JPH04198399A - Cleaning - Google Patents

Abstract

PURPOSE:To enable the subject safe and strong cleaning without corrosion of the object for cleaning mentioned below and without danger of catching fire by immersing the inner wall of a reaction chamber of a semi-conductor production apparatus or the inner equipment thereof in a solution containing at least a perfluoropolyether, etc. CONSTITUTION:An object for cleaning is immersed in a solution containing at least a perfluoropolyether or tetradecafluorohexane and further containing at least one compound selected from hexane, perfluorooctane and diethyl ether to remove stains adhering thereto. In addition to the above-mentioned immersion method, the spray method, a method where stains are wiped off using a fabric- like material moistened with the solution, etc., can be used.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method for cleaning deposits (dirt) on the walls and internal jigs of a reaction chamber of semiconductor manufacturing equipment.

The purpose is to provide a safe and powerful cleaning method that does not corrode the object to be cleaned and does not cause the cleaning agent to catch fire.

l) The object to be cleaned is immersed in a solution containing at least perfluoropolyether or tetradecafluorohexane to remove dirt adhering to the object.

2) The solution is configured to contain one or more of hexane, perfluorooctane, and diethyl ether.

3) The solution is configured to be sprayed in the form of a mist onto the object to be cleaned.

4) The object to be cleaned is configured to be wiped with a cloth-like object moistened with the solution.

[Industrial application field]

The present invention relates to a method for cleaning deposits (dirt) on the walls and internal jigs of a reaction chamber of a semiconductor manufacturing apparatus.

In semiconductor manufacturing equipment, various reactive gases and organic solvents are used, and as the number of times they are used increases, deposits mainly composed of these substances adhere and accumulate on the reaction chamber walls and internal jigs.

It is difficult to control the manufacturing process to eliminate these deposits, and these deposits impair the reproducibility of the semiconductor manufacturing process. Therefore, it is necessary to remove the deposits every certain number of times of use.

The present invention can be used as a safe and powerful cleaning method for this purpose.

[Conventional technology]

The following methods are used as conventional cleaning methods.

■ Trichlorethylene, acetone, xylene.

Cleaning with an organic solvent such as alcohol ■ Cleaning with hydrofluoric acid ■ Cleaning with a mixed solution of methoxypropanol and butyl acetate [Problems to be Solved by the Invention] The above conventional methods had the following problems.

■ Trichlorethylene can no longer be used due to environmental pollution.

In addition, acetone, xylene, and alcohol have low flash points and emit flammable vapors at room temperature and easily catch fire, making them dangerous and having weak cleaning power.

■ Hydrofluoric acid reacts with most metals and generates hydrogen, which is dangerous.

Furthermore, handling of hydrofluoric acid is dangerous even when used for cleaning substances other than metals.

■ A mixed solution of methoxypropanol and butyl acetate has a low flash point and is dangerous, as well as a strong odor (difficult to handle).

The object of the present invention is to provide a safe and powerful cleaning method that does not corrode the object to be cleaned and does not cause the cleaning agent to catch fire.

[Means to solve the problem]

What is the solution to the above problem?

1) Clean the object with at least perfluoropolyether (
(See Figure 1 for the chemical formula) or immersed in a solution containing tetradecafluorohexane (C8F14).

A cleaning method for removing dirt attached to the object to be cleaned.

Or 2) Hexane (CH3(CH2)4CH3) in the solution
, perfluorooctane [CH, (CH2)8CH2
F), diethyl ether ((tHsOc2H5
), the cleaning method according to l) above,
or 3) the cleaning method described in 1) or 2) above, characterized in that the solution is sprayed onto the object to be cleaned in the form of a mist; or 4) the object to be cleaned is wetted with a cloth-like material moistened with the solution. This is achieved by the cleaning method described in 1) or 2) above, which is characterized by wiping.

Here, FIG. 1 shows the chemical formula of perfluoropolyether.

[Effect]

Since perfluoropolyether and tetradecafluorohexane are inert, they do not corrode metals, do not swell or dissolve rubber and plastics, and do not deteriorate them.

It is also soluble in high fluorine solvents and organic solvents.

It is almost insoluble in fats and oils and water, and has the effect of impairing the adhesion between high fluorine substances and other substances.

The mechanism seems to be related to the lipophilicity of perfluoropolyether and tetradecafluorohexane with high fluorine substances. Furthermore, it has been confirmed that these substances do not react with high fluorine substances.

The present invention takes advantage of the above properties of perfluoropolyether and tetradecafluorohexane.

It is designed to remove deposits without corroding the object to be cleaned.

On the other hand, the smaller the kinematic viscosity of the solvent for removing deposits, the greater the cleaning power. Therefore, at a temperature of 25°C, the t is about the same as water.
Solvents with cSt<centistokes) or less are preferable. In addition, as the temperature of the solvent increases, the kinematic viscosity decreases, so it is better to wash at a high temperature. however.

In the case of perfluoropolyethers and tetradecafluorohexane with a boiling point of 150°C or higher, perfluoroisobutylene C (CF
, )2C=CF2) may be generated, so it is better to use it within a temperature range that does not exceed the boiling point.

Furthermore, in order to prevent soil re-deposition, it is necessary to adjust the cleaning speed and concentration of perfluoropolyether and tetradecafluorohexane.

For this purpose, hexane, or perfluorooctane,
Alternatively, it can be adjusted by mixing a solvent containing at least one of diethyl ethers with perfluoropolyether or tetradecafluorohexane.

〔Example〕

The object to be cleaned in this embodiment is semiconductor manufacturing equipment. The inner wall of the reaction chamber of the etching device and the internal jig. In this case, the deposits deposited in reaction chamber 7 were formed when 5i02 was etched using plasma of a mixed gas of CF and CHF3.

Example I: First, a silicon (Si) jig placed in a reaction chamber was taken out and directly immersed in tetradecafluorohexane.

When the stain was light (light brown), the stain was separated from the jig in about 3 hours, and when it was 9 severe (brown), it took 24 hours to separate from the jig.

Example 2: Take out the Teflon parts placed in the reaction chamber.

Soaked directly in tetradecafluorohexane.

It took about 2 hours to separate from the Teflon parts when the stain was light, and about 20 hours when the stain was heavy. On this occasion,
No deterioration was observed in the Teflon parts.

Example 3 Tetradecafluorohexane was atomized and sprayed onto the reaction chamber wall (made of aluminum, surface coated with Teflon) using a sprayer.

As a result, the dirt on the inner wall was separated from the inner wall and removed. At this time, no corrosion was observed on the inner wall.

Example 4: The dirt on the O-ring used to seal between the inside and outside of the reaction chamber was wiped off with a case moistened with tetradecafluorohexane. The dirt on the O-ring was separated from the O-ring and removed. At this time, no deterioration of the O-ring was observed.

Similar effects were obtained when perfluoropolyether was used in place of the tetradecafluorohexane used in Examples 1 to 4.

[Effects of the Invention] As explained above, according to the present invention, a safe and powerful cleaning method that does not corrode the object to be cleaned and has no risk of the cleaning agent catching fire has been obtained.

As a result, it was possible to contribute to improving the reproducibility of the manufacturing process of semiconductor devices.

[Brief explanation of the drawing]

Figure 1 shows the chemical formula of perfluoropolyether.

Claims (1)

[Scope of Claims] 1) A cleaning method characterized by immersing an object to be cleaned in a solution containing at least perfluoropolyether or tetradecafluorohexane to remove stains attached to the object. 2) The cleaning method according to claim 1, wherein the solution contains one or more of hexane, perfluorooctane, and diethyl ether. 3) The cleaning method according to claim 1 or 2, characterized in that the solution is sprayed in the form of a mist onto the object to be cleaned. 4) The cleaning method according to claim 1 or 2, characterized in that the object to be cleaned is wiped with a cloth-like material moistened with the solution.