JP2777498B2 - Substrate cleaning method - Google Patents

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 a substrate such as a photomask used for manufacturing an LSI. In particular, the present invention relates to a method for cleaning a photomask surface.

[0002]

2. Description of the Related Art Conventionally, the following method has been used for cleaning a photomask. FIG. 4 is a diagram illustrating a method of cleaning a photomask of a brush scrub type. In FIG. 4, reference numeral 1 denotes a glass substrate serving as a transparent substrate of a photomask;
Is an opaque light-shielding pattern made of Cr or the like formed on the glass substrate 1, and 3 is a brush.

When such a glass substrate 1 is cleaned with a brush 3, there is a portion where the brush 3 does not adhere to the glass substrate 1 due to the influence of the light shielding pattern 2. Could not be removed.

In order to solve the above problems,
Conventionally, a photomask cleaning method using a high-pressure water method has been adopted. FIG. 5 is a diagram showing a method for cleaning a photomask of a high-pressure water method. In FIG. 5, reference numeral 4 denotes a Freon nozzle, and 5 denotes high-pressure water. The high-pressure water method is a method of spraying high-pressure freon (high-pressure water) 5 from the Freon nozzle 4 onto the glass substrate 1 to remove foreign matter.

However, even if these methods are used, the force for peeling off the foreign matter from the glass substrate 1 is accompanied by the lateral movement of the solution, and it is difficult to separate the foreign matter from the glass substrate 1. There were many.

In order to solve this problem, a method of cleaning a photomask using a reduced pressure bubbling method has been used.
FIG. 6 is a diagram illustrating a method of cleaning a photomask of a reduced pressure bubbling method. In FIG. 6, 6 is a decompressed gas,
7 is hot water and 8 is air bubbles. The decompression bubbling method is a method in which hot water (solution) 7 immersed in the glass substrate 1 is decompressed to generate bubbles 8 on the surface of the glass substrate 1 for cleaning. According to this method, the bubbles 8 generated in the solution 7 act in a direction to separate the foreign matter from the glass substrate 1, and the foreign matter is removed.

In a conventional photomask cleaning method, a brush scrub method, a high-pressure water method,
A decompression bubbling method, an ultrasonic method, or the like has been used.

[0008]

In the conventional method for cleaning a substrate, especially a photomask as described above, the brush scrubbing method cannot clean the portion where the brush 3 does not come into contact, and the high pressure water method has a high cleaning ability. In addition, the decompression bubbling method has a problem that the location where the bubbles 8 are generated is not limited to the lower part of the foreign matter, and there is no cleaning effect in a portion where the bubbles 8 are not generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a method of cleaning a substrate which can effectively clean a transparent portion of the substrate.

[0010]

According to a first aspect of the present invention, there is provided a method of cleaning a substrate, wherein an opaque light-shielding pattern is formed.
The surface of the glass substrate is placed on the freon surface seen in a container.
Immersing in parallel and excimer laser light
By irradiating the back surface of the substrate perpendicularly to the back surface, the shielding
A surface that generates freon bubbles on the surface other than the light pattern
And a step.

According to a second aspect of the present invention, there is provided a glass substrate having an opaque light-shielding pattern formed on a surface thereof.
While rotating it along the substrate surface,
To inject freon into the center of the rotation axis of the surface.
And excimer laser light from the back side of the glass substrate.
Irradiate perpendicularly to the back side to apply light other than the light shielding pattern
Generating freon bubbles on the surface.
It is.

[0012]

[0013]

[0014]

In the method for cleaning a substrate according to the first aspect of the present invention, the opaque light shielding pattern is formed by the first step.
The surface of the glass substrate on which
It is immersed in parallel to the liquid level on . Further, by the second step, excimer laser light is emitted from the back surface of the glass substrate.
Irradiated perpendicularly to the back surface, the light shielding pattern
Bubbles Freon is found is generated on the outer surface.

In the method of cleaning a substrate according to a second aspect of the present invention, the first step includes the step of forming an opaque surface.
The glass substrate on which the light-shielding pattern is formed rotates along the substrate surface.
While being rotated, the surface is rotated by a Freon nozzle.
Freon is injected into the center of the turning shaft . In the second step, excimer laser light is applied to the back of the glass substrate.
The light is radiated perpendicularly to the back surface from the
Bubbles of Freon is found to occur on the surface other than the over down.

[0016]

[0017]

[0018]

[Embodiment 1] The configuration of a photomask cleaning apparatus using Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a photomask cleaning apparatus using the first embodiment of the present invention. In the drawings, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, reference numeral 9 denotes a freon observed in a container, 10 denotes an excimer laser light source, and 11 denotes an excimer laser light generated from the excimer laser light source.

Next, the first embodiment will be described with reference to FIG. FIGS. 2A and 2B are diagrams showing Embodiment 1 of the present invention. In FIG. 2, 12 is a foreign substance,
13 is a freon gas.

In FIG. 2A, when the surface of the glass substrate 1 is immersed in the Freon 9, the Freon 9 penetrates into the gap between the foreign matter 12 and the Glass substrate 1. In FIG. 1B, the excimer laser beam 11 emitted from the back surface of the glass substrate 1 is absorbed by the Freon 9 and evaporates by increasing the temperature, and the gas 13 of the Freon 9 separates the foreign matter 12 from the glass substrate 1. .

That is, light transmitted through the transparent portion of the photomask is absorbed by the freon and converted into thermal energy. As a result, the temperature of the freon rises and evaporates.
Since this phenomenon occurs only in the region of the freon where light is absorbed, it is vaporized on the surface of the substrate. Freon is soaked between the foreign matter and the substrate surface, and the foreign matter is separated from the substrate by freon bubbles generated in this portion.

The first embodiment of the present invention, as described above,
Since the surface of the substrate is immersed in Freon and excimer laser light is irradiated from the back of the substrate, the foreign particles attached to the substrate surface are directly affected by the bubbles of freon generated below the foreign materials in the direction of separating them from the substrate. This has the effect of being able to be effectively removed.

[0024] Further, since the foreign matter adhering to the light transmitting portion of the substrate is all subjected to the force in the direction of separating from the substrate without being affected by the pattern step, the foreign matter can be effectively removed. To play.

Embodiment 2 FIG. The configuration of a photomask cleaning apparatus using Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a view showing a photomask cleaning apparatus using the second embodiment of the present invention. The glass substrate 1, the light-shielding pattern 2, and the excimer laser light source 10 are completely different from those of the cleaning apparatus using the first embodiment. Are identical. In the drawings, the same reference numerals indicate the same or corresponding parts. In FIG. 3, reference numeral 14 denotes a Freon nozzle that injects Freon 9.

Next, the second embodiment will be described. The surface of the glass substrate 1 is set as the upper surface, and the Freon 9 is sprayed from the upper Freon nozzle 14 while rotating the surface.
Then, the excimer laser light 11 is irradiated from the back surface of the glass substrate 1.

Embodiment 3 FIG. Example 1 and Example 2 described above
In this embodiment, the liquid that wets the substrate surface is freon. However, it is needless to say that the intended purpose can be achieved with water, warm water, or the like.

Embodiment 4 FIG. Example 1 and Example 2 described above
In the above, the liquid that wets the substrate surface is Freon, but it is needless to say that the intended purpose can be achieved with other organic solvents and the like.

Embodiment 5 FIG. Example 1 and Example 2 described above
In the above, the light irradiated from the back side of the substrate was excimer laser light, but it is not limited to this, and the used liquid effectively absorbed it,
If the combination has a wavelength and intensity to be vaporized, Nd:
Needless to say, the intended purpose can be achieved with a YAG laser, a carbon dioxide laser, an N ₂ laser, an infrared ray, or the like.

Embodiment 6 FIG. In the first and second embodiments described above, the liquid that wets the substrate surface is chemically decomposed by absorbing the irradiation light.
It may be a substance that becomes a gas, or such a substance
May be a mixed liquid. Also, the mixture
Two or more types that generate gas by chemical reaction
It may be a gas mixture of the above substances.

Embodiment 7 FIG. Example 1 and Example 2 described above
In the above, the liquid for wetting the substrate surface may be reduced to 1 atm or less in order to induce effective vaporization.

Embodiment 8 FIG. The bubbles for removing foreign substances are not used under the condition that the liquid itself that wets the substrate surface is vaporized, but when water containing carbon dioxide is used, the carbon dioxide gas is vaporized by the energy of the irradiated light. In some cases, the effect of generating bubbles may be used. As in this case, a combination of substances in which another substance contained in the liquid is vaporized may be used.

In the above description, the case where the photomask is cleaned has been described. However, it goes without saying that the present invention can also be used for cleaning other liquid crystal panels and optical components.

[0034]

According to the method for cleaning a substrate according to the first aspect of the present invention, as described above, an opaque light-shielding pattern is formed.
Of the freon that was seen in the container on the surface of the formed glass substrate
Dipping parallel to the liquid surface and excimer laser light
Irradiate vertically from the back of the glass substrate to the back
Freon bubbles are generated on the surface other than the light-shielding pattern.
And a step of causing the transparent portion of the substrate to be effectively cleaned.

The method of cleaning a substrate according to claim 2 of the present invention, as described above, the opaque light-shielding pattern on the surface
While rotating the glass substrate on which the
The Freon nozzle to the center of the rotation axis of the surface.
Injecting Leon and excimer laser light
Irradiate vertically from the back of the glass substrate to the back
Freon bubbles are generated on the surface other than the light-shielding pattern.
And a step of causing the transparent portion of the substrate to be effectively cleaned.

[0036]

[0037]

[Brief description of the drawings]

FIG. 1 is a diagram showing a photomask cleaning apparatus using a first embodiment of the present invention.

FIG. 2 is a diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a photomask cleaning apparatus using a second embodiment of the present invention.

FIG. 4 is a view showing a conventional photomask cleaning method of a brush scrub method.

FIG. 5 is a view showing a conventional photomask cleaning method of a high-pressure water system.

FIG. 6 is a view showing a conventional photomask cleaning method of a reduced pressure bubbling method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 glass substrate 2 light-shielding pattern 9 freon 10 excimer laser light source 11 excimer laser beam 12 foreign matter 13 freon gas 14 freon nozzle

Claims (2)

(57) [Claims] 1. A glass on which an opaque light-shielding pattern is formed.
The substrate surface should be parallel to the freon liquid level seen in the container.
Dipping, excimer laser light from the back of the glass substrate to the back
To the surface other than the light-shielding pattern
Generating freon bubbles . 2. An opaque light-shielding pattern is formed on the surface.
While rotating the glass substrate along the substrate surface,
Injects freon to the center of the rotation axis of the surface by the nozzle
And exposing the excimer laser light from the back side of the glass substrate to the back side
To the surface other than the light-shielding pattern
Generating freon bubbles .