JP2002090982A - Method for manufacturing photomask, and photomask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flawing of an exposure system due to the breaking of glass or another trouble without lowering the precision of exposure using a glass dry plate excellent in dimensional stability. SOLUTION: A pattern for exposure is formed on one face of a glass base and a transparent substrate is stuck to the other face by way of an adhesive layer to obtain the objective photomask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask for manufacturing a printed wiring board, a plasma display (PDP), and the like, and more particularly, to protecting an exposure machine from damage to a photomask using glass as a support. It relates to a photomask that can be used.

[0002]

2. Description of the Related Art Generally, a printed wiring board is formed by laminating a photoresist such as a dry film on the surface of a substrate material, and closely contacting the surface of the photoresist on which the pattern for exposure is formed with a photomask. After exposing the photoresist through the photomask, the photomask is peeled off, the photoresist is developed, and an etching process is performed. The photomask peeled off at this time is
It is used repeatedly for the production of the next printed wiring board.

In recent years, there has been a remarkable demand for higher density of printed wiring boards and the like, and it has become necessary to improve the dimensional accuracy of a photomask used for this purpose. For this purpose, a photomask using a glass dry plate having glass as a support and provided thereon a layer made of a photosensitive emulsion is used. In such a photomask, a transparent protective film having a thickness of several μm may be attached to the surface on which the pattern for exposure is formed for the purpose of preventing adhesion of a photoresist.

[0004] Such a photomask using glass as a support significantly reduces the dimensional change during the exposing operation of a printed wiring board, as compared with a photomask using a film as a support, and enables highly accurate exposure of an original. To make it possible,
There is a problem that the glass may be damaged while performing the exposure operation many times, thereby damaging the exposure machine. This problem is caused only by pasting a transparent protective film on the surface on which the pattern for exposure is formed, because these films are extremely thin to prevent the exposure accuracy from deteriorating. The above problem cannot be prevented.

On the other hand, in order to prevent scattering of window glass and the like, two sheets of window glass are bonded via a plastic film, or a plastic film is bonded to one surface of the window glass via an adhesive layer. The way to do it is generally done. However, in the field of performing close contact printing of photosensitive materials, the presence of an extra film or adhesive layer between the exposure light source and the photosensitive material results in many layer interfaces, and the presence of these interfaces causes It is necessary to reduce the interface between the exposure light source and the photosensitive material as much as possible and to reduce the thickness of the intervening layer as much as possible because the refraction of light makes it impossible to reproduce a highly accurate image. It is believed that. Therefore, sticking an adhesive film having a thickness enough to prevent a problem due to breakage of glass on a glass dry plate is contrary to the idea of using a glass dry plate to improve accuracy, and it is completely meaningless. Was thought to be.

[0006]

SUMMARY OF THE INVENTION According to the present invention, even if a photomask using a glass dry plate is used, the exposure machine is damaged due to breakage of the glass without deteriorating the accuracy of the exposure using the glass dry plate. It is an object of the present invention to solve the above problem.

In recent years, an exposing machine capable of irradiating high-precision parallel rays has been developed, and the present inventor has proposed such a method for performing high-precision original exposure using a glass dry plate as described above. The present invention has been completed by paying attention to the situation that a suitable exposure machine is used. In other words, if exposure is performed with high-precision parallel rays, even if an adhesive film having a certain thickness is bonded to the surface opposite to the surface on which the exposure pattern of the photomask is formed, the exposure using a glass dry plate can be performed. The present invention has been completed, considering that it is possible to solve the problem of damaging the exposure device due to breakage of glass or the like without lowering the accuracy of the method.

[0008]

According to a method of manufacturing a photomask of the present invention for solving the above-mentioned object, an exposure pattern is formed on one surface of a glass support, and the exposure pattern of the glass support is formed. A transparent substrate is attached to the surface opposite to the formed surface via an adhesive layer.

Further, the photomask of the present invention has an exposure pattern formed on one surface of a glass support, and an adhesive layer on the surface of the glass support opposite to the surface on which the exposure pattern is formed. Characterized in that a transparent base material is adhered through the substrate.

[0010]

Embodiments of the present invention will be described below.

The method for producing the photomask of the present invention and the method for forming an exposure pattern on one surface of a glass support used for the photomask include a method of forming a photomask having a thickness of several mm usually used as glass for a glass drying plate. It can be obtained by applying a photosensitive solution such as a silver salt photosensitive emulsion to a uniform thickness on a glass plate, drying and drying an exposed pattern to develop.

The glass support having the exposure pattern formed on one surface in this manner is used for exposing a photoresist such as a dry film laminated on the surface of a printed circuit board material to a wiring pattern. The surface of the glass support on which the pattern for exposure is formed is brought into close contact with the surface of the glass support, and is used for exposure. At this time, in order to prevent scratches on the surface of the glass support on which the pattern for exposure is formed, and to prevent adhesion of a photoresist, the surface on which the pattern for exposure is formed is about 1 to 20 μm as necessary. It is possible to attach a thin transparent protective film.

Next, in the present invention, a transparent substrate is attached to the surface of the glass support opposite to the surface on which the exposure pattern is formed, via an adhesive layer. In this manner, the transparent substrate is attached to the surface opposite to the surface on which the exposure pattern of the glass support is formed, so that even if the glass support is damaged in the exposure operation process, which has conventionally been a problem, In addition, it is possible not only to prevent the glass from being scattered and to prevent the exposure apparatus from being damaged, but also to reduce damage to the glass support in the exposure operation step.

Such a transparent substrate needs to have a light transmittance that does not hinder exposure, and has excellent mechanical strength in order to prevent scattering due to breakage of the glass support.
It is necessary to have flexibility. Examples of such a substrate include films of polycarbonate, polyester, polypropylene, and the like. In consideration of workability, cost, and the like, a biaxially stretched polyester film is particularly preferable. The lower limit of the thickness of the transparent substrate is 10 μm in order to suppress breakage of the glass support and scattering of glass pieces.
m or more, preferably 25 μm or more, more preferably 10 μm or more.
It is desirable that the thickness be 0 μm or more. The upper limit of the thickness of the transparent substrate is desirably 350 μm or less, preferably 300 μm or less, and more preferably 250 μm or less so as not to impair light transmittance and exposure accuracy.

The surface of the transparent substrate opposite to the pressure-sensitive adhesive layer may be subjected to a hard coat treatment, a non-glare treatment, an antistatic treatment or the like, if necessary.

The transparent substrate is laminated via a pressure-sensitive adhesive layer on a glass support on which a pattern for exposure is formed. As the pressure-sensitive adhesive constituting this pressure-sensitive adhesive layer, generally used acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives and the like are used, but it is necessary that the transparency is not impaired. Further, an adhesive having performance such as antistatic property may be used.

The lower limit of the thickness of the pressure-sensitive adhesive layer is desirably 2 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, so as to obtain the necessary adhesiveness for preventing scattering of glass fragments. . The upper limit of the thickness of the pressure-sensitive adhesive layer is desirably 60 μm or less, preferably 40 μm or less, and more preferably 30 μm or less so as not to impair light transmittance and exposure accuracy.

The pressure-sensitive adhesive layer is generally laminated by dissolving or dispersing the above-mentioned pressure-sensitive adhesive in a solvent as required, and applying the solution to a transparent substrate or a glass support by a known coating method.

[0019]

Embodiments of the present invention will be described below. In this example, “%” and “parts” are based on weight unless otherwise specified.

[Example] One side of a biaxially stretched transparent polyester film (Diafoil O-300E, 188 µm: Mitsubishi Chemical Polyester Film Co., Ltd.) was coated on one surface with an adhesive diluted with a solvent (SK Dyne 1501B: Soken Chemical Co., Ltd.). Apply
Drying was performed to form an adhesive layer having a thickness of 10 μm.

Next, an exposure original was closely adhered to the photosensitive surface of a glass dry plate (Kodak Precision Line Plate LPFP: Kodak Corporation) having a thickness of about 5 mm, and developed to form an exposure pattern on one surface. A glass support was obtained.

On the surface of the glass support on which the pattern for exposure is formed, a protective film made of a 6 μm-thick plastic film for preventing adhesion of a resist (Kimotect PA8)
X: Kimotosha).

Next, on the surface of the glass support opposite to the surface on which the pattern for exposure is formed, the adhesive layer of the polyester film having the above-mentioned adhesive layer formed thereon is opposed to each other and laminated. A mask was made.

This photomask, which was obtained by bonding a protective film alone without laminating a polyester film, was used as a comparative sample, and was subjected to JIS-A5759.
An impact destruction test was performed using a test device specified by the method A for anti-scattering performance. In addition, the test piece was arrange | positioned so that the impact by an impact body might be performed from the surface opposite to the surface to which the protective film was stuck. In addition, in order to confirm the impact resistance of the sample, start the test with a lighter impact body,
The test was carried out under appropriate weight until the glass support was broken.

As a result of the above test, it was confirmed that the photomask of the present invention had higher strength (impact resistance) due to the impact of the impacting body than the comparative sample. As for the scattering state of the glass pieces, a considerable number of the glass pieces were scattered in the comparative sample, but no scattering of the glass pieces was observed in the photomask of the present invention.

When a printing test of a high-density pattern was performed using the photomask of the present invention and a comparative sample, the reproducibility of the images did not change at all.

[0027]

According to the present invention, it is possible to obtain a photomask which does not deteriorate the exposure machine due to breakage of the glass without deteriorating the accuracy of exposure using a glass dry plate having excellent dimensional stability. .

Claims (2)

[Claims] An exposure pattern is formed on one surface of a glass support, and a transparent substrate is provided on a surface of the glass support opposite to a surface on which the exposure pattern is formed, via an adhesive layer. A method for manufacturing a photomask, which is attached. 2. A pattern for exposure is formed on one surface of a glass support, and a transparent substrate is provided on a surface of the glass support opposite to a surface on which the pattern for exposure is formed via an adhesive layer. A photomask, which is attached.