Patent ID: 11331888

Abstract:
A composite film for electronic device using high frequency band signals, which is low in dielectric tangent, excellent in embedding properties relative to unevenness of a circuit, etc., and excellent in surface smoothness, and has high adhesion to plated copper is provided; and a printed wiring board containing a cured material of the composite film for electronic device and a method of producing the printed wiring board are also provided. Specifically, the composite film for electronic device is a composite film for electronic device using high frequency band signals, including a layer A having a minimum melt viscosity at 80 to 150° C. of 100 to 4,000 Pa·s; and a layer B having a minimum melt viscosity at 80 to 150° C. of 50,000 Pa·s or more. The composite film for electronic device is low in thermal expansion properties and excellent in handling properties of film.