Nippon Steel Chemical Co., Ltd.

Dai Nippon Printing Co., Ltd.

Kazuto Okamura

Makoto Shimose

Kazutoshi Taguchi

Kazunori Ohmizo

Katsuya Sakayori

Terutoshi Momose

Shigeki Kawano

Michiaki Uchiyama

Tomoko Togashi

Takuhei Ohta

Katsufumi Hiraishi

Naoya Okabayashi

Kazunori Oomizo

The present invention provides a laminate comprising an insulating layer having suppressed dusting properties, an insulating film comprising the insulating layer, and an electronic circuit component comprising a pattern of the insulating layer. The laminate has a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer. The insulating layer comprises a laminate of two or more wet etchable insulating unit layers. At the interface between the inorganic material layer and the insulating layer, surface irregularities of the inorganic material layer have been transferred onto the surface of the insulating layer. The average height of the surface irregularities transferred onto the insulating layer is less than the thickness of the outermost insulating unit layer in the insulating layer.

Wet etchable laminated body, insulation film, and electronic circuit part using the laminated body and the film

This invention relates to a laminate comprising an insulating polyimide resin layer etchable by an aqueous alkaline solution and a metal foil. The laminate has an insulating resin layer composed of a plurality of polyimide resin layers on the metal foil and the insulating resin layer has at least one polyimide resin layer (A) with a coefficient of linear thermal expansion (CTE) of 30&#xd7;10/&#xb0; C. or less and at least one polyimide resin layer (B) with a glass transition temperature (Tg) of 300&#xb0; C. or below, the layer in contact with the metal foil is the polyimide resin layer (B), the bonding strength between the metal foil and the polyimide resin layer (B) in contact therewith is 0.5 kN/m or more, and the average rate of etching of the insulating resin layer by a 50 wt % aqueous solution of potassium hydroxide at 80&#xb0; C. is 0.5 &#x3bc;m/min or more. The laminate is useful for flexible printed circuits and the like.

Laminate and process for producing the same

This invention relates to a laminate which changes in dimension to such a small extent as not to cause curling and warpage when the ambient humidity changes and is useful for flexible printed wiring boards. The laminate possesses a polyimide layer or layers of polyimides formed on a conductor by coating and at least one of the polyimide layers is composed of polyimide of low hygroscopic expansion obtained by the reaction of diamines containing 20 mol % or more of 4,4'-diamino-2,2&#x2032;-dimethylbiphenyl with a tetracarboxylic acid compound and exhibiting a coefficient of linear hygroscopic expansion of 15&#xd7;10/% RH or less.

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Chiba, Japan

Kazuto Okamura