Japan Gore-tex Inc.

Akira Urakami

Kazuhiko Ohashi

Sunao Fukutake

Minoru Hatakeyama

Makoto Ogawa

Yoshito Hazaki

A dielectric film for a printed wiring board that has excellent heat resistance, moisture resistance, insulation properties, adhesiveness, ease of handling, ease of processing, and the like, and possesses low elasticity and high elongation as stress relief functions. The dielectric film has drawn porous polytetrafluoroethylene used as the base material; this is impregnated with an adhesive or fusible resin; the post-solidification tensile modulus of elasticity is 0.1 to 1.8 GPa; and the tensile elongation at break (at 25&#xb0; C.) is at least 4.0%. A semiconductor device, comprising a multilayer printed board having a plurality of circuit layers, and a semiconductor element mounted on the multilayer printed board, this semiconductor device having an insulating/adhesive layer with a stress relief function between the outermost circuit layer of the multilayer board on the side of the semiconductor element, and the circuit layer adjacent thereto; and the insulating/adhesive layer is formed from the dielectric film. Also, a printed wiring board therefor.

Dielectric film for printed wiring board, multilayer printed board, and semiconductor device

A printed circuit board assembly having a coverlay film which is a composite film consisting of a porous fluoropolymer film coated with a thermoplastic or heat-curing adhesive is disclosed. The coverlay film has excellent conformability and adhesion to the printed circuit board and low dielectric constant.

Printed circuit board with a coverlay film

A resin-sealed semiconductor device, including a chip mounting die pad, porous fluorocarbon material located just beneath the die pad, beneath a die-pad supporting layer, gold lead wires, or in a sealing resin surrounding the other components, wherein any water vapor generated by the heat of soldering will be held within the porous fluorocarbon rather than crack the sealant under internal pressure.

Growing community of inventors

Okayama, Japan

Akira Urakami