CN116564848A - Supercritical fluid cleaning system and cleaning method - Google Patents
Supercritical fluid cleaning system and cleaning method Download PDFInfo
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- CN116564848A CN116564848A CN202210106871.6A CN202210106871A CN116564848A CN 116564848 A CN116564848 A CN 116564848A CN 202210106871 A CN202210106871 A CN 202210106871A CN 116564848 A CN116564848 A CN 116564848A
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- 238000004140 cleaning Methods 0.000 title claims abstract description 293
- 239000012530 fluid Substances 0.000 title claims abstract description 207
- 238000000034 method Methods 0.000 title claims abstract description 35
- 239000007788 liquid Substances 0.000 claims abstract description 44
- 230000009471 action Effects 0.000 claims abstract description 9
- 238000010438 heat treatment Methods 0.000 claims description 49
- 238000001816 cooling Methods 0.000 claims description 34
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 18
- 238000004891 communication Methods 0.000 claims description 13
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 9
- 239000001569 carbon dioxide Substances 0.000 claims description 9
- 230000006835 compression Effects 0.000 claims description 5
- 238000007906 compression Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 abstract description 15
- 230000010355 oscillation Effects 0.000 abstract description 9
- 238000004090 dissolution Methods 0.000 abstract description 6
- 235000012431 wafers Nutrition 0.000 description 31
- 238000005406 washing Methods 0.000 description 15
- 230000008859 change Effects 0.000 description 11
- 238000001035 drying Methods 0.000 description 11
- 230000001502 supplementing effect Effects 0.000 description 8
- 230000009467 reduction Effects 0.000 description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000003749 cleanliness Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002301 combined effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229940095676 wafer product Drugs 0.000 description 1
Classifications
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- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
- H01L21/67057—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing with the semiconductor substrates being dipped in baths or vessels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B13/00—Accessories or details of general applicability for machines or apparatus for cleaning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
-
- 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
-
- 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
- H01L21/02041—Cleaning
- H01L21/02101—Cleaning only involving supercritical fluids
-
- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
-
- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/67034—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for drying
-
- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67242—Apparatus for monitoring, sorting or marking
- H01L21/67253—Process monitoring, e.g. flow or thickness monitoring
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Cleaning By Liquid Or Steam (AREA)
- Cleaning Or Drying Semiconductors (AREA)
Abstract
The invention provides a supercritical fluid cleaning system and a cleaning method, wherein the system comprises the following steps: the device comprises a cleaning cavity and a supercritical cleaning fluid supply device, wherein the cleaning cavity is used for accommodating a sample to be cleaned, and the surface of the sample is at least partially adhered with liquid to be cleaned; the supercritical cleaning fluid supply device supplies cleaning fluid required by cleaning and drives the cleaning fluid to enter the cleaning cavity in a mode that the pressure is increased and higher than the supercritical pressure, the temperature is increased and higher than the supercritical temperature, and the sample to be cleaned is oscillated and cleaned under the action of the fluctuation pressure; and driving the supercritical cleaning fluid to flow out of the cleaning chamber in such a manner that the pressure drop is not lower than the supercritical pressure. According to the invention, the pressure of the cleaning fluid is changed, so that the cleaning fluid is used for carrying out oscillation cleaning on the sample to be cleaned in a pressure fluctuation mode, the dissolution speed of the supercritical cleaning fluid on the liquid to be cleaned is improved in the pressurizing process, the liquid to be cleaned can be brought out in the depressurizing process, the cleaning efficiency is improved, and the method is suitable for cleaning a large quantity of samples to be cleaned.
Description
Technical Field
The invention relates to the technical field of cleaning devices, in particular to a supercritical fluid cleaning system and a supercritical fluid cleaning method.
Background
Semiconductor wafers are one of the most important materials in the semiconductor industry, and have high demands on their surface cleanliness. In the semiconductor wafer cleaning process, the wafer surface drying treatment is an indispensable link, because a small amount of liquid (usually water) still exists on the wafer surface after the wafer cleaning process is completed, the drying purpose is to remove the liquid on the wafer surface, prevent the wafer surface from recontamination or occurrence of defects such as water mark, etc., influence the performance of the wafer, and reduce the yield of the wafer.
At present, many drying techniques for the wafer surface have been developed, mainly spin-drying techniques, marangoni drying techniques, and isopropyl alcohol (Isopropyl alcohol, IPA) drying techniques. For batch cleaning wafers, mainly using the IPA drying method, the wafer needs to be immersed in IPA liquid before drying, and water on the wafer surface is dissolved into IPA due to mutual solubility, and instead liquid IPA is used. IPA leaves the wafer surface through multiple actions such as gravity, surface tension, volatilization and the like, so that the purpose of drying the wafer surface is achieved.
In the field of wafer cleaning, as the semiconductor process node is further reduced and the aspect ratio of the pattern is increasingly larger, the IPA breaks the pattern structure of the wafer due to the action of surface tension in the process of leaving the surface of the wafer, and even the structure is adhered, collapsed and the like, so that the wafer product is invalid.
The existing method for processing the residual IPA on the surface of the wafer is to slowly dissolve the IPA on the surface of the wafer by adopting supercritical carbon dioxide fluid with almost 0 surface tension, finally replace the IPA on the surface of the wafer with the supercritical carbon dioxide fluid, and finally leave the supercritical carbon dioxide fluid on the surface of the wafer by evaporating through cooling and depressurization. However, the method is limited by the dissolution rate of IPA in supercritical carbon dioxide, and cannot be used for drying batch wafers in a short time, so that the drying efficiency is low.
Disclosure of Invention
In order to solve the problems, the invention provides a supercritical fluid cleaning system and a cleaning method, wherein the pressure of cleaning fluid is changed by pressurizing or depressurizing, so that the cleaning fluid can be cleaned in an oscillating manner, the dissolving speed of the supercritical cleaning fluid to the cleaned liquid is improved in the pressurizing process, the cleaned liquid can be brought out in the depressurizing process, the cleaning efficiency is improved, and the supercritical fluid cleaning system is suitable for batch cleaning of samples to be cleaned.
The present invention provides a supercritical fluid cleaning system comprising: the device comprises a cleaning cavity and a supercritical cleaning fluid supply device, wherein the cleaning cavity is used for accommodating a sample to be cleaned, and the surface of the sample is at least partially adhered with liquid to be cleaned; the supercritical cleaning fluid supply device supplies cleaning fluid required by cleaning and drives the cleaning fluid to enter the cleaning cavity in a mode that the pressure is increased and higher than the supercritical pressure, the temperature is increased and higher than the supercritical temperature, and the sample to be cleaned is oscillated and cleaned under the action of the fluctuation pressure; and driving the supercritical cleaning fluid to flow out of the cleaning chamber in such a manner that the pressure drop is not lower than the supercritical pressure.
According to the invention, the pressure of the cleaning fluid is changed, so that the cleaning fluid is used for carrying out oscillation cleaning on the sample to be cleaned in a pressure fluctuation mode, the dissolution speed of the supercritical cleaning fluid to the liquid to be cleaned is improved in the pressurizing process, the liquid to be cleaned can be brought out in the depressurizing process, the cleaning efficiency is improved, and the method is suitable for cleaning a large quantity of samples to be cleaned.
In an alternative technical scheme of the invention, the supercritical cleaning fluid supply device comprises a cavity, a heating device and a cooling device, wherein an outlet of the cavity is communicated with an inlet of the heating device, an outlet of the heating device is communicated with an inlet of the cleaning cavity, an outlet of the cleaning cavity is communicated with an outlet of the cooling device, and an outlet of the cooling device is communicated with an inlet of the cavity;
the cavity is used for containing cleaning fluid, a piston is arranged in the cavity, one side of the piston is connected with the driving device, one side of the piston, which is far away from the driving device, and the inner wall of the cavity are surrounded to form a space occupied by the cleaning fluid, and the driving device drives the piston to move along the inner wall of the cavity to raise or lower the pressure of the cleaning fluid;
the heating device is used for heating the cleaning fluid to form supercritical cleaning fluid;
the cooling device is used for cooling the supercritical cleaning fluid which flows out of the cleaning cavity and is dissolved with the liquid to be cleaned.
In an alternative technical scheme of the invention, the device further comprises a separator for separating the cleaning fluid and the cleaned fluid, the separator comprises a first interface, a second interface and a third interface, the cavity is provided with a first inlet and a first outlet, the first inlet and the first outlet are respectively positioned at two ends of the cavity, the first inlet is relatively far away from the piston, the first outlet is relatively close to the piston, the first interface is communicated with the first outlet through a first pipeline, the second interface is communicated with the first inlet through a second pipeline, and the third interface is a discharge port; the first pipeline is provided with a first one-way valve, the second pipeline is provided with a second one-way valve, the first one-way valve controls the one-way flow of fluid from the cavity to the separator, and the second one-way valve controls the one-way flow of cleaning fluid from the separator to the cavity; the separator is in communication with the space occupied by the cleaning fluid when the piston is located on a side of the first outlet remote from the first inlet, and is not in communication with the space occupied by the cleaning fluid when the piston is located between the first inlet and the first outlet.
According to the technical scheme, the separator is connected with the cavity through the two pipelines, and the flow direction of fluid is controlled through the first one-way valve and the second one-way valve, so that the cyclic utilization of cleaning fluid is realized, the convenience and the controllability are realized, and the structure of the supercritical fluid cleaning system is simplified; the separator and the fluid occupy space to be communicated or not communicated by changing the position of the piston, so that the structure is simple, the operation is convenient, and the system structure is simplified.
In an alternative technical scheme of the invention, the cleaning device further comprises a third one-way valve arranged between the cavity and the heating device, a fourth one-way valve arranged between the heating device and the cleaning cavity and a fifth one-way valve arranged between the cooling device and the cavity.
According to this technical scheme, the setting of check valve can prevent that liquid from flowing backward, influences the cleaning performance.
In an alternative technical scheme of the invention, the device further comprises a cleaning fluid supplementing pipeline, an outlet of the cleaning fluid supplementing pipeline is communicated with a pipeline between an outlet of the cavity and an inlet of the heating device, and the cleaning fluid supplementing pipeline is further provided with a switch valve.
According to the technical scheme, the cleaning fluid supplementing pipeline is simple in structure, and fluid can be supplemented into the fluid supply device according to requirements, so that the cleaning fluid quantity required by cleaning is met.
In an alternative technical scheme of the invention, the driving device is an electric driving rod or a flywheel in a Stirling cycle system, and the flywheel is in driving connection with the piston through a connecting rod.
According to the technical scheme, the electric driving rod is adopted to drive the piston to change the volume of the cavity, the operation is simple and easy, and the working efficiency of the cleaning system is improved by electric driving. The flywheel in the Stirling cycle system is used for driving the piston to change the volume of the cavity through the connecting rod, and a power source for the piston to move in the cavity is not required to be additionally arranged, and only a certain external heat source is required.
In an alternative embodiment of the present invention, the supercritical cleaning fluid supply apparatus is one or more.
According to the technical scheme, one cleaning cavity can be provided with the supercritical fluid supply device, so that oscillation cleaning in different pressure fluctuation ranges is realized, the applicability of a cleaning system to different supercritical cleaning fluids and to the cleaned liquid is improved, and the cleaning efficiency is improved.
In an alternative technical scheme of the invention, the supercritical cleaning fluid supply device comprises an expansion cavity, a heating device, a heat regenerator, a cooling device and a compression cavity which are sequentially connected to form a Stirling cycle, wherein an inlet of the cleaning cavity is connected to a pipeline between an outlet of the heater and the heat regenerator, and an outlet of the cleaning cavity is connected to a pipeline between the heat regenerator and the cooling device.
In an alternative embodiment of the present invention, the cleaning fluid is carbon dioxide and the sample to be cleaned is a wafer.
According to the technical scheme, supercritical carbon dioxide with almost 0 surface tension is used as cleaning fluid, and the wafer is cleaned by combining oscillation caused by pressure fluctuation, so that the defects of low IPA dissolution efficiency and easy damage of a wafer structure in the conventional wafer cleaning can be overcome.
The invention also provides a cleaning method of the supercritical fluid system, which comprises the following steps:
pressurizing: driving the cleaning fluid to flow out and enter the cleaning cavity in a mode that the pressure is increased and is higher than the supercritical pressure;
and a heating step: heating the cleaning fluid to form a supercritical cleaning fluid;
and (3) cleaning: the supercritical cleaning fluid oscillates and cleans the sample to be cleaned under the action of the fluctuation pressure;
step of depressurization: driving the supercritical cleaning fluid in which the liquid to be cleaned is dissolved to flow out of the cleaning chamber in such a manner that the pressure drops not lower than the supercritical pressure thereof;
and (3) a cooling step: the supercritical cleaning fluid in which the liquid to be cleaned is dissolved is cooled to obtain the liquid to be cleaned and the cleaning fluid.
Drawings
Fig. 1 is a schematic structural view of a supercritical fluid cleaning system according to a first embodiment of the present invention.
Fig. 2 is a schematic diagram of a first pressure variation rule according to the first embodiment of the present invention.
Fig. 3 is a schematic diagram of a second pressure variation rule according to the first embodiment of the present invention.
Fig. 4 is a schematic diagram of a third pressure variation rule according to the first embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a supercritical fluid cleaning system according to a second embodiment of the present invention.
Fig. 6 is a schematic diagram of a pressure change rule according to a second embodiment of the present invention.
Reference numerals:
a cavity 1; a first outlet 11; a first inlet 12; a piston 13; an electric drive lever 14; a heating device 2; a cleaning chamber 3; a cooling device 4; a separator 5; a first interface 51; a second interface 52; a third interface 53; a first check valve 61; a second check valve 62; a third check valve 63; a fourth check valve 64; a fifth check valve 65; a sixth check valve 66; a seventh check valve 67; a cleaning fluid replenishment line 71; an expansion chamber 81; a regenerator 82; compressing the chamber 83.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
[ first embodiment ]
The present invention provides a supercritical fluid cleaning system comprising: one or more medium circulation loops, each medium circulation loop comprises a cavity 1, a heating device 2, a cleaning cavity 3 and a cooling device 4 which are sequentially connected through pipelines; the heating device 2 is used for heating the cleaning fluid to form supercritical cleaning fluid; the cleaning cavity 3 is used for accommodating a sample to be cleaned (not shown in the figure) with a cleaning liquid attached to at least part of the surface and a supercritical cleaning fluid, and the supercritical cleaning fluid is used for oscillating and cleaning the sample to be cleaned under the action of the fluctuation pressure; the cooling device 4 is used for cooling the supercritical cleaning fluid which flows out of the cleaning cavity 3 and is dissolved with the liquid to be cleaned; the cavity 1 is internally provided with a piston 13, one side of the piston 13 is connected with a driving device, one side of the piston 13 away from the driving device and the inner wall of the cavity 1 enclose a space occupied by cleaning fluid, and an electric driving rod 14 drives the piston 13 to move along the inner wall of the cavity 1 to change the size of the space occupied by the cleaning fluid, so that the pressure of the cleaning fluid is increased or reduced.
According to the invention, the pressure of the cleaning fluid is changed by changing the space occupied by the cleaning fluid in the cavity 1, so that the driving force of the cleaning fluid flowing is provided, the cleaning fluid is enabled to perform oscillation cleaning on a sample to be cleaned in a pressure fluctuation mode, the dissolution speed of the supercritical cleaning fluid to the liquid to be cleaned is improved in the pressurizing process, the liquid to be cleaned can be brought out in the depressurizing process, the cleaning efficiency is improved, and the method is suitable for cleaning a large number of samples to be cleaned.
Specifically, in the embodiment of the invention, before the cleaning fluid enters the medium circulation loop, heating pretreatment is not needed, so that the system structure of the front end of the cavity 1 is simplified; compared with the heating of the cleaning fluid before entering the medium circulation loop, the heating device 2 is arranged on a pipeline between the outlet of the cavity 1 and the inlet of the cleaning cavity 3, and can be matched with the cooling device 4 to realize the circulation process of boosting, heating, cleaning, reducing pressure and cooling the cleaning fluid, thereby realizing the cleaning of the sample to be cleaned by multiple oscillation; further, the heating device 2 heats the cleaning fluid at the outlet of the cavity 1, and the heating device 2 is provided with an automatic temperature control device (not shown in the figure) to control the temperature of the cleaning fluid in the heating device 2 to be near the set temperature, so that the cleaning cavity 3 is kept at a constant temperature. In the embodiment of the invention, the pressure of the system (the pressure in the system is the same everywhere) is not lower than the supercritical pressure of the cleaning fluid, the pressure increase and the pressure decrease are carried out on the basis of not lower than the supercritical pressure, and the temperature in the cleaning cavity 3 is not lower than the supercritical temperature of the cleaning fluid; by heating the washing chamber 3, the temperature in the washing chamber 3 can be kept not lower than the supercritical temperature of the washing fluid, by providing a pressure sensor in the washing chamber 3, monitoring the pressure in the washing chamber 3, the control module can be configured to increase the overall system pressure by supplementing the washing fluid via the supplementing line 71 when the lowest pressure in the washing chamber 3 is lower than the supercritical pressure of the washing fluid.
In a preferred embodiment of the invention, the drive means is an electric drive rod 14 or a flywheel (not shown) in the Stirling cycle system, which flywheel is connected to the piston 13 by means of a connecting rod. The electric driving rod 14 is adopted to drive the piston to change the volume of the cavity 1, so that the cleaning system is simple and easy to operate, and the working efficiency of the cleaning system is improved by electric driving; the flywheel in the Stirling cycle system is used for driving the piston to change the volume of the cavity through the connecting rod, a power source for the piston to move in the cavity 1 is not required to be additionally arranged, only a certain external heat source (namely a heating device) is required, the heating device 2 can be in the forms of electric heating, solar heating and the like, and the heating mode is not limited.
Specifically, as shown in fig. 2, by changing the space occupied by the cleaning fluid in the cavity 1, the pressure fluctuation rule of the cleaning fluid in the cavity 1 is shown as 2, and the interval P1-P2 of the pressure fluctuation should be above the supercritical pressure of the cleaning fluid; in the time period of t1-t2, increasing the space occupied by the cleaning fluid to realize depressurization, in the time period of t2-t3, reducing the space occupied by the cleaning fluid to realize pressure increase, and completing a cycle after pressure increase and pressure decrease, wherein the time length of pressure increase and the time length of pressure decrease can be the same or different, the pressure can be adjusted according to actual needs, and the pressure fluctuates between P1 and P2; as shown in fig. 3, the pressure fluctuation law includes pressure maintaining, namely, pressure maintaining is performed for a period of time when the pressure is increased to reach the preset pressure, pressure maintaining is performed for a period of time when the pressure is decreased to reach the preset pressure, and one cycle is completed after the system is subjected to pressure increasing, pressure maintaining, pressure reducing and pressure maintaining; in the pressure maintaining mode, the position of the piston 13 is unchanged, the pressure of the system is unchanged, the supercritical cleaning fluid is more mutually dissolved with the cleaned fluid, and when the pressure is reduced, more cleaned fluid can be brought out, so that the cleaning efficiency is improved. The purpose of the constant pressure is to make the supercritical cleaning fluid and the liquid to be cleaned dissolve more mutually, as shown in fig. 4, the pressure fluctuation rule may be that pressure is maintained when the pressure is increased or reduced to reach a specified pressure, the system completes a cycle through pressure increase, pressure maintaining and pressure reduction, although not shown, the pressure fluctuation rule may also complete a cycle after pressure increase, pressure reduction and pressure maintaining, where in a cycle, the time sequence of pressure increase and pressure reduction is not limited, the pressure can be increased first, then reduced, also reduced first, then increased, and the technician can adjust the change rule of the pressure according to the actual situation, which is not limited by the example of the embodiment of the present invention. Although the pressure increase and the pressure decrease are linearly increased or linearly decreased in fig. 2, 3 and 4, the pressure change curve is not limited to this, and may be a sine function or a cosine function, or may be changed in other manners.
In a preferred embodiment of the present invention, the supercritical fluid cleaning system further comprises one or more separators 5, the separators 5 being connected to the chamber 1, the separators 5 being for separating the cleaning fluid and the liquid to be cleaned flowing out from the cleaning chamber 3; as the space occupied by the cleaning fluid increases, the separator 5 communicates with the space occupied by the cleaning fluid; when the space occupied by the cleaning fluid is reduced, the separator 5 is not in communication with the space occupied by the cleaning fluid. Further, according to the different states of the cleaning fluid after being cooled and returned to the cavity 1, the cleaning fluid can be a gas-liquid separator or a liquid-liquid separation device, etc., the structure of the gas-liquid separator and the structure of the liquid-liquid separator can refer to the conventional method in the prior art, and the cleaning fluid is not repeated here, so that the separated cleaning fluid can be reused, and the cleaning cost is saved; the fluid separated from the liquid to be cleaned is recycled in the system, so that the cleanliness of the cleaning fluid is improved, and the cleaning fluid polluted by the liquid to be cleaned is prevented from being used for cleaning the sample to be cleaned; the cleaning fluid is cleaned in a circulating mode, so that the continuity and repeatability of sample oscillation cleaning are realized, and the cleaning efficiency is improved.
Specifically, each separator 5 includes a first interface 51, a second interface 52 and a third interface 53, a first inlet 12 and a first outlet 11 are disposed on the cavity 1, the first inlet 12 and the first outlet 11 are respectively located at two ends of the cavity 1, the first inlet 12 is relatively far away from the piston 13, the first outlet 11 is relatively close to the piston 13, the first interface 51 is communicated with the first outlet 11 through a first pipeline, the second interface 52 is communicated with the first inlet 12 through a second pipeline, the third interface 53 is a discharge port, a first check valve 61 is disposed on the first pipeline, a second check valve is disposed on the second pipeline, the first check valve 61 controls unidirectional flow of fluid from the cavity 1 to the separator 5, and the second check valve 62 controls unidirectional flow of cleaning fluid from the separator 5 to the cavity 1; by moving the piston 13 in the direction of the first outlet 11, when the piston 13 is located on the side of the first outlet 11 remote from the first inlet (on the left side of the piston 13 in the figure), the separator 5 communicates with the space occupied by the washing fluid, and at this time the space occupied by the washing fluid increases and the pressure decreases; by moving the piston 13 in the direction of the first inlet 12, the separator 5 is not in communication with the space occupied by the washing fluid when the piston 13 is located between the first inlet 12 and the first outlet 11. In the embodiment of the invention, the separator 5 is connected with the cavity 1 through two pipelines, and controls the fluid to flow unidirectionally through the first check valve 61 and the second check valve 62, so that the recycling of the cleaning fluid is realized, the convenience and the controllability are realized, and the structure of the supercritical fluid cleaning system is simplified; and the separator 5 is controlled to be communicated or not communicated with the space occupied by the cleaning fluid by moving the piston 13, so that a switching valve is omitted, the system structure is simplified, and the cost is saved.
In a preferred embodiment of the invention, two or more medium circulation circuits share a single washing chamber 3. Namely, one cleaning cavity 3 can be provided with two or more medium circulation loops, so that oscillation cleaning in different pressure fluctuation ranges is realized, and the cleaning efficiency and the cleaning effect are improved; the medium circulation loop at least comprises a cavity body 1, a heating device 2, a cleaning cavity 3 and a cooling device 4 which are sequentially communicated; as shown in fig. 1, a cleaning chamber 3 is provided with 2 medium circulation loops, including two chambers 1 and two pistons 13, and when the system includes multiple medium circulation loops, the range and rate of pressure change of the system are determined by the scavenge volumes, phase differences (0-180 °) of the pistons 13 and the speed of movement of the pistons 13 in the multiple chambers 1, so that a technician can adjust parameters such as scavenge volumes, phase differences, and movement speeds of the pistons 13 according to practical situations, which are not limited by the embodiment of the present invention.
In a preferred embodiment of the present invention, the cleaning fluid supplying pipe 71 is further included, an outlet of the cleaning fluid supplying pipe 71 is communicated with a pipe between an outlet of the cavity 1 and an inlet of the heating device 2, and an on-off valve is further provided on the cleaning fluid supplying pipe 71.
According to the technical scheme, the cleaning fluid can be supplemented into the cavity 1 according to the requirement, so that the cleaning fluid quantity required by cleaning is met; compared with the method of directly supplementing the supercritical cleaning fluid into the cleaning cavity 3, the cleaning fluid supplementing pipeline 71 is arranged before the heating device 2, so that the cleaning fluid is sent into the cleaning cavity 3 after being heated, the temperature and the pressure of the supercritical cleaning fluid in the cleaning cavity 3 can be ensured to be consistent with the temperature and the pressure of the supercritical cleaning fluid at the outlet of the heating device, and the structure of the system is facilitated to be simplified.
In a preferred embodiment of the invention, a third one-way valve 63 is provided between the chamber 1 and the heating device 2, a fourth one-way valve 64 is provided between the heating device 2 and the washing chamber 3, and a fifth one-way valve 65 is provided between the cooling device 4 and the chamber 1. Through the mode, liquid backflow can be prevented, and the cleaning effect is affected.
In a preferred embodiment of the invention, the cleaning fluid is carbon dioxide and the sample to be cleaned is a wafer. The supercritical fluid cleaning system of the embodiment of the invention can be used for cleaning the wafer, adopts supercritical carbon dioxide with almost 0 surface tension as cleaning fluid, and solves the defects of low IPA dissolution efficiency and easy damage of the wafer structure in the existing wafer cleaning by combining oscillation caused by pressure fluctuation. Although the present invention gives the above examples, it does not constitute a limitation on the type of washing fluid and the type of sample to be washed, and a skilled person can select different washing fluids and wash different samples according to actual requirements.
The invention also provides a working method of the supercritical fluid cleaning system, which comprises the following steps:
pressurizing: driving the cleaning fluid to flow out of the cavity 1 in a manner that the pressure is increased and is higher than the supercritical pressure;
and a heating step: heating the pressurized cleaning fluid to form supercritical cleaning fluid, wherein the supercritical cleaning fluid enters the cleaning cavity 3 under fluctuating pressure;
and (3) cleaning: the supercritical cleaning fluid oscillates and cleans the sample to be cleaned under the action of the fluctuation pressure;
step of depressurization: driving the supercritical cleaning fluid in which the liquid to be cleaned is dissolved to flow out of the cleaning chamber 3 in such a manner that the pressure drops not lower than the supercritical pressure;
and (3) a cooling step: the supercritical cleaning fluid in which the liquid to be cleaned is dissolved is cooled to obtain the liquid to be cleaned and the cleaning fluid.
In a preferred embodiment of the present invention, the method further comprises a step of separating the liquid to be cleaned from the cleaning fluid: the position of the piston 13 is adjusted such that the piston 13 is located to the left of the first outlet, thereby communicating the space occupied by the cleaning fluid with the separator 5, the cleaning fluid and the liquid to be cleaned in the cleaning chamber 3 enter the separator 5 via the first outlet 11, the liquid to be cleaned is discharged from the discharge outlet, and the cleaning fluid flows into the chamber 1 via the first inlet 12.
[ second embodiment ]
A second embodiment of the present invention provides a supercritical fluid cleaning system, which is different from the first embodiment in that in the first embodiment, the reason for the pressure reduction of the system is the combined effect of the volume increase occupied by the cleaning fluid in the cavity and the temperature reduction, and in the second embodiment, the volume of the system is unchanged, the pressure reduction is mainly caused by the temperature reduction, and the circulating cleaning can be realized only by an external heat source without a power source. The change rule of the pressure in the second embodiment of the present invention is shown in fig. 6, and is substantially the same as the change trend of the pressure in the first embodiment, and will not be described herein.
Specifically, the supercritical cleaning fluid supply device includes an expansion chamber 81, a heating device 2, a regenerator 82, a cooling device 4, and a compression chamber 83 sequentially connected to form a stirling cycle, an inlet of the cleaning chamber 3 is connected to a pipeline between an outlet of the heater 2 and the regenerator 82, and an outlet of the cleaning chamber 3 is connected to a pipeline between the regenerator 82 and the cooling device 4. Further, a sixth check valve 66 is provided on the inlet pipe of the cleaning chamber 3, a seventh check valve 67 is provided on the outlet pipe of the cleaning chamber 3, the sixth check valve 66 controls the unidirectional flow of the cleaning fluid from the heating device 2 to the cleaning chamber 3, and the seventh check valve 67 controls the unidirectional flow of the cleaning fluid from the cleaning chamber 3 to the cooling device 4.
In the second embodiment of the present invention, the cleaning device further comprises a separator 5, wherein the first interface and the second interface of the separator 5 are communicated with the pipeline between the cooling device 4 and the compression cavity 83 through pipelines, and the first check valve 61 and the second check valve 62 are respectively arranged on the pipelines corresponding to the first interface and the second interface, so that the cleaning fluid dissolved with the liquid to be cleaned is prevented from entering the compression cavity 83 without passing through the separator.
In a preferred embodiment of the present invention, the stirling cycle system has an α, β or γ type structure, and may be of a single-action type or a multi-action type.
Taking a coupling system of an alpha Stirling cycle system and a cleaning cavity as an example, a cleaning method according to a second embodiment of the present invention comprises: in the constant volume heating process of the Stirling cycle, the left piston and the right piston synchronously move left, the low-temperature cleaning fluid is heated and heated in the heat regenerator 82 to be boosted to form supercritical cleaning fluid, and a part of supercritical cleaning fluid enters the cleaning cavity 3; in the isovolumetric cooling process of the Stirling cycle, the left piston and the right piston synchronously move right, supercritical cleaning fluid flows out of the cleaning cavity 3 and enters the cooling device 4, the temperature of the supercritical cleaning fluid is reduced, the pressure is reduced, and the pressure fluctuation rule in the whole cycle process is shown in figure 6. During this operation, the volume ratio of the two piston cylinders and the phase difference of the two pistons can be designed to adjust the range of pressure fluctuation.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. A supercritical fluid cleaning system, comprising: the device comprises a cleaning cavity and a supercritical cleaning fluid supply device, wherein the cleaning cavity is used for accommodating a sample to be cleaned, the surface of which is at least partially adhered with liquid to be cleaned; the supercritical cleaning fluid supply device supplies cleaning fluid required by cleaning and drives the cleaning fluid to enter the cleaning cavity in a mode of increasing pressure and being higher than supercritical pressure and increasing temperature and being higher than supercritical temperature, and the sample to be cleaned is cleaned in an oscillating mode under the action of the fluctuation pressure; and driving the supercritical cleaning fluid to flow out of the cleaning chamber in such a manner that the pressure drop is not lower than the supercritical pressure.
2. The supercritical fluid cleaning system of claim 1, wherein the supercritical fluid supply apparatus comprises a chamber, a heating apparatus, and a cooling apparatus, an outlet of the chamber being in communication with an inlet of the heating apparatus, an outlet of the heating apparatus being in communication with an inlet of the cleaning chamber, an outlet of the cleaning chamber being in communication with an outlet of the cooling apparatus, an outlet of the cooling apparatus being in communication with an inlet of the chamber;
the cavity is used for containing cleaning fluid, a piston is arranged in the cavity, one side of the piston is connected with a driving device, one side of the piston, which is far away from the driving device, and the inner wall of the cavity are surrounded to form a space occupied by the cleaning fluid, and the driving device drives the piston to move along the inner wall of the cavity to raise or lower the pressure of the cleaning fluid;
the heating device is used for heating the cleaning fluid to form supercritical cleaning fluid;
the cooling device is used for cooling the supercritical cleaning fluid which flows out of the cleaning cavity and is dissolved with the liquid to be cleaned.
3. The supercritical fluid cleaning system according to claim 2, further comprising a separator for separating the cleaning fluid and the liquid to be cleaned, the separator comprising a first port, a second port and a third port, the chamber being provided with a first inlet and a first outlet, the first inlet and the first outlet being located at two ends of the chamber, respectively, and the first inlet being located relatively far from the piston, the first outlet being relatively close to the piston, the first port being in communication with the first outlet via a first conduit, the second port being in communication with the first inlet via a second conduit, the third port being a discharge port; the first pipeline is provided with a first one-way valve, the second pipeline is provided with a second one-way valve, the first one-way valve controls the one-way flow of fluid from the cavity to the separator, and the second one-way valve controls the one-way flow of cleaning fluid from the separator to the cavity; the separator is in communication with the space occupied by the cleaning fluid when the piston is located on a side of the first outlet remote from the first inlet, and is not in communication with the space occupied by the cleaning fluid when the piston is located between the first inlet and the first outlet.
4. The supercritical fluid cleaning system of claim 3, further comprising a third one-way valve disposed between the cavity and the heating device, a fourth one-way valve disposed between the heating device and the cleaning cavity, and a fifth one-way valve disposed between the cooling device and the cavity.
5. The supercritical fluid cleaning system of claim 2, further comprising a cleaning fluid replenishment line, an outlet of the cleaning fluid replenishment line in communication with a line between the outlet of the chamber and the inlet of the heating device, the cleaning fluid replenishment line further provided with an on-off valve.
6. The supercritical fluid cleaning system of any one of claims 2 to 5, wherein the drive means is an electrically driven rod or the drive means is a flywheel in a stirling cycle system, the flywheel being drivingly connected to the piston by a connecting rod.
7. The supercritical fluid cleaning system of any one of claims 2 to 5, wherein the supercritical cleaning fluid supply apparatus is one or more.
8. The supercritical fluid cleaning system of claim 1, wherein the supercritical cleaning fluid supply apparatus comprises an expansion chamber, a heating apparatus, a regenerator, a cooling apparatus, and a compression chamber connected in sequence to form a stirling cycle, an inlet of the cleaning chamber is connected to a line between an outlet of the heater and the regenerator, and an outlet of the cleaning chamber is connected to a line between the regenerator and the cooling apparatus.
9. The supercritical fluid cleaning system of claim 1, wherein the cleaning fluid is carbon dioxide and the sample to be cleaned is a wafer.
10. A method of cleaning a supercritical fluid system as claimed in any one of claims 1 to 9, comprising the steps of:
pressurizing: driving the cleaning fluid to flow out and enter the cleaning cavity in a manner of increasing the pressure and being higher than the supercritical pressure;
and a heating step: heating the pressurized cleaning fluid to form supercritical cleaning fluid, wherein the supercritical cleaning fluid enters a cleaning cavity under fluctuating pressure;
and (3) cleaning: the supercritical cleaning fluid oscillates and cleans the sample to be cleaned under the action of the fluctuation pressure;
step of depressurization: driving the supercritical cleaning fluid in which the liquid to be cleaned is dissolved to flow out of the cleaning chamber in such a manner that the pressure drops to not lower than the supercritical pressure thereof;
and (3) a cooling step: the supercritical cleaning fluid in which the liquid to be cleaned is dissolved is cooled to obtain the liquid to be cleaned and the cleaning fluid.
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PCT/CN2022/083624 WO2023142257A1 (en) | 2022-01-28 | 2022-03-29 | Cleaning system and cleaning method using supercritical fluid |
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CN117490268A (en) * | 2023-12-29 | 2024-02-02 | 广州广钢气体能源股份有限公司 | Carbon dioxide cooling system for chip cleaning and conveying system |
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JP3725629B2 (en) * | 1996-09-25 | 2005-12-14 | シャープ株式会社 | Supercritical fluid cleaning equipment |
JP2005072568A (en) * | 2003-08-06 | 2005-03-17 | Sony Corp | Method and device for cleaning microstructure, semiconductor device and manufacturing method therefor, and mictostructure and manufacturing method therefor |
EP2672002B1 (en) * | 2011-02-02 | 2022-03-30 | YKK Corporation | Cleaning method and cleaning device |
CN106734493B (en) * | 2016-12-20 | 2018-06-26 | 桂林电子科技大学 | A kind of middle-size and small-size internal high-pressure forming machine of bulging pressure fluctuation loading |
CN106733945B (en) * | 2016-12-30 | 2022-11-29 | 上海颐柏热处理设备有限公司 | Supercritical state cleaning system and method |
CN212703441U (en) * | 2020-07-17 | 2021-03-16 | 上海复璐帝流体技术有限公司 | Supercritical fluid cleaning device |
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CN117490268A (en) * | 2023-12-29 | 2024-02-02 | 广州广钢气体能源股份有限公司 | Carbon dioxide cooling system for chip cleaning and conveying system |
CN117490268B (en) * | 2023-12-29 | 2024-03-26 | 广州广钢气体能源股份有限公司 | Carbon dioxide cooling system for chip cleaning and conveying system |
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