JP3190221B2 - Cleaning method for fine particles on the surface of precision parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fine particles (particles) adhering to the surface of precision parts such as liquid crystal substrates and semiconductor substrates.
Tickle) relates to a method for cleaning dirt .

[0002]

BACKGROUND OF THE INVENTION attached, such as a liquid crystal substrate and semiconductor wafer
The As a method for removing the fine particles, alkaline washing solution using (ammonia water, an aqueous solution containing an alkali soluble surfactant), a cleaning method is known in which a combination of physical action such as an ultrasonic or a brush .

[0003]

The object of the invention is to be Solved However, your in the prior art
Alkali In its removal of particulates can not sufficiently be performed, moreover, from the alkaline cleaning agent to the surface of the object to be cleaned Io
There has been a drawback that down to or to remain.

[0004] The present invention is to solve the drawbacks of the prior art described above, the removal of fine particles sufficiently performed, and no residual alkali ions, particulate contamination to sell high quality substrate for washing <br/> Kiyoshi The aim is to provide a method.

[0005]

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

Next, the present invention will be described more specifically. The water should dissolve the ozone gas, high purity water low content of impurity is appropriate as possible. For example, water such as ion exchange water can be suitably used . The water containing and dissolving the ozone gas is produced according to a conventional method, but the ozone content is preferably 1 to 15 ppm, more preferably 6 to 8 ppm.

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

FIGS. 1, 2 and 3 are cross-sectional views for schematically explaining the action of the ozone-containing water. When the ozone-containing water (not shown) is sprayed onto the substrate 1 (see FIG. 1) to which the fine particles 2 are attached , the fine particles are taken into the substrate surface by the oxidizing action of the ozone-containing water, as shown in FIG. Such an oxide film 3 is formed.

The oxide film 3 is easily peeled off from the substrate 1 while taking in fine particles as shown in FIG. 3 by an etching action of an alkaline cleaning agent (not shown) described below.
A clean substrate can be obtained.

As shown in the following reaction formula , the hydroxyl ion (OH ⁻ ) contained in the water and the ozone dissolved in the water are
This is because the oxidation is carried out by a base catalyzed reaction with . O ₃ + H ₂ O → HO ₃ ⁺ + OH ⁻ (O ₃ is an ozone gas, HO ₃ ⁺ is a peroxide ion,
OH ⁻ is a hydroxyl ion) HO ₃ ⁺ + OH ⁻ → 2HO ₂ .O ₃ + HO ₂ → HO.2O ₂ (HO. Is a hydroxyl radical)

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

As the alkaline surfactant, aliphatic amine salts, alkyl benzene sulfonates, polyoxyethylene alkyl phenyl ether sulfates and the like are particularly suitable.

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%, more preferably 1 to 2 wt%.

As a cleaning method using an alkaline cleaning agent, it is practical to spray a cleaning agent from a nozzle toward a substrate to be cleaned. The amount of injection was 0.1 mm / cm ^{2 of} substrate.
5 to 5 ml, desirably 1 to 2 ml, and the injection speed is 0.1 ml.
It is suitably 5 to 5 m / sec, preferably 1 to 2 m / sec.

The cleaning with the ozone-containing water and the cleaning liquid is performed by moving the substrate 1 in the direction of the arrow using a transport roller 4 rotating in the direction of the arrow by a driving device (not shown) as shown in FIG. It is practical to carry out continuously.

The effect can be further enhanced by using a rotating brush and an ultrasonic generator (not shown) at the time of cleaning.

After washing, it is rinsed with high-purity water. At this time, it was found that by dissolving the ozone gas in the rinsing water, a substrate with less impurities could 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 15 ppm.
8 ppm, injection amount is 0.5 to 5 ml per 1 cm ² of substrate,
Desirably 1-2 ml, or injection speed is 1-2 m / sec
It is appropriate to use c.

It has also been found that the use of rinsing water containing ozone gas makes it possible to reduce the residual amount of alkali ions to substantially zero.

[0019]

[Action] Water in which ozone gas is dissolved is sprayed onto the object to be cleaned, and then the substrate is washed with an alkaline cleaning agent to form an oxide film in which fine particles adhered to the surface of the object to be cleaned are captured. At the same time, it is peeled off. In addition, by adding ozone to the rinsing water, the efficiency of removing fine particles is greatly improved, and the remaining amount of alkali ions is reduced to 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 section 6, an alkali cleaning shower section 8, and a brush cleaning section (rinse section) 11. A substrate 1 made of a glass plate is supplied from an inlet B to an ozone-containing water shower unit 6 by a transport roller 4 rotating in the direction of an arrow by a driving device (not shown). Purified water is sprayed at a rate of ² ml per 1 cm ² of the substrate as a shower at 1 m / sec to form an oxide film (not shown, see FIG. 2) incorporating dirt such as fine particles.

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

[0022] sends the substrate 1 by the transfer roller 4 brush cleaning portion (rinse section) 11, rub the surface lightly with a nylon brush 9 that is rotated in the direction of the arrow, the wash water containing 6ppm ozone, the substrate 1 cm ² Rinse water shower 1 at a rate of 2 ml per 1 m / sec shower
It was injected from 0 and taken out from the outlet 11.

[0023]

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

[0024]

Comparative Example 1 In place of the experimental example, the polystyrene removal rate was 78 when pure water not containing ozone was used in the rinsing section.
% And the residual ratio of alkali ions was zero.

[0025]

COMPARATIVE EXAMPLE 2 The substrate was directly supplied to the alkali washing shower section of the above embodiment, and the removal rate when using ozone-free rinsing water was 88%, and the residual rate of alkali ions was 2%.
%Met.

[0026]

According to the present invention, a high-quality substrate with sufficient removal of dirt and no residual cleaning agent can be obtained.

[0027]

[Brief description of the 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]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Fine particles (dirt) 3 Oxide film 4 Conveyance roller 5 Ozone-containing water shower 6 Ozone-containing water shower part 7 Alkaline cleaning shower 8 Alkaline cleaning shower part 9 Nylon brush 10 Rinse water shower 11 Brush cleaning part A Cleaning device B Inlet part C exit

Continuation of the front page (56) References JP-A-63-310604 (JP, A) JP-A-53-106387 (JP, A) JP-A-5-104071 (JP, A) JP-A-59-104132 (JP) JP-A-2-97022 (JP, A) JP-A-4-79221 (JP, A) JP-A-1-305595 (JP, A) JP-A-1-140727 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B08B 3/02-3/12 C11D ⁷ /02-7/04 H01L 21/304 643

Claims (2)

(57) [Claims] 1. A method for cleaning particulates on the surface of precision parts, which comprises spraying water in which ozone gas is dissolved onto an object to be cleaned, followed by cleaning with an alkaline cleaning agent. 2. After the object to be cleaned and washed with an alkaline detergent, method of cleaning particulate contamination of a precision part surfaces according to claim 1, wherein the washing with water containing dissolved ozone.