Sumitomo Electric Industries, Limited

Ippei Tanaka

Hiroshi Ueda

Koji Nitta

Yoshio Oka

Hideki Matsuoka

Takashi Kasuga

Masamichi Yamamoto

Eiko Imazaki

Shigeaki Uemura

Takayuki Yonezawa

According to one aspect of the present disclosure, a printed circuit board includes: an insulating base film; and a plurality of wiring portions formed on a surface of the base film, wherein the wiring portions include a seed layer that is directly or indirectly layered on the surface of the base film and a metal layer that is layered on the seed layer, wherein the base film has a wiring area including the plurality of wiring portions and a non-wiring area not including the wiring portions, wherein the plurality of wiring portions include at least one outermost boundary wiring portion and a plurality of inner wiring portions other than the outermost boundary wiring portion, wherein the outermost boundary wiring portion is formed on an outermost side of the base film in the wiring area and at a boundary between the wiring area and the non-wiring area, wherein an average width of the outermost boundary wiring portion is 30 μm or more, wherein an average width of the inner wiring portions is 20 μm or less, and wherein an average aspect ratio of the inner wiring portions is 1.5 or more.

Printed circuit board and method of manufacturing printed circuit board

A method of making a printed circuit board includes a step of providing a double-sided plate that is an insulating substrate having conductive layers on respective surfaces thereof, a first coating step of coating a first surface of the double-sided plate with a first photosensitive resin film, a second coating step of coating a second surface of the double-sided plate with a second photosensitive resin film, a first exposure step of exposing the photosensitive resin film coating the first surface after the first and second coating steps, and a second exposure step of exposing the photosensitive resin film coating the second surface after the first exposure step, wherein a maximum depth of a depression in an outermost surface of the second photosensitive resin film used in the second exposure step is less than 1.0 &#x3bc;m.

Method of making printed circuit board and laminated structure

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Osaka, Japan

Ippei Tanaka