの研磨中において、流量制御バルブ56を操作することで、研磨パッド3の表面温度を変化させることができる。
When the pad temperature adjusting member 11 is a heat exchange member (see FIG. 5), the PID control unit 40 operates the flow rate control valves 42 and 56 during polishing of the wafer W, thereby adjusting the surface temperature of the polishing pad 3. Can be changed. When the pad temperature adjusting member 11 is a cooling nozzle (see FIG. 8), the PID control unit 40 changes the surface temperature of the polishing pad 3 by operating the flow rate control valve 56 during polishing of the wafer W. Can do.
パッド温度測定器39は、ウェーハWを研磨しているときの研磨パッド3の表面温度を測定し、表面温度の測定値をPID制御部40に送る。PID制御部40は、研磨パッド3の表面温度の測定値をパッド温度測定器39から取得し、研磨パッド3の表面温度の時間変化に基づいて、PIDパラメータを算定するように構成されている。
The pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 when the wafer W is being polished, and sends the measured value of the surface temperature to the PID control unit 40. The PID control unit 40 is configured to acquire a measured value of the surface temperature of the polishing pad 3 from the pad temperature measuring device 39 and calculate a PID parameter based on a temporal change in the surface temperature of the polishing pad 3.
PIDパラメータは、リミットサイクル法、ステップ応答法、およびジーグラ・ニコルスの限界感度法のうちのいずれかを用いて、研磨パッド3の表面温度の時間変化に基づいて算定される。これらの方法によって算定されたPIDパラメータをファジィ推論に基づいて調整してもよく、目標値追従性と外乱抑制性とをともに最適化することができる2自由度PID方式を用いてPIDパラメータを算定してもよい。
The PID parameter is calculated based on the time change of the surface temperature of the polishing pad 3 using any one of the limit cycle method, the step response method, and the limit sensitivity method of Ziegler Nichols. PID parameters calculated by these methods may be adjusted based on fuzzy inference, and PID parameters are calculated using a two-degree-of-freedom PID method that can optimize both target value tracking and disturbance suppression. May be.
PID制御部40は、上述の方法により算定されたPIDパラメータを備えたPID演算式(後述する)を用いて、研磨パッド3の温度目標値と表面温度の測定値との偏差を最小にするための流量制御バルブ42,56の操作量を算定する。そして、PID制御部40は、ウェーハWの研磨中において、算定された操作量に従って流量制御バルブ42,56を操作する。
The PID control unit 40 uses a PID arithmetic expression (described later) having a PID parameter calculated by the above method to minimize the deviation between the temperature target value of the polishing pad 3 and the measured value of the surface temperature. The operation amounts of the flow control valves 42 and 56 are calculated. The PID control unit 40 operates the flow rate control valves 42 and 56 according to the calculated operation amount during polishing of the wafer W.
PID制御部40は、ウェーハWの研磨中において、自動的にPIDパラメータを算定するように構成されている。以下、PIDパラメータを算定する方法の一例であるリミットサイクル法について、図面を参照して説明する。
The PID control unit 40 is configured to automatically calculate PID parameters during polishing of the wafer W. Hereinafter, a limit cycle method, which is an example of a method for calculating PID parameters, will be described with reference to the drawings.
図9はリミットサイクル法を説明するための図である。図9において、符号PVは研磨パッド3の表面温度の測定値を示しており、符号MVは流量制御バルブ42,56の操作量を示しており、符号SVは研磨パッド3の表面温度の温度目標値を示している。なお、図9における測定値PVと時間との関係を示すグラフ(図9の上側のグラフ)において、縦軸は測定値PVを示しており、横軸は時間を示している。図9における流量制御バルブ42,56の操作量MVと時間との関係を示すグラフ(図9の下側のグラフ)において、縦軸は流量制御バルブ42,56の操作量MVを示しており、横軸は時間を示している。
FIG. 9 is a diagram for explaining the limit cycle method. In FIG. 9, symbol PV indicates a measured value of the surface temperature of the polishing pad 3, symbol MV indicates an operation amount of the flow rate control valves 42 and 56, and symbol SV indicates a temperature target of the surface temperature of the polishing pad 3. The value is shown. In the graph showing the relationship between the measured value PV and time in FIG. 9 (upper graph in FIG. 9), the vertical axis indicates the measured value PV, and the horizontal axis indicates time. In the graph showing the relationship between the operation amount MV of the flow control valves 42 and 56 in FIG. 9 and time (the lower graph in FIG. 9), the vertical axis shows the operation amount MV of the flow control valves 42 and 56. The horizontal axis indicates time.
流量制御バルブ42,56が全開と全閉とを繰り返すように流量制御バルブ42,56の操作量が決定される。より具体的には、第1流量制御バルブ42が全開(操作量100%)であるとき、第2流量制御バルブ56は全閉(操作量0%)である。さらに、第2流量制御バルブ56が全開(操作量100%)であるとき、第1流量制御バルブ42は全閉(操作量0%)である。このように、流量制御バルブ42,56が全開と全閉とを繰り返す動作は流量制御バルブ42,56の2位置動作と呼ばれる。
The operation amount of the flow control valves 42 and 56 is determined so that the flow control valves 42 and 56 are fully opened and fully closed. More specifically, when the first flow control valve 42 is fully open (operation amount 100%), the second flow control valve 56 is fully closed (operation amount 0%). Further, when the second flow control valve 56 is fully opened (operation amount 100%), the first flow control valve 42 is fully closed (operation amount 0%). As described above, the operation in which the flow control valves 42 and 56 are repeatedly fully opened and fully closed is called a two-position operation of the flow control valves 42 and 56.
流量制御バルブ42,56の2位置動作の制御について、図10を参照しつつ説明する。図10は流量制御バルブ42,56の2位置動作を示す図である。図10において、縦軸は流量制御バルブ42,56の操作量MVを示しており、横軸は偏差eを示している。第1流量制御バルブ42の操作量が0%であり、かつ第2流量制御バルブ56の操作量が100%であるとき、流量制御バルブ42,56の操作量は-Mである。第1流量制御バルブ42の操作量が100%であり、かつ第2流量制御バルブ56の操作量が0%であるとき、流量制御バルブ42,56の操作量は+Mである。
The control of the two-position operation of the flow control valves 42 and 56 will be described with reference to FIG. FIG. 10 is a view showing the two-position operation of the flow control valves 42 and 56. In FIG. 10, the vertical axis represents the operation amount MV of the flow control valves 42 and 56, and the horizontal axis represents the deviation e. When the operation amount of the first flow control valve 42 is 0% and the operation amount of the second flow control valve 56 is 100%, the operation amounts of the flow control valves 42 and 56 are -M. When the operation amount of the first flow control valve 42 is 100% and the operation amount of the second flow control valve 56 is 0%, the operation amounts of the flow control valves 42 and 56 are + M.
図9に示すように、測定値PVが温度目標値SVよりも高いときには、PID制御部40は、第1流量制御バルブ42を操作量0%で全閉にし、かつ第2流量制御バルブ56を操作量100%で全開にして、研磨パッド3の表面温度を低下させる。測定値PVが温度目標値SVよりも低いときは、PID制御部40は、第1流量制御バルブ42を操作量100%で全開にし、かつ第2流量制御バルブ56を操作量0%で全閉にして、研磨パッド3の表面温度を上昇させる。言い換えれば、PID制御部40は、測定値PVが温度目標値SVよりも高いときには、冷却側の操作量-Mを出力し、測定値PVが温度目標値SVよりも低いときには、加熱側の操作量+Mを出力する。このように、PID制御部40は、流量制御バルブ42,56を繰り返し開閉させて、研磨パッド3の表面温度を周期的に変化させる。このような周期的な温度変化はリミットサイクル波形と呼ばれる。発生させるリミットサイクル波形の周期は、2~3周期でもよい。
As shown in FIG. 9, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 fully closes the first flow rate control valve 42 with an operation amount of 0% and sets the second flow rate control valve 56. The surface temperature of the polishing pad 3 is lowered by fully opening at an operation amount of 100%. When the measured value PV is lower than the temperature target value SV, the PID control unit 40 fully opens the first flow rate control valve 42 with an operation amount of 100% and fully closes the second flow rate control valve 56 with an operation amount of 0%. Thus, the surface temperature of the polishing pad 3 is raised. In other words, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 outputs the cooling side operation amount −M, and when the measured value PV is lower than the temperature target value SV, the PID control unit 40 operates the heating side. Output amount + M. As described above, the PID control unit 40 repeatedly opens and closes the flow rate control valves 42 and 56 to periodically change the surface temperature of the polishing pad 3. Such a periodic temperature change is called a limit cycle waveform. The cycle of the limit cycle waveform to be generated may be 2 to 3 cycles.
ウェーハWの研磨が進行するにつれて研磨パッド3の表面温度は徐々に上昇するため、PID制御部40は、第1開閉バルブ41を閉じた状態において、流量制御バルブ56の開閉を繰り返すことによっても、リミットサイクル波形を発生させることができる。つまり、PID制御部40は、測定値PVが温度目標値SVよりも高いときには、流量制御バルブ56を操作量100%で全開とし、測定値PVが温度目標値SVよりも低いときには流量制御バルブ56を操作量0%で全閉としてもよい。
Since the surface temperature of the polishing pad 3 gradually increases as the polishing of the wafer W progresses, the PID control unit 40 can also repeat opening and closing the flow control valve 56 with the first opening and closing valve 41 closed. Limit cycle waveforms can be generated. That is, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 fully opens the flow control valve 56 at an operation amount of 100%, and when the measured value PV is lower than the temperature target value SV, the flow control valve 56. May be fully closed with an operation amount of 0%.
パッド温度調整部材11が冷却ノズルである場合において、PID制御部40は、研磨パッド3の表面上に供給される冷却流体の流量を制御することにより、リミットサイクル波形を発生させることができる。つまり、測定値PVが温度目標値SVよりも高いときには、PID制御部40は、流量制御バルブ56を全開にして、研磨パッド3の表面上に冷却流体を供給する。測定値PVが温度目標値SVよりも低いときには、PID制御部40は、流量制御バルブ56を全閉にして、研磨パッド3の表面への冷却流体の供給を停止する。
When the pad temperature adjusting member 11 is a cooling nozzle, the PID control unit 40 can generate a limit cycle waveform by controlling the flow rate of the cooling fluid supplied onto the surface of the polishing pad 3. That is, when the measured value PV is higher than the temperature target value SV, the PID control unit 40 opens the flow rate control valve 56 and supplies the cooling fluid onto the surface of the polishing pad 3. When the measured value PV is lower than the temperature target value SV, the PID control unit 40 fully closes the flow rate control valve 56 and stops the supply of the cooling fluid to the surface of the polishing pad 3.
PID制御部40は、発生したリミットサイクル波形に基づいて研磨パッド3の表面温度の振幅Xおよびむだ時間Ltを決定する。むだ時間Ltは、第1流量制御バルブ42を全閉し、かつ第2流量制御バルブ56を全開した時刻から、パッド表面温度が下降し始める時刻までの時間差L1を求め、第1流量制御バルブ42を全開し、かつ第2流量制御バルブ56を全閉した時刻から、パッド表面温度が上昇し始める時刻までの時間差L2を求め、時間差L1と時間差L2との和を2で割り算することで得られる。つまり、むだ時間Ltは下記式(1)から決定することができる。
Lt=(L1+L2)/2 (1) ThePID control unit 40 determines the surface temperature amplitude X and the dead time Lt of the polishing pad 3 based on the generated limit cycle waveform. The dead time Lt is obtained as a time difference L1 from the time when the first flow rate control valve 42 is fully closed and the second flow rate control valve 56 is fully opened to the time when the pad surface temperature starts to decrease. Is obtained by dividing the sum of the time difference L1 and the time difference L by 2 from the time when the second flow control valve 56 is fully closed to the time when the pad surface temperature starts to rise. . That is, the dead time Lt can be determined from the following equation (1).
Lt = (L1 + L2) / 2 (1)
Lt=(L1+L2)/2 (1) The
Lt = (L1 + L2) / 2 (1)
振幅Xは、研磨パッド3の温度目標値SVとパッド表面温度の極大値との差(絶対値)A1を算出し、研磨パッド3の温度目標値SVとパッド表面温度の極小値との差(絶対値)A2を算出し、差A1と差A2との和を2で割り算することで求められる。つまり、振幅Xは、下記式(2)から決定することができる。
X=(A1+A2)/2 (2) As the amplitude X, a difference (absolute value) A1 between the temperature target value SV of thepolishing pad 3 and the maximum value of the pad surface temperature is calculated, and the difference between the temperature target value SV of the polishing pad 3 and the minimum value of the pad surface temperature ( (Absolute value) A2 is calculated, and the sum of the difference A1 and the difference A2 is divided by 2. That is, the amplitude X can be determined from the following equation (2).
X = (A1 + A2) / 2 (2)
X=(A1+A2)/2 (2) As the amplitude X, a difference (absolute value) A1 between the temperature target value SV of the
X = (A1 + A2) / 2 (2)
PID制御部40は、流量制御バルブ42,56の操作量の振幅M、研磨パッド3の表面温度の振幅X、およびむだ時間Ltを用いて、限界感度Kcおよび限界周期Tcをそれぞれ算出する。限界感度Kcは下記式(3)を用いることによって求められ、限界周期Tcは下記式(4)を用いることによって求められる。
Kc=4×M/(π×X) (3)
Tc=4×Lt (4) ThePID control unit 40 calculates the limit sensitivity Kc and the limit period Tc using the amplitude M of the manipulated variable of the flow control valves 42 and 56, the amplitude X of the surface temperature of the polishing pad 3, and the dead time Lt, respectively. The limit sensitivity Kc is obtained by using the following formula (3), and the limit period Tc is obtained by using the following formula (4).
Kc = 4 × M / (π × X) (3)
Tc = 4 × Lt (4)
Kc=4×M/(π×X) (3)
Tc=4×Lt (4) The
Kc = 4 × M / (π × X) (3)
Tc = 4 × Lt (4)
PID制御部40は、算定された限界感度Kcおよび限界周期Tcから、PIDパラメータを算定する。PIDパラメータは、流量制御バルブ42,56をPID制御するために必要なパラメータであり、比例ゲインKpと、積分時間Tiと、微分時間Tdとを含んでいる。以下、PIDパラメータを算定する方法について説明する。
The PID control unit 40 calculates PID parameters from the calculated limit sensitivity Kc and limit period Tc. The PID parameter is a parameter necessary for PID control of the flow rate control valves 42 and 56, and includes a proportional gain Kp, an integration time Ti, and a differentiation time Td. Hereinafter, a method for calculating the PID parameter will be described.
図11はPIDパラメータの算定に用いられる係数の一例を示す図である。図11には、定値制御向き(Ziegler and Nichols)および追値制御向き(Chien, Hrones, and Reswick)の制御ルールにおけるPIDパラメータ(およびPIパラメータ)の算定に用いられる係数が表されている。なお、PIDパラメータを算定するための係数は図11に表された数値に限定されるものではない。これら係数はウェーハWの研磨条件に応じて予め決定されている。所定の係数と限界感度Kcおよび限界周期Tcとを、それぞれ、かけ算することによって、PIDパラメータ(つまり、比例ゲインKp、積分時間Ti、および微分時間Td)を算定することができる。
FIG. 11 is a diagram showing an example of coefficients used for calculating PID parameters. FIG. 11 shows coefficients used for calculation of PID parameters (and PI parameters) in the control rules of the fixed value control direction (Ziegler and Nichols) and the follow-up control direction (Chien, Herones, and Rewick). Note that the coefficient for calculating the PID parameter is not limited to the numerical values shown in FIG. These coefficients are determined in advance according to the polishing conditions of the wafer W. A PID parameter (that is, proportional gain Kp, integration time Ti, and differentiation time Td) can be calculated by multiplying the predetermined coefficient, the limit sensitivity Kc, and the limit period Tc, respectively.
上述したように、PID制御部40は、この算定されたPIDパラメータを備えたPID演算式を用いて、温度目標値SVと研磨パッド3の表面温度の測定値PVとの偏差を最小にするための流量制御バルブ42,56の操作量を算定する。PID演算式は、
と表すことができる。
As described above, the PID control unit 40 uses the PID arithmetic expression including the calculated PID parameter to minimize the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3. The operation amounts of the flow control valves 42 and 56 are calculated. The PID formula is
It can be expressed as.
図12はPIDパラメータを算定するときのフィードバック制御系を示す図である。図12に示すように、測定値PVと温度目標値SVとの偏差eに対して、非線形要素N(X)としての偏差eを基準とした流量制御バルブ42,56の2位置動作を行い、偏差eを最小にするための制御対象P(jω)への入力、すなわち、流量制御バルブ42,56の操作量MVを算定する。このようにして、PID制御部40は、流量制御バルブ42,56を操作して、研磨パッド3の表面温度を所望の目標温度に維持する。
FIG. 12 is a diagram showing a feedback control system when calculating PID parameters. As shown in FIG. 12, with respect to the deviation e between the measured value PV and the temperature target value SV, the two-position operation of the flow rate control valves 42 and 56 is performed based on the deviation e as the non-linear element N (X). An input to the control object P (jω) for minimizing the deviation e, that is, an operation amount MV of the flow control valves 42 and 56 is calculated. In this way, the PID control unit 40 operates the flow rate control valves 42 and 56 to maintain the surface temperature of the polishing pad 3 at a desired target temperature.
本実施形態では、PID制御部40は、専用のコンピュータまたは汎用のコンピュータから構成される。図13は、PID制御部40の構成を示す模式図である。PID制御部40は、プログラムやデータなどが格納される記憶装置110と、記憶装置110に格納されているプログラムに従って演算を行うCPU(中央処理装置)などの処理装置120と、データ、プログラム、および各種情報を記憶装置110に入力するための入力装置130と、処理結果や処理されたデータを出力するための出力装置140と、インターネットなどのネットワークに接続するための通信装置150を備えている。
In the present embodiment, the PID control unit 40 is configured by a dedicated computer or a general-purpose computer. FIG. 13 is a schematic diagram illustrating a configuration of the PID control unit 40. The PID control unit 40 includes a storage device 110 that stores programs and data, a processing device 120 such as a CPU (central processing unit) that performs operations according to programs stored in the storage device 110, data, programs, and An input device 130 for inputting various information to the storage device 110, an output device 140 for outputting processing results and processed data, and a communication device 150 for connecting to a network such as the Internet are provided.
記憶装置110は、処理装置120がアクセス可能な主記憶装置111と、データおよびプログラムを格納する補助記憶装置112を備えている。主記憶装置111は、例えばランダムアクセスメモリ(RAM)であり、補助記憶装置112は、ハードディスクドライブ(HDD)またはソリッドステートドライブ(SSD)などのストレージ装置である。
The storage device 110 includes a main storage device 111 accessible by the processing device 120 and an auxiliary storage device 112 that stores data and programs. The main storage device 111 is, for example, a random access memory (RAM), and the auxiliary storage device 112 is a storage device such as a hard disk drive (HDD) or a solid state drive (SSD).
入力装置130は、キーボード、マウスを備えており、さらに、記録媒体からデータを読み込むための記録媒体読み込み装置132と、記録媒体が接続される記録媒体ポート134を備えている。記録媒体は、非一時的な有形物であるコンピュータ読み取り可能な記録媒体であり、例えば、光ディスク(例えば、CD-ROM、DVD-ROM)や、半導体メモリー(例えば、USBフラッシュドライブ、メモリーカード)である。記録媒体読み込み装置132の例としては、CDドライブ、DVDドライブなどの光学ドライブや、カードリーダーが挙げられる。記録媒体ポート134の例としては、USB端子が挙げられる。記録媒体に記録されているプログラムおよび/またはデータは、入力装置130を介してPID制御部40に導入され、記憶装置110の補助記憶装置112に格納される。出力装置140は、ディスプレイ装置141、印刷装置142を備えている。印刷装置142は省略してもよい。上述した温度表示器45は、PID制御部40のためのディスプレイ装置として用いてもよい。この場合は、ディスプレイ装置141は省略してもよい。
The input device 130 includes a keyboard and a mouse, and further includes a recording medium reading device 132 for reading data from the recording medium and a recording medium port 134 to which the recording medium is connected. The recording medium is a non-transitory tangible computer-readable recording medium, such as an optical disc (eg, CD-ROM, DVD-ROM) or semiconductor memory (eg, USB flash drive, memory card). is there. Examples of the recording medium reading device 132 include an optical drive such as a CD drive and a DVD drive, and a card reader. An example of the recording medium port 134 is a USB terminal. The program and / or data recorded on the recording medium is introduced into the PID control unit 40 via the input device 130 and stored in the auxiliary storage device 112 of the storage device 110. The output device 140 includes a display device 141 and a printing device 142. The printing device 142 may be omitted. The temperature indicator 45 described above may be used as a display device for the PID control unit 40. In this case, the display device 141 may be omitted.
PID制御部40は、記憶装置110に電気的に格納されたプログラムに従って動作する。図14はプログラムに従って動作するPID制御部40の動作ステップを示すフローチャートである。PID制御部40は、研磨ヘッド1に指令を与えて、ウェーハWを研磨パッド3の表面に押し付けてウェーハWを研磨する動作を研磨ヘッド1に実行させるステップ(図14のステップ1参照)と、ウェーハWの研磨中において、流量制御バルブ42,56を操作することで、研磨パッド3の表面温度を変化させるステップと(図14のステップ2参照)、研磨パッド3の表面温度を測定する動作をパッド温度測定器39に実行させ、研磨パッド3の表面温度の測定値を取得するステップと(図14のステップ3,4参照)、研磨パッド3の表面温度の時間変化に基づいて、PIDパラメータを算定するステップと(図14のステップ5参照)、PIDパラメータを備えたPID演算式を用いて、温度目標値SVと研磨パッド3の表面温度の測定値PVとの偏差を最小にするための流量制御バルブ42,56の操作量を計算するステップと(図14のステップ6参照)、この操作量に基づいて流量制御バルブ42,56を操作するステップ(図14のステップ7参照)とを実行する。
The PID control unit 40 operates according to a program electrically stored in the storage device 110. FIG. 14 is a flowchart showing the operation steps of the PID control unit 40 that operates according to a program. The PID control unit 40 instructs the polishing head 1 to cause the polishing head 1 to perform an operation of pressing the wafer W against the surface of the polishing pad 3 to polish the wafer W (see Step 1 in FIG. 14). During polishing of the wafer W, the step of changing the surface temperature of the polishing pad 3 by operating the flow rate control valves 42 and 56 (see step 2 of FIG. 14) and the operation of measuring the surface temperature of the polishing pad 3 are performed. Based on the step of causing the pad temperature measuring device 39 to execute the measurement of the surface temperature of the polishing pad 3 (see Steps 3 and 4 in FIG. 14) and the time variation of the surface temperature of the polishing pad 3, Using the step of calculating (see step 5 in FIG. 14) and the PID calculation formula including the PID parameter, the temperature target value SV and the surface temperature of the polishing pad 3 A step of calculating an operation amount of the flow control valves 42 and 56 for minimizing a deviation from the constant value PV (see step 6 in FIG. 14), and a step of operating the flow control valves 42 and 56 based on the operation amount (See step 7 in FIG. 14).
これらステップをPID制御部40に実行させるためのプログラムは、非一時的な有形物であるコンピュータ読み取り可能な記録媒体に記録され、記録媒体を介してPID制御部40に提供される。または、プログラムは、インターネットなどの通信ネットワークを介してPID制御部40に提供されてもよい。
The program for causing the PID control unit 40 to execute these steps is recorded on a computer-readable recording medium that is a non-temporary tangible material and provided to the PID control unit 40 via the recording medium. Alternatively, the program may be provided to the PID control unit 40 via a communication network such as the Internet.
次に、PIDパラメータを算定する方法の他の例であるステップ応答法について、図面を参照して説明する。図15はステップ応答法を説明するための図である。図15において、符号PVは研磨パッド3の表面温度の測定値を示しており、符号MVは流量制御バルブ42,56の操作量を示している。図15の縦軸は測定値PVおよび操作量MVを示しており、図15の横軸は時間を示している。
Next, a step response method, which is another example of a method for calculating PID parameters, will be described with reference to the drawings. FIG. 15 is a diagram for explaining the step response method. In FIG. 15, symbol PV indicates a measured value of the surface temperature of the polishing pad 3, and symbol MV indicates an operation amount of the flow rate control valves 42 and 56. The vertical axis in FIG. 15 indicates the measured value PV and the manipulated variable MV, and the horizontal axis in FIG. 15 indicates time.
図15に示すように、PID制御部40は、第1流量制御バルブ42を全閉から全開に切り替え、かつ第2流量制御バルブ56を全開から全閉に切り替えて、研磨パッド3の表面温度を変化させる。パッド温度測定器39は、このときの研磨パッド3の表面温度を測定し、PID制御部40に送る。PID制御部40は、この測定値をパッド温度測定器39から取得し、研磨パッド3の表面温度の時間変化を示す曲線の接線TLの傾きRを算定し、接線TLの傾きR、むだ時間Lt、および時定数τを決定する。なお、図15に示す測定値PVの曲線はプロセス反応曲線と呼ばれる。
As shown in FIG. 15, the PID control unit 40 switches the first flow rate control valve 42 from fully closed to fully open, and switches the second flow rate control valve 56 from fully open to fully closed, so that the surface temperature of the polishing pad 3 is increased. Change. The pad temperature measuring device 39 measures the surface temperature of the polishing pad 3 at this time and sends it to the PID control unit 40. The PID control unit 40 acquires this measurement value from the pad temperature measuring device 39, calculates the slope R of the tangent TL of the curve indicating the time change of the surface temperature of the polishing pad 3, and calculates the slope R of the tangent TL and the dead time Lt. , And a time constant τ. The curve of the measured value PV shown in FIG. 15 is called a process reaction curve.
PID制御部40は、第1開閉バルブ41を閉じた状態において、第2流量制御バルブ56を全開から全閉に切り替えることによっても、プロセス反応曲線を発生させることができる。パッド温度調整部材11が冷却ノズルである場合も、PID制御部40は、研磨パッド3の表面上に供給される冷却流体の流量を制御することにより、プロセス反応曲線を発生させることができる。つまり、PID制御部40は、流量制御バルブ56を全開から全閉に切り替えることにより、プロセス反応曲線を発生させることができる。
The PID control unit 40 can also generate a process reaction curve by switching the second flow rate control valve 56 from fully open to fully closed while the first opening / closing valve 41 is closed. Even when the pad temperature adjusting member 11 is a cooling nozzle, the PID control unit 40 can generate a process reaction curve by controlling the flow rate of the cooling fluid supplied onto the surface of the polishing pad 3. That is, the PID control unit 40 can generate a process reaction curve by switching the flow control valve 56 from fully open to fully closed.
図15に示すように、接線TLは、測定値PVを0%から100%までの数値で表したとき、測定値PVが所定の数値(本実施形態では63%)まで上昇したときのプロセス反応曲線上の点P1を通る接線である。傾きRは接線TLに基づいて求められる。むだ時間Ltは、第1流量制御バルブ42を全開とした時刻から、接線TLと横軸との交点P2における時刻までの時間差を算定することで求められる。時定数τは、交点P2における時刻から点P1に対応する時刻までの時間差を算定することで求められる。
As shown in FIG. 15, the tangent TL indicates the process reaction when the measured value PV increases to a predetermined value (63% in the present embodiment) when the measured value PV is represented by a value from 0% to 100%. It is a tangent line passing through the point P1 on the curve. The slope R is obtained based on the tangent line TL. The dead time Lt is obtained by calculating the time difference from the time when the first flow control valve 42 is fully opened to the time at the intersection P2 between the tangent TL and the horizontal axis. The time constant τ is obtained by calculating the time difference from the time at the intersection P2 to the time corresponding to the point P1.
PID制御部40は、接線TLの傾きR、むだ時間Lt、および時定数τを用いてPIDパラメータを算定する。より具体的には、比例ゲインKpは下記式(6)を用いることによって求めることができる。
Kp=a/(R×Lt) (6) ThePID control unit 40 calculates the PID parameter using the slope R of the tangent line TL, the dead time Lt, and the time constant τ. More specifically, the proportional gain Kp can be obtained by using the following equation (6).
Kp = a / (R × Lt) (6)
Kp=a/(R×Lt) (6) The
Kp = a / (R × Lt) (6)
積分時間Tiは下記式(7)または下記式(8)を用いることによって求めることができる。
Ti=b×Lt (7)
Ti=b×τ (8) The integration time Ti can be obtained by using the following formula (7) or the following formula (8).
Ti = b × Lt (7)
Ti = b × τ (8)
Ti=b×Lt (7)
Ti=b×τ (8) The integration time Ti can be obtained by using the following formula (7) or the following formula (8).
Ti = b × Lt (7)
Ti = b × τ (8)
微分時間Tdは下記式(9)を用いることによって求めることができる。
Td=c×Lt (9)
ここで、上記式(6)~(9)における係数a,b,cは所定の数値であり、例えば、係数aは1.2であり、係数bは2.0であり、係数cは0.5である。 The differential time Td can be obtained by using the following formula (9).
Td = c × Lt (9)
Here, the coefficients a, b, and c in the above equations (6) to (9) are predetermined numerical values, for example, the coefficient a is 1.2, the coefficient b is 2.0, and the coefficient c is 0. .5.
Td=c×Lt (9)
ここで、上記式(6)~(9)における係数a,b,cは所定の数値であり、例えば、係数aは1.2であり、係数bは2.0であり、係数cは0.5である。 The differential time Td can be obtained by using the following formula (9).
Td = c × Lt (9)
Here, the coefficients a, b, and c in the above equations (6) to (9) are predetermined numerical values, for example, the coefficient a is 1.2, the coefficient b is 2.0, and the coefficient c is 0. .5.
PID制御部40は、この算定されたPIDパラメータを備えたPID演算式(上記式(5)参照)を用いて温度目標値SVと研磨パッド3の表面温度の測定値PVとの偏差を最小にするための流量制御バルブ42,56の操作量を算定する。
The PID control unit 40 minimizes the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3 using the PID calculation formula (see the above formula (5)) having the calculated PID parameter. The amount of operation of the flow control valves 42 and 56 is calculated.
次に、PIDパラメータを算定する方法のさらに他の例であるジーグラ・ニコルスの限界感度法について、図面を参照して説明する。図16はジーグラ・ニコルスの限界感度法を説明するための図である。図16において、符号PVは研磨パッド3の表面温度の測定値を示しており、符号SVは研磨パッド3の表面温度の温度目標値を示しており、符号Puは限界ゲインの周期を示している。曲線Kp1は第1のゲインによる測定値PVの制御曲線であり、曲線Kp2は第1のゲインKp1よりも大きな第2のゲインによる測定値PVの制御曲線であり、曲線Kp3は第2のゲインKp2よりも大きな第3のゲインによる測定値PVの制御曲線である(Kp1<Kp2<Kp3)。図16の縦軸は測定値PVを示しており、図16の横軸は時間を示している。
Next, the Ziegler-Nichols limit sensitivity method, which is still another example of the method for calculating the PID parameter, will be described with reference to the drawings. FIG. 16 is a diagram for explaining the limit sensitivity method of Ziegler-Nichols. In FIG. 16, symbol PV indicates a measured value of the surface temperature of the polishing pad 3, symbol SV indicates a temperature target value of the surface temperature of the polishing pad 3, and symbol Pu indicates a period of a limit gain. . The curve Kp1 is a control curve of the measured value PV by the first gain, the curve Kp2 is a control curve of the measured value PV by the second gain larger than the first gain Kp1, and the curve Kp3 is the second gain Kp2. It is a control curve of the measured value PV with a larger third gain (Kp1 <Kp2 <Kp3). The vertical axis in FIG. 16 indicates the measured value PV, and the horizontal axis in FIG. 16 indicates time.
PID制御部40は、積分時間Tiおよび微分時間Tdを無効にした状態で、第1のゲインKp1、第2のゲインKp2、および第3のゲインKp3をこの順に増加させて、温度目標値SVと測定値PVとの間にハンチング(測定値PVの波形)を発生させる。一実施形態では、ゲインの数値は10ずつ増加される。図16では、第3のゲインKp3を出力したときに、ハンチングが生じている。この第3のゲインKp3は限界ゲインKuに決定される。
The PID control unit 40 increases the first gain Kp1, the second gain Kp2, and the third gain Kp3 in this order in a state where the integration time Ti and the differentiation time Td are invalidated, and the temperature target value SV Hunting (waveform of measured value PV) is generated between measured values PV. In one embodiment, the gain value is increased by ten. In FIG. 16, hunting occurs when the third gain Kp3 is output. The third gain Kp3 is determined as the limit gain Ku.
PID制御部40は、この限界ゲインKuの周期Puを算定する。PID制御部40は、限界ゲインKuおよび周期Puを用いて、PIDパラメータ(比例ゲインKp、積分時間Ti、微分時間Td)を算定する。より具体的には、比例ゲインKpは下記式(10)を用いることによって求めることができ、積分時間Tiは下記式(11)を用いることによって求めることができ、微分時間Tdは下記式(12)を用いることによって求めることができる。
Kp=a×Ku (10)
Ti=b×Pu (11)
Td=c×Pu (12)
ここで、上記式(10)~(12)における係数a,b,cは所定の数値であり、例えば、係数aは0.6であり、係数bは0.5であり、係数cは0.125である。 ThePID control unit 40 calculates the period Pu of the limit gain Ku. The PID control unit 40 calculates PID parameters (proportional gain Kp, integration time Ti, derivative time Td) using the limit gain Ku and the period Pu. More specifically, the proportional gain Kp can be obtained by using the following equation (10), the integration time Ti can be obtained by using the following equation (11), and the differential time Td can be obtained by the following equation (12). ) Can be used.
Kp = a × Ku (10)
Ti = b × Pu (11)
Td = c × Pu (12)
Here, the coefficients a, b, and c in the above equations (10) to (12) are predetermined numerical values, for example, the coefficient a is 0.6, the coefficient b is 0.5, and the coefficient c is 0. .125.
Kp=a×Ku (10)
Ti=b×Pu (11)
Td=c×Pu (12)
ここで、上記式(10)~(12)における係数a,b,cは所定の数値であり、例えば、係数aは0.6であり、係数bは0.5であり、係数cは0.125である。 The
Kp = a × Ku (10)
Ti = b × Pu (11)
Td = c × Pu (12)
Here, the coefficients a, b, and c in the above equations (10) to (12) are predetermined numerical values, for example, the coefficient a is 0.6, the coefficient b is 0.5, and the coefficient c is 0. .125.
PID制御部40は、この算定されたPIDパラメータを備えたPID演算式(上記式(5)参照)を用いて温度目標値SVと研磨パッド3の表面温度の測定値PVとの偏差を最小にするための流量制御バルブ42,56の操作量を算定する。
The PID control unit 40 minimizes the deviation between the temperature target value SV and the measured value PV of the surface temperature of the polishing pad 3 using the PID calculation formula (see the above formula (5)) having the calculated PID parameter. The amount of operation of the flow control valves 42 and 56 is calculated.
本実施形態によれば、PID制御部40は、ウェーハWの研磨中において、研磨パッド3の表面温度の時間変化に基づいてPIDパラメータを自動的に算定することができるため、PIDパラメータを決定するための試行錯誤による実験、特別な知識や経験、ノウハウは不要であり、熟練者に頼る必要はない。したがって、短時間で、かつ効率的にPIDパラメータを決定することができる。さらに、本実施形態によれば、時間や人員を大幅に削減することができるため、コストを削減することができる。
According to the present embodiment, the PID control unit 40 can automatically calculate the PID parameter based on the temporal change in the surface temperature of the polishing pad 3 during the polishing of the wafer W, and therefore determines the PID parameter. For this reason, trial and error experiments, special knowledge, experience, and know-how are not necessary, and there is no need to rely on skilled workers. Therefore, the PID parameter can be determined efficiently in a short time. Furthermore, according to the present embodiment, time and personnel can be significantly reduced, and thus costs can be reduced.
PID制御部40は、上述したPID演算式を用いて計算した操作量で流量制御バルブ42,56を操作した結果として予想される研磨パッド3の表面温度のシミュレーションを実行するように構成されている。シミュレーション結果が表示される研磨パッド3の表面位置はユーザーによって任意に決定され、PID制御部40は、PIDパラメータおよび温度目標値SVに基づいてシミュレーションを実行する。
The PID control unit 40 is configured to execute a simulation of the surface temperature of the polishing pad 3 that is expected as a result of operating the flow control valves 42 and 56 with the operation amount calculated using the PID arithmetic expression described above. . The surface position of the polishing pad 3 on which the simulation result is displayed is arbitrarily determined by the user, and the PID control unit 40 executes the simulation based on the PID parameter and the temperature target value SV.
さらに、PID制御部40は、温度目標値SVを変更した場合に予想される研磨パッド3の表面温度の時間推移を示すシミュレーションをさらに実行するように構成されている。図17は研磨パッド3の表面温度の時間推移を示すシミュレーション結果を示す図である。図17に示すように、研磨パッド3の表面温度の時間推移のシミュレーション結果は温度表示器45に表示される。シミュレーション結果が表示される研磨パッド3の表面位置はユーザーによって任意に決定される。
Furthermore, the PID control unit 40 is configured to further execute a simulation showing the time transition of the surface temperature of the polishing pad 3 expected when the temperature target value SV is changed. FIG. 17 is a diagram showing simulation results showing the time transition of the surface temperature of the polishing pad 3. As shown in FIG. 17, the simulation result of the time transition of the surface temperature of the polishing pad 3 is displayed on the temperature display 45. The surface position of the polishing pad 3 on which the simulation result is displayed is arbitrarily determined by the user.
ウェーハWの研磨プロセスごとに適切なPIDパラメータは異なるため、PID制御部40は、ウェーハWの研磨プロセスごとにPIDパラメータを自動的に決定するように構成されている。ウェーハWの研磨プロセスは、例えば、ウェーハWの膜厚、研磨パッド、スラリーの種類によって変更される。
Since an appropriate PID parameter is different for each polishing process of the wafer W, the PID control unit 40 is configured to automatically determine the PID parameter for each polishing process of the wafer W. The polishing process of the wafer W is changed depending on, for example, the film thickness of the wafer W, the polishing pad, and the type of slurry.
図18は、PIDパラメータがウェーハWの研磨プロセスごとに算定される様子を示すフローチャートである。まず、適切なPIDパラメータを算定するために、リミットサイクル法、ステップ応答法、およびジーグラ・ニコルスの限界感度法のうちのいずれかを用いて1枚のウェーハWを研磨する(図18のステップ1参照)。このとき、ウェーハWは、PIDパラメータを算定するための研磨レシピに従って研磨される。なお、リミットサイクル法を用いる場合、1枚のウェーハWを研磨するときの温度目標値SVは、実際の研磨プロセスにおいてウェーハWを研磨するときの温度目標値と同じである。
FIG. 18 is a flowchart showing how the PID parameters are calculated for each wafer W polishing process. First, in order to calculate an appropriate PID parameter, one wafer W is polished by using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method (step 1 in FIG. 18). reference). At this time, the wafer W is polished according to a polishing recipe for calculating PID parameters. When the limit cycle method is used, the temperature target value SV when polishing one wafer W is the same as the temperature target value when polishing the wafer W in an actual polishing process.
リミットサイクル法、ステップ応答法、およびジーグラ・ニコルスの限界感度法から最も適切なPIDパラメータを算定し(図18のステップ2参照)、算定されたPIDパラメータを反映したウェーハWの研磨を実行する(図18のステップ3参照)。このウェーハWの研磨時における研磨プロセスとは異なる研磨プロセスによりウェーハWを研磨する場合は、再度、1枚のウェーハWを研磨して、最も適切なPIDパラメータを算定する(図18のステップ4参照)。なお、研磨パッド3の温度目標値SVのみを変更する場合、PID制御部40は、予想される研磨パッド3の表面温度のシミュレーションを実行してもよい(図18のステップ5参照)。この場合、温度表示器45には、流量制御バルブ42,56を操作してから研磨パッド3の表面温度が変化するまでの時間、研磨パッド3の表面温度の変化に生じたオーバーシュートの大きさ、温度目標値SVと測定値PVとの偏差、研磨パッド3の表面温度の測定値PVの波形に生じたハンチングの大きさが表示されてもよい。
The most appropriate PID parameter is calculated from the limit cycle method, the step response method, and the Ziegler-Nichols limit sensitivity method (see step 2 in FIG. 18), and polishing of the wafer W reflecting the calculated PID parameter is executed (see FIG. 18). (See Step 3 in FIG. 18). When the wafer W is polished by a polishing process different from the polishing process at the time of polishing the wafer W, one wafer W is polished again, and the most appropriate PID parameter is calculated (see step 4 in FIG. 18). ). When only the temperature target value SV of the polishing pad 3 is changed, the PID control unit 40 may execute a simulation of the expected surface temperature of the polishing pad 3 (see Step 5 in FIG. 18). In this case, the temperature indicator 45 includes the time from the operation of the flow rate control valves 42 and 56 to the change of the surface temperature of the polishing pad 3 and the magnitude of the overshoot caused in the change of the surface temperature of the polishing pad 3. The deviation between the temperature target value SV and the measured value PV, and the magnitude of hunting generated in the waveform of the measured value PV of the surface temperature of the polishing pad 3 may be displayed.
上述した実施形態は、本発明が属する技術分野における通常の知識を有する者が本発明を実施できることを目的として記載されたものである。上記実施形態の種々の変形例は、当業者であれば当然になしうることであり、本発明の技術的思想は他の実施形態にも適用しうることである。したがって、本発明は、記載された実施形態に限定されることはなく、特許請求の範囲によって定義される技術的思想に従った最も広い範囲に解釈されるものである。
The above-described embodiments are described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.
本発明は、ウェーハなどの基板を研磨する研磨方法、研磨装置、および該研磨装置の研磨パッドの表面温度を制御するためのコンピュータプログラムを記録した記録媒体に利用可能である。
The present invention can be used for a polishing method for polishing a substrate such as a wafer, a polishing apparatus, and a recording medium on which a computer program for controlling the surface temperature of a polishing pad of the polishing apparatus is recorded.
1 研磨ヘッド
2 研磨テーブル
3 研磨パッド
4 研磨液供給ノズル
5 パッド温度調整システム
11 パッド温度調整部材
20 ドレッサ
30 流体供給システム
31 流体供給タンク
32 加熱流体供給管
33 加熱流体戻り管
39 パッド温度測定器
40 PID制御部
41 第1開閉バルブ
42 第1流量制御バルブ
45 温度表示器
51 冷却流体供給管
52 冷却流体排出管
55 第2開閉バルブ
56 第2流量制御バルブ
61 加熱流路
62 冷却流路
71 上下動機構(垂直移動機構)
110 記憶装置
120 処理装置
130 入力装置
140 出力装置
150 通信装置 DESCRIPTION OFSYMBOLS 1 Polishing head 2 Polishing table 3 Polishing pad 4 Polishing liquid supply nozzle 5 Pad temperature adjustment system 11 Pad temperature adjustment member 20 Dresser 30 Fluid supply system 31 Fluid supply tank 32 Heating fluid supply pipe 33 Heating fluid return pipe 39 Pad temperature measuring device 40 PID control unit 41 First on-off valve 42 First flow control valve 45 Temperature indicator 51 Cooling fluid supply pipe 52 Cooling fluid discharge pipe 55 Second on-off valve 56 Second flow control valve 61 Heating flow path 62 Cooling flow path 71 Vertical movement Mechanism (vertical movement mechanism)
110Storage Device 120 Processing Device 130 Input Device 140 Output Device 150 Communication Device
2 研磨テーブル
3 研磨パッド
4 研磨液供給ノズル
5 パッド温度調整システム
11 パッド温度調整部材
20 ドレッサ
30 流体供給システム
31 流体供給タンク
32 加熱流体供給管
33 加熱流体戻り管
39 パッド温度測定器
40 PID制御部
41 第1開閉バルブ
42 第1流量制御バルブ
45 温度表示器
51 冷却流体供給管
52 冷却流体排出管
55 第2開閉バルブ
56 第2流量制御バルブ
61 加熱流路
62 冷却流路
71 上下動機構(垂直移動機構)
110 記憶装置
120 処理装置
130 入力装置
140 出力装置
150 通信装置 DESCRIPTION OF
110
Claims (18)
- 基板を研磨パッドの表面に押し付けて該基板を研磨し、
前記基板の研磨中に、パッド温度調整部材に流れる流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させ、
前記研磨パッドの表面温度を測定し、
前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定し、
前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算し、
前記基板の研磨中に、前記操作量に従って前記流量制御バルブを操作することを特徴とする研磨方法。 Polishing the substrate by pressing the substrate against the surface of the polishing pad;
By operating a flow rate control valve for controlling the flow rate of the fluid flowing to the pad temperature adjusting member during polishing of the substrate, the surface temperature of the polishing pad is changed,
Measuring the surface temperature of the polishing pad;
Based on the time change of the surface temperature of the polishing pad, PID parameters are calculated,
Calculate the manipulated variable of the flow rate control valve to minimize the deviation between the temperature target value and the measured value of the surface temperature of the polishing pad, using a PID arithmetic expression having the PID parameter,
A polishing method, wherein the flow rate control valve is operated according to the operation amount during polishing of the substrate. - 前記研磨パッドの表面温度を測定する工程は、前記研磨パッドの中心と外周部とを含む領域における温度分布を測定する工程を含むことを特徴とする請求項1に記載の研磨方法。 2. The polishing method according to claim 1, wherein the step of measuring the surface temperature of the polishing pad includes a step of measuring a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
- 前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材を前記研磨パッドの表面に接触させ、または近接させて該パッド温度調整部材に流れる流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする請求項1に記載の研磨方法。 The step of changing the surface temperature of the polishing pad controls the flow rate of the fluid flowing through the pad temperature adjusting member by bringing the pad temperature adjusting member into contact with or close to the surface of the polishing pad during polishing of the substrate. 2. The polishing method according to claim 1, wherein the polishing step is a step of changing a surface temperature of the polishing pad by operating a flow rate control valve.
- 前記研磨パッドの表面温度を変化させる工程は、前記基板の研磨中に、パッド温度調整部材から前記研磨パッドの表面上に供給される流体の流量を制御するための流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させる工程であることを特徴とする請求項1に記載の研磨方法。 The step of changing the surface temperature of the polishing pad is performed by operating a flow rate control valve for controlling the flow rate of the fluid supplied from the pad temperature adjusting member onto the surface of the polishing pad during polishing of the substrate. The polishing method according to claim 1, wherein the polishing method is a step of changing a surface temperature of the polishing pad.
- 前記流体は、加熱流体および冷却流体であることを特徴とする請求項1に記載の研磨方法。 The polishing method according to claim 1, wherein the fluid is a heating fluid and a cooling fluid.
- 前記PIDパラメータを算定する工程は、リミットサイクル法、ステップ応答法、ジーグラ・ニコルスの限界感度法のうちのいずれかを用いて、前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定する工程であることを特徴とする請求項1に記載の研磨方法。 The step of calculating the PID parameter is to calculate the PID parameter based on the time change of the surface temperature of the polishing pad using any one of a limit cycle method, a step response method, and a limit sensitivity method of Ziegler Nichols. The polishing method according to claim 1, wherein the polishing method is a step of:
- 前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行することを特徴とする請求項1に記載の研磨方法。 The polishing method according to claim 1, wherein a simulation of a surface temperature of the polishing pad expected as a result of operating the flow rate control valve with an operation amount calculated using the PID arithmetic expression is executed.
- 前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行することを特徴とする請求項7に記載の研磨方法。 8. The polishing method according to claim 7, further comprising executing a simulation showing a time transition of the surface temperature of the polishing pad expected when the temperature target value is changed.
- 研磨パッドを支持する研磨テーブルと、
基板を前記研磨パッドに押し付ける研磨ヘッドと、
前記研磨パッドの表面温度を調整するパッド温度調整システムとを備え、
前記パッド温度調整システムは、
流体が流れる流路が内部に形成されたパッド温度調整部材と、
前記流路に接続された流体供給管と、
前記流体供給管に取り付けられた流量制御バルブと、
前記研磨パッドの表面温度を測定するパッド温度測定器と、
前記流量制御バルブを操作するPID制御部とを備え、
前記PID制御部は、
前記基板の研磨中において、前記流量制御バルブを操作して、前記研磨パッドの表面温度を変化させ、
前記研磨パッドの表面温度の測定値を前記パッド温度測定器から取得し、
前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定し、
前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算し、
前記操作量に従って前記流量制御バルブを操作することを特徴とする研磨装置。 A polishing table that supports the polishing pad;
A polishing head for pressing a substrate against the polishing pad;
A pad temperature adjustment system for adjusting the surface temperature of the polishing pad;
The pad temperature adjustment system includes:
A pad temperature adjusting member having a flow path through which the fluid flows;
A fluid supply pipe connected to the flow path;
A flow control valve attached to the fluid supply pipe;
A pad temperature measuring device for measuring the surface temperature of the polishing pad;
A PID control unit for operating the flow rate control valve,
The PID control unit
During polishing of the substrate, the flow control valve is operated to change the surface temperature of the polishing pad,
Obtaining a measured value of the surface temperature of the polishing pad from the pad temperature measuring device;
Based on the time change of the surface temperature of the polishing pad, PID parameters are calculated,
Calculate the manipulated variable of the flow rate control valve to minimize the deviation between the temperature target value and the measured value of the surface temperature of the polishing pad, using a PID arithmetic expression having the PID parameter,
A polishing apparatus, wherein the flow rate control valve is operated according to the operation amount. - 前記パッド温度測定器は、赤外線放射温度計、熱電対温度計、サーモグラフィ、およびサーモパイルのうち、少なくとも1つの温度測定器であることを特徴とする請求項9に記載の研磨装置。 The polishing apparatus according to claim 9, wherein the pad temperature measuring device is at least one temperature measuring device selected from an infrared radiation thermometer, a thermocouple thermometer, a thermography, and a thermopile.
- 前記パッド温度測定器は、前記研磨パッドの中心と外周部とを含む領域における温度分布を測定するように構成されていることを特徴とする請求項9に記載の研磨装置。 The polishing apparatus according to claim 9, wherein the pad temperature measuring device is configured to measure a temperature distribution in a region including a center and an outer peripheral portion of the polishing pad.
- 前記パッド温度調整システムは、前記パッド温度測定器によって測定された前記研磨パッドの表面温度を表示する温度表示器をさらに備えていることを特徴とする請求項9に記載の研磨装置。 10. The polishing apparatus according to claim 9, wherein the pad temperature adjusting system further includes a temperature indicator for displaying a surface temperature of the polishing pad measured by the pad temperature measuring device.
- 前記パッド温度調整部材は、前記研磨パッドの表面に冷却流体を吹きかける冷却ノズルであることを特徴とする請求項9に記載の研磨装置。 The polishing apparatus according to claim 9, wherein the pad temperature adjusting member is a cooling nozzle that sprays a cooling fluid onto a surface of the polishing pad.
- 前記パッド温度調整部材は、前記研磨パッドの表面に接触可能なパッド接触面を有することを特徴とする請求項9に記載の研磨装置。 10. The polishing apparatus according to claim 9, wherein the pad temperature adjusting member has a pad contact surface capable of contacting the surface of the polishing pad.
- 前記PID制御部は、リミットサイクル法、ステップ応答法、ジーグラ・ニコルスの限界感度法のうちのいずれかを用いてPIDパラメータを算定することを特徴とする請求項9に記載の研磨装置。 The polishing apparatus according to claim 9, wherein the PID control unit calculates a PID parameter using any one of a limit cycle method, a step response method, and a Ziegler-Nichols limit sensitivity method.
- 前記PID制御部は、前記PID演算式を用いて計算した操作量で前記流量制御バルブを操作した結果として予想される前記研磨パッドの表面温度のシミュレーションを実行するように構成されていることを特徴とする請求項9に記載の研磨装置。 The PID control unit is configured to execute a simulation of a surface temperature of the polishing pad expected as a result of operating the flow rate control valve with an operation amount calculated using the PID arithmetic expression. The polishing apparatus according to claim 9.
- 前記PID制御部は、前記温度目標値を変更した場合に予想される前記研磨パッドの表面温度の時間推移を示すシミュレーションをさらに実行するように構成されていることを特徴とする請求項16に記載の研磨装置。 The said PID control part is comprised so that it may further perform the simulation which shows the time transition of the surface temperature of the said polishing pad anticipated when the said temperature target value is changed, It is characterized by the above-mentioned. Polishing equipment.
- 研磨ヘッドに指令を与えて、基板を研磨パッドの表面に押し付けて該基板を研磨する動作を前記研磨ヘッドに実行させるステップと、
パッド温度調整部材に流れる流体の流量を制御するために設けられた流量制御バルブを操作することで、前記研磨パッドの表面温度を変化させるステップと、
前記研磨パッドの表面温度の測定値を取得するステップと、
前記研磨パッドの表面温度の時間変化に基づいて、PIDパラメータを算定するステップと、
前記PIDパラメータを備えたPID演算式を用いて、温度目標値と前記研磨パッドの表面温度の測定値との偏差を最小にするための前記流量制御バルブの操作量を計算するステップと、
前記操作量に従って前記流量制御バルブを操作するステップをコンピュータに実行させるためのプログラムを記録した非一時的なコンピュータ読み取り可能な記録媒体。 Giving a command to the polishing head, causing the polishing head to perform an operation of pressing the substrate against the surface of the polishing pad and polishing the substrate;
Changing the surface temperature of the polishing pad by operating a flow rate control valve provided to control the flow rate of the fluid flowing through the pad temperature adjusting member;
Obtaining a measured value of the surface temperature of the polishing pad;
Calculating a PID parameter based on time variation of the surface temperature of the polishing pad;
Calculating a manipulated variable of the flow control valve for minimizing a deviation between a temperature target value and a measured value of the surface temperature of the polishing pad, using a PID arithmetic expression having the PID parameter;
A non-transitory computer-readable recording medium recording a program for causing a computer to execute the step of operating the flow control valve according to the operation amount.
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TW (1) | TW201806700A (en) |
WO (1) | WO2018034308A1 (en) |
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US20210402554A1 (en) * | 2020-06-29 | 2021-12-30 | Applied Materials, Inc. | Control of steam generation for chemical mechanical polishing |
JP2022545628A (en) * | 2019-08-13 | 2022-10-28 | アプライド マテリアルズ インコーポレイテッド | Low temperature metal CMP to minimize dishing and corrosion while improving pad asperities |
EP4171873A4 (en) * | 2020-06-29 | 2024-07-24 | Applied Materials Inc | Temperature and slurry flow rate control in cmp |
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JP7374751B2 (en) * | 2018-12-28 | 2023-11-07 | 株式会社荏原製作所 | Pad temperature adjustment device, pad temperature adjustment method, polishing device, and polishing system |
US11919124B2 (en) | 2018-12-28 | 2024-03-05 | Ebara Corporation | Pad-temperature regulating apparatus, method of regulating pad-temperature, polishing apparatus, and polishing system |
JP7240931B2 (en) * | 2019-03-29 | 2023-03-16 | 株式会社荏原製作所 | Heat exchanger cleaning and polishing equipment |
JP7421413B2 (en) | 2020-05-08 | 2024-01-24 | 株式会社荏原製作所 | Pad temperature adjustment device, pad temperature adjustment method, and polishing device |
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- 2016-08-17 JP JP2016159963A patent/JP2018027582A/en active Pending
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JP2011079076A (en) * | 2009-10-05 | 2011-04-21 | Toshiba Corp | Polishing device and polishing method |
JP2011136406A (en) * | 2009-12-28 | 2011-07-14 | Ebara Corp | Substrate polishing apparatus, substrate polishing method, and apparatus for regulating temperature of surface of polishing pad for substrate polishing apparatus |
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JP2022545628A (en) * | 2019-08-13 | 2022-10-28 | アプライド マテリアルズ インコーポレイテッド | Low temperature metal CMP to minimize dishing and corrosion while improving pad asperities |
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US20210402554A1 (en) * | 2020-06-29 | 2021-12-30 | Applied Materials, Inc. | Control of steam generation for chemical mechanical polishing |
WO2022006008A1 (en) * | 2020-06-29 | 2022-01-06 | Applied Materials, Inc. | Control of steam generation for chemical mechanical polishing |
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EP4171873A4 (en) * | 2020-06-29 | 2024-07-24 | Applied Materials Inc | Temperature and slurry flow rate control in cmp |
Also Published As
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TW201806700A (en) | 2018-03-01 |
JP2018027582A (en) | 2018-02-22 |
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