JPS632105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for cleaning glass. For drying conventionally cleaned surfaces such as glass,
When air-dried in the air or in nitrogen, there was a problem in that substances contained in these gases dissolved in the water during drying and remained on the glass surface after drying. Therefore, as an improvement method, there is a method of blowing dry nitrogen with an air gun, air knife, etc. However, with this method, a lot of dust adheres due to the rapid air flow, and the water blown up by the air flow may be 4 to 5 μm in size. There was a problem that water droplets adhered and did not dry as they were, making it impossible to obtain a clean surface free of particles. SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned problems, the present invention provides a cleaning method in which drying after cleaning is faster than natural drying, and therefore a clean surface free from adhesion of dust accompanying water droplets can be obtained. That is, the present invention includes a step of applying an aqueous polyvinyl alcohol solution to the surface of the glass prior to cleaning, a step of heat-treating the glass, a step of friction-cleaning the surface of the glass with a liquid containing water, and a step of drying the surface of the glass. A method for cleaning glass characterized by comprising steps. An embodiment of the present invention will be described below. In this example, a mask (1 in the figure) used in the manufacture of semiconductor devices (in which a partially etched chromium film or a developed emulsion film of silver halide and gelatin is formed on the surface of a glass plate (1 in the figure)) was used as the glass. This is done using a mask cleaning machine (one that automatically rubs the mask with a detergent using a sponge, rinses it with pure water, and dries it with an air knife) with the air knife piping removed.The mask comes into direct contact with the semiconductor. , even the slightest dirt is transferred to the semiconductor during photolithography, so _a clean surface without any dirt is required. ) H) - _o ] step of applying an aqueous solution, then evaporating water by heat treatment at 100°C for 30 minutes, then cleaning with a mask cleaning machine with the air knife piping removed, and natural drying. It takes about 40 minutes to air-dry ordinary wet glass, but the surface of the mask cleaned with the pretreatment of the present invention has a water film 2 as shown in the drawing, as shown by the arrow 3, even without applying an air knife. It shrinks and dries in about 10 seconds.For this reason, there are no stains caused by ingredients dissolved in the air, or water droplets or dust adhesion caused by the use of an air knife.
Note that heat treatment is absolutely necessary, and if it is not performed, drying after washing will not be quick. Table 1 shows the results when a 5-inch square mask was air-dried without applying polyvinyl alcohol, when it was applied with an air knife without applying polyvinyl alcohol, and when it was dried by the method of the present invention. These are the results of counting dust and water droplets larger than a few μm on the surface using an automatic photomask inspection device.

[Table] It can be seen that the surface cleaned by the cleaning method of the present invention has significantly fewer particles on the surface. Although it is only a matter of speculation, the reason why it dries so quickly is thought to be due to the presence of a thin molecular film of polyvinyl alcohol on the surface of the glass. At that time, even if polyvinyl alcohol covers the dust particles, a clean surface is obtained after cleaning because the dust particles are larger than the thickness of the molecular film, so the dust particles are scraped off during cleaning. It is assumed that In this embodiment, a photomask has been described, but it can also be applied to general glass. According to the cleaning method of the present invention, not only the drying time is short, but also a glass surface that is clean with respect to dust of at least several micrometers or more and free of adhesion of water droplets or dust can be obtained.

[Brief explanation of the drawing]

The drawing shows how the water film rapidly shrinks during the drying process of the present invention. In the figure,
1 is the mask, 2 is the edge of the shrinking water film, and 3 is the direction in which the water film is shrinking.

Claims (1)

[Claims] 1 Prior to cleaning, the method includes the steps of applying an aqueous polyvinyl alcohol solution to the surface of the glass, heat-treating the glass, friction-cleaning the surface of the glass with a liquid containing water, and drying the surface of the glass. A glass cleaning method characterized by: