Nippon Steel Chemical Co., Ltd.

Hiroyuki Chinju

Hisashi Watanabe

Takashi Tanaka

Kaoru Okamoto

Isamu Takarabe

Seigo Oka

Keiji Yoshizawa

Taeko Hayama

Soichiro Kawamura

This invention relates to laminates in which a layer of polyimide precursors and a layer of photosensitive resins are formed one on top of another on an electric conductor such as a stainless steel foil and also to laminates consisting of a stainless steel foil and successive layers of polyimide precursors and photosensitive resins useful for the manufacture of HDD suspensions. In particular, the use of resins containing a repeating unit derivable from specific aromatic diamines and aromatic carboxylic acid dianhydrides as polyimide precursors makes it possible to fabricate an insulator of high fabrication accuracy and reliability on an electric conductor and, in addition, the laminates are useful as materials for the manufacture of HDD suspensions of an integrated circuit/wiring structure with high accuracy.

Laminates

A laminate comprising at least two layers of a photosensitive resin layer and a polyimide precursor resin layer; a process for formation of an insulating protective layer using a laminate which comprises laminating a laminate comprising at least photosensitive resin layer and a polyimide precursor resin layer on an insulating board having an exposed circuit; selectively exposing the photosensitive resin layer to active light; developing the resultant photosensitive resin layer; removing the exposed polyimide precursor resin layer by etching it with an alkaline solution using the photosensitive resin layer as a mask; removing the photosensitive resin layer; and then curing the residual polyimide precusor resin layer; and a process for preparation of a printed circuit which comprises forming a polymide precursor resin layer on an insulating board having an exposed circuit, patterning the resin layer with an alkaline solution, and then curing it. The laminate of this invention can provide extremely easily an insulating protective layer for circuits having a high processing precision and excellent in reliability on insulation. Further, a printed circuit having a high processing precision and excellent in reliability on insulation can be provided extremely easily by the processes of this invention.

Laminate for insulation protection of circuit boards

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Chiba, Japan

Hiroyuki Chinju