| 摘要 |
PROBLEM TO BE SOLVED: To provide a flexible substrate not having a curl and the curl of a polyimide film after the etching of a metal foil, including no thermoplastic polyimide having the high coefficient of linear expansion and having high adhesion strength. SOLUTION: The flexible substrate is constituted by forming a polyimide layer on the metal foil and characterized in that the average coefficient of linear expansion of the polyimide layer is 5×10<SP>-6</SP>to 25×10<SP>-6</SP>(1/°C), when the cross section of the flexible substrate is confirmed in the transmitted light mode of an optical microscope, the hue in the polyimide layer is observed as a single layer and, when the polyimide layer is analyzed in a film thickness direction using Raman spectroscopy, the maximum value of an orientation parameter is present on the surface side of the metal foil from the central part of the surface on the metal foil side of the polyimide layer and the surface on the opposite of the metal foil thereof. COPYRIGHT: (C)2006,JPO&NCIPI |
