US20060252349A1 - Semiconductor wafer polishing apparatus having magneto-rhelogical elastic pad - Google Patents
Semiconductor wafer polishing apparatus having magneto-rhelogical elastic pad Download PDFInfo
- Publication number
- US20060252349A1 US20060252349A1 US11/197,715 US19771505A US2006252349A1 US 20060252349 A1 US20060252349 A1 US 20060252349A1 US 19771505 A US19771505 A US 19771505A US 2006252349 A1 US2006252349 A1 US 2006252349A1
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- United States
- Prior art keywords
- wafer
- magneto
- elastic pad
- electromagnets
- polishing apparatus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 32
- 238000005498 polishing Methods 0.000 title claims abstract description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 19
- 239000000126 substance Substances 0.000 claims description 18
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims description 6
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 6
- 239000004814 polyurethane Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 4
- 239000010941 cobalt Substances 0.000 claims description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229920002635 polyurethane Polymers 0.000 claims description 4
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 3
- 229920002943 EPDM rubber Polymers 0.000 claims description 3
- 244000043261 Hevea brasiliensis Species 0.000 claims description 3
- 229910001567 cementite Inorganic materials 0.000 claims description 3
- 239000002270 dispersing agent Substances 0.000 claims description 3
- 229920001971 elastomer Polymers 0.000 claims description 3
- 229910001337 iron nitride Inorganic materials 0.000 claims description 3
- 239000012948 isocyanate Substances 0.000 claims description 3
- 150000002513 isocyanates Chemical class 0.000 claims description 3
- 229920003052 natural elastomer Polymers 0.000 claims description 3
- 229920001194 natural rubber Polymers 0.000 claims description 3
- 229920002857 polybutadiene Polymers 0.000 claims description 3
- 229920005862 polyol Polymers 0.000 claims description 3
- 150000003077 polyols Chemical class 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 239000005060 rubber Substances 0.000 claims description 3
- 229920002379 silicone rubber Polymers 0.000 claims description 3
- 239000004945 silicone rubber Substances 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 229920003051 synthetic elastomer Polymers 0.000 claims description 3
- 239000005061 synthetic rubber Substances 0.000 claims description 3
- 239000011369 resultant mixture Substances 0.000 claims 3
- 239000012258 stirred mixture Substances 0.000 claims 2
- 235000012431 wafers Nutrition 0.000 description 56
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 238000007517 polishing process Methods 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- -1 Fe2O3 Chemical compound 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007373 indentation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920003225 polyurethane elastomer Polymers 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- B24B37/11—Lapping tools
- B24B37/20—Lapping pads for working plane surfaces
- B24B37/24—Lapping pads for working plane surfaces characterised by the composition or properties of the pad materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
Definitions
- the present invention relates to a semiconductor polishing apparatus having a magneto-rheological elastic pad.
- the invention relates to a semiconductor polishing apparatus, in which, a plurality of electromagnets are arranged in a row at the lower portion of the magneto-rheological elastic pad to allow each electromagnet to selectively generate magnetic field so that the central and the surrounding part of a wafer dielectric layer contacting with the abrasive can be processed to the same level without a deflection by adjusting pressure according to multi-area of magneto-rheological elastic pad corresponding to the position of each magnetic field, thereby greatly reducing a defect rate of a semiconductor device.
- a large-scale integrated semiconductor device has a multi-layer structure formed by alternate piling of a circuit pattern layer and a dielectric layer insulating the circuit pattern layer.
- the dielectric layer is piled on the circuit layer, irregularities can be made on the dielectric layer according to an indentation of the circuit layer. Therefore, a planarization process is required in manufacturing the large-scale integrated semiconductor device to reduce the indentation.
- CMP Chemical Mechanical Planarization
- the CMP process includes a fixing process of a semiconductor wafer in a wafer holder.
- a polishing pad and the wafer rotate together in a condition that the wafer contacts with the polishing pad.
- the polishing pad is coated with colloid silica of a suspension of SiO 2 particles as an abrasive.
- the abrasive has particle sizes in a various range from several nm to several ⁇ m.
- the abrasive is coated in the form of slurry by using a wand which is provided to the wafer holder and the pad.
- material removal rate from the wafer is a combination of the chemical and the mechanical removal rate.
- the mechanical removal rate is proportional to relative speed and pressure of the wafer.
- the chemical removal rate is a function of slurry particle size and solution pH, which has the maximum removal rate when slurry having about 11.5 pH is used.
- the rotating wafer as shown in FIG. 1 has faster rotational speed in the outer part than the central part, therein there exists a pressure inequality between the wafer 1 and the abrasive pad as shown in FIG. 2 .
- the undescribed numeral 3 represents the wafer holder.
- a thickness deflection of the wafer can occur because more materials are polished in the outer part than the central part, as shown in FIG. 3 .
- polishing in the outer part can damage the circuit layer below the dielectric layer. Therefore, the pressure inequality due to the different relative speed between the outer and the central part is critical factor causing the failure of semiconductor devices.
- pressure is controlled by the replacement of pads having different stiffness.
- pressure of an unflat support below a pad platen is controlled, which has problems that the wafer needs to be mounted in a very accurate way and the control cannot be done in real-time.
- the present invention has been made in view of the above problems occurring in the prior art, and it is an object of the present invention to provide a semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which, a plurality of electromagnets are arranged in a row at the lower portion of the magneto-rheological elastic pad to selectively generate a magnetic field for each electromagnet and a multi-area pressure of the magneto-rheological elastic pad corresponding to the magnetic field position is adjusted in such a way that the central and the surrounding part of a dielectric layer of the wafer contacting with the abrasive can be processed to the same level without a deflection, thereby decreasing the failure rate of the semiconductor device.
- the semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which the dielectric layer of the wafer fixed in the wafer holder to contact the abrasive coated on a rotating plate is polished.
- the apparatus of the invention includes: a magneto-rheological elastic pad formed by a plurality of segments received to be fixed on the rotating plate; a plurality of electromagnets each having equal or larger diameter than that of wafer to selectively pressurize a part or the entire area of the wafer, each electromagnet being arranged at the lower portion of the rotating plate in such a way that its central part accords with the central axis of the wafer holder; and a controller for selectively generating the magnetic field at a part or the entire part of the electromagnets.
- a magnetic substance is mixed with a solvent and a dispersant.
- the mixture is stirred with an elastic substance after stirring and dispersing in a powerful mixer.
- this mixture is stirred in a solution of polyurethane polyol using a ball mill for about 10 hours. This is allowed for hardening for 24 hours at the temperature of 90° C. ⁇ 110° C. after adding one part of isocyanate, thereafter the magnetic field of about 1 Tesla is applied until the hardening is completed.
- the elastic substance may one of natural rubber, EPDM, polybutadien, acrylonitrile rubber, synthetic rubber, polyurethane and silicone rubber, or the combinations thereof.
- the magnetic substance may be one of iron, alloy iron, iron oxide such as Fe 2 O 3 , Co doped Fe 2 O 3 and Fe 3 O 4 , iron nitride, iron carbide, nickel, cobalt, chrome dioxide, stainless steel and Fe powder.
- the magneto-rheological elastic pad is formed to have a thickness of 0.1 mm ⁇ 50 mm, preferably 1 mm ⁇ 10 mm.
- the magnetic field is selectively applied to a part or the entire part of the magneto-rheological elastic pad formed by a plurality of segments.
- stiffness of the magneto-rheological elastic pad increases, pressure between the abrasive particle in the form of slurry and the wafer also increases so that the polishing process can be performed to the same level without a deflection between the central and the surrounding part of the wafer.
- the equal planarization can significantly reduce not only the failure of the semiconductor device but also the production cost by preventing defective semiconductor wafers from manufacturing.
- FIG. 1 shows a speed distribution according to a wafer radius during the wafer polishing process by a conventional semiconductor wafer polishing apparatus
- FIG. 2 is a schematic diagram showing a pressure distribution according to a wafer radius during the wafer polishing process by the conventional semiconductor wafer polishing apparatus;
- FIG. 3 is a schematic diagram showing a deflection between the central and the surrounding part during the wafer polishing process by the conventional semiconductor wafer polishing apparatus;
- FIG. 4 is a side view of a semiconductor wafer polishing apparatus having a magneto-rheological elastic pad according to one embodiment of the invention
- FIG. 5 is a plane figure of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention.
- FIG. 6 is a side view illustrating an operating mode of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention.
- FIG. 7 is a photograph showing an arrangement of magnetic substances after hardening of the magneto-rheological elastic pad.
- FIG. 4 and 5 are a side view and a plane figure of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention, respectively.
- FIG. 6 and 7 are a side view illustrating an operating mode of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention, and a photograph showing an arrangement of magnetic substances after hardening of the magneto-rheological elastic pad, respectively.
- the semiconductor wafer polishing apparatus includes the magneto-rheological elastic pad 23 received and fixed in a rotating plate 21 , in which the top surface thereof is coated with the abrasive 27 in the form of slurry by an abrasive supply line 25 .
- a magnetic substance is mixed with a solvent and a dispersant.
- the mixture is stirred with an elastic substance after stirring and dispersing in a powerful mixer.
- this mixture is stirred in a solution of polyurethane polyol using a ball mill for about 10 hours. This is allowed for hardening for 24 hours at the temperature of 90° C. ⁇ 110° C. after adding one part of isocyanate. Thereafter the magnetic field of about 1 Tesla is applied until the hardening is completed.
- Change of elastic strength without the application of magnetic field is less than 5%, but this value with the application of magnetic field increases up to 30% ⁇ 50% because dipole is formed between particles due to the arrangement of magnetic substances in a row as shown in FIG. 7 .
- magnetic field by the electromagnet is applied perpendicularly to a surface of urethane.
- the magneto-rheological elastic pad 23 is available when the thickness thereof is in the range of 0.1 mm ⁇ 50 mm, preferably 1 mm ⁇ 10 mm.
- one or a combination of more than two of natural rubber, EPDM, polybutadien, acrylonitrile rubber, synthetic rubber, polyurethane and silicone rubber is used as the elastic substance.
- one of iron, alloy iron, iron oxide such as Fe 2 O 3 , Co doped Fe 2 O 3 and Fe 3 O 4 , iron nitride, iron carbide, nickel, cobalt, chrome dioxide, stainless steel and Fe powder forms the magnetic substance.
- the alloy iron is made by adding aluminum, silicone, cobalt, nickel, vanadium, molybdenum, chromium, tungsten, manganese and/or copper to iron.
- a plurality of electromagnets are arranged in a row, in which more than three electromagnets of odd numbers are arranged in such a way that the center of electromagnet 33 in the middle accords with the central axis 11 a of the wafer holder 11 .
- a controller 40 make a plurality of the electromagnets 31 ⁇ 35 to selectively generate magnetic field at a part or the entire part.
- magnetic field can be applied to each segment by the controller 40 , and field intensity for the magnetic field can be adjusted in real-time.
- the polishing process by adding multi-pressure to the wafer 13 operated with the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to the present invention, in order to flatten the wafer 13 is as follows.
- the current flows at the electromagnets 32 , 33 , 34 , while the current does not flow at the electromagnets 31 , 35 according to the electric signal of the controller 40 as illustrated in FIG. 6 . Therefore, the segments of the magneto-rheological elastic pad 23 corresponding to the electromagnets 32 , 33 , 34 are activated so that they have larger elasticity magnitude than those of the electromagnets 31 , 35 .
- segment pressure of the magneto-rheological elastic pad 23 corresponding to the electromagnets 32 , 33 , 34 is increased so that the polishing speed in the central part of the wafer becomes faster.
- magnetic field applied by the electromagnets 32 , 33 , 34 acts on the corresponding segments of the magneto-rheological elastic pad 23 so that the resulting elastic projection can pressurize the abrasive 27 , thereby the entire surface of the wafer 13 is polished at the same speed.
- this local adjustment for the polishing speed can solve problems of the conventional technologies such as speed distributions and pressure differences according to the wafer radius, thereby it significantly reduce the failure of the semiconductor device.
- the magnetic field is selectively applied to a part or the entire part of the magneto-rheological elastic pad formed by a plurality of segments.
- stiffness of the magneto-rheological elastic pad increases, pressure between the abrasive particle in the form of slurry and the wafer also increases so that the polishing process can be performed to the same level without a deflection between the central and the surrounding part of the wafer.
- the equal planarization can significantly reduce not only the failure of the semiconductor device, but also the production cost by preventing defective semiconductor wafers from manufacturing.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Abstract
Disclosed herein is a semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which the dielectric layer of the wafer fixed in the wafer holder to contact the abrasive coated on a rotating plate is polished. The semiconductor wafer polishing apparatus comprises a magneto-rheological elastic pad formed by a plurality of segments received to be fixed on the rotating plate; a plurality of electromagnets, having equal or larger diameter than that of wafer to selectively pressurize a part or the entire area of the wafer, which is arranged at the lower portion of the rotating plate in such a way that the central part accords with the central axis of the wafer holder; and a controller for selectively generating the magnetic field at a part or the entire part of the electromagnets.
Description
- 1. Field of the Invention
- The present invention relates to a semiconductor polishing apparatus having a magneto-rheological elastic pad. Particularly, the invention relates to a semiconductor polishing apparatus, in which, a plurality of electromagnets are arranged in a row at the lower portion of the magneto-rheological elastic pad to allow each electromagnet to selectively generate magnetic field so that the central and the surrounding part of a wafer dielectric layer contacting with the abrasive can be processed to the same level without a deflection by adjusting pressure according to multi-area of magneto-rheological elastic pad corresponding to the position of each magnetic field, thereby greatly reducing a defect rate of a semiconductor device.
- 2. Background of the Related Art
- In general, a large-scale integrated semiconductor device has a multi-layer structure formed by alternate piling of a circuit pattern layer and a dielectric layer insulating the circuit pattern layer. When the dielectric layer is piled on the circuit layer, irregularities can be made on the dielectric layer according to an indentation of the circuit layer. Therefore, a planarization process is required in manufacturing the large-scale integrated semiconductor device to reduce the indentation. CMP (Chemical Mechanical Planarization) technique for semiconductor wafers is widely used to flatten wafers in manufacturing the large-scale integrated semiconductor.
- The CMP process includes a fixing process of a semiconductor wafer in a wafer holder. A polishing pad and the wafer rotate together in a condition that the wafer contacts with the polishing pad. Normally, the polishing pad is coated with colloid silica of a suspension of SiO2 particles as an abrasive.
- The abrasive has particle sizes in a various range from several nm to several μm. In general, the abrasive is coated in the form of slurry by using a wand which is provided to the wafer holder and the pad.
- In this case, material removal rate from the wafer is a combination of the chemical and the mechanical removal rate. Generally, the mechanical removal rate is proportional to relative speed and pressure of the wafer. The chemical removal rate is a function of slurry particle size and solution pH, which has the maximum removal rate when slurry having about 11.5 pH is used.
- However, when the wafer is polished using a conventional wafer polishing apparatus, the rotating wafer as shown in
FIG. 1 has faster rotational speed in the outer part than the central part, therein there exists a pressure inequality between thewafer 1 and the abrasive pad as shown inFIG. 2 . Theundescribed numeral 3 represents the wafer holder. - In other words, a thickness deflection of the wafer can occur because more materials are polished in the outer part than the central part, as shown in
FIG. 3 . In this case, polishing in the outer part can damage the circuit layer below the dielectric layer. Therefore, the pressure inequality due to the different relative speed between the outer and the central part is critical factor causing the failure of semiconductor devices. - In the conventional technology, pressure is controlled by the replacement of pads having different stiffness. In another technology, pressure of an unflat support below a pad platen is controlled, which has problems that the wafer needs to be mounted in a very accurate way and the control cannot be done in real-time.
- Therefore, the present invention has been made in view of the above problems occurring in the prior art, and it is an object of the present invention to provide a semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which, a plurality of electromagnets are arranged in a row at the lower portion of the magneto-rheological elastic pad to selectively generate a magnetic field for each electromagnet and a multi-area pressure of the magneto-rheological elastic pad corresponding to the magnetic field position is adjusted in such a way that the central and the surrounding part of a dielectric layer of the wafer contacting with the abrasive can be processed to the same level without a deflection, thereby decreasing the failure rate of the semiconductor device.
- To accomplish the above objects, according to the present invention, there is provided the semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which the dielectric layer of the wafer fixed in the wafer holder to contact the abrasive coated on a rotating plate is polished. The apparatus of the invention includes: a magneto-rheological elastic pad formed by a plurality of segments received to be fixed on the rotating plate; a plurality of electromagnets each having equal or larger diameter than that of wafer to selectively pressurize a part or the entire area of the wafer, each electromagnet being arranged at the lower portion of the rotating plate in such a way that its central part accords with the central axis of the wafer holder; and a controller for selectively generating the magnetic field at a part or the entire part of the electromagnets.
- To form the magneto-rheological elastic pad, first, a magnetic substance is mixed with a solvent and a dispersant. The mixture is stirred with an elastic substance after stirring and dispersing in a powerful mixer. Next, this mixture is stirred in a solution of polyurethane polyol using a ball mill for about 10 hours. This is allowed for hardening for 24 hours at the temperature of 90° C.˜110° C. after adding one part of isocyanate, thereafter the magnetic field of about 1 Tesla is applied until the hardening is completed.
- In this case, the elastic substance may one of natural rubber, EPDM, polybutadien, acrylonitrile rubber, synthetic rubber, polyurethane and silicone rubber, or the combinations thereof.
- In addition, the magnetic substance may be one of iron, alloy iron, iron oxide such as Fe2O3, Co doped Fe2O3 and Fe3O4, iron nitride, iron carbide, nickel, cobalt, chrome dioxide, stainless steel and Fe powder.
- Furthermore, the magneto-rheological elastic pad is formed to have a thickness of 0.1 mm˜50 mm, preferably 1 mm˜10 mm.
- In addition, it is preferable that more than three electromagnets of odd numbers are arranged in a row.
- Therefore, in the present invention, the magnetic field is selectively applied to a part or the entire part of the magneto-rheological elastic pad formed by a plurality of segments. As stiffness of the magneto-rheological elastic pad increases, pressure between the abrasive particle in the form of slurry and the wafer also increases so that the polishing process can be performed to the same level without a deflection between the central and the surrounding part of the wafer. The equal planarization can significantly reduce not only the failure of the semiconductor device but also the production cost by preventing defective semiconductor wafers from manufacturing.
- The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:
-
FIG. 1 shows a speed distribution according to a wafer radius during the wafer polishing process by a conventional semiconductor wafer polishing apparatus; -
FIG. 2 is a schematic diagram showing a pressure distribution according to a wafer radius during the wafer polishing process by the conventional semiconductor wafer polishing apparatus; -
FIG. 3 is a schematic diagram showing a deflection between the central and the surrounding part during the wafer polishing process by the conventional semiconductor wafer polishing apparatus; -
FIG. 4 is a side view of a semiconductor wafer polishing apparatus having a magneto-rheological elastic pad according to one embodiment of the invention; -
FIG. 5 is a plane figure of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention; -
FIG. 6 is a side view illustrating an operating mode of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention; and -
FIG. 7 is a photograph showing an arrangement of magnetic substances after hardening of the magneto-rheological elastic pad. - Reference will now made in detail to the preferred embodiment of the present invention with reference to the attached drawings. It is noted that details on the well-known components and their functions will not be described.
-
FIG. 4 and 5 are a side view and a plane figure of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention, respectively. In addition,FIG. 6 and 7 are a side view illustrating an operating mode of the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to one embodiment of the invention, and a photograph showing an arrangement of magnetic substances after hardening of the magneto-rheological elastic pad, respectively. - In the present invention, the semiconductor wafer polishing apparatus includes the magneto-rheological
elastic pad 23 received and fixed in arotating plate 21, in which the top surface thereof is coated with the abrasive 27 in the form of slurry by anabrasive supply line 25. - To form the magneto-rheological
elastic pad 23, first, a magnetic substance is mixed with a solvent and a dispersant. The mixture is stirred with an elastic substance after stirring and dispersing in a powerful mixer. Next, this mixture is stirred in a solution of polyurethane polyol using a ball mill for about 10 hours. This is allowed for hardening for 24 hours at the temperature of 90° C.˜110° C. after adding one part of isocyanate. Thereafter the magnetic field of about 1 Tesla is applied until the hardening is completed. - Change of elastic strength without the application of magnetic field is less than 5%, but this value with the application of magnetic field increases up to 30%˜50% because dipole is formed between particles due to the arrangement of magnetic substances in a row as shown in
FIG. 7 . In this case, magnetic field by the electromagnet is applied perpendicularly to a surface of urethane. - In addition, the magneto-rheological
elastic pad 23 is available when the thickness thereof is in the range of 0.1 mm˜50 mm, preferably 1 mm˜10 mm. - In this case, one or a combination of more than two of natural rubber, EPDM, polybutadien, acrylonitrile rubber, synthetic rubber, polyurethane and silicone rubber is used as the elastic substance. In addition, one of iron, alloy iron, iron oxide such as Fe2O3, Co doped Fe2O3 and Fe3O4, iron nitride, iron carbide, nickel, cobalt, chrome dioxide, stainless steel and Fe powder forms the magnetic substance.
- Furthermore, the alloy iron is made by adding aluminum, silicone, cobalt, nickel, vanadium, molybdenum, chromium, tungsten, manganese and/or copper to iron.
- At the lower portion of the
rotating plate 21, a plurality of electromagnets are arranged in a row, in which more than three electromagnets of odd numbers are arranged in such a way that the center ofelectromagnet 33 in the middle accords with the central axis 11 a of thewafer holder 11. - Therefore, to use a plurality of the
electromagnets 31˜35, having equal or larger diameters than the wafer as shown inFIG. 5 , is desirable in order to pressurize a part or the entire part of thewafer 13 by means of the magneto-rheological pad 23. - In addition, a
controller 40 make a plurality of theelectromagnets 31˜35 to selectively generate magnetic field at a part or the entire part. At this stage, magnetic field can be applied to each segment by thecontroller 40, and field intensity for the magnetic field can be adjusted in real-time. - The polishing process by adding multi-pressure to the
wafer 13, operated with the semiconductor wafer polishing apparatus having the magneto-rheological elastic pad according to the present invention, in order to flatten thewafer 13 is as follows. - First, during the
wafer holder 11 fixing therotating plate 21 and thewafer 13 rotates, the current flows at theelectromagnets electromagnets controller 40 as illustrated inFIG. 6 . Therefore, the segments of the magneto-rheologicalelastic pad 23 corresponding to theelectromagnets electromagnets - Accordingly, segment pressure of the magneto-rheological
elastic pad 23 corresponding to theelectromagnets - Accordingly, magnetic field applied by the
electromagnets elastic pad 23 so that the resulting elastic projection can pressurize the abrasive 27, thereby the entire surface of thewafer 13 is polished at the same speed. - Furthermore, this local adjustment for the polishing speed can solve problems of the conventional technologies such as speed distributions and pressure differences according to the wafer radius, thereby it significantly reduce the failure of the semiconductor device.
- As describe above, in the present invention, the magnetic field is selectively applied to a part or the entire part of the magneto-rheological elastic pad formed by a plurality of segments. As stiffness of the magneto-rheological elastic pad increases, pressure between the abrasive particle in the form of slurry and the wafer also increases so that the polishing process can be performed to the same level without a deflection between the central and the surrounding part of the wafer. The equal planarization can significantly reduce not only the failure of the semiconductor device, but also the production cost by preventing defective semiconductor wafers from manufacturing.
- While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.
Claims (7)
1. A semiconductor wafer polishing apparatus having a magneto-rheological elastic pad, in which the dielectric layer of the wafer fixed in the wafer holder to contact the abrasive coated on a rotating plate is polished, the semiconductor wafer polishing apparatus comprising:
a) a magneto-rheological elastic pad formed by a plurality of segments received to be fixed on the rotating plate;
b) a plurality of electromagnets each having equal or larger diameter than that of wafer to selectively pressurize a part or the entire area of the wafer, each electromagnet being arranged at the lower portion of the rotating plate in such a way that its central part accords with the central axis of the wafer holder; and
c) a controller for selectively generating the magnetic field at a part or the entire part of the electromagnets.
2. The apparatus according to claim 1 , wherein the magneto-rheological elastic pad is formed by the steps of:
a) mixing of a magnetic substance with a solvent and a dispersant;
b) stirring and dispersing the above mixture in a powerful mixer to stir the resultant mixture with an elastic substance;
c) stirring the stirred mixture again in a solution of polyurethane polyol using a ball mill for about 10 hours;
d) adding one part of isocyanate to the stirred mixture to harden the resultant mixture for 24 hours at the temperature of 90° C.˜110° C.; and
e) applying magnetic field of about 1 Tesla to the resultant mixture until the hardening is completed.
3. The apparatus according to claim 2 , wherein the elastic substance is one selected from the group consisting of natural rubber, EPDM, polybutadien, acrylonitrile rubber, synthetic rubber, polyurethane, silicone rubber, and combinations thereof.
4. The apparatus according to claim 2 , wherein the magnetic substance is one selected from the group consisting of iron, alloy iron, iron oxide, iron nitride, iron carbide, nickel, cobalt, chrome dioxide, stainless steel and Fe powder.
5. The apparatus according to claim 4 , wherein the iron oxide is one selected from the group consisting of Fe2O3, Co doped Fe2O3 and Fe3O4.
6. The apparatus according to claim 2 , wherein the magneto-rheological elastic pad has a thickness of 0.1 mm˜50 mm.
7. The apparatus according to claim 1 , wherein more than three electromagnets having odd numbers are arranged in a row.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR10-2005-37745 | 2005-05-04 | ||
KR1020050037745A KR100646451B1 (en) | 2005-05-04 | 2005-05-04 | Semiconductoo Waper Abrasive Apparatus Having A Elaotic Pad |
Publications (1)
Publication Number | Publication Date |
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US20060252349A1 true US20060252349A1 (en) | 2006-11-09 |
Family
ID=37394585
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/197,715 Abandoned US20060252349A1 (en) | 2005-05-04 | 2005-08-05 | Semiconductor wafer polishing apparatus having magneto-rhelogical elastic pad |
Country Status (2)
Country | Link |
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US (1) | US20060252349A1 (en) |
KR (1) | KR100646451B1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103302604A (en) * | 2013-06-25 | 2013-09-18 | 中国科学院光电技术研究所 | Polishing grinding disc for inhibiting full-band errors of optical surface |
CN103692294A (en) * | 2013-11-11 | 2014-04-02 | 中国科学院上海光学精密机械研究所 | Ultrahigh precision processing method for meter-scale optical element |
US20140273766A1 (en) * | 2013-03-15 | 2014-09-18 | Applied Materials, Inc. | Polishing System with Front Side Pressure Control |
CN109986416A (en) * | 2019-03-12 | 2019-07-09 | 湘潭大学 | A kind of uniform profile copy grinding device of free form surface and method for grinding |
CN114800253A (en) * | 2022-06-06 | 2022-07-29 | 浙江大学杭州国际科创中心 | Grinding device and method for silicon carbide wafer |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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KR101974727B1 (en) * | 2017-07-20 | 2019-05-02 | 인하대학교 산학협력단 | Pick-and-place apparatus |
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Publication number | Priority date | Publication date | Assignee | Title |
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US20140273766A1 (en) * | 2013-03-15 | 2014-09-18 | Applied Materials, Inc. | Polishing System with Front Side Pressure Control |
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CN103692294A (en) * | 2013-11-11 | 2014-04-02 | 中国科学院上海光学精密机械研究所 | Ultrahigh precision processing method for meter-scale optical element |
CN109986416A (en) * | 2019-03-12 | 2019-07-09 | 湘潭大学 | A kind of uniform profile copy grinding device of free form surface and method for grinding |
CN114800253A (en) * | 2022-06-06 | 2022-07-29 | 浙江大学杭州国际科创中心 | Grinding device and method for silicon carbide wafer |
Also Published As
Publication number | Publication date |
---|---|
KR20060115275A (en) | 2006-11-08 |
KR100646451B1 (en) | 2006-11-14 |
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