Photosensitive dry film, and printed wiring board with photosensitive dry film

Patent metadata

Field	Value
Publication number	US-12259652-B2
Application number	US-202117408307-A
Country	US
Kind code	B2
Filing date	Aug 20, 2021
Priority date	Aug 26, 2020
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

The present disclosure provides a photosensitive dry film enabling a photocured film being excellent in insulation reliability and resolution and having a frosted appearance to be obtained. A photosensitive dry film including a support film having a first main surface and a second main surface opposite to the first main surface, and a photosensitive resin layer provided on the first main surface, in which the first main surface has an irregular surface formed by chemical etching.

First claim

What is claimed is:

1. A photosensitive dry film comprising a support film having a first main surface and a second main surface opposite to the first main surface, and a photosensitive resin layer provided on the first main surface, wherein
the first main surface has an irregular surface formed by chemical etching, and
wherein an arithmetic average surface roughness Sa of the irregular surface of the first main surface is 0.40 μm or more and 1.00 μm or less,
wherein the photosensitive resin layer is formed from a photosensitive resin composition, and the photosensitive resin composition comprises an aliphatic-based urea compound (C), and
wherein the aliphatic-based urea compound comprises a cyclic aliphatic structure.

2. The photosensitive dry film according to claim 1 , wherein the second main surface is a smooth surface having an arithmetic average surface roughness Sa lower than the arithmetic average surface roughness Sa of the first main surface.

3. The photosensitive dry film according to claim 1 , wherein the photosensitive resin composition further comprises a photosensitive resin (A), an epoxy compound (B), a reactive diluent (D), and a photopolymerization initiator (E).

4. The photosensitive dry film according to claim 3 , wherein the epoxy compound (B) comprises at least one selected from a bisphenol A-type epoxy resin, a biphenyl-type epoxy resin and an alicyclic epoxy resin.

5. The photosensitive dry film according to claim 1 , for use in formation of a solder resist film.

6. A method for producing a printed wiring board, comprising:
a step of bonding the photosensitive resin layer of the photosensitive dry film according to claim 1 , to a printed wiring board,
a step of applying ultraviolet light from above the support film of the photosensitive dry film, to photocure the photosensitive resin layer,
a step of releasing the support film from the photosensitive dry film and developing the photosensitive resin layer photocured, to form a photocured film having a predetermined pattern, and
a step of subjecting the photocured film having a predetermined pattern to a thermal curing treatment, to form a cured film having an irregular surface section, wherein
an arithmetic average surface roughness Sa of the irregular surface section of the cured film is 0.40 μm or more and 1.00 μm or less.

Assignees

• Tamura Seisakusho Kk

Inventors

• Takashima Ryoya
• Ishizaka Masanobu
• Imai Shinji

Classifications

• G03F7/30

  Imagewise removal using liquid means · CPC title

• G03F7/033

  the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers · CPC title

• H05K3/0023

  by exposure and development of a photosensitive insulating layer · CPC title

• H05K3/287

  Photosensitive compositions · CPC title

• H05K3/281

  by means of a preformed insulating foil (H05K3/284 takes precedence) · CPC title