Hitachi Cable, Inc.

Hiroyuki Takasaka

Toshio Kawamura

Hiroshi Sugimoto

Yuju Endo

Toshi Sasaki

Takashi Suzumura

Shigeharu Takahagi

Noboru Imai

Toshikatsu Hiroe

Makoto Aida

Kenichi Kaneko

Nagayoshi Matsuo

Hiroyuki Okabe

Shigeo Nishino

A multilayer wiring board includes a core insulating layer with a first conductive wiring, a first insulating layer with a softening temperature lower than the core insulating layer, and a second insulating layer formed on the core insulating layer through the first insulating layer, the second insulating layer with a second conductive wiring electrically connected to the first conductive wiring and a softening temperature higher than the first insulating layer. The first insulating layer is mainly formed of a liquid crystal polymer. The core insulating layer and the second insulating layer are mainly formed of a polyimide resin or a bismaleimide triazine resin. The first conductive wiring and the second conductive wiring are electrically connected through a conductive via formed penetrating through the first insulating layer and the second insulating layer in a thickness direction.

Multilayer wiring board and method of making the same

A method for punching an insulating film is composed of using plural divided punches having a clearance between each two of the divided punches. The clearance absorbs thermal expansion of the divided punches caused by receiving a heat from a heater. A punched insulating film is stuck to a lead frame by being pressed between the divided punches and the heater.

Method for sticking an insulating film to a lead frame

The occurrence of burrs and chips in punching an insulating film is suppressed by adjusting an edge tearing resistance of the insulating film. The edge tearing resistance is preferably 50 to 70 kgf/20 mm for the purpose of suppressing the burrs and the chips.

Insulating film with improved punching characteristics and lead frame

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Ibaraki, Japan

Hiroyuki Takasaka