JP2008155159A - Treatment apparatus using supercritical fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment apparatus using a supercritical fluid, which has a simple constitution and in which the supercritical fluid can be reused easily. <P>SOLUTION: The treatment apparatus using the supercritical fluid comprises: treatment vessels 10A, 10B in each of which a fluid in a compression chamber 13 can be compressed or decompressed by a piston 12 to be slid in a cylinder 11; a hydraulic actuator 30 for driving the piston 12; a pressure accumulator 40 for storing the fluid, which is supplied to the compression chamber 13, under predetermined pressure; a fluid passage 17 in which the fluid can be moved between the pressure accumulator 40 and the compression chamber 13; and a fluid control means for controlling the movement of the fluid in the fluid passage 17. The fluid stored in the pressure accumulator 40 is introduced into the compression chamber 13 through the fluid passage 17. The piston 12 is driven by the hydraulic actuator 30 to compress the fluid in the compression chamber 13 and the compressed fluid is kept in a supercritical state. The object M to be treated in the compression chamber 13 is subjected to predetermined treatment by using the fluid of the supercritical state. The fluid, which is used for predetermined treatment, in the compression chamber 13 is returned to the pressure accumulator 40 through the fluid passage 17 by means of the pressure in the compression chamber 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a processing apparatus that performs predetermined processing such as cleaning, extraction, and reaction with a supercritical fluid.

  Substances have their own temperature and pressure called the critical point. The temperature and pressure higher than the critical point are called supercritical states. In this state, the substance has both gas and liquid properties. It becomes a supercritical fluid. Supercritical fluids have both surface diffusivity (gas properties) that can enter even fine areas and solubility properties (liquid properties) that easily dissolve substances, and by changing temperature and pressure It has the feature that the physical properties can be changed continuously.

  In recent years, taking advantage of this feature, using supercritical fluid, cleaning (cleaning of precision machine parts, resist removal in semiconductors, etc.), extraction (caffeine, fragrance, etc.), reaction (decomposition of organic substances, etc.), etc. Have been considered, and devices for this purpose have also been developed.

For example, as a reaction device using a supercritical fluid, a reaction device including a cylinder and a piston is known (see, for example, Patent Document 1 and Patent Document 2). In this reactor, water vapor and a substance to be reacted are introduced into a cylinder, the water vapor in the compression chamber is compressed by a piston to react with the substance to be reacted as supercritical water, and then the piston is moved in the opposite direction. Then, the temperature and pressure of the supercritical water are lowered to return to water vapor, and water vapor containing the product of the reactant is taken out from the cylinder.
JP 2005-66484 A JP 2002-263465 A

However, the conventional apparatus has the following problems.
In order to bring water and carbon dioxide into a supercritical state, heating is required together with pressurization, and after the treatment, temperature lowering is required along with decompression. A preheater is required for heating, and a cooler is required for lowering the temperature, which complicates the system.

    Also, when handling solids with conventional technology using carbon dioxide as a supercritical fluid, the processor is opened when the solids are taken out, so it is connected to the inside of the processor and the processor every time it is taken out. You will lose carbon dioxide in the heater and cooler.

  Therefore, the present invention provides a processing apparatus using a supercritical fluid that has a simple configuration and can easily reuse a supercritical fluid.

In the processing apparatus using a supercritical fluid according to the present invention, the following means are adopted in order to solve the above problems.
The invention according to claim 1 is supplied to the compression chamber, a processor that can pressurize and depressurize the fluid in the compression chamber formed in the cylinder by a piston that slides in the cylinder, an actuator that drives the piston. A pressure accumulator that stores a fluid at a predetermined pressure, a fluid passage that allows the fluid to flow between the pressure accumulator and the compression chamber, and a fluid control means that controls the fluid flow in the fluid passage; The fluid stored in the pressure accumulator is introduced into the compression chamber through the fluid passage, and the piston is driven by the actuator to compress the fluid in the compression chamber to bring the fluid into a supercritical state. Then, a predetermined process is performed on the processing object in the compression chamber with the fluid in the supercritical state, and the fluid in the compression chamber is transferred to the accumulator through the fluid passage by the pressure of the compression chamber after the processing. A processing apparatus according to a supercritical fluid, characterized in that the feed.
With this configuration, the piston is driven and the fluid in the compression chamber is compressed to heat the fluid, so that a preheater is unnecessary and the system configuration is simplified.
After the treatment, the fluid in the compression chamber is returned to the accumulator by the pressure in the compression chamber or by movement of the piston, so that no pressurizing means (such as a pump) is required for returning, and the temperature of the fluid is lowered by reducing the pressure. System configuration is simplified. In addition, the dead volume in the processor is minimized by removing the object after removing the heater and cooler and moving the piston, so that the supercritical fluid can be easily reused. Thus, the amount of discarded fluid can be reduced.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the processing object is a solid.
By configuring in this way, it is easy to separate the object to be processed and the fluid, so that it becomes easy to return only the fluid in the compression chamber to the pressure accumulator after the processing.

The invention according to claim 3 is the invention according to claim 1 or 2, characterized in that the fluid contains carbon dioxide as a main component.
Since carbon dioxide has a relatively low critical temperature and critical pressure, the operating temperature and operating pressure can be set relatively low, and the design temperature and design pressure can be set relatively low.

The invention according to claim 4 is characterized in that in the invention according to any one of claims 1 to 3, there is provided an air communication means for enabling the compression chamber and the atmosphere to be connected / blocked.
By comprising in this way, it becomes possible to flow air into a compression chamber or to discharge the air of a compression chamber.

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the fluid passage includes a purifying means for purifying the fluid.
By configuring in this way, the contaminated fluid can be purified and returned to the accumulator by performing a predetermined treatment with the supercritical fluid, and the purity of the fluid to be reused is maintained at a predetermined level. can do.

The invention according to claim 6 is the invention according to claim 5, wherein the purifying means includes at least one of activated carbon, a filter, an organic solvent tank, and a gas-liquid separator.
By comprising in this way, the optimal purification | cleaning according to the quality of the stain | pollution | contamination of fluid can be performed.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the cylinder includes a temperature adjusting means.
By comprising in this way, the temperature condition of the supercritical state formed by compression with a piston can be hold | maintained until the predetermined process by a supercritical fluid is completed.

The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the temperature detection means for detecting the temperature of the compression chamber and the pressure detection means for detecting the pressure of the compression chamber. And a piston control means for controlling the moving speed and the moving amount of the piston so that the temperature and pressure of the compression chamber become desired values.
With this configuration, the temperature and pressure of the compression chamber can be controlled to desired values.

The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein a predetermined medicine is added to the compression chamber before the fluid in the compression chamber is compressed by the piston. Means are provided.
With this configuration, it is possible to more effectively perform a predetermined process using the supercritical fluid.

The invention according to claim 10 is the invention according to any one of claims 1 to 9, wherein the actuator reciprocates the piston when the fluid in the compression chamber is in a supercritical state. It is characterized by that.
With this configuration, pressure vibration can be applied to the supercritical fluid in the compression chamber while maintaining the supercritical state.

According to an eleventh aspect of the present invention, in the first aspect of the invention, a plurality of the processing devices are provided, and each piston of the plurality of processing devices is driven by a single actuator.
With this configuration, it is possible to operate a plurality of processors with one actuator.

According to a twelfth aspect of the present invention, the actuator according to the eleventh aspect of the present invention, wherein the actuator includes an operating shaft having reciprocating motions at both ends, and each operating portion of the operating shaft has a piston of the processor. Are connected.
With this configuration, the two processors can be operated in conjunction with each other.

The invention according to claim 13 is the invention according to claim 2, wherein the piston is provided with an object attaching / detaching means for detachably attaching the processing object to a front end of the piston, and the cylinder includes the object to be processed. An opening for attaching / detaching an object to / from the piston is provided.
By comprising in this way, a process target object can be easily attached or detached with respect to a piston through opening.

The invention according to claim 14 is characterized in that, in the invention according to claim 2, the cylinder is provided with a valve for taking the processing object into and out of the cylinder.
By comprising in this way, a process target object can be easily taken in / out of a cylinder via a valve | bulb.

According to the first aspect of the invention, the configuration of the processing device is simplified. In addition, the supercritical fluid can be easily reused, and the amount of discarded fluid can be reduced.
According to the invention which concerns on Claim 2, it becomes easy to return only the fluid in a compression chamber to a pressure accumulator after a process.
According to the third aspect of the invention, the design temperature and the design pressure can be set relatively low, so that an economical apparatus design can be achieved. Moreover, since it is nonflammable, there is no fear of ignition by compression heat.

According to the invention which concerns on Claim 4, since air can be made to flow in into a compression chamber, taking in / out of a process target object can be performed easily. Moreover, since the air of a compression chamber can be discharged | emitted, the density | concentration of the fluid in a compression chamber can be made high.
According to the invention which concerns on Claim 5, since the purified fluid can be returned to an accumulator, the purity of the fluid used for a reuse can be kept predetermined.
According to the invention which concerns on Claim 6, after performing the optimal purification | cleaning according to the quality of the stain | pollution | contamination of the fluid, a fluid can be returned to a pressure accumulator.

According to the seventh aspect of the present invention, the temperature condition in the supercritical state formed by the compression by the piston can be maintained until the predetermined process with the supercritical fluid is completed. Can be implemented.
According to the eighth aspect of the invention, the temperature and pressure of the compression chamber can be controlled to desired values, so that a desired supercritical state can be easily formed.

According to the ninth aspect of the present invention, it is possible to more effectively perform the predetermined processing with the supercritical fluid.
According to the tenth aspect of the present invention, pressure vibration can be applied to the supercritical fluid in the compression chamber while maintaining the supercritical state, so that the efficiency of predetermined processing (washing, extraction, reaction, etc.) can be increased. it can.

According to the invention which concerns on Claim 11, since it becomes possible to operate a some processor with one actuator, processing efficiency can be improved.
According to the invention which concerns on Claim 12, since two processors can be operated interlockingly, processing efficiency can be improved.

According to the invention which concerns on Claim 13, a process target object can be easily attached or detached to and from a piston through opening.
According to the invention which concerns on Claim 14, a process target object can be easily taken in / out of a cylinder via a valve | bulb.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a supercritical fluid processing apparatus (hereinafter abbreviated as a processing apparatus) according to the present invention will be described below with reference to the drawings of FIGS.
First, the configuration of the processing apparatus will be described. As shown in FIG. 1, the processing apparatus 1 in this embodiment includes two processing units 10A and 10B (hereinafter referred to as processing unit 10 when it is not necessary to distinguish between them), and hydraulic pressure for driving the processing units 10A and 10B. The main components of the actuator 30 are a cylinder 60 for storing carbon dioxide (CO2) as a fluid to be made a supercritical fluid in a high-pressure liquid, and a pressure accumulator 40 for holding and storing the gasified carbon dioxide at a predetermined pressure. As prepared.

  The processor 10 includes a cylinder 11 and a piston 12 that slides inside the cylinder 11, and a space surrounded by the cylinder 11 and the piston 12 in the cylinder 11 is a compression chamber 13, as shown in FIG. Further, the fluid in the compression chamber 13 can be compressed by moving the piston 12 in the axial direction of the cylinder 11 from the bottom dead center to the top dead center side. Further, the cylinder 11 can separate the cylinder head 11b from the cylinder body 11a, and the cylinder head 11b is normally disposed at a fixed position indicated by a solid line in FIG. 2 to seal the cylinder body 11a. Only when the processing object M is closed and put in and out, the tip of the cylinder body 11a is opened by moving away from the cylinder body 11a as shown by a two-dot chain line in FIG. It is preferable that the cylinder head 11b can be automatically opened and closed by hydraulic pressure or the like.

  A fitting (object attaching / detaching means) 14 is provided on the tip surface of the piston 12 so that the processing object M can be attached and detached. The cylinder 11 and the piston 12 are provided with temperature adjusters 15 and 16 for adjusting the temperature of the compression chamber 13, and the temperature adjusters 15 and 16 are controlled by the control device 50. As the temperature controllers 15 and 16, for example, an electric heater or a jacket type in which a heat medium such as water circulates can be adopted.

The cylinder 11 is connected with a fluid passage 17 that allows the compression chamber 13 and the pressure accumulator 40 to communicate with each other, and a blow passage 18 that allows the compression chamber 13 and the atmosphere to communicate with each other. A blow valve (atmospheric communication means) 19 is provided in the blow passage 18, and the blow valve 19 is controlled to be opened and closed by a control device 50. Further, the cylinder 11 is provided with a temperature sensor (temperature detection means) 51 for detecting the temperature in the compression chamber 13, and the fluid passage 17 has a pressure for detecting the pressure in the compression chamber 13. A sensor (pressure detection means) 52 is provided, and these sensors 51 and 52 output an electrical signal corresponding to the detected value to the control device 50.
Each piston 12 of the processors 10 </ b> A and 10 </ b> B is connected to an operating shaft 32 of the hydraulic actuator 30.

  The hydraulic actuator 30 includes a cylinder 31 and an operating shaft 32 that passes through the cylinder 31 and is movable in the axial direction. A piston portion 33 provided in the center of the operating shaft 32 has two oil chambers 34a, 34b, the hydraulic oil is supplied to one oil chamber, and the hydraulic oil is discharged from the other oil chamber, whereby the piston 33 is slid in the axial direction, thereby causing the operating shaft 32 to reciprocate linearly. It is configured to be able to. Then, both ends of the operating shaft 32 are operating parts 35, and the pistons 12 of the processors 10A and 10B are connected to the operating parts 35, respectively.

  Therefore, in the processing apparatus of this embodiment, the two processors 10A and 10B can be operated in conjunction with one hydraulic actuator 30. However, when the operating shaft 32 of the hydraulic actuator 30 is moved to the left in FIG. 1, in the processor 10A, the piston 12 moves in the direction of reducing the volume of the compression chamber 13, but in the processor 10B. The piston 12 moves in the direction in which the volume of the compression chamber 13 is enlarged. Conversely, when the operating shaft 32 of the hydraulic actuator 30 is moved to the right in FIG. 1, in the processor 10A, the piston 12 moves in the direction of expanding the volume of the compression chamber 13, and in the processor 10B. The piston 12 moves in the direction of reducing the volume of the compression chamber 13.

  The oil chambers 34a and 34b of the cylinder 31 are connected to an electric hydraulic pump 37 by an oil passage 36 provided with a flow path switching valve 38. By switching the flow path switching valve 38, the oil chamber 34a and the oil chamber 34b are connected. It is possible to supply the hydraulic oil in one of the oil chambers to the suction of the electric hydraulic pump 37 and supply the hydraulic oil boosted by the electric hydraulic pump 37 to the other oil chamber. The flow path switching valve 38 and the electric hydraulic pump 37 are controlled by the control device 50.

An intake / exhaust valve 20 and a throttle valve 21 are provided in the fluid passage 17 connecting the compression chamber 13 and the pressure accumulator 40. The throttle valve 21 is disposed at a position closer to the accumulator 40 than the intake / exhaust valve 20, and is adjusted to a predetermined opening degree in advance and held in a normally open state. The intake / exhaust valve 20 is controlled to open and close by the control device 50. The pressure sensor 52 described above is disposed closer to the cylinder 11 than the intake / exhaust valve 20.
Further, the fluid passage 17 is branched into a supply path 22 and a return path 23 at a portion closer to the pressure accumulator 40 than the throttle valve 21, and is connected to the pressure accumulator 40. The supply path 22 is provided with a filter 24 and a check valve 25a, and the return path 23 is provided with a filter 24 and a check valve 25b.

The filter 24 removes foreign matters mixed in the carbon dioxide gas, which is a fluid, and can be composed of, for example, a filtration membrane, sintered metal, activated carbon, silica gel, zeolite, or the like alone or in combination. The filters 24 provided in the supply path 22 and the return path 23 have the same configuration.
The check valve 25 a provided in the supply path 22 allows the fluid to flow from the pressure accumulator 40 toward the cylinder 11 and prevents the fluid from flowing from the cylinder 11 toward the pressure accumulator 40. On the other hand, the check valve 25 b provided in the return path 23 allows the fluid to flow from the cylinder 11 toward the pressure accumulator 40 and prevents the fluid from flowing from the pressure accumulator 40 toward the cylinder 11. . In this embodiment, the intake / exhaust valve 20 and the check valves 25a and 25b constitute fluid control means for controlling the flow of fluid in the fluid passage 17.
A management device 41 that manages carbon dioxide in the pressure accumulator 40 is attached to the pressure accumulator 40. Specifically, the management of carbon dioxide is to measure and monitor the CO ₂ concentration, the number of particles, or the organic matter concentration.

  The cylinder 60 and the pressure accumulator 40 are connected by a supply passage 42 including a pressure reducing valve 43, and pressure gauges 44 a and 44 b are provided upstream and downstream of the pressure reducing valve 43. The high-pressure liquid carbon dioxide stored in the cylinder 60 is depressurized by the pressure reducing valve 43 to become carbon dioxide gas and is supplied to the pressure accumulator 40. The pressure reducing valve 43 always supplies a predetermined pressure (for example, 0. 0). 9 MPa).

  Next, the operation of the processing apparatus 1 will be described by taking as an example the case where a cleaning process is performed on a silicon wafer as a processing target using the processing apparatus 1. As described above, in the processing apparatus 1 of this embodiment, the two processors 10A and 10B are operated in conjunction with one hydraulic actuator 30. FIG. 3 is a time schedule of the two processors 10A and 10B. In FIG. 3, the A system corresponds to the processor 10A, and the B system corresponds to the processor 10B.

As is clear from the time schedule of FIG. 3, the series of steps is the same for the processors 10A and 10B with only a time lag.
Hereinafter, the processes of the processors 10A and 10B will be described in order with reference to FIGS. In addition, since the content of each process is the same also in processor 10A, 10B, the content of each process is demonstrated in 10A of processors, and it keeps only describing which process is performed about the processor 10B at the same time. 4 to 14, the blow valve 19 and the intake / exhaust valve 20 are indicated by white display in an open state and black display by a closed state. In the object installation process, the cylinder heads 11b of the processors 10A and 10B are actually detached from the cylinder body 11a as described above, but this is omitted in the figure. Further, it is assumed that the pressure accumulator 40 is always filled with carbon dioxide gas adjusted to a predetermined pressure (for example, 0.9 MPa) by the pressure reducing valve 43.

  First, in step 1, as shown in FIG. 4, the A-system blow valve 19 is opened, the intake / exhaust valve 20 is closed, the piston 12 of the processor 10A is moved to the top dead center, and the dead space of the compression chamber 13 is reached. To minimize. Then, the tip of the cylinder body 11a is opened by moving the cylinder head 11b of the processor 10A away from the cylinder body 11a, and the silicon wafer M is inserted into the cylinder body 11a from here, and the tip of the piston 12 is attached by the fixture 14. (A system: object installation process). After completing the attachment of the silicon wafer M, the cylinder head 11b of the processor 10A is returned to a fixed position to close the cylinder body 11a. During this time, the B system opens the blow valve 19 and closes the intake / exhaust valve 20 to stand by.

Next, the process proceeds to Step 2 and, as shown in FIG. 5, both the A-system blow valve 19 and the intake / exhaust valve 20 are opened, and the carbon dioxide gas stored in the pressure accumulator 40 is passed through the filter 24 and the check valve 25a. Then, the fluid is supplied to the compression chamber 13 of the processor 10A through the fluid passage 17, the throttle valve 21, and the intake / exhaust valve 20. Thereby, the air remaining in the compression chamber 13 can be completely discharged from the blow valve 19 and replaced with carbon dioxide gas (A system: CO ₂ purge step). At this time, the B system continues the previous standby state.

Next, the process proceeds to step 3, and as shown in FIG. 6, the A-system blow valve 19 is closed, and the pressure of the carbon dioxide gas in the compression chamber 13 of the processor 10 </ b> A is equal to the internal pressure (0.9 MPa) of the pressure accumulator 40. While introducing the carbon dioxide gas to the same pressure, the hydraulic actuator 30 is operated to move the piston 12 of the processor 10A to the bottom dead center (A system: CO ₂ press-fitting process). At this time, in the system B, the piston 12 of the processing unit 10B moves to the top dead center with the movement of the piston 12 of the processing unit 10A, but otherwise the conventional standby state is continued.
Next, go to step 4. In step 4, the CO ₂ injection process is continued for the A system, and the B system shifts to the object installation process (see FIG. 6).

Next, go to step 5. In step 5, as shown in FIG. 7, the CO ₂ press-in process is continued for the A system, and the B system shifts to the CO ₂ purge process. At this time, the pressure of carbon dioxide gas in the compression chamber 13 of the processor 10A is maintained at 0.9 MPa, and the temperature of the carbon dioxide gas is room temperature (normal temperature).

  Next, the process proceeds to step 6, and as shown in FIG. 8, both the A-system blow valve 19 and the intake / exhaust valve 20 are closed, and the hydraulic actuator 30 is operated to bring the piston 12 of the processor 10A closer to the top dead center. By moving in the direction and compressing the carbon dioxide gas in the compression chamber 13 of the processor 10A to a supercritical state of a predetermined pressure (for example, 20 MPa) and a predetermined temperature (for example, 80 ° C.). Carbon dioxide is converted into a supercritical fluid (A system: pressurization step). At this time, the temperature and pressure in the compression chamber 13 are detected by the temperature sensor 51 and the pressure sensor 52 provided in the processor 10A, and based on the detection result, the fluid temperature in the compression chamber 13 is compressed by the compression heat. The moving speed (compression speed) of the piston 12 is controlled so as to be heated to a predetermined temperature. The control of the moving speed of the piston 12 can be performed by the control device 50 controlling the rotational speed of the electric hydraulic pump 37. Then, when the pressure in the compression chamber 13 reaches the predetermined pressure, the movement of the piston 12 is stopped. In this embodiment, the electric hydraulic pump 37 and the control device 50 constitute piston control means.

  Theoretically, in the case of carbon dioxide (γ = 4/3), in the adiabatic compression, the gas temperature T1 = 20 ° C. and the gas pressure P1 = 0.9 MPa before compression are compressed to the gas pressure. When P2 = 20 MPa, the gas temperature after compression is T2 = 362 ° C., and the compression ratio (gas volume V1 before compression / gas volume V2 after compression) at this time is about 10 times. In isothermal compression under the same conditions, the compression ratio is about 22 times. Here, for example, assuming that the inner diameter of the compression chamber 13 is ID = 330 mm and the length L of the compression chamber 13 before compression is L = 500 mm, when the gas temperature is heated to the set temperature only by the compression heat, the set temperature Accordingly, the length of the compression chamber 13 after compression is 50 to 23 mm.

  In order to prevent the pressure in the compression chamber 13 from becoming excessive, when the pressure in the compression chamber 13 exceeds the predetermined pressure, the intake / exhaust valve 20 is opened to accumulate the pressure in the compression chamber 13. It may be allowed to escape to the vessel 40, or the blow valve 19 may be opened to escape to the atmosphere. Alternatively, although not shown, a safety valve may be provided in the cylinder 11, and excess pressure may be released from the safety valve to the atmosphere when the predetermined pressure is exceeded. Alternatively, a position sensor may be provided in the cylinder 11, and the piston 12 may be stopped when the position sensor detects that the piston 12 has reached top dead center.

Further, when the compression speed for compressing the carbon dioxide gas in the compression chamber 13 is determined in advance and it is difficult to manage the temperature only by the compression heat, the temperature adjustment provided in the processor 10A is performed. By controlling the vessels 15 and 16, a desired temperature can be obtained.
Further, also when the inside of the compression chamber 13 is kept in the predetermined supercritical state for a predetermined time, the temperature regulators 15 and 16 are controlled to control the temperature of the supercritical fluid in the compression chamber 13 to the predetermined temperature. Can be held.

Then, the silicon wafer M is cleaned by the supercritical fluid in the compression chamber 13 by maintaining the compression chamber 13 of the processor 10A in a supercritical state for a predetermined time. At this time, the B system shifts to the CO ₂ injection process. At this time, if necessary, the piston 12 of the processing unit 10A is reciprocated by the hydraulic actuator 30 while maintaining the supercritical state in the compression chamber 13 of the processing unit 10A. A pressure vibration may be applied to increase the cleaning effect.

Next, it progresses to step 7, and as shown in FIG. 9, the intake / exhaust valve 20 is opened, and the carbon dioxide gas in the compression chamber 13 of processor 10A is returned to the pressure accumulator 40 by the gas pressure. More specifically, the carbon dioxide gas in the compression chamber 13 of the processor 10A passes through the intake / exhaust valve 20, the fluid passage 17, the throttle valve 21, the check valve 25b, and the filter 24 according to the gas pressure to the accumulator 40. Be transported. Note that the carbon dioxide that has been made a supercritical fluid in the compression chamber 13 in step 6 is released from the supercritical state and becomes carbon dioxide gas because the pressure decreases simultaneously with opening of the intake / exhaust valve 20 in step 6. In particular, in this embodiment, since the throttle valve 21 is provided between the intake / exhaust valve 20 and the check valve 25b in the fluid passage 17, the carbon dioxide gas is reliably supercritical before flowing into the filter 24. Can be released from the state. Thereafter, the hydraulic actuator 30 is further operated to move the piston 12 of the processor 10A to the top dead center, thereby promoting the transfer of the carbon dioxide gas to the pressure accumulator 40, and the carbon dioxide gas remaining in the compression chamber 13 Minimize the amount (A system: CO ₂ return process).
Since the carbon dioxide gas passes through the filter 24 when returned from the compression chamber 13 to the pressure accumulator 40, foreign matters mixed in the carbon dioxide gas when the silicon wafer M is washed can be captured by the filter 24. Foreign substances and the like can be prevented from flowing into the pressure accumulator 40. Therefore, the purity reduction of the carbon dioxide gas in the pressure accumulator 40 can be prevented.
At this time, the B system continues the CO ₂ injection process.

Next, the process proceeds to Step 8, and as shown in FIG. 10, the A-system intake / exhaust valve 20 is closed, the blow valve 19 is opened, and the carbon dioxide gas remaining in the compression chamber 13 is blown by the residual gas pressure. 19 and the pressure in the compression chamber 13 is changed to atmospheric pressure (A system: CO ₂ blow process). At this time, the B system continues the CO ₂ injection process.

Next, the process proceeds to Step 9. In Step 9, the A system shifts to the object installation process, and the B system continues the CO ₂ injection process (see FIG. 10).
Next, the process proceeds to Step 10. In Step 10, as shown in FIG. 11, the A system shifts to the CO ₂ purge process, and the B system continues the CO ₂ press-fitting process.
Next, the process proceeds to step 11. In step 11, as shown in FIG. 12, the A system shifts to the CO ₂ press-in process, and the B system shifts to the pressurization process.
Next, the process proceeds to step 12. In step 12, as shown in FIG. 13, the A system continues the CO ₂ injection process, and the B system shifts to the CO ₂ return process.
Next, the process proceeds to step 13. In step 13, as shown in FIG. 14, the A system continues the CO ₂ injection process, and the B system shifts to the CO ₂ blow process.
Then, it returns to step 4 again (refer FIG. 6), and repeats the process of steps 4-13.

As shown in FIG. 1, an adding means for adding a predetermined additive (for example, a surfactant or alcohol) is connected in advance to the fluid passage 17 closer to the processor 10A than the intake / exhaust valve 20. The additive may be supplied to the compression chamber 13 together with carbon dioxide gas as needed during the CO ₂ injection step. If it does in this way, a cleaning effect can be heightened at the time of a pressurization process.

As described above, according to the processing apparatus 1 of this embodiment, the piston 12 is driven and the carbon dioxide gas is heated by the compression heat when the carbon dioxide gas in the compression chamber 13 is compressed. This is unnecessary and simplifies the system configuration.
In addition, since the carbon dioxide gas in the compression chamber 13 is returned to the accumulator 40 by the gas pressure after the silicon wafer M is cleaned, no pressurizing means (such as a pump) is required for the return, and the system configuration is simple. Become. In addition, carbon dioxide gas, which is a supercritical fluid, can be easily reused, and the amount of carbon dioxide gas discarded can be reduced, which is economical.

In this embodiment, since the object to be processed is a solid silicon wafer M, the object to be processed and the carbon dioxide gas can be easily separated, and only the carbon dioxide gas in the compression chamber 13 can be easily stored after the cleaning. 40 can be returned.
In this embodiment, since the fluid is carbon dioxide, the critical temperature and the critical pressure are relatively low. Therefore, the operation temperature and the operation pressure can be relatively low, and the design temperature and the design pressure are set relatively low. Therefore, an economical device design is possible.
Further, since the two processors 10A and 10B can be operated in conjunction with one hydraulic actuator 30, the processing efficiency is extremely high.

[Other Examples]
In the above-described embodiment, the cylinder head 11b can be separated from the cylinder body 11a in order to insert and remove the processing object M. However, the method of inserting and removing the processing object M with respect to the cylinder 11 is not limited to this. .
For example, the cylinder head 11b and the cylinder body 11a may not be separated from each other, and an opening through which the processing object M is taken in and out of the cylinder body 11a may be provided.
Alternatively, as shown in FIG. 15, in the cylinder 11, a closing passage 71 </ b> A and a discharging passage 71 </ b> B are provided at positions facing the compression chamber 13 in the radial direction, a closing valve 72 </ b> A is provided in the closing passage 71 </ b> A, and a discharging passage 71 </ b> B is provided. A discharge valve 72B is provided. For example, the input valve 72A is opened, and the sample holder 73 into which the processing object M is inserted is inserted into the compression chamber 13 through the input valve 72A. After the insertion, the input valve 72A and the discharge valve 72B are inserted. Is closed and a predetermined process (cleaning or the like) is performed in the same manner as in the previous embodiment, and then the input valve 72A and the discharge valve 72B are opened, and the sample holder 73 in the compression chamber 13 is taken out through the discharge valve 72B. You may make it insert the sample holder 73 in which the new process target object M was inserted in the compression chamber 13 via the valve 72A.

Further, when two processing units 10 are not connected but constituted by a single processing unit 10, one end on the bottom dead center side of the cylinder 11 is opened, and the piston 12 is removed from the cylinder 11 from this opening. The processing object M may be inserted into the cylinder 11 or the processing object M may be attached to the piston 12 and then the piston 12 may be inserted into the cylinder 11 again. In this case, the piston 12 can be easily inserted into the cylinder 11 by forming the opening-side end portion of the cylinder 11 into a tapered shape that expands in diameter as it advances toward the opening end. Further, the same effect can be obtained by forming the cylinder 11 straight and reducing the diameter of the piston 12 as the tip of the piston 12 is advanced.
In addition, it is convenient to provide a drain valve that communicates with the compression chambers 13 of the processors 10A and 10B because the residue in the compression chambers 13 can be discharged.

In the above-described embodiment, a filter is used as the purification means. However, activated carbon, a filter, an organic solvent tank, a gas-liquid separator, or a combination thereof may be used.
In the embodiment, the actuator for driving the piston is a hydraulic actuator, but an actuator of another driving system such as an electric actuator may be used.
Further, as means for interlocking a plurality of processors, a piston of the processor may be provided at the tip of a plurality of piston rods connected to a crankshaft like an internal combustion engine.
Moreover, the process with respect to the process target performed by the processing apparatus 1 is not restricted to washing | cleaning, Extraction, reaction, etc. may be sufficient.
The fluid is not limited to carbon dioxide, and ammonia or propane can be used.

It is a block diagram in one Example of the processing apparatus by the supercritical fluid which concerns on this invention. It is an enlarged view of the processor in the said Example. It is a time schedule of the processing apparatus in the said Example. FIG. 4 is a diagram for explaining Step 1; FIG. 6 is a diagram for explaining Step 2; It is a figure explaining steps 3 and 4. FIG. FIG. 5 is a diagram for explaining Step 5; FIG. 6 is a diagram for explaining Step 6; FIG. 7 is a diagram for explaining Step 7; It is a figure explaining steps 8 and 9. FIG. FIG. 10 is a diagram illustrating step 10. FIG. 10 is a diagram for explaining step 11; FIG. 10 is a diagram illustrating step 12. FIG. 10 is a diagram illustrating step 13. It is a principal part block diagram in the other Example of the processing apparatus by the supercritical fluid which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 10A, 10B by supercritical fluid Processor 11 Cylinder 12 Piston 13 Compression chamber 14 Attachment (object attaching / detaching means)
15, 16 Temperature controller (temperature adjusting means)
17 Fluid passage 19 Blow valve (atmospheric communication means)
20 Intake / exhaust valve (fluid control means)
24 Filter (Purification means)
25a, 25b Check valve (fluid control means)
30 Hydraulic actuator (actuator)
32 Actuating shaft 35 Actuating section 37 Electric hydraulic pump (piston control means)
40 accumulator 50 control device (piston control means)
51 Temperature sensor (temperature detection means)
52 Pressure sensor (pressure detection means)
72A Input valve (valve)
72B Discharge valve (valve)
M Silicon wafer (object to be processed)

Claims (14)

A processor capable of increasing or decreasing the pressure of the fluid in the compression chamber formed in the cylinder by a piston sliding in the cylinder;
An actuator for driving the piston;
A pressure accumulator for storing the fluid supplied to the compression chamber at a predetermined pressure;
A fluid passage that allows the fluid to flow between the accumulator and the compression chamber;
Fluid control means for controlling fluid flow in the fluid passage;
A fluid stored in the pressure accumulator is introduced into the compression chamber through the fluid passage, the piston is driven by the actuator to compress the fluid in the compression chamber, and the fluid is brought into a supercritical state, A predetermined process is performed on the processing object in the compression chamber with the fluid in the supercritical state, and the fluid in the compression chamber is returned to the accumulator through the fluid passage by the pressure of the compression chamber after the processing. A processing apparatus using a supercritical fluid characterized by the following.   The processing apparatus using a supercritical fluid according to claim 1, wherein the processing object is a solid.   3. The processing apparatus using supercritical fluid according to claim 1, wherein the fluid contains carbon dioxide as a main component.   The processing apparatus using a supercritical fluid according to any one of claims 1 to 3, further comprising atmospheric communication means that enables connection and interruption between the compression chamber and the atmosphere.   The processing apparatus using a supercritical fluid according to any one of claims 1 to 4, wherein the fluid passage includes a purifying unit that purifies the fluid.   6. The processing apparatus using a supercritical fluid according to claim 5, wherein the purification means includes at least one of activated carbon, a filter, an organic solvent tank, and a gas-liquid separator.   The said cylinder is provided with a temperature control means, The processing apparatus by the supercritical fluid of any one of Claims 1-6 characterized by the above-mentioned.   A temperature detection means for detecting the temperature of the compression chamber and a pressure detection means for detecting the pressure of the compression chamber, and the moving speed and movement of the piston so that the temperature and pressure of the compression chamber become desired values. The processing apparatus using a supercritical fluid according to any one of claims 1 to 7, further comprising piston control means for controlling the amount.   The supercritical fluid according to any one of claims 1 to 8, further comprising addition means for adding a predetermined drug to the compression chamber before the fluid in the compression chamber is compressed by the piston. By the processing equipment.   The processing apparatus using a supercritical fluid according to any one of claims 1 to 9, wherein the actuator reciprocates the piston when the fluid in the compression chamber is in a supercritical state. .   The processing apparatus using a supercritical fluid according to claim 1, wherein a plurality of the processing devices are provided, and each piston of the plurality of processing devices is driven by a single actuator.   The super actuator according to claim 11, wherein the actuator includes an operating shaft that has an operating portion at both ends and performs reciprocating motion, and a piston of the processor is connected to each operating portion of the operating shaft. Processing equipment using critical fluid.   The piston is provided with an object attaching / detaching means for detachably attaching the processing object to a front end of the piston, and the cylinder is provided with an opening for attaching / detaching the processing object to / from the piston. The processing apparatus using a supercritical fluid according to claim 2.   The processing apparatus using a supercritical fluid according to claim 2, wherein the cylinder is provided with a valve for taking the processing object into and out of the cylinder.

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