JPH05254023A - Laminating method of photosensitive film - Google Patents

Abstract

PURPOSE:To improve the follow-up properties of photosensitive film and prevent void from being left in lamination by a method wherein the photosensitive film, which is reduced by forming photosensitive layer on flexible backing film, and substrate, which is produced by forming conductor pattern on insulating substrate, are laminated under heat and reduced pressure to each other under the condition that the photosensitive layer directly contacts with the surface, on which the conductor pattern is formed, and, after that, heated further. CONSTITUTION:Photosensitive film is laminated onto substrate by the publicly known laminating method and, firther, left under the atmospheric pressure and temperature of 50 deg.C or higher. The heating temperature is 50C or higher preferably about 60-100 deg.C. The satisfactory heating time is 1-15min, preferably about 3-10min. As the heating means, oven, infrared radiation, far infrared radiation, hot roller, hot plate or the like is employed. The laminating method concerned is especially profitable, when the height of the conductor formed on insulating substrate is 10mum or more and when the thickness of photosensitive layer before lamination is 1,5 times or less as much as the height of the conductor.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for laminating a photosensitive film on a substrate.

[0002]

2. Description of the Related Art In manufacturing a printed wiring board, a photosensitive film (dry film resist) is used as an etching resist, a plating resist and a solder resist. As a method of laminating this photosensitive film on a substrate, etching resist, plating resist,
Since the surface of the substrate used is relatively smooth, a method using a heated rubber roll under normal pressure is often used. However, when a substrate applied like a solder resist has a conductor pattern on an insulating substrate and has large irregularities, when laminating with a heating rubber roll under normal pressure, the substrate and the photosensitive film are A serious defect occurs that voids remain between them.

As a solution to this, a method of laminating a photosensitive film on a substrate under a reduced pressure, that is, a vacuum laminating method is already known.

[0004]

However, even when the above-mentioned vacuum laminating method is used, the photosensitive film is not suitable for the substrate especially when the thickness of the photosensitive film is smaller than the height of the conductor on the substrate surface. It does not completely adhere to the surface irregularities, leaving voids depending on the location, resulting in defects. The present invention is
It is an object of the present invention to solve the above problems and to provide a laminating method capable of improving the followability of a photosensitive film with respect to irregularities on the substrate surface and leaving no voids.

[0005]

According to the present invention, a photosensitive film having a photosensitive layer formed on a flexible support film is formed on a substrate having a conductor pattern formed on an insulating substrate, and the photosensitive layer has a surface having the conductor pattern. The method for laminating a photosensitive film is characterized by heating and laminating under reduced pressure so as to overlap with, and then heating at 50 ° C. or higher under normal pressure.

The present invention will be described in detail below. Specifically, the laminating method of the present invention comprises laminating a photosensitive film on a substrate by a known vacuum laminating method and then leaving this film under atmospheric pressure at a temperature of 50 ° C. or higher. .. The heating temperature is 50 ° C or higher, preferably 60
The heating time is about 1 to 15 minutes, preferably about 3 to 10 minutes.

As the heating means, there are an oven, infrared rays, far infrared rays, a heat roller, a hot plate and the like, but ovens, infrared rays or far infrared rays are preferable. With a heat roller or heat plate, heat is well transferred to the protrusions on the surface of the substrate, but because the surface of the roller and the surface of the heat plate do not adhere to the recesses, the heat is transferred unevenly This is because the embedding property of is likely to be poor.

Although the details of the mechanism by which the effect of heating and leaving is left unclear, it is not clear that when heated at a temperature of 50 ° C. or higher under normal pressure, the concave portions on the surface of the substrate are heated and laminated under reduced pressure (vacuum lamination). It is considered that this is because the photosensitive layer of the photosensitive film, which has been heated and has improved fluidity, is drawn into the voids in a reduced pressure state that remain between the photosensitive films.

The lamination method of the present invention is particularly advantageous when the height of the conductor formed on the insulating substrate is 10 μm or more, and the thickness of the photosensitive layer before lamination is 1.5 times the conductor height. The smaller case is also particularly advantageous.

[0010]

EXAMPLES Hereinafter, examples will be described. (Example 1) A 0.8 mm-thick glass epoxy substrate having a copper conductor pattern portion having a height of 45 μm on its surface
A photosensitive film comprising a 5 μm thick polyester (PET) film and a 38 μm thick photosensitive layer having the following composition:
The photosensitive layer and the substrate were laminated under reduced pressure under the following conditions (vacuum lamination) so that they overlap each other. 80 immediately after that
After leaving it in a hot air dryer at ℃ for 5 minutes, it was taken out and cooled to room temperature. When the surface of the substrate was observed in detail with a magnifying glass, no void was observed between the substrate and the photosensitive film.

Laminating conditions-Vacuum laminator HLM-570V manufactured by Hitachi Aishi Co., Ltd.-Preheating of substrate 80 ° C-Preheating substrate temperature 110 ° C-Heat shoe temperature 100 ° C-Air cylinder pressure of laminating roll 4.5 kg / cm ² Pressure in vacuum chamber 10mmHg ・ Laminating speed 0.8m / min

Composition of photosensitive layer: 55 parts by weight of methyl methacrylate / styrene / butyl acrylate / methacrylic acid (56/5/15/24 weight ratio) copolymer; 25 parts by weight of trimethylolpropane tris (ethoxyacrylate); tetrapropylene glycol di Acrylate 10 parts by weight-2,4,6-tribromophenoxyethyl acrylate 10 parts by weight-Benzophenone 4.8 parts by weight-Michler's ketone 0.2 parts by weight-Chlorinated copper phthalocyanine 0.25 parts by weight-5-Amino-1H-tetrazole 0.25 parts by weight ・ Hydroquinone monomethyl ether 0.04 parts by weight

(Comparative Example 1) In Example 1, the vacuum laminated product was allowed to cool to room temperature without being left in a hot air dryer at 80 ° C for 5 minutes. When the surface of the substrate was observed in detail with a magnifying glass, a large number of voids were found in the concave portions (portions where the conductor did not exist) on the surface of the substrate.

[0014]

As described above, according to the laminating method of the present invention, a photosensitive film having a photosensitive layer formed on a flexible supporting film is formed on a substrate having a conductive pattern formed on an insulating substrate, and the photosensitive layer is formed on the conductive layer. After heating and stacking under reduced pressure so as to overlap the surface having the pattern, it is further heated at 50 ° C. or higher under normal pressure. A photosensitive film having a relatively thin photosensitive layer can be easily laminated in a completely adhered state without leaving voids.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical display location // B29L 9:00 4F 31:34 4F (72) Inventor Yoichi Sakai Noboto Tama-ku, Kawasaki City, Kanagawa Prefecture 3816 Address Ryoko Electronic Industry Co., Ltd.

Claims (1)

[Claims] 1. A photosensitive film having a photosensitive layer formed on a flexible support film is heated under reduced pressure on a substrate having a conductive pattern formed on an insulating substrate so that the photosensitive layer overlaps the surface having the conductive pattern. After stacking, further at normal pressure 50 ℃
A method for laminating a photosensitive film, which comprises heating as described above.