JPH04104841A - Clean draft chamber - Google Patents

Abstract

PURPOSE:To prevent the leakage of a harmful chemical vapor into a clean room by providing a line for supplying a cleaned downflow air current to a treating tank set in a chamber and a line for entraining the chemical vapor generated from the treating tank in the downflow air current and exhausting the vapor outside the system. CONSTITUTION:An air blower 4 and an exhaust fan 7 are operated in a clean draft chamber 1, and the clean air in a clean room is heated by a duct heater 12 and then cleaned by a high-performance filter 3 to form a downflow air current A which flows down in the chamber space 1a toward a treating tank 2. When the current A arrives at the upper surface of the tank 2, the current flows into the suction port 14 of a suction hood 13 opened around the upper surface as a high-speed sucked gas current C which is sucked and exhausted outside the system through a trap 15, exhaust channel 16, exhaust duct 6 and exhaust fan 7. The chemical vapor blocked by the current A is hardly diffused or leaked into the space 1a, and the vapor is sucked into the suction port 14 of the hood 13 by the induction of the current C immediately after appearing on the upper surface of the tank 2. The recrystallization of the chemical vapor and the deposition of the crystal product on the upper lid are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a clean draft chamber that is installed in a clean room and performs chemical treatment of semiconductor wafers or the like or concentration treatment of semiconductor chemicals.

[Conventional technology]

Semiconductor manufacturing processes include chemical cleaning processes for semiconductor wafers using chemicals, etching processes, and the like.

In other words, in the chemical cleaning process, semiconductor wafers are cleaned by immersing them in a solution containing hydrogen peroxide, ammonia, hydrochloric acid, sulfuric acid, etc. that is heated to high temperature, and in the etching process, the semiconductor wafer is cleaned using solutions containing hydrofluoric acid, nitric acid, etc. By the way, when performing such chemical processing on semiconductor wafers, the chemical solution is usually placed in a clean draft chamber installed in a clean room to avoid particle contamination on the semiconductor wafers. A treatment tank containing the chemicals is installed to perform the various chemical treatment operations described above.

This clean draft chamber blows clean downflow airflow from above through a high-performance filter (HEPA filter, ULPA filter) into a processing tank installed in the chamber, and removes chemical vapor generated from the processing tank during the chemical processing process. This prevents harmful chemical vapor from leaking into the clean room by enveloping it in the downflow airflow and exhausting it out of the system.

On the other hand, as an energy-saving clean draft chamber that can reliably exhaust chemical vapor with as little air volume as possible, a structure as shown in Fig. 7 has been proposed in Japanese Patent Application Laid-Open No. 63-248449. .

That is, in FIG. 7, l is a clean draft chamber, 2 is a processing tank installed on the workbench inside the chamber, 2a is a heater for heating a chemical solution, 3 is a high-performance filter such as an LPA filter installed on the ceiling side of the chamber, 4 is an air supply fan arranged on the vL side above the fan 3, 5 is an exhaust port opened on the back side of the chamber, 6 is an exhaust duct connected to the exhaust port,
7 is an exhaust fan, 8 is a second air supply fan disposed at the bottom of the chamber, and 9 is a high-performance filter disposed in the passage of the air supply duct 10 that opens on the upper front side of the processing tank 2.

In a clean draft chamber with such a configuration, for example,
The semiconductor wafer is accommodated in a carrier by operation of a handling robot or the like and immersed in a chemical solution in the processing PF2, and a predetermined chemical solution treatment process is performed.

If the air supply fan 4.8 is operated at this time, there will be a downflow airflow (arrow A) flowing from the ceiling side through the high-performance filter 3 into the chamber, and a processing tank flowing from the front to the rear of the chamber. A horizontal air curtain airflow (arrow B) is formed that flows above the air curtain 2.

As a result, the harmful chemical vapor generated and rising from the processing tank 2 is enveloped by the downflow airflow A and the air curtain airflow B, suppressing its diffusion and escape to the surroundings, and sucking it out of the system through the exhaust duct 6. Exhausted.

By the way, the configuration of the clean draft chamber described above is suitable for chemical treatment of semiconductor wafers and one of the chemical solutions described below.
The following problems remain when performing the Ill shrinking process.

(1) Processing tanks and rinsing tanks filled with chemicals are lined up in a clean draft chamber, and when semiconductor wafers are transferred between the processing tanks and rinsing tanks by robot operation from the front of the chamber, the robot's hands, carriers, etc. As the member crosses the horizontal air curtain airflow B, turbulence occurs in the laminar flow of the air curtain, and this turbulence in the laminar flow further interferes with the downflow airflow A, disturbing the laminar flow, and as a result, processing The ability to envelop the chemical vapor generated from the tank is extremely degraded.

(2) For example, a honeycomb-shaped rectifier plate is built into the outlet of the air supply duct that blows out the horizontal air curtain airflow B, but in such a structure, the rectifier plate becomes a source of dust and enters the processing tank. There is a risk that the chemical liquid semiconductor wafers contained therein may be contaminated.

(3) If processing tanks are arranged in a row in front of each other in the chamber, impurities generated from the processing tanks in the front row (on the upstream side of the air curtain airflow) will There is a risk that the chemical solution riding on the curtain airflow B may interfere with and contaminate the chemical solutions in the processing tanks arranged in the rear row (downstream side of the air curtain airflow).

(4) On the other hand, it is necessary to maintain the various chemical solutions used in the semiconductor manufacturing process at a high purity level (preferably at ppt level), and in order to control the purity of the chemical solutions, the chemical solutions are analyzed from time to time to measure impurity concentrations. things are being done. In this case, the chemical analysis method involves first placing a chemical sample in an evaporation dish as a pretreatment, heating it to evaporate and concentrate it, and using an atomic absorption analyzer, flame spectrophotometer, etc., on the concentrated chemical sample.
Generally, a method is adopted in which content components are analyzed using equipment such as a fluorescent X-ray analyzer.

In this case, in order to avoid contamination such as dust from getting into the chemical solution during the pre-treatment step of concentrating the drug sample, the clean space of the clean draft chamber described above is used to remove the drug W1. The sample is subjected to shrinkage processing.

Specifically, as shown in FIG. 8, a plurality of evaporation dishes 11 individually filled with chemical samples are placed on a heater 28 (actual plate) in a processing tank 2 installed in a clean draft chamber. While being heated and contracted side by side, the chemical vapor generated from each evaporating dish and rising upward during this concentration process is enveloped in the downflow airflow A and air curtain airflow B and exhausted to the outside of the system.

However, as described in FIG. 7, when a horizontal air curtain air flow B is blown out to the upper surface of the processing tank 2, air is generated from the chemical solution in one shot tray lined up on the upstream side with respect to the air curtain air fiB. A problem arises in that these impurities interfere with and contaminate the chemical solution in the evaporation dishes arranged downstream.

Therefore, the inventors of the present invention have developed a method for connecting a plurality of processing tanks arranged in rows and columns inside a clean draft chamber, or between a plurality of evaporation dishes for chemical liquid concentration arranged in front and back rows in the same processing tank. A clean draft chamber capable of preventing the interference contamination of impurities as described above was developed and proposed in Japanese Patent Application No. 1-102.025.

The contents are as follows: For a processing tank installed in a clean draft chamber, a suction hood that surrounds the upper surface of the processing tank and communicates with the exhaust system is placed, and an air intake port that opens on the inner circumference side of the suction hood is used to The chemical vapor generated from the processing tank is sucked together with the downflow airflow flowing down from the processing tank and exhausted to the outside of the system.

According to the above configuration, the downflow airflow that flows down inside the chamber from above toward the processing tank becomes a high-speed suction airflow through the intake port that opens around the top surface of the processing tank and flows into the suction hood. It is sucked in, and from here it is sucked and exhausted out of the system via the exhaust route. From this number two, the harmful chemical vapor generated and rising from the processing tank is attracted by the aforementioned high-speed suction airflow that is sucked into the suction hood.
Without diffusing into the space inside the chamber, it is immediately sucked into the suction hood from the area around the upper surface of the chemical tank and exhausted to the outside of the system. Therefore, it is possible to effectively prevent the interference of the chemical liquid H μ between the processing tanks arranged in rows and columns in the chamber or between the single-shot plates for chemical liquid concentration housed side by side in the processing tanks.

(Third point to be solved by the invention!) By the way, when actually performing chemical processing work using the proposed clean draft chamber, it is necessary to ensure that the chemical vapor generated from the processing tank is not diffused to the surrounding area. Although this can be prevented, it has become clear that the following problems occur.

In other words, the airflow that flows down from above toward the processing tank in the chamber has almost the same temperature as the room temperature in the clean room (which is air conditioned to a relatively low temperature by air conditioning equipment), so the airflow is generated from the processing tank and rises up. The chemical liquid components (for example, components such as ammonium fluoride and ammonium chloride) contained in the chemical liquid vapor are cooled by the downflow air current, and recrystallization is promoted. As a result, a large amount of crystalline products adheres and accumulates inside the above-mentioned suction bow hood 3 and the exhaust duct leading to the suction hood.

This deposit is removed by cleaning after stopping the operation of the clean draft chamber during regular maintenance inspections, but cleaning and removal work is extremely troublesome as it is highly toxic. However, especially if crystalline products adhering to the suction hood peel off from the hood and fall into the chemical solution, this becomes a source of contamination.

The present invention has been made in consideration of the above points, and is designed to prevent interference contamination between treatment tanks or between evaporation dishes for concentrating chemical solutions housed side by side in a treatment tank during various chemical treatments. It is an object of the present invention to provide a clean draft chamber that can effectively prevent recrystallization of chemical liquid vapor generated from a processing tank or individual evaporation dishes.

(Means for Solving the Problems) In order to solve the above problems, the present invention is configured as follows.

(1) An air supply system that sends purified downflow airflow from above to the processing tank installed in the chamber, and an exhaust system that sucks and exhausts the chemical vapor generated from the processing tank into the downflow airflow outside the system. system, a suction hood that surrounds the upper surface area of the processing tank and communicates with the exhaust system for each processing tank installed in the chamber, and heating means for downflow airflow provided in the air supply system. Configure a clean draft chamber.

(2) In the configuration of item 1 of (1) above, the intake port is opened over the entire circumference of the suction hood.

(3) In the configuration described in item (1) above, a tube is provided downstream of the suction hood to separate and collect the crystalline product of the chemical liquid component from the exhaust flow.

(4) In the configuration described in item (1) above, the chemical solution supply pipe piped to the chemical solution tank bypasses the outer periphery of the suction hood and is drawn into the upper surface of the chemical solution tank.

(5) In the configuration described in item (1) 1 above, chemical liquid concentration processing is performed by arranging chemical liquid evaporating dishes equipped with chemical liquid heaters in front and back rows in the processing tank.

(6) In the configuration of item (1) above, the downflow airflow heating means is provided upstream of the high-performance filter.

(7) An air supply system that blows purified downflow air from above toward a processing tank with a top lid installed in the chamber, a hot plate for heating the chemical solution installed at the bottom of the processing tank, and the bottom surface of the processing tank. , an air guide port opened at the top of the side surface, and an exhaust system that sucks and exhausts the guided air flow flowing into the processing tank through the air guide port to the outside of the system, thereby forming a clean draft chamber.

(8) An air supply system that sends purified downflow air from above to a processing tank with a top lid installed inside the chamber, a real plate for heating the chemical solution installed at the bottom of the processing tank, and A second air supply system that cleans the air and pushes it into the tank through air guide ports opened on the lower surface and upper side of the processing tank, and a guide airflow that flows inside the processing tank and flows down inside the chamber. A clean draft chatuba is constructed by including an exhaust system that combines the downflow airflow and suctions and exhausts the air to the outside of the system.

(Operation) With the configuration described in item (1) above, clean air heated and heated by the heating means of the air supply system is blown into the chamber as a downflow airflow and flows down toward the processing tank located at the lower part of the chamber. The downflow airflow that has reached the upper surface of the processing tank is drawn into the suction hood as a high-speed suction airflow through the intake port that opens around the processing tank, and is exhausted from there to the outside of the system via the exhaust system. If various chemical processing operations are carried out in the processing tank in this state, harmful chemical vapors generated and rising from the processing tank will be attracted by the high-speed suction airflow, and will not diffuse into the space inside the chamber. The liquid is immediately sucked into the suction hood from the area around the top surface, and from there it is suctioned and exhausted outside the system via the exhaust system.Therefore, there is no interference between the processing tanks lined up in the chamber or the chemical evaporation plates housed side by side in the processing tank. It is possible to reliably prevent contamination of chemical vapors that interact with each other.Furthermore, since the downflow airflow is heated to a raised temperature (for example, about 100°C) by a heating means, even if the chemical vapor comes into contact with the downflow airflow, it will not reheat. It does not crystallize and can effectively prevent crystal products from adhering and depositing in the suction hood or the exhaust duct downstream thereof.

In this case, by opening the intake port over the entire circumference of the suction hood as described in (2), for example, when evaporating dishes are arranged in front and back rows in the processing tank to perform concentration processing of the chemical solution. However, the chemical vapor generated from each evaporating dish is sucked into the suction cup hood without passing over the other evaporating dishes. Therefore, interference contamination between the evaporating plates can be reliably prevented.

In addition, the trap described in item (3) combined on the downstream side of the suction hood works to separate and collect crystal products generated when the chemical vapor after passing through the suction hood is cooled by the ambient temperature from the exhaust flow. Therefore, it is possible to prevent these crystal products from depositing in the exhaust system duct on the downstream side.

In addition, as in item (4), the chemical solution supply pipe that supplies the chemical solution for processing semiconductor wafers to the processing tank can be routed to the top surface of the chemical solution tank bypassing the outer periphery of the suction hood, thereby connecting the processing tank and the suction hood. There is no need to secure piping space between them, and the suction hood's intake port can be opened close to the upper surface area of the chemical solution tank, and maintenance work can be carried out without removing the suction hood even when inspecting the chemical solution supply pipe. I can do it.

In addition, if the chemical solution is concentrated by arranging evaporation dishes in the processing tank as described in item (5), the chemical vapor generated from the evaporation dishes and rising up will flow directly into the suction hood that opens around the upper surface of the processing tank. Since the chemical liquid is sucked in, it is possible to safely perform the chemical liquid contraction operation by arranging a plurality of evaporating dishes in front and back rows without fear of interference and contamination. Moreover, by adopting a structure in which a heater is integrated into each evaporating dish, it is possible to individually manage the temperature of the chemical solution in each evaporating dish by thermo control, for example, to prevent sudden boiling of the chemical solution.

Furthermore, the duct heater in item (6) heats and raises the temperature of the downflow airflow blown into the chamber through the high-performance filter. Therefore, the chemical vapor generated from the processing tank does not come into contact with the downflow airflow and recrystallize.

On the other hand, in the configuration of item (7), the downflow airflow flowing down inside the chamber flows through the inside of the processing tank with a top lid installed in the chamber, and the chemical solution tank 5 for semiconductor wafer processing accommodated therein or the chemical solution Together with the chemical vapor generated from the concentrating evaporation dish, it is sucked out of the system through the exhaust system.

Here, the air flowing into the tank through the air guide opening on the bottom of the processing tank is heated and heated up as it flows around the hot plate installed at the bottom of the tank, so the chemical vapor rising from the evaporation dish etc. prevents it from recrystallizing upon contact with the guiding air current. In addition, the guiding airflow that flows on the back side of the top lid through the opening at the top of the side of the processing tank functions as an air curtain to suppress the chemical vapor, and the chemical vapor is directed to the top of the processing tank (the downflow airflow directly hits the top surface of the top lid). This works to prevent recrystallization by touching the back side of the liquid (where the temperature is low).This can at least prevent the formation of crystals of the chemical component in the processing tank.

Furthermore, in the configuration of item (8), the clean downflow air flowing down inside the chamber flows so as to wrap around the processing tank, and then is exhausted to the outside of the system through the exhaust system. On the other hand, in addition to the downflow airflow mentioned above, a clean airflow sent through the second air supply system is forced into the treatment tank and guided by spring in the same manner as described in the above (7). While preventing the generated chemical vapor from recrystallizing, it is forcibly exhausted together with the chemical vapor.

Therefore, in addition to preventing recrystallization of the chemical liquid vapor, leakage and diffusion of the chemical liquid vapor to the surroundings can be reliably prevented.

〔Example〕

Embodiment 1: FIGS. 1 to 3 are block diagrams of a clean draft chamber according to an embodiment of the present invention used for chemical liquid processing of semiconductor wafers and am treatment process of chemical liquid corresponding to claims 1 to 6 of the present invention. The same members corresponding to FIGS. 7 and 8 are given the same reference numerals.

First, in FIG. 1, in the upper part of the clean draft chamber 1, there is a high-performance filter 3 as a ULPA filter,
A duct heater 12 is installed upstream of the air supply fan 4 and the filter 3, and a processing tank 2 is installed in the lower part across the chamber interior space 18. In addition, processing tank 2
On the upper surface side, a suction hood 13 is provided surrounding the outer periphery of the chemical liquid tank 2.
is installed, and an intake port 14 facing the upper circumferential area of the processing tank 2 is opened on the inner peripheral surface side of the suction hood 13.

Further, a trap 15 is installed downstream of the suction hood 13 and communicates with the exhaust duct 5 via an exhaust air cylinder 16. Further, reference numeral 17 denotes a chemical liquid supply pipe that is piped between the chemical liquid storage tank 18 and the processing tank 2 via a liquid sending pump 19. A lead-in pipe is connected to the upper surface of the processing tank 2.

Furthermore, 20 is a cover such as a transparent vinyl curtain that covers the open front surface of the chamber 1.

Further, FIG. 2 shows an embodiment of the evaporating dish 11 used when concentrating a chemical sample in the processing tank 2. That is, the evaporation dish 11 is filled with various chemical solutions 21 (first
The outer periphery of the plate 11a made of platinum or Teflon, which has high corrosion resistance for samples (see figure), is surrounded by a case Ilb made of nickel, and a chemical solution heating heater Ilc is placed inside the case Ilb made of nickel.
It is a structure that incorporates the Although not shown, a dish temperature detection sensor, a thermostat, etc. are installed in the case llb, and the heater llc is energized to control the evaporation dish 1.
This is to avoid a drastic situation in which the chemical sample stored in 1 suddenly boils and overflows.

Although not shown, when performing chemical treatment processes such as chemical cleaning and etching treatment on semiconductor wafers,
A chemical liquid tank filled with a chemical liquid is housed in the processing tank 2 to perform chemical liquid processing.

In the clean draft chamber with the above configuration, the air supply fan 4
．． When the exhaust fan 7 is operated, the clean air taken in from the clean room is heated and heated by the duct heater 12, and the downflow airflow A, which has been purified by the high-performance filter 3, flows down the chamber space 1a toward the processing tank 2. do. When the downflow airflow A reaches the upper surface of the processing tank 2, it flows into the intake port 14 of the suction hood 13 that opens around the upper surface as a high-speed suction airflow C, and from there flows into the air intake port 14 of the suction hood 13, which is opened around the upper surface of the processing tank 2. Exhaust wind barrel 16. The air is sucked and exhausted out of the system through an exhaust duct 6 and an exhaust fan 7. Further, a part of the downflow airflow A is combined with the above-mentioned exhaust flow through an exhaust port 5 opened at the rear of the chamber 1, and is exhausted. Note that the above-mentioned air supply fan 4. The exhaust fan 7 controls the operation of the drive motor at an appropriate speed by, for example, inverter control.

Here, when various chemical liquid processing 1 is carried out in the processing tank 2, for example, when a plurality of evaporation plates 11 are arranged in front and back rows as shown in FIG. 3 and a chemical liquid sample is concentrated, chemical vapor rises from the processing tank 2. However, this chemical vapor is suppressed by the downflow airflow A flowing down from above and flows into the chamber space 1.
The air hardly diffuses and escapes to A, and is immediately sucked into the suction port 14 of the suction hood 13 when it emerges from the upper surface of the processing tank 2 due to the attraction effect of the high-speed suction air flow C mentioned above. Note that a small amount of vapor that is not sucked into the suction hood 13 and leaks into the chamber space 1a is exhausted together with the downflow airflow A through the exhaust port 5 on the back side. Therefore, the chemical solution 21 placed in the evaporation dish 11 is not contaminated with foreign matter such as dust from the surroundings, and there is no interference contamination caused by chemical vapor between the evaporation dishes 11, and the chemical solution sample can be simultaneously processed using a plurality of evaporation dishes. Concentration processing can proceed.

Moreover, since the downflow air mA flowing down inside the chamber is heated and heated by the duct heater 12, components 1 of the chemical vapor, such as ammonium fluoride and ammonium chloride (these components recrystallize when exposed to cold air), etc. Recrystallization of the components in the surrounding area of the processing tank 2 can be effectively prevented. Note that in order to prevent recrystallization of the chemical liquid components, the downflow airflow A is set at 100" by the duct heater 12.
It is best to heat it to about C.

Furthermore, in the case where a chemical liquid tank filled with a chemical liquid is housed in the processing tank 2 instead of the evaporation dish 11 described above to perform chemical liquid processing on semiconductor wafers, the chemical liquid is replenished into the chemical liquid tank through the chemical liquid supply pipe 17. be exposed. On the other hand, on the downstream side of the suction hood 13, the temperature of the exhaust flow is absorbed by the surroundings and gradually decreases, and crystals of the chemical components begin to grow in the exhaust flow. It is separated and collected from the airflow as it passes through. Note that cooling water 22 is stored at the bottom of the expansion chamber of the trap 15 to cool the exhaust flow and improve the collection efficiency of crystalline products. Note that the playing card 15 is periodically washed with washing water to remove collected crystal products.

Embodiment 2: FIG. 4 shows an embodiment corresponding to claim 7 of the present invention. In this embodiment, the processing tank 2 installed in the chamber
is a box body equipped with an upper lid 2b, and the bottom part thereof is a hot plate 2 for heating an evaporating dish 11 for concentrating a chemical solution, as shown in the figure.
It is equipped with c. Further, on the lower surface and the upper front surface of the processing tank 2, there are air guide ports 2d, 2 that pass through the chamber internal space 1a.
In addition, an air guide port 2f on the exhaust side that communicates with the exhaust duct 6 is opened in the upper rear surface at a position opposite to the above-mentioned air guide port 2e.

The other configurations are basically the same as the clean draft chamber of Example 1.

Note that among the air guide ports 2d, 2e, and 2f, the air guide port 2d on the lower surface side is opened in the area around the real brake 2c, and the air guide ports 2e, 2f on the front and rear surfaces are placed on the hot plate 2c. The opening extends over almost the entire width of the treatment 12 at a position above the evaporation dish 11 .

With such a configuration, the air supply fan 4. When the exhaust fan 7 is operated, the downflow airflow A flowing down inside the chamber flows into the tank through the air guide ports 2d and 2e, which are missing from the front and bottom sides of the processing tank 2, and flows into the tank through the air guide ports 2f on the rear side to the exhaust fan. 7, and the arrows Al, A2. A guiding airflow shown as A3 is formed. Here, the guided airflow A1 is heated and raised in temperature when passing through the area around the plate 2c (the hot plate heat generation temperature when performing chemical concentration processing is about 300°C). On the other hand, the guiding airflow A2A3 acts as an air curtain that shields the space between the evaporating dish 11 and the upper lid 2b of the processing tank 2 located above it.

Therefore, when a chemical liquid sample is concentrated in the evaporating dish 11 housed in the processing tank 2 under the above-mentioned air blowing condition, the chemical liquid vapor generated and rising from the evaporating dish 11 is enveloped by the above-mentioned blown air current flowing through the tank. It is sucked and exhausted out of the system through the exhaust duct 6 without leaking or diffusing outside the chamber.

Moreover, in this case, the guided airflow A1 flowing from the lower surface side of the processing tank 2 is heated by the hot brake 2c and has a high temperature, so that recrystallization of the chemical vapor is suppressed. In addition, the chemical vapor that attempts to rise upward in the tank is caused by a guiding airflow A2 that forms an air curtain. It is blocked by A3 and does not come into direct contact with the top lid 2b (the temperature of the top lid is low because the downflow airflow A flows directly in waves), so that no crystal products are deposited on the back surface of the top lid. Incidentally, the upper lid 2b is normally closed, and is opened when the one-shot tray 11 is taken in or taken out.

In addition, in this embodiment, since an air curtain is formed inside the processing tank 2 that flows in the front-rear direction, when the evaporation pans 11 are arranged in two rows, front and back, when performing four-condensation processing on a chemical sample, the evaporation speed is reduced. Interference contamination of chemical vapor occurs between the dishes. Therefore, it is essential to use the evaporating dishes 11 side by side in left and right rows.

Embodiment 3: FIGS. 5 and 6 show an embodiment corresponding to claim 8 of the present invention. That is, in Example 2, the downflow airflow blown into the chamber is blown into the processing tank with a top lid, whereas in this example, clean air obtained from a separate air supply system from the downflow airflow is used. The chemical vapor is evacuated by blowing air into the processing tank with a top lid.

That is, on the front side of the processing tank 2 with a top lid installed in the chamber, a wind barrel 23 isolated from the chamber interior space through which the downflow airflow A flows is defined, and a high-performance filter 24. The air supply fan 25 and the air supply fan 25 are combined to constitute a second air supply system that obtains a blown air flow. Then, the lower surface of the processing tank 2 is connected to the wind barrel 23 .

Air guide ports 2d and 2e are opened on the front surface as in the second embodiment, and furthermore, an air guide port 2f communicating with the exhaust duct 6 is opened on the rear surface of the processing tank. Further, the downflow airflow A flows around the upper and lower surfaces of the processing tank 2, merges with the guiding airflow that has passed through the processing tank, and is sucked and exhausted into the exhaust duct 6.

In addition, in the illustrated example, as shown in FIG. 6, the air supply of the second air supply system described above is installed at the bottom of the clean draft chamber H for weighing, which is installed adjacent to the clean draft chamber I for concentrating the chemical sample. A fan 25 is installed so that a part of the downflow airflow flowing down inside the clean draft chamber H is taken in by the air supply fan 25 and the airflow is sent to the wind cylinder 23. Note that the air flow can also be directly taken in from inside the clean room.

With this configuration, the air flow obtained through the air supply fan 25 of the second air supply system and the high-performance filter 24 is forced into the processing tank 2 through the air guide ports 2d and 2e, and the air flow is created in the tank. Di, D2. Form D3.

Note that this guided airflow DI, D2. D3 is the guiding airflow Al described in Example 2, A2. It corresponds to A3. As a result, as in Example 2, a portion of the chemical solution generated from the evaporation dish 11 during the concentration process of the chemical sample is passed through the tank by the guided airflow Di, D2. It is sucked out of the system while being wrapped in D3. In addition, since the guiding air flow D1 is heated and heated by the real brake (2c) installed in the tank, the chemical vapor does not recrystallize.

In addition, in Example 2.3, a case was described in which a chemical liquid sample was subjected to a concentration process. The process can be done.

(Effects of the Invention) The clean draft chamber according to the present invention is configured as described above and has the following effects.

In the configuration of claim 1, there is provided an air supply system that blows a purified downflow airflow from above to a processing tank installed in a chamber, and a system that envelops chemical vapor generated from the processing tank in the downflow airflow. An exhaust system that sucks and exhausts the air to the outside,
Each processing tank installed in the chamber is equipped with a suction hood that surrounds the upper surface of the processing tank and communicates with the exhaust system, and a downflow airflow heating means provided in the air supply system. A clean draft chamber for chemical processing of semiconductor wafers, etc., and concentration processing of semiconductor chemicals *i
-, processing tank installed in the chamber or C inside the processing tank
While suppressing interference contamination caused by chemical liquid vapor between two evaporating dishes for chemical liquid concentration stored side by side and recrystallization of the chemical liquid/\-va, harmful chemical liquid vapor generated during the chemical liquid processing process is released to the surrounding area. Exhaust can be treated without leakage or diffusion.

In the structure of the second aspect, since the suction port of the suction hood is opened over the entire circumference, it is possible to more effectively induce the chemical liquid vapor by the suction airflow to the suction hood.

In the structure of claim 3, since the trap is combined at the rear stage of the suction hood, the crystal products of the chemical liquid components generated in the exhaust flow are separated and collected to prevent the crystal products from adhering and depositing in the exhaust duct on the downstream side. can be prevented.

In the structure of claim 4, the chemical solution supply pipe to the processing tank is routed to the top surface of the processing tank bypassing the outer periphery of the suction hood, so that the pipe does not interfere with the function of the suction hood, and the chemical solution is Maintenance work on the supply pipe can be easily carried out.

In claim 5, chemical liquid evaporation plates equipped with chemical liquid heaters are arranged in front and rear rows in the processing tank to perform the chemical liquid concentration process, so that a plurality of evaporation plates can be housed at the same time in the same processing tank and the chemical liquid vapor can be heated. Chemical solution concentration processing can be carried out without interference and contamination.
Moreover, the chemical solution stored in each evaporation dish is individually heated.
By controlling the temperature with a heater, troubles such as sudden boiling of chemical samples can be avoided.

In the configuration of claim 6, since the duct heater is disposed upstream of the high-performance filter as a means for heating the downflow airflow, the downflow airflow sent toward the processing tank can be directly heated.

In the structure of claim 7, there is provided an air supply system for blowing a purified downflow air stream from above toward a processing tank with a top lid installed in the chamber, and a water plate for heating a chemical solution installed at the bottom of the processing tank. A clean draft chamber is constructed by comprising an air guide port opening at the bottom surface and upper side of the processing tank, and an exhaust system that sucks and exhausts the guided airflow flowing into the inside of the processing tank through the air guide port to the outside of the system. Accordingly, as in the structure of claim 1, interference contamination caused by chemical vapor between the processing tanks installed in the chamber or evaporation dishes for chemical liquid concentration housed side by side in the processing tank and recrystallization of the chemical vapor are suppressed. At the same time, harmful chemical vapor generated during the chemical treatment process can be exhausted without leaking or diffusing into the surroundings. Moreover, the treatment tank is equipped with a top lid,
In addition, because a guided air heated by a hot plate is flowed through the tank, it is possible to more effectively prevent the chemical vapor from spreading around the tank, and also prevent the recrystallization of the chemical vapor and the adhesion of crystal products to the top lid. .

The structure of claim 8 includes: an air supply system that blows a purified downflow airflow from above toward a processing tank with a top lid installed in the chamber; and a real plate for heating the chemical solution installed at the bottom of the processing tank. , a second air supply system that cleans the air taken in from the outside and then pushes it into the tank through air guide ports opened at the bottom surface and the upper side of the processing tank; and a guide airflow flowing inside the processing tank; By providing an exhaust system for merging the downflow airflow flowing down inside the chamber and suctioning and exhausting the air to the outside of the system, the processing tank installed in the chamber or arranged in the processing tanks as in the structure of claim 1 is provided. While suppressing interference contamination caused by chemical vapor between stored chemical liquid concentration evaporation dishes and recrystallization of chemical liquid vapor, no harmful chemical vapor generated during the chemical processing process leaks or spreads to the surrounding area. The exhaust can be treated.

In addition, the processing tank is equipped with an upper lid, and inside the tank, air is heated by a hot plate and flowed from the second air supply system, and around it, a downflow airflow flowing down inside the chamber flows. As a result, it is possible to more effectively prevent the chemical vapor from spreading around, and to prevent recrystallization of the chemical vapor and adhesion of crystal products to the top lid.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the structure of a clean draft chamber showing Embodiment 1 of the present invention, and FIG. 2 is a chemical solution 'a' used in FIG. 1.
FIG. 3 is a plan view of the arrangement of the evaporating dishes arranged in the processing tank in FIG. 1; FIG. 5
The figure is a sectional view of a clean draft chamber according to a third embodiment of the present invention, FIG. 6 is a front view of FIG. 5, FIG. 7 is a sectional view of a conventional clean draft chamber, and FIG. 8 is a sectional view of a conventional clean draft chamber. In Figure 0, which is a working state diagram of the chemical concentration process performed in the clean draft chamber, 1: clean draft chamber, 2: processing tank, 2b = upper lid, 2c: hot plate, 2d, 2e, 2f: air guide port, 3. 24: High performance filter, 4, 25: Air supply fan, 6: Exhaust duct, 7: Exhaust fan, 11: Evaporation dish, 11C: Heater, 1
3; Suction hood, 14: @ air mouth, 15 Nidrap, 17
: Chemical liquid supply pipe, 21: Chemical liquid, A: Downflow airflow, C
: High-speed suction airflow, D: Second blast airflow, AI, A2.
A3. Di, D2. D3: Guiding airflow,
. Attorney Yamaguchi Tsuyoshi - 1st 2nd picture 3rd picture 4th picture and Ketan Tadashi

Claims (1)

[Claims] 1) A clean draft chamber used for chemical liquid processing or chemical liquid concentration processing of semiconductor wafers, etc., in which a cleaned downflow airflow is blown from above to a processing tank installed in the chamber. An air supply system, an exhaust system that sucks and exhausts the chemical vapor generated from the processing tank into a downflow airflow outside the system, and an exhaust system that surrounds and exhausts the upper surface area of each processing tank installed in the chamber. A clean draft chamber comprising: a suction hood communicating with the air supply system; and heating means for downflow airflow provided in the air supply system. 2) The clean draft chamber according to claim 1, wherein the suction port is open to the entire circumference of the suction hood. 3) The clean draft chamber according to claim 1, further comprising a trap provided downstream of the suction hood for separating and collecting crystalline products of chemical liquid components from the exhaust flow. 4) The clean draft chamber according to claim 1, wherein the chemical supply pipe connected to the processing tank bypasses the outer periphery of the suction hood and is led into the upper surface of the processing tank. 5) The clean draft chamber according to claim 1, wherein chemical liquid concentration processing is performed by arranging chemical liquid evaporating dishes equipped with chemical liquid heaters in front and back rows in the processing tank. 6) The clean draft chamber according to claim 1, wherein the heating means for the downflow airflow is a duct heater disposed upstream of the high-performance filter. 7) A clean draft chamber used for chemical liquid processing or chemical liquid concentration processing of semiconductor wafers, etc., and an air supply system that blows a cleaned downflow air stream from above toward a processing tank with a top lid installed inside the chamber. A hot plate for heating the chemical solution installed at the bottom of the processing tank, an air guide opening opened on the bottom surface and upper side of the processing tank, and a suction airflow flowing inside the processing tank through the air guide port to the outside of the system. A clean draft chamber characterized by being equipped with an exhaust system. 8) A clean draft chamber used for chemical liquid processing or chemical liquid concentration processing of semiconductor wafers, etc., and an air supply system that sends cleaned downflow air from above toward a processing tank with a top lid installed inside the chamber. A hot plate for heating the chemical liquid was installed at the bottom of the processing tank, and a second system that cleans the air taken in from the outside and pushes it into the tank through air guide ports opened at the bottom and upper sides of the processing tank. A clean draft chamber comprising: an air supply system; an exhaust system that combines a guiding airflow flowing inside a processing tank and a downflow airflow flowing down inside the chamber and sucking and exhausting the mixture to the outside of the system.