| 摘要 |
PROBLEM TO BE SOLVED: To provide a flexible circuit board having excellent dimensional accuracy by suppressing occurrence of a curl. SOLUTION: In this circuit board, two or more plastic films are laminated, and a conductor layer is formed at least one of the films for constituting the laminate. In this case, linear expansion coefficient ellipses of the two films disposed on both outermost layers of the laminated film have 1.4×10(1/ deg.) or less of a maximum value of a difference of the coefficients obtained by superposing it on parts corresponding to film surfaces and 0.7 or less of eccentricity of thermal shrinkage factor ellipse of the plastic film.
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