JPH08155408A - Method for washing precise part - Google Patents

Abstract

PURPOSE: To obtain a substrate of high quality free from a contaminant and a washing agent by ejecting water having ozone gas dissolved therein to an article to be washed and subsequently washing the article with an alkalline washing agent. CONSTITUTION: A washing apparatus A is constituted of an ozone-containing water shower part 6, an alkali washing shower part 8 and a brush washing part 11 and a substrate 1 composed of a glass plate is fed from an inlet part B by feed rollers 4. For example, high purity water containing 6ppm of ozone is ejected to the substrate 1 from the ozone-containing water shower 5 of the ozone-containing water shower part 6 to form an oxide film in which a contaminant such as fine particles is taken. Subsequently, for example, washing water containing 14wt.% of NH3 is ejected to the substrate 1 from the alkali washing shower 7 of the alkali washing shower part 8. Thereafter, the surface of the substrate 1 is lightly rubbed with the nuylon brush of the brush washing part 11 and washing water containing 6ppm of ozone is ejected to the substrate 1 from a rinsing water shower 10 and the washed substrate is taken out of an outlet part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning precision parts such as liquid crystal substrates and semiconductor substrates.

[0002]

2. Description of the Related Art As a method for removing fine particle stains on liquid crystal substrates and semiconductor wafers that are contaminated with fine particle stains,
A cleaning method is known in which an alkaline cleaning liquid (aqueous solution containing ammonia water, an alkaline surfactant, etc.) is used, and fine particles are removed by using ultrasonic waves and a physical action such as a brush.

[0003]

However, the prior art has problems that the removal of fine particle dirt and the like is insufficient and that an alkaline cleaning agent remains on the surface of the object to be cleaned.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a cleaning method for obtaining a high-quality substrate in which stains are sufficiently removed and a cleaning agent does not remain. To do.

[0005]

In order to achieve the above object, in the present invention, water in which ozone gas is dissolved is sprayed onto an object to be cleaned, then washed with an alkaline cleaning agent, and the object to be cleaned is treated with an alkaline agent. After cleaning with a cleaning agent, it is cleaned with water in which ozone gas is dissolved.

Next, the present invention will be described more specifically. As the water in which the ozone gas is to be dissolved, high-purity water with a minimum content of impurities is suitable. For example, water containing ozone gas in which water such as ion-exchanged water can be suitably used is dissolved and contained according to a conventional method. The ozone content is preferably 1 to 5 ppm, more preferably 6 to 8 ppm.

The injection amount of water in which ozone is dissolved (abbreviated as ozone-containing water) is 0.5 to 1 cm ^{2 of the} substrate to be cleaned.
5 ml, preferably 1-2 ml, and the injection speed is 0.5-
5 m / sec, preferably 1 to 2 m / sec is suitable.

1, 2, and 3 are cross-sectional views for schematically explaining the action of ozone-containing water. When ozone-containing water (not shown) is jetted onto the substrate 1 (see FIG. 1) on which dirt such as fine particles 2 is attached, the ozone-containing water is oxidized to form fine particles on the substrate surface. , An oxide film 3 as shown in FIG. 2 is formed.

The oxide film 3 can be easily peeled off from the substrate 1 while the fine particles are still taken in as shown in FIG. 3 by the action of an alkaline cleaning agent (not shown) described below to obtain a clean substrate. This is probably due to the etching action of the alkaline cleaning solution.

The oxidizing action of ozone is, as shown in Eqs. 1, 2 and 3, a hydroxyl radical (H-) having a strong oxidizing power due to the action of hydroxyl ions (OH ⁻ ) contained in water and ozone.
O.) is generated, and it is thought that this radical oxidizes.

[Equation 1]

[Equation 2]

(Equation 3)

Next, the substrate is washed with an alkaline detergent. As the alkaline cleaning agent, ammonia water or an aqueous liquid containing an alkaline surfactant can be preferably used.

Aliphatic amine salts, alkylbenzene fulphonates, polyoxyethylene alkylphenyl ether sulfates and the like are particularly suitable as the alkaline surfactant.

In the case of ammonia water, the NH ₃ content is 2-3.
0 wt%, preferably 10 to 14 wt%, and in the case of a surfactant solution, the concentration is preferably 0.5 to 5 wt%, preferably 1 to 2 wt%.

As a cleaning method using an alkaline cleaning agent, it is practical to spray the cleaning agent from a nozzle onto a substrate as an object to be cleaned. Injection quantity, the substrate 1 cm ² per 0.
5 to 5 ml, preferably 1 to 2 ml, and the injection speed is 0.
It is suitable to be 5 to 5 m / sec, preferably 1 to 2 m / sec.

For the cleaning with the ozone-containing water and the cleaning liquid, the substrate 1 is moved in the direction of the arrow by using the conveying roller 4 which is rotated in the direction of the arrow by the driving device (not shown) as shown in FIG. However, it is practical to do it continuously.

The effect can be further enhanced by using a rotating brush and an ultrasonic generator (not shown) together during cleaning.

After washing, rinse with high-purity water. At this time, it was found that by dissolving ozone gas in the rinse water, a substrate with less impurities can be obtained. (The content of impurities can be reduced to a fraction or less.) The content of ozone gas is 1 to 15 ppm, preferably 6 to
8 ppm, injection amount is 0.5-5 ml per 1 cm ² of substrate,
Desirably 1-2 ml, or jet speed is 1-2 m / se
c is appropriate.

It has also been found that the residual amount of alkali ions can be made substantially zero by using rinse water containing ozone gas.

[0019]

[Function] By spraying water in which ozone gas is dissolved onto the object to be cleaned and then cleaning with an alkaline cleaning agent, an oxide film containing dirt such as particles adhering to the surface of the object to be cleaned is formed. Is removed together with the oxide film.
Further, by including ozone in the rinse water, the efficiency of removing fine particles and the like is greatly improved, and the residual amount of alkali ions is made zero.

[0020]

[Embodiment 1] An embodiment of the present invention will be described with reference to FIG.
A is a cleaning device including an ozone-containing water shower unit 6, an alkali cleaning shower unit 8, and a brush cleaning unit (rinse unit) 11. A substrate 1 made of a glass plate is supplied from an inlet portion B to a ozone-containing water shower section 6 by a conveying roller 4 which rotates in a direction of an arrow by a driving device (not shown), and the ozone-containing water shower 5 contains 6 ppm of ozone. Purified water is sprayed as a shower of 1 m / sec at a rate of ² ml per cm ² of the substrate to form an oxide film (not shown, see FIG. 2) in which dirt such as fine particles is incorporated.

Next, the substrate 1 is supplied to the alkali cleaning shower unit 8 by the transport roller 4, and the cleaning water containing 14 wt% of NH ₃ is supplied from the alkali cleaning shower 7 to the substrate 1 cm ^2.
It was sprayed as a shower of 1 m / sec at a rate of 2 ml per one.

The substrate 1 is sent to the brush cleaning section (rinsing section) 11 by the transport roller 4, the surface is lightly rubbed by the nylon brush 9 rotated in the direction of the arrow, and cleaning water containing 6 ppm of ozone is added to the substrate 1 cm ² Rinse water shower 1 as a 1 m / sec shower at a rate of 2 ml per
It was injected from 0 and taken out from the outlet 11.

[0023]

Example 2 The above examples were evaluated using a glass substrate having 10 1 μm polystyrene particles attached per cm ² . The removal rate of polystyrene particles is 98%,
The residual rate of alkali ions was zero (below the detection limit).

[0024]

Comparative Example 1 Instead of the experimental example, the removal rate of polystyrene was 78 when pure water containing no ozone was used in the rinse section.
%, The residual rate of alkali ions was zero.

[0025]

[Comparative Example 2] When the substrate was directly supplied to the alkali cleaning shower unit of the above-mentioned Example and the rinse water containing no ozone was used, the removal rate was 88% and the residual rate of alkali ions was 2.
%Met.

[0026]

EFFECTS OF THE INVENTION It is possible to obtain a high-quality substrate in which stains are sufficiently removed and no cleaning agent remains.

[0027]

[Brief description of drawings]

FIG. 1 is a cross-sectional view for schematically explaining the operation of the present invention.

FIG. 2 is a cross-sectional view for schematically explaining the operation of the present invention.

FIG. 3 is a cross-sectional view for schematically explaining the operation of the present invention.

FIG. 4 is a cross-sectional view for explaining the method of the present invention.

[Explanation of symbols]

 1 Substrate 2 Fine Particles (Dirt) 3 Oxide Film 4 Transport Roller 5 Ozone-Containing Water Shower 6 Ozone-Containing Water Shower Part 7 Alkaline Cleaning Shower 8 Alkali Cleaning Shower Part 9 Nylon Brush 10 Rinse Water Shower 11 Brush Cleaning Part A Cleaning Device B Inlet Part C exit

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[Procedure amendment]

[Submission date] January 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

Next, the present invention will be specifically described. As the water in which the ozone gas is to be dissolved, high-purity water with a minimum content of impurities is suitable. For example, water containing ion gas such as ion-exchanged water, in which ozone gas is dissolved and contained, is produced according to a conventional method. The ozone content is preferably 1 to 15 ppm, more preferably 6 to 8 ppm.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The oxidizing action of ozone is, as shown in Eqs. 1, 2 and 3, a hydroxyl radical (H-) having a strong oxidizing power due to the action of hydroxyl ion (OH ⁻ ) contained in water and ozone.
O.) is generated, and it is thought that this radical oxidizes.

[Equation 1]

[Equation 2]

(Equation 3)

Claims (2)

[Claims] 1. A method for cleaning precision parts, characterized in that water in which ozone gas is dissolved is sprayed onto an object to be cleaned and then cleaned with an alkaline cleaning agent. 2. The cleaning method according to claim 1, wherein the object to be cleaned is cleaned with an alkaline cleaning agent and then cleaned with water in which ozone gas is dissolved.