San-Ei Kagaku Co., Ltd.

Yukihiro Koga

Kazunori Kitamura

Kiyoshi Sato

Takeshi Saito

A method produces an undercoat-covered smoothed printed wiring board, requiring no step of polishing the surface of the printed wiring board. A method for producing a solder-resist-covered printed wiring board causes no depression in an area between circuit traces. A printed wiring board so produced is also described. The method for producing a printed wiring board includes applying a photo- and heat-curable resin composition onto at least a part of a surface of a printed wiring substrate; placing an optically transparent smoothing member on the resin layer; moving a hard roller on the smoothing member to thin the applied resin layer to a thickness of interest; placing a negative-image mask on the smoothing member; exposing the applied resin layer to light via the negative-image mask; removing the optically transparent smoothing member; removing a light-unexposed portion of the applied resin layer through development; and completely heat-curing the cured light-exposed portion.

Printed wiring board and method for producing the same

In a curable resin composition containing an inorganic filler, the average particle diameter of the inorganic filler is 1 &#x3bc;m or less and the content of the inorganic filler is 50 wt % or less. The curable resin composition can be preferably used for a halogen-free resin substrate and the like having a small load on an environment as a hole-plugging curable resin composition as well as used to provide a hole-plugging build-up printed wiring board having a via-on-via structure (in particular, a stacked via structure) having an excellent crack-resistant property, an excellent insulation/connection reliability, and the like.

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Tokyo, Japan

Yukihiro Koga