JP3068714B2 - Processing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing technique, and more particularly to a technique effective when applied to a washing and drying step of a semiconductor wafer.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, for example, after a semiconductor wafer is treated with a predetermined chemical solution, the chemical solution is removed by washing with pure water or the like, and moisture attached to the wafer is dried and removed following the washing process. Is performed. A cleaning / drying apparatus is used as an apparatus for cleaning / drying the semiconductor wafer.

Conventionally, in this type of washing and drying apparatus, first,
Diluting and mixing hydrofluoric acid (HF), hydrochloric acid (HCl), ammonia (NH ₄ OH), hydrogen peroxide solution (H ₂ O ₂ ), etc., which are processing chemicals, are supplied to a processing tank having an upper opening, Cleaning by etching is performed.

Next, pure water is supplied to another processing tank having an upper opening or the above-described processing tank to perform a water washing process. Furthermore,
Similarly, isopropyl alcohol (IPA), which is a volatile processing liquid, is supplied to another processing tank having an upper opening, and the processing liquid is heated and dried by IPA vapor, or hot air is supplied for drying or centrifugal force. The semiconductor wafer is dried with a spinner or the like.

As described above, in the current cleaning and drying method, the processing tank is open to the atmosphere (atmosphere of a clean room), and the processing liquid is generally discharged by a head. The liquid pipe is a thick pipe.
In addition, the drainage exhaust gas is connected to a factory piping, and a predetermined detoxification process is performed.

[0006]

As described above, in the conventional apparatus for cleaning and drying a semiconductor wafer, the processing atmosphere is open to the atmosphere, and the atmosphere is not sufficiently clean. For this reason, as the circuit pattern formed on the wafer is further miniaturized, it has become necessary to use a closed type (closed system) processing atmosphere. The present inventor has found that there is a problem that a backflow of the air or the like occurs at the time of drainage from the closed processing tank, thereby contaminating the processing atmosphere in the closed processing tank.

Further, when a closed processing atmosphere is made of a highly clean inert gas (nitrogen, argon, etc.) and a semiconductor wafer is washed and dried in a highly clean state, a backflow of the atmosphere occurs. There is also a problem that a natural oxide film is formed on a semiconductor wafer.

This is because reliability of a semiconductor manufacturing apparatus has been reduced in view of the fact that the allowable limit for contamination and adhered foreign matter is decreasing with the miniaturization and high performance of semiconductor integrated circuits formed on a semiconductor wafer. This is an important problem from the viewpoint of improving the degree of productivity and the productivity (yield) of semiconductor wafers.

SUMMARY OF THE INVENTION An object of the present invention is to provide a processing technique capable of reliably preventing contamination in a closed processing tank and a change in atmosphere due to a backflow of air or the like when draining and exhausting.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0011]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, according to the processing method of the present invention, in a processing method of performing a desired processing by supplying a desired processing fluid to an object to be processed in a closed processing tank, the processing is performed and then generated in the closed processing tank. The discharge and exhaust of the waste liquid are forcibly performed by reducing the pressure of a discharge pipe route connected to the closed processing tank.

Further, according to the processing method of the present invention, in the processing method of the first aspect, the discharge pipe path is filled with an inert gas, and the invasion of outside air through the discharge pipe path into the closed processing tank is prevented. It is like that.

Further, according to the processing method of the present invention, when introducing a processing fluid such as a chemical solution, pure water or gas into the closed processing tank, the pressure in the closed processing tank is reduced. It is controlled to be constant within a predetermined range.

Further, the processing apparatus of the present invention comprises a sealed processing tank for isolating a processing object accommodated therein from the outside air, and a processing fluid supply for supplying a desired processing fluid to the processing object in the sealing processing tank. Means, a discharge pipe for discharging and exhausting waste liquid from the closed processing tank, a buffer tank interposed in the discharge pipe path, and first vacuum generating means for reducing the pressure of the buffer tank. The discharge and exhaust of the waste liquid generated in the tank is forcibly performed by reducing the pressure in the buffer tank.

Further, in the processing apparatus according to the present invention, the vacuum generating means generates a negative pressure by entraining the gas in the exhaust path by the inert gas jet and forcibly discharging the gas. And a vacuum generator.

In the processing apparatus according to the present invention, a pressure measuring means for detecting an internal pressure of the closed processing tank and a second vacuum generating means for performing a pressure reducing operation in the closed processing tank are provided. And pressure control means for controlling the second vacuum generating means in a closed loop on the basis of the internal pressure value of the sealed processing tank obtained from the pressure measuring means, thereby controlling the internal pressure of the sealed processing tank to be constant within a desired range. It is a thing.

Further, the processing apparatus of the present invention is characterized in that:
Alternatively, in the processing apparatus according to the sixth aspect, the second vacuum generating means may include a vacuum generator that generates a negative pressure by entraining and forcibly discharging the gas in the exhaust path by the inert gas jet. .

Further, the processing apparatus of the present invention is characterized in that
In the processing apparatus described in 5, 6, or 7, a plurality of discharge pipes connected to the closed processing tank are provided in accordance with the type of waste liquid, and a dedicated waste liquid tank is provided in each discharge pipe path. Of the waste liquid tank in the common buffer tank,
By reducing the pressure inside the common buffer tank by the first vacuum generating means, the waste liquid generated in the closed processing tank is forcibly discharged and exhausted.

[0020]

According to the above-mentioned means, the flow direction of the waste liquid and the exhaust gas is forcibly maintained in the direction from the inside of the sealed processing tank to the outside when the waste liquid is discharged from the sealed processing tank and the exhaust operation is performed. It is ensured that outside air including foreign matter flows back into the closed processing tank through the discharge pipe route, etc., and that the inside of the closed processing tank is a highly clean closed processing space with an inert gas atmosphere. Becomes possible.

As a result, for example, in the washing and drying process of a semiconductor manufacturing apparatus, a semiconductor wafer which has been treated highly in a sealed processing tank can be protected from recontamination due to adhesion of foreign matter, and undesired natural oxidation on the surface of the semiconductor wafer can be prevented. The formation of a film can be prevented.

[0022]

Embodiment 1 An example of a processing method and apparatus according to the present invention will be described below in detail with reference to the drawings.

In the following description, as an example of the processing, a case where a semiconductor wafer or the like is cleaned and dried will be described.

FIG. 1 is a conceptual diagram showing an example of the configuration of the cleaning / drying apparatus of the present embodiment.

In FIG. 1, a treatment tank 1 is a container that can be sealed and is made of a material that can withstand washing and drying. Above the processing tank 1, a processing fluid supply pipe 11 for supplying a chemical solution, pure water, gas and the like is connected via a valve 11a. A discharge pipe 12 for discharging and exhausting waste liquid and waste gas generated inside the processing tank 1 is provided below the processing tank 1, and a path of the discharge pipe 12 is provided through a valve 12 a. The buffer tank 2 is connected.
Further, the buffer tank 2 is connected to the outside of the apparatus, for example, a factory pipe (not shown) via a valve 15.

The buffer tank 2 includes the buffer tank 2
A vacuum generator 3 that performs an operation of reducing the pressure is connected via a valve 14. Further, an inert gas supply pipe 13 for supplying, for example, nitrogen, argon, or the like is connected to the buffer tank 2 via a valve 13a, and the waste liquid is discharged from the buffer tank 2 to the outside of the apparatus via a valve 15. Or pressurize the inside of the buffer tank 2 when exhausting,
The inside of the buffer tank 2 and the inside of the discharge pipe 12 are always kept in an inert gas atmosphere.

An operating fluid supply pipe 16 for supplying an inert gas such as nitrogen gas is connected to the vacuum generator 3 via a valve 16a. That is, the vacuum generator 3 generates a negative pressure based on the so-called aspirator principle, and uses an inert gas flow injected and supplied from the working fluid supply pipe 16 as a working fluid instead of a water flow.

Hereinafter, an example of the operation of the present embodiment will be described.

First, an object to be processed such as a semiconductor wafer (not shown) is accommodated in the processing tank 1, and a valve 11a is opened to open a processing fluid such as a chemical solution, pure water, or gas inside the processing tank 1. , For example, cleaning and drying of an object to be processed (not shown) are performed.

Thereafter, by operating the vacuum generator 3 and opening the valve 12 a of the discharge pipe 12 while the buffer tank 2 is depressurized, the waste liquid and the waste gas in the processing tank 1 are transferred into the buffer tank 2. The suction and discharge are forcibly performed, and after the discharge is completed, the valve 12a is closed.

Further, the valve 12a is closed to shut off the vacuum generator 3 and the buffer tank 2,
The valve 15 is opened to connect the buffer tank 2 to a pipe (not shown) outside the apparatus. In this state, the valve 13 a is opened and the inert gas pressurized through the inert gas supply pipe 13 is introduced into the buffer tank 2. Thus, the waste liquid and the like in the buffer tank 2 are forcibly discharged to the outside of the apparatus, and then the valve 15 is closed.

As described above, according to the processing apparatus of the present embodiment, when discharging the waste liquid or waste gas from the processing tank 1 to the outside through the discharge pipe 12, the discharge pipe 12 is forcibly set to a negative pressure. , The backflow of outside air containing foreign matter and the like into the inside of the processing tank 1 through the discharge pipe 12 is reliably prevented, and the object to be processed such as a semiconductor wafer housed inside the processing tank 1 is removed. Further, re-contamination due to adhesion of foreign matter after washing and drying is avoided. Also,
Since the inside of the discharge pipe 12 and the buffer tank 2 is filled with the inert gas supplied from the inert gas supply pipe 13, an object to be processed such as a semiconductor wafer comes into contact with oxygen in the outside air, which is undesirable. Problems such as formation of an oxide film are reliably avoided. As a result, good processing results can be obtained in, for example, cleaning and drying processing of semiconductor wafers and the like.

[0033]

Embodiment 2 FIG. 2 is a conceptual diagram showing a main part of a processing apparatus according to another embodiment of the present invention.

The second embodiment is different from the first embodiment in that the internal pressure of the processing tank 1 is controlled.

Above the processing tank 20, a processing fluid supply pipe 31 for supplying a chemical solution, pure water, gas and the like is provided with a valve 31a.
Connected through. In this case, a pressure gauge 22 for measuring the internal pressure of the processing tank 20 and the processing tank 2
The vacuum generator 21 for exhausting the inside of the chamber 0 is connected via a valve 33.

The configuration of the vacuum generator 21 is the same as that of the vacuum generator 3, and generates a negative pressure using an inert gas flow supplied from outside via a working fluid supply pipe 34 and a valve 34a as a working fluid. The opening of the valve 34a is controlled by the comparator 24. The comparator 24 controls the opening degree of the valve 34 a of the vacuum generator 21 so as to cancel the difference between the predetermined pressure set in the register 23 and the internal pressure of the processing tank 20 measured by the pressure gauge 22.

That is, when a chemical solution, pure water, an inert gas, or the like is supplied to the hermetically sealed processing tank 20 at the start of the cleaning / drying processing or the like, the internal pressure of the processing tank 20 increases as it is, However, in the case of this embodiment, when the internal pressure of the processing tank 20 rises during the supply of the processing fluid, the comparator 24 that detects this through the pressure gauge 22 outputs a signal to the vacuum generator 21. By performing suction of the processing tank 20 by
It operates so as to keep the internal pressure of the processing tank 20 constant.

Therefore, the supply of the processing fluid to the processing tank 20 can be performed smoothly, and the problem that the inside of the processing tank 20 becomes excessively negative and the outside air enters can be solved.

[0039]

Embodiment 3 FIG. 3 is a conceptual diagram showing an example of a processing apparatus according to still another embodiment of the present invention.

In the case of the third embodiment, a plurality of discharge pipes 52, discharge pipes 53,
Discharge pipe 54 is connected to valve 52a, valve 53, respectively.
a, via a valve 54a, and further, inside the buffer tank 2A, dedicated waste tanks 42, 43, and 44 corresponding to each of these discharge pipes 52 to 54 are provided.
Where each of the waste liquid tanks 42 to 44 is connected to a pipe outside the apparatus via a valve 56, a valve 57, and a valve 58, respectively. is there.

With such a configuration, there is an advantage that a single vacuum generator 3 can separate and collect a plurality of kinds of waste liquids with a simple structure.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and may be variously modified without departing from the gist thereof. Needless to say.

[0043]

The effects obtained by the typical inventions disclosed in the present application will be briefly described as follows.

That is, according to the treatment method of the present invention, it is possible to prevent the reverse contamination of the closed treatment tank due to the backflow of the air or the like when draining and exhausting the gas. The highly clean airtight processing space can be maintained, and the highly clean semiconductor wafer can be protected again from contamination and formation of a natural oxide film.

Further, according to the processing apparatus of the present invention, it is possible to prevent reverse contamination in the closed processing tank due to backflow of the air or the like when draining and exhausting the gas. The highly clean airtight processing space can be maintained, and the highly clean semiconductor wafer can be protected again from contamination and formation of a natural oxide film.

Therefore, it is possible to reduce the influence on miniaturization, high performance, and the like of a semiconductor integrated circuit formed on an object to be processed such as a semiconductor wafer, thereby contributing to improvement in reliability of a semiconductor element and a semiconductor manufacturing apparatus. be able to.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of a configuration of a processing apparatus according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a main part of a processing apparatus according to another embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of a processing apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing tank (closed processing tank) 2 Buffer tank 2A Buffer tank (common buffer tank) 3 Vacuum generator (first vacuum generating means) 11 Processing fluid supply pipe (processing fluid supply means) 11a valve 12 discharge pipe 12a valve 13 non Active gas supply pipe 13a valve 14 valve 15 valve 16 working fluid supply pipe 16a valve 20 processing tank 21 vacuum generator (second vacuum generation means) 22 pressure gauge (pressure measurement means) 23 register (pressure control means) 24 comparator (pressure) Control means) 31 Processing fluid supply pipe 31a Valve 33 valve 34 Working fluid supply pipe 34a valve 42 Waste liquid tank 43 Waste liquid tank 44 Waste liquid tank 52 Discharge pipe 52a Valve 53 Discharge pipe 53a Valve 54 Discharge pipe 54a Valve 56 Valve 57 Valve 58 Valve

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yuhisa Nitta 2326 Imai, Ome-shi, Tokyo Inside Device Development Center, Hitachi, Ltd. (56) References JP-A-3-234021 (JP, A) JP-A Sho 63-264115 (JP, A) JP-A-5-82496 (JP, A) JP-A-5-41137 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/304 648 B08B 3/04

Claims (8)

(57) [Claims] 1. A processing method for performing a desired processing by supplying a desired processing fluid to an object to be processed in a closed processing tank, wherein after performing the processing, a waste liquid generated in the closed processing tank is removed. Discharge and exhaust are forcibly performed by reducing the pressure of a discharge pipe route connected to the closed processing tank. 2. The processing method according to claim 1, wherein the exhaust pipe path is filled with an inert gas to prevent outside air from entering the closed processing tank through the discharge pipe path. 3. The method according to claim 1, wherein when the processing fluid such as a chemical, pure water, or gas is introduced into the closed processing tank, the pressure in the closed processing tank is controlled to be constant within a predetermined range. 3. The processing method according to 1 or 2. 4. A sealed processing tank for isolating an object to be processed housed therein from outside air, processing fluid supply means for supplying a desired processing fluid to the object to be processed in the sealed processing tank, A discharge pipe for discharging and exhausting waste liquid from the tank, a buffer tank interposed in the discharge pipe path, and first vacuum generating means for reducing the pressure of the buffer tank;
A processing apparatus wherein discharge and exhaust of waste liquid generated in the closed processing tank are forcibly performed by reducing the pressure in the buffer tank. 5. The vacuum generator according to claim 4, wherein said vacuum generating means comprises a vacuum generator for generating a negative pressure by forcibly discharging and forcibly discharging gas in an exhaust path by an inert gas jet. Processing equipment. 6. A pressure measuring means for detecting an internal pressure of the closed processing tank, a second vacuum generating means for performing a pressure reducing operation in the closed processing tank, and an internal pressure of the closed processing tank obtained from the pressure measuring means. 6. A pressure control means for controlling the second vacuum generating means in a closed loop on the basis of the value to thereby keep the internal pressure of the closed processing tank constant within a desired range. The processing device according to the above. 7. The vacuum generator according to claim 1, wherein the second vacuum generating means includes a vacuum generator for generating a negative pressure by entraining and forcibly discharging the gas in the exhaust path by an inert gas jet. 7. The processing apparatus according to 4, 5, or 6. 8. The discharge pipe connected to the closed processing tank is provided in a plurality of paths according to the type of the waste liquid, and a dedicated waste liquid tank is interposed in each discharge pipe path, and a plurality of waste liquids are provided. The tank is housed inside a common buffer tank, and the inside of the common buffer tank is depressurized by the first vacuum generating means, thereby forcibly discharging and exhausting waste liquid generated in the closed processing tank. The processing apparatus according to claim 4, 5, 6, or 7, wherein