JPS60262156A - Photosensitive laminate - Google Patents

Abstract

PURPOSE:To prevent irradiation fog due to diffused light at the time of exposure and to form an image high in fidelity to an original by forming a photosensitive laminate composed of a plastic film support having a turbidity coefft. of <=2% and a photosensitive layer formed on the support. CONSTITUTION:The plastic film support having a turbidity coefft. of <=2% is made of polyethylene terephthalate, polypropylene, polycarbonate, ethylene-vinyl acetate copolymer, or the like. This turbidity coefft. (%) is defined as T2/T0X 100, where T0 is the total light transmittance and T0 = parallel light transmittance T1 + scattered light transmittance T2. This photosensitive laminate is composed of the support and the photosensitive layer or these two and a protective layer. Since said laminate is small in an image line width to be changed, the dimension of the original image is enhanced in fidelity, and it can be used for micropatterning of a printed circuit plate.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a photosensitive laminate.

(Prior art) Photosensitive laminates (hereinafter referred to as photosensitive films) are known in which a plastic film is laminated as a support on one side of a photosensitive layer, or a protective film is further laminated on the side of the photosensitive layer. However, to form an image using this photosensitive film, the photosensitive layer and a substrate such as a copper-clad laminate are stacked and pressed together so that they are in contact (hereinafter referred to as lamination), and then the original image is exposed to light.

This is done by peeling off the plastic film and developing it with an alkaline developer or a solvent developer.

However, the general polyester film conventionally used as a support for photosensitive film contains fine particles of the same composition, and when exposed to light, it appears as a refreshing haze. be observed.

When a photosensitive film is made using this general-use polyester film and exposed after being laminated with a substrate,
Light is scattered in areas other than the transparent areas of the original image and acts on the photosensitive layer below the opaque areas, so the width of the layer hardened by exposure (hereinafter referred to as resist) becomes thicker than the width of the original image (line The amount of width change is quite large), and the reproducibility of the original image width cannot be obtained. Furthermore, in the case of low exposure, the resist width becomes narrower due to haze, resulting in the same result. For this reason, as printed circuit boards have become increasingly finely patterned, this film has become difficult to use for these applications.

(Object of the invention) The object of the present invention is to provide a photosensitive film that overcomes the above-mentioned drawbacks.

(Structure of the Invention) The present invention relates to a photosensitive film using a plastic film having a turbidity of 2q6 or less as a support.

Turbidity in the present invention is calculated by the formula: turbidity ('16) = T2 / TOx 100 as total light transmittance ('ro) - parallel light transmittance (T1) and random light transmittance (T2). Ru. Typically, a Beckman spectrophotometer is used for this measurement. If the turbidity value is high, the transmittance value of parallel light will be low, and the amount of change in line width will increase during exposure, making it impossible to match the fine pattern of the printed circuit board. Less than 2% plastic film is used (1%).

The photosensitive film of the present invention has a structure of a support/photosensitive layer or a structure of a support/photosensitive layer/protective film. In the former case, leave it as it is; in the latter case, remove the protective film and laminate it so that the photosensitive layer is in contact with the substrate.

After exposure through the support, the support is peeled off and developed.

The plastic film with a turbidity of 2 or less used in the present invention includes polyethylene terephthalate film, polypropylene film, polycarbonate film, ethylene-vinyl acetate copolymer film, etc. Polyethylene terephthalate film and polypropylene film are used as the photosensitive layer. This is preferable from the viewpoint of releasability.

Products include Lumirror T-60 (polyethylene terephthalate film) manufactured by Toshi Co., Ltd., Torefane T-2400 (polypropylene film) manufactured by Toshi Co., Ltd., Tijinpan Light Film (polycarbonate film) manufactured by Teijin Co., Ltd., and Mitsui Polymer Co., Ltd. Examples include Evaflex Film (ethylene-vinyl acetate copolymer film) manufactured by Chemical Co., Ltd.

The photosensitive layer of the present invention is not particularly limited.

For example binder polymers, photoreactive monomers, photoinitiators.

A layer of a photosensitive resin composition of a known alkali development type, solvent development type, dry development type, etc. made of a dye or the like is used.

As the protective film, polyethylene film, polypropylene film, nylon film, polyester film, etc., which serve to protect the photosensitive layer, are used. However, this protective film is required not to strongly adhere to the photosensitive layer.

(Effect of the invention) The present invention provides the following excellent effects.

In other words, there is very little exposure fog due to scattered light during exposure, and conversely, when exposure is low, there is no effect of haze, so the resist does not become thin and an image faithful to the original image is formed with little change in line width. , especially suitable for fine pattern applications.

The effect of the present invention is remarkable in a low exposure area where the amount of exposure is small. 1 Normally, a 10 times effect is observed when the sensitivity is 6 steps or less on a 21-step step tablet.

Since the photosensitive film of the present invention has a small amount of change in line width, it can be used for fine patterns on printed wiring boards, keeping the dimensions of the original picture faithful.

(Example) Examples according to the present invention will be described.

Example 1 4 of an alkali-developable photosensitive resin composition using a 25 μm thick polyethylene terephthalate film (Lumirror T-60 manufactured by Toshi Co., Ltd.) with a turbidity of 0.6 cm as a support.
A 0% by weight methyl ethyl ketone solution i (V-865AFT-50, manufactured by Hitachi Chemical Co., Ltd.) was applied using a roll coater and dried.

The thickness of the photosensitive layer after drying was 25 μm. Next, a protective layer of polyethylene film having a thickness of 40 μm was layered on the photosensitive layer and pressed to form a three-layer structure, which was then rolled into a roll to produce a photosensitive film. Peel off the polyethylene film from the above photosensitive film.

The roll temperature was set to 1 so that the photosensitive layer was in contact with the copper-clad laminate.
Lamination was carried out at 60°C. The temperature of the copper-clad laminate at this time was 60°C. Next, place the original picture on the support surface,
Exposure was carried out using an ultra-high pressure ultraviolet exposure machine (HMW-201, Newly manufactured by Oak Seisakusho) so that the sensitivity became a step tablet of 8 steps/21 steps, and then the support was peeled off and developed (2% by weight of anhydrous soda carbonate). aqueous solution, 30°C, 45 seconds). After development.

The line width of the 100 μm thick portion of the transparent part of the original image was measured and found to be 101 μm, and the amount of change in line width was only +1 μm.

Example 2 The laminated plate obtained in Example 1 was exposed to light so that the sensitivity became a 6 step/21 step tablet, and developed in the same manner as in Example 1. The amount of change in line width was -2 μm.

Example 3 Using the laminated laminate plate obtained in Example 1, a step tablet with a sensitivity of 10 steps/21 steps was produced"' 7Th
,L,J: U□. , Keiga,. □, 1.

The amount of change in line width was +31 tm.

Example 4 Development was carried out in the same manner as in Example 1 using a 30 μm thick polypropylene film (I. Lejuan T-2400, manufactured by Toshi Co., Ltd.) having a turbidity of 0.5% as a support. The amount of change in line width was +1 μm.

Comparative Example 1 Development was carried out in the same manner as in Example 1 using a 25 μm thick polyethylene terephthalate film (Lumirror S-16 manufactured by Toshi Co., Ltd.) with a turbidity of 0.5% as a support. The line width change amount is +6 μm, 6 times that of Example 1, and Example 4.
It was three times as large as the previous year.

Comparative Example 2 Using the support of Comparative Example 1, development was carried out in the same manner as in Example 2. The amount of change in line width was 120 μm, which was 10 times as much as in Example 2.

Comparative Example 3 Using the support of Comparative Example 1, development was carried out in the same manner as in Example 3. The amount of change in line width was +21 μm, which was 7 times as much as in Example 3.

Examples show that the amount of change in line width is 1/3 to 1/10 compared to conventional photosensitive films.

Claims (1)

[Scope of Claims] 1. A photosensitive laminate using a plastic film having a turbidity of 2% or less as a support. 2. The photosensitive laminate according to claim 1, wherein the plastic film is a polyethylene terephthalate film. 3. The photosensitive laminate according to claim 1, wherein the plastic film is a polypropylene film.