JP3982791B2 - High pressure processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-pressure processing apparatus using a high-pressure processing fluid. More specifically, the present invention relates to a semiconductor substrate, an FPD (Flat Panel Display) substrate such as a glass substrate for a liquid crystal display device, a glass substrate for a photomask, and an optical disk substrate. The present invention relates to a high-pressure processing apparatus that performs high-pressure processing of a substrate, for example, processing for removing contaminants attached to the substrate, by supplying a high-pressure processing fluid (hereinafter simply referred to as “substrate”).
[0002]
[Prior art]
In recent years, attention has been paid to the use of a low-viscosity, high-pressure processing fluid such as supercritical carbon dioxide as a stripping solution or rinsing liquid in accordance with the flow of defluorination in cleaning substrates on which electronic components and the like are formed. Yes.
[0003]
In addition, with the recent reduction (shrinking) of semiconductor devices, the device design rules (technology nodes) are further miniaturized, and the momentum is further accelerated. In such a semiconductor device, it is necessary to clean very fine grooves (trench) and holes (holes) in terms of structure. The former is a capacitor (capacitor portion of the capacitor) and horizontal wiring (planar wiring), and the latter is vertical wiring (three-dimensional wiring, connection between horizontal wiring and horizontal wiring, connection to the gate electrode of a transistor), etc. .
[0004]
In such a fine structure, the ratio between the width and the depth, that is, the so-called aspect ratio (aspect ratio) has become very large, and a narrow groove with a narrow width and a deep hole with a small diameter are formed. Such widths and diameters are submicron, and an aspect ratio of more than 10 has appeared. After manufacturing such a fine structure on a semiconductor substrate by dry etching or the like, not only the flat portion at the top, but also the resist debris on the side walls and bottom of the grooves and holes, the resist altered by dry etching, the bottom metal And contamination of resist compounds, oxidized metals, etc. remains.
[0005]
Conventionally, these contaminations have been washed with a solution-type chemical. However, in such a fine structure, the penetration of the chemical solution and the replacement with pure water do not go smoothly, resulting in poor cleaning. In addition, in order to prevent the electrical delay due to the etched insulator from being delayed by the wiring, a low dielectric constant material (so-called low-k material) must be used. The problem of getting worse is occurring. In addition, when the metal for wiring is exposed, there is a restriction that a chemical solution that dissolves the metal cannot be used.
[0006]
Supercritical fluids are attracting attention for cleaning the fine structure of semiconductor devices due to their characteristics. A supercritical fluid does not remain even if it penetrates into an insulator having a low dielectric constant like a solution-type chemical solution, so that its characteristics are not changed. Therefore, it can be said that it is very suitable for cleaning the fine structure of a semiconductor device, and has attracted much attention.
[0007]
As shown in FIG. 4, the supercritical fluid refers to a state of a substance obtained at a critical pressure Pc or higher and a critical temperature Tc or higher (shaded portion in the figure). Since this supercritical fluid has an intermediate property between liquid and gas, it can be said that it is suitable for precise cleaning. In other words, supercritical fluid has a density close to that of a liquid and has high solubility, so it is effective for cleaning organic components, and it has excellent diffusibility like gas. Because of its low viscosity, it is suitable for cleaning fine parts.
[0008]
Carbon dioxide, water, nitrous oxide, ammonia, ethanol or the like is used as the substance to be changed to the supercritical fluid. Carbon dioxide is mainly used because it has a critical pressure Pc of 7.4 MPa and a critical temperature Tc of about 31 ° C., and can easily obtain a supercritical state and is nontoxic.
[0009]
A configuration shown in FIG. 5 is conceivable as an apparatus for performing a substrate cleaning process using the supercritical fluid. The high-pressure processing apparatus shown in FIG. 5 includes a cylinder 21 filled with liquid carbon dioxide, a condenser 22, a pressure-increasing means 23, a heater 24, a mixer 30, a substrate cleaning tank 25, and a circulation pump. 26, a decompressor 27, a separation / recovery tank 28, and valves V1 to V5.
[0010]
Hereinafter, the cleaning operation of the high-pressure processing apparatus having this configuration will be briefly described.
First, a substrate that is an object to be cleaned is placed in the substrate cleaning tank 25 and sealed. When the substrate is installed, the following cleaning process is started. First, the liquid carbon dioxide in the cylinder 21 is supplied to the condenser 22 and stored as a liquid. The liquid carbon dioxide is pressurized to a pressure equal to or higher than the critical pressure Pc in the pressure increasing means 23, further heated to a temperature equal to or higher than the critical temperature Tc in the heater 24 to become supercritical carbon dioxide, and sent to the mixer 30. The mixer 30 mixes the predetermined auxiliary agent A and supercritical carbon dioxide supplied via the valve V5 and sends them to the substrate cleaning tank 25.
[0011]
Here, the auxiliary agent will be described.
Since carbon dioxide fluid has a solubility of about hexane, it can easily remove moisture and oil on the surface of the substrate, but it has insufficient solubility in polymer contaminants such as resists and etching polymers. Therefore, it is difficult to remove and remove these contaminants with carbon dioxide alone. For this reason, an auxiliary agent is used so that a chemical solution (auxiliary agent) is further added to carbon dioxide so that the polymer contaminant can be peeled off and removed.
[0012]
In the substrate cleaning tank 25, cleaning is performed by bringing the supercritical carbon dioxide into contact with the substrate. This substrate cleaning is performed by circulating the supercritical carbon dioxide mixed with the auxiliary agent A for a predetermined period by closing the valves V1 and V2, opening the valves V3 and V4, and turning on the operation of the circulation pump 26. Is called. This circulation cleaning of the substrate is performed for the purpose of shortening the time required for the cleaning.
[0013]
Supercritical carbon dioxide mixed with auxiliaries A in which contaminants after cleaning the substrate (organic substances, inorganic substances, metals, particles, water, etc. dissolved or dispersed from the substrate into the supercritical carbon dioxide by cleaning) are mixed is reduced in pressure. After the final decompression is performed in the vessel 27 and vaporization is performed, the gas is separated into gaseous carbon dioxide, auxiliary agent A, and contaminants in the separation and recovery tank 28. The separated auxiliary A and contaminants are discharged, and gaseous carbon dioxide is recovered and reused in the condenser 22. The above cleaning process is repeated for a predetermined time to complete the substrate cleaning.
[0014]
[Problems to be solved by the invention]
On the other hand, in the conventional high-pressure processing apparatus described above, since the substrate is cleaned by circulating the supercritical fluid and the auxiliary agent, the mixed auxiliary agent gradually becomes inactive as the cleaning time elapses ( In other words, the auxiliary agent concentration in the supercritical fluid decreases. For this reason, the mixer 30 is mixed with an amount of auxiliary agent considering the deactivation.
[0015]
However, in the conventional high-pressure treatment apparatus, it is impossible to accurately grasp how much the auxiliary agent is deactivated in the circulation cleaning process. Therefore, usually, the amount of auxiliary agent (the auxiliary agent concentration in the supercritical fluid) to be mixed with the supercritical fluid is determined based on standard values, empirical values, and the like. For this reason, a problem that the amount of the auxiliary agent is excessively large and the auxiliary agent is consumed wastefully, and a problem that the amount of the auxiliary agent is too small and the substrate cleaning is insufficient are generated.
[0016]
Further, the conventional high-pressure processing apparatus cannot accurately grasp the completion point of the substrate cleaning process. For this reason, it is necessary to take a long cleaning time so that the substrate is sufficiently cleaned, which causes a deterioration in the throughput of the processing process.
[0017]
Such a problem is not limited to a cleaning method using a supercritical fluid, but a subcritical fluid that is a high-pressure processing fluid or a high-pressure gas such as ammonia is used to develop, clean, and dry a substrate in a sealed processing tank. The same applies to high-pressure processing.
[0018]
The subcritical fluid generally refers to a high-pressure liquid in a region before the critical point in FIG. Although fluids in this region may be distinguished from supercritical fluids, physical properties such as density change continuously, so there are no physical boundaries and they are used as subcritical fluids. In some cases. In the subcritical or broad sense, those existing in the supercritical region near the critical point are also called high-density liquefied gas.
[0019]
Therefore, the object of the present invention is to stabilize the substrate processing performance by grasping the chemical concentration in the processing fluid in the circulation processing process, accurately grasping the completion point of the substrate processing, and optimally controlling the chemical concentration. The present invention also provides a high-pressure processing apparatus that improves throughput.
[0022]
[Means for Solving the Problems and Effects of the Invention]
A first invention is an apparatus for processing a substrate using a supercritical fluid,
A supercritical fluid supply unit for supplying a predetermined supercritical fluid;
A mixing unit for mixing a predetermined chemical solution with the supplied supercritical fluid;
A substrate processing unit that uses a supercritical fluid mixed with a chemical solution, circulates the fluid for a predetermined period, and processes a substrate installed in the processing tank;
A concentration detector for detecting the concentration of the chemical in the supercritical fluid mixed with the circulating chemical,
A concentration control unit for controlling the amount of the chemical solution supplied to the mixing unit based on the chemical solution concentration detected by the concentration detection unit so that the chemical solution concentration in the supercritical fluid is always a predetermined value ;
Density control unit, when the chemical concentration detected by the concentration detecting portion is stabilized, you characterized in that it is determined that the substrate processing in the substrate processing unit has been completed.
[0023]
As described above, according to the first invention, the concentration of the chemical solution in the supercritical fluid in the circulation process is detected, and the supply of the chemical solution is controlled so that the concentration is always constant. As a result, there is no excessive supply or insufficient supply, and the substrate can always be processed with a chemical solution having a constant concentration. Therefore, there is no wasteful consumption of the chemical solution, and there is no reduction in the cleaning capability accompanying the deactivation of the chemical solution over time due to the circulation treatment, and the substrate processing performance can be stabilized. In addition, according to the first invention, since the completion point of the substrate processing can be accurately determined, it is not necessary to perform the processing for a long time in order to prevent the occurrence of insufficient processing, and the throughput of the processing process can be improved. It becomes possible.
[0026]
The second invention is an invention subordinate to the first invention,
An optical concentration detection method using a characteristic that light is absorbed or scattered by a chemical solution is used for the concentration detection unit.
[0027]
The third invention is an invention subordinate to the second invention,
The concentration detection unit is characterized by simultaneously detecting concentrations of two or more kinds of chemical solutions using two or more different light wavelengths according to the characteristics of the chemical solutions.
[0028]
As described above, according to the second and third inventions, it is possible to accurately and easily detect the concentration of one or more chemical solutions in a fluid by making good use of the optical characteristics of the chemical solution. I can .
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a configuration of a high-pressure processing apparatus according to an embodiment of the present invention. In FIG. 1, the high-pressure processing apparatus according to the present embodiment includes a cylinder 1, a condenser 2, a booster 3, a heater 4, a mixer 10, a concentration detector 11, a concentration controller 12, It comprises a substrate cleaning tank 5, a circulation pump 6, a decompressor 7, a separation / recovery tank 8, and valves V1 to V7.
[0030]
First, each structure of the high-pressure processing apparatus of this embodiment is demonstrated.
The cylinder 1 is filled with liquefied carbon dioxide used for cleaning the substrate. The condenser 2 cools and liquefies the gaseous carbon dioxide supplied from the separation and recovery tank 8. The pressurizing means 3 boosts the liquid carbon dioxide liquefied by the condenser 2 to a predetermined pressure equal to or higher than the critical pressure Pc. The heater 4 heats the liquid carbon dioxide boosted by the booster 3 to a predetermined temperature that is equal to or higher than the critical temperature Tc. Thereby, the liquid carbon dioxide changes to a supercritical fluid (see FIG. 4). This supercritical carbon dioxide corresponds to one of high-pressure processing fluids applicable to the present invention.
[0031]
Three types of chemical solutions are supplied to the mixer 10 through valves V5 to V7 under the control of the concentration controller 12. In the high-pressure processing apparatus of the present invention, in order to remove polymer contaminants such as resist and etching polymer attached to the semiconductor substrate, the chemical solution is considered in view of the fact that the cleaning power is insufficient with only the high-pressure fluid of carbon dioxide. A cleaning process is performed with a processing fluid to which is added. The chemical solution to be added is referred to as an auxiliary agent. As the auxiliary agent, it is preferable to use a basic compound as a cleaning component. This is because the basic compound has an action of hydrolyzing a high-resistive polymer substance and has a high cleaning effect. Specific examples of the basic compound include 1 selected from the group consisting of quaternary ammonia hydroxide, quaternary ammonia fluoride, alkylamine, alkanolamine, hydroxylamine (NH2OH) and ammonium fluoride (NH2F). More than one kind of compound may be mentioned. It is preferable that 0.05-8 mass% of washing | cleaning components are contained with respect to a high pressure fluid.
[0032]
When the cleaning component such as the basic compound is incompatible with the high-pressure fluid, it is preferable to use a compatibilizing agent that can serve as an auxiliary for dissolving or uniformly dispersing the cleaning component in carbon dioxide. The compatibilizing agent is not particularly limited as long as the washing component can be compatibilized with a high-pressure fluid, but preferred examples include alcohols such as methanol, ethanol, and isopropanol, and alkyl sulfoxides such as dimethyl sulfoxide. What is necessary is just to select a compatibilizing agent suitably in the range of 10-50 mass% of a high pressure fluid in a washing | cleaning process.
[0033]
That is, a predetermined auxiliary agent A is supplied via the valve V5, a predetermined auxiliary agent B is supplied via the valve V6, and a predetermined compatibilizer is supplied via the valve V7. In this embodiment, two kinds of aids A, but will be described the case of using B, type and number of aids, can be freely set based on the target substrate or cleaning purposes or the like. The mixer 10 mixes the auxiliaries A and B and the compatibilizer supplied with the generated supercritical carbon dioxide, and sends them to the substrate cleaning tank 5.
[0034]
The concentration detector 11 detects the concentrations of the auxiliary agents A and B in the supercritical fluid, respectively. The concentration controller 12 controls the opening and closing of the valves V5 and V6 based on the detection result given from the concentration detector 11.
[0035]
In the substrate cleaning tank 5 as the processing tank, the substrate is cleaned using supercritical carbon dioxide produced and mixed with the auxiliary agents A and B and the compatibilizing agent.
[0036]
The decompressor 7 decompresses the supercritical carbon dioxide mixed with the auxiliary agents A and B and the compatibilizing agent that have been cleaned in the substrate cleaning tank 5. As a result, supercritical carbon dioxide is vaporized. In the separation / recovery tank 8, the carbon dioxide vaporized by the decompressor 7, the chemical solution (auxiliaries A and B and the compatibilizing agent), and contaminants are separated, and gaseous carbon dioxide is supplied to the condenser 2 again. Is done.
[0037]
The valves V1 and V2 are valves used for separating the circulation path of the cleaning process and the supply / recovery path of the processing fluid. The valve V <b> 1 is provided on a pipe that connects the secondary side of the booster 3 and the primary side of the heater 4. The valve V <b> 2 is provided on a pipe that connects the secondary side of the substrate cleaning tank 5 and the primary side of the decompressor 7.
[0038]
The valves V3 and V4 are valves used for forming a circulation path for the cleaning process. The valve V3 is provided on a pipe connecting the discharge port of the circulation pump 6 and the primary side of the heater 4. The valve V4 is provided on a pipe connecting the secondary side of the substrate cleaning tank 5 and the suction port of the circulation pump 6.
[0039]
The valve V <b> 5 is a valve used for supplying the auxiliary agent A to the mixer 10, and is provided on a pipe connecting the tank (not shown) in which the auxiliary agent A is stored and the mixer 10. The valve V <b> 6 is a valve used to supply the auxiliary agent B to the mixer 10, and is provided on a pipe connecting the tank (not shown) in which the auxiliary agent B is stored and the mixer 10. The valve V <b> 7 is a valve used to supply the compatibilizer to the mixer 10, and is provided on a pipe connecting the tank (not shown) in which the compatibilizer is stored and the mixer 10.
[0040]
Here, the piping system leading to the cylinder 1 and the substrate cleaning tank 5 corresponds to the fluid supply unit of the present invention. A piping system including the decompressor 7 and the separation / recovery tank 8 downstream from the substrate cleaning tank 5 functions as a fluid recovery unit that recovers and reuses the supercritical fluid after the substrate cleaning. The substrate cleaning tank 5 constitutes a substrate processing unit.
[0041]
Next, the substrate cleaning operation performed by the high-pressure processing apparatus according to the present embodiment having this configuration will be described with further reference to FIG. FIG. 2 is a flowchart showing the procedure of the auxiliary agent concentration control method performed in the high pressure processing apparatus of the present embodiment.
In the present embodiment, the case where carbon dioxide is used as the high-pressure fluid will be described. However, other substances that can be changed to a supercritical fluid state such as nitrous oxide, alcohol, ethanol, and water may be used. The substrate cleaning method used in the substrate cleaning tank of this embodiment may be either a batch method or a single wafer method for simultaneously cleaning a plurality of substrates.
[0042]
First, a substrate that is an object to be cleaned is placed in the substrate cleaning tank 5. When the substrate is installed, the following cleaning process is started in which the valves V1 and V2 are opened and the valves V3 to V7 are closed.
[0043]
First, carbon dioxide is stored in the cylinder 1 as a liquid at a pressure of 5 to 6 MPa, and this liquid carbon dioxide is supplied to the condenser 2 and stored as a liquid. The liquid carbon dioxide is pressurized to a pressure equal to or higher than the critical pressure Pc in the pressure increasing means 3, further heated to a predetermined temperature equal to or higher than the critical temperature Tc in the heater 4 to become a supercritical fluid, and sequentially sent to the mixer 10. Here, the predetermined pressure and temperature can be freely set based on the type of the substrate to be cleaned and the desired cleaning performance.
[0044]
As an initial state, the concentration controller 12 controls the opening and closing of the valves V5 and V6 to supply the auxiliary agents A and B to the mixer 10 so that the concentration in the supercritical carbon dioxide becomes a predetermined value, respectively ( Step S21). The mixer 10 mixes the supplied auxiliaries A and B and supercritical carbon dioxide, and supercritical carbon dioxide in which the auxiliaries A and B are mixed at a predetermined concentration passes through the concentration detector 11 and is a substrate cleaning tank. Send to 5.
[0045]
At this time, the opening and closing of the valve V7 is also controlled, and the compatibilizing agent is also supplied to the mixer 10 at the same time. The supply amount of the compatibilizer is a predetermined amount set in advance. In this embodiment, the compatibilizing agent acts to disperse the auxiliary agents A and B in supercritical carbon dioxide, and the concentration does not change during the substrate cleaning period, or the substrate cleaning power is affected even if the concentration changes. This is because it is selected as a chemical solution that is not to be allowed.
[0046]
When the supercritical carbon dioxide supply / recovery path (between the secondary side of the pressurizing means 3 and the primary side of the pressure reducer 7) is filled with supercritical carbon dioxide mixed with the auxiliary agents A and B and the compatibilizing agent. By closing the valves V1 and V2, opening the valves V3 and V4 and turning on the circulation pump 6, the supercritical carbon dioxide mixed with the auxiliary agents A and B and the compatibilizing agent is circulated for a predetermined period. The substrate is cleaned. In the substrate cleaning tank 5, the substrate is cleaned with the supercritical carbon dioxide in the high pressure state.
[0047]
When the substrate is cleaned by circulating supercritical carbon dioxide mixed with the auxiliary agents A and B and the compatibilizer, the auxiliary agents A and B are used and the concentration in the supercritical carbon dioxide gradually decreases. come. Therefore, in the present invention, the concentration detector 11 detects the concentrations of the auxiliary agents A and B in the supercritical carbon dioxide, and sequentially transmits the detection results to the concentration controller 12 (step S22).
[0048]
Then, the concentration controller 12 controls the valve V5 so that the concentrations of the auxiliary agents A and B in the supercritical carbon dioxide can always be kept at a predetermined value according to the concentration detected by the concentration detector 11 (steps S23 to S25). The auxiliary agents A and B are additionally supplied to the mixer 10 by individually controlling the opening and closing of V6 (steps S26 to S28).
[0049]
Here, when both the concentrations of the auxiliary agents A and B detected by the concentration detector 11 are stable (the concentration does not decrease and the predetermined value is maintained), the concentration controller 12 completes the substrate cleaning. It is determined that the auxiliary agents A and B are not supplied (step S29). Thus, in the present invention, changes in the concentrations of the auxiliary agents A and B are detected, and the change in concentration is used as an index for completion of substrate cleaning.
[0050]
When the completion of the substrate cleaning is confirmed according to the above judgment, the valve V2 is opened and the supercritical carbon dioxide mixed with the auxiliary agents A and B is collected / reused. The supercritical carbon dioxide in which the auxiliary substances A and B in which the pollutants are dissolved or dispersed and the compatibilizing agent are mixed is decompressed and vaporized in the decompressor 7 and then separated into gaseous carbon dioxide gas in the separation and recovery tank 8. , Separated into chemicals (auxiliaries A and B and compatibilizers) and contaminants. The separated chemicals (auxiliaries A and B and compatibilizer) and contaminants are discharged, and the carbon dioxide gas is recovered and reused in the condenser 2.
[0051]
Contaminants may be deposited as solids and mixed into the chemical solution to be separated. The liquid (or solid) component composed of the auxiliary agent and the compatibilizing agent containing the separated contaminants is discharged, and the gaseous carbon dioxide is recovered and reused in the condenser 2. For example, the decompressor 7 maintains the supercritical carbon dioxide at about 80 ° C. or more, and reduces the pressure from 15 MPa to 6 MPa to make gaseous carbon dioxide.
[0052]
Next, an example of a specific configuration of the concentration detector 11 that detects the concentrations of the auxiliary agents A and B in the supercritical carbon dioxide will be described with reference to FIG. FIG. 3 shows an optical concentration detector 11 using light absorption or scattering (Raman scattering).
[0053]
The light from the light source 31 is collected by the lens 32, passes through the supercritical carbon dioxide mixed with the auxiliary agents A and B flowing in the pipe, and is emitted to the light detection unit 33. Here, of the emitted light, the light component of the specific wavelength a is absorbed by the auxiliary agent A, and the light component of the specific wavelength b is absorbed by the auxiliary agent B. Therefore, the light detection unit 33 detects only the amount of the light components having the specific wavelengths a and b that are not absorbed by the auxiliary agents A and B in the supercritical carbon dioxide.
[0054]
The amount of light absorbed by the auxiliary agent increases or decreases with the auxiliary agent concentration. Therefore, the amplification calculation unit 34 amplifies the light detected by the light detection unit 33 as necessary, and then, based on the amount of the light component of the specific wavelength a and the amount of the light component of the specific wavelength b, the auxiliary agent A, Each density of B is calculated, and a density signal for controlling the density controller 12 according to the calculation result is output. As described above, in the concentration detector 11 of FIG. 3, the concentration detection for each auxiliary agent can be detected by effectively utilizing the fact that the light wavelength absorbed by the auxiliary agent A and the optical wavelength absorbed by the auxiliary agent B are different. It is possible.
[0055]
Alternatively, the light detection unit 33 may detect the scattered light, and the concentration of each auxiliary agent may be detected based on the spectral intensity of the scattered light.
[0056]
As described above, according to the high-pressure processing apparatus according to one embodiment of the present invention, the concentration of the auxiliary agent in the supercritical fluid in the circulation cleaning process is detected, and the auxiliary agent is supplied so that the concentration is always constant. To control. As a result, there is no excessive supply or insufficient supply, and the substrate can always be cleaned with an auxiliary agent having a constant concentration. Therefore, there is no wasteful consumption of the auxiliary agent, and there is no reduction in the cleaning ability due to the deactivation of the auxiliary agent over time due to the circulation cleaning, and the substrate cleaning performance can be stabilized. In addition, since the completion point of the substrate cleaning process can be accurately determined, it is not necessary to perform cleaning for a long time in order to prevent the occurrence of insufficient cleaning, and the throughput of the processing process can be improved.
[0057]
In addition, this invention is not limited to the Example and modification which were mentioned above, It can implement also with another form as follows.
[0058]
(1) In the above embodiment, when the auxiliary agent concentration in the supercritical carbon dioxide is detected and the opening and closing of the supply valve is sequentially controlled so that the auxiliary agent concentration in the supercritical fluid is always maintained at a constant value. Explained. However, the auxiliary agent is first mixed with the supercritical carbon dioxide at a sufficient concentration in advance, and the auxiliary agent concentration does not decrease without additional supply of the auxiliary agent due to the concentration change (concentration is saturated). Only when the substrate cleaning process is completed may be determined.
[0059]
(2) If a chemical solution whose concentration varies during the substrate cleaning period is selected as the compatibilizer, the compatibilizer concentration in the supercritical fluid is detected by detecting the compatibilizer concentration in the supercritical carbon dioxide. You may control so that it may always be kept at a constant value.
[0060]
(3) In the above embodiment, the decompressor 7 is disposed downstream of the substrate cleaning tank 5 and vaporizes the supercritical fluid, and then sends it to the separation / recovery tank 8. You may comprise so that gas-liquid separation may be carried out after decompressing.
[0061]
(4) In the above embodiment, the processing fluid is supplied to the substrate cleaning tank 5 as a supercritical fluid. The predetermined high-pressure state supplied to the substrate cleaning tank 5 may be 1 MPa or more, preferably , A fluid with high density, high solubility, low viscosity, and high diffusivity. Therefore, it cannot be overemphasized that it can implement using a subcritical fluid or high-pressure gas. Further, the cleaning process can be suitably carried out by supplying a processing fluid whose pressure is increased to 5 MPa or more. And it is preferable to carry out at 5-30 Mpa, More preferably, it is performing these processes under 7.1-20 Mpa.
[0062]
(5) Moreover, although the said high voltage | pressure processing apparatus demonstrated the board | substrate washing | cleaning, it may be used for board | substrate drying or board | substrate development. That is, the substrate after rinsing (water washing) is carried in and installed in the substrate cleaning tank 5. The water adhering to the substrate in the substrate cleaning tank 5 is dissolved and removed in a high-pressure processing fluid in a supercritical or subcritical state. Thereafter, the processing fluid is recovered and reused as in the above embodiment. When the high-pressure processing apparatus of the present invention is used for drying or development, xylene, methyl isobutyl ketone, a quaternary ammonium compound, a fluorine-based polymer, or the like is used as a chemical solution depending on the properties of the resist to be dried or developed. do it.
[0063]
In addition, various design changes can be made within the scope of technical matters described in the claims.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a high-pressure processing apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure of an auxiliary agent concentration control method performed in a high pressure processing apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a specific configuration example of the concentration detector 11 of FIG. 1;
FIG. 4 is a diagram illustrating a supercritical fluid.
FIG. 5 is a block diagram showing an example of the configuration of a conventional apparatus that performs substrate cleaning using a supercritical fluid.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,21 ... Cylinders 2, 22 ... Condensers 3, 23 ... Boosting means 4, 24 ... Heaters 5, 25 ... Substrate cleaning tanks 6, 26 ... Circulating pumps 7, 27 ... Decompressors 8, 28 ... Separation and recovery tanks DESCRIPTION OF SYMBOLS 10, 30 ... Mixer 11 ... Concentration detector 12 ... Concentration controller 31 ... Light source 32 ... Lens 33 ... Light detection part 34 ... Amplification calculating part V1-V7 ... Valve

Claims (3)

An apparatus for processing a substrate using a supercritical fluid,
A supercritical fluid supply unit for supplying a predetermined supercritical fluid;
A mixing unit for mixing a predetermined chemical with the supplied supercritical fluid;
Using a supercritical fluid mixed with the chemical solution, circulating the fluid for a predetermined period, and processing a substrate installed in a processing tank; and
A concentration detector that detects the concentration of the chemical in the supercritical fluid mixed with the circulating chemical.
A concentration control unit for controlling the amount of the chemical solution supplied to the mixing unit based on the chemical solution concentration detected by the concentration detection unit so that the chemical solution concentration in the supercritical fluid always becomes a predetermined value; With
The high-pressure processing apparatus, wherein the concentration control unit determines that the substrate processing in the substrate processing unit is completed when the concentration of the chemical solution detected by the concentration detection unit is stabilized.   The high-pressure processing apparatus according to claim 1, wherein an optical concentration detection method using a characteristic that light is absorbed or scattered by the chemical solution is used for the concentration detection unit.   The high-pressure processing according to claim 2, wherein the concentration detection unit simultaneously detects the concentrations of two or more kinds of the chemical solutions using two or more different light wavelengths according to the characteristics of the chemical solutions. apparatus.

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