Two-layer flexible substrate
AssigneeNippon Mining & Metals Co., Ltd.
InventorsKatsuyuki Tsuchida, Hironori Kobayashi, Ryu Murakami, Masashi Kumagai
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Abstract
The invention provides a two-layer flexible substrate free of surface defects and having excellent etching characteristics and adherence to a resist. The two-layer flexible substrate has a copper layer provided on one or both faces of an insulator film without using an adhesive, wherein the surface roughness (Ra) of the copper layer is 0.10 to 0.25 μm, and wherein the average crystal grain size [of copper] is no greater than 0.8 μm at 1 μm from the insulator film in the cross-section of the copper layer. Preferably, the insulator film is a polyimide film.
Claims6
A layered flexible substrate comprising a copper layer provided on one or both faces of an insulator film without using an adhesive, wherein the surface roughness (Ra) of the copper layer is 0.10 to 0.25 μm and the average crystal grain size of the copper is no greater than 0.8 μm up to a position of 1 μm from the insulator film in the cross-section of the copper layer and the copper layer has a glossy surface and is free of surface defects.
Dependencies are inferred from the claim text.