Mitsui Minings & Melting Co., Ltd.

Joji Fujii

Mitsuyoshi Matsuda

Hiroaki Tsuyoshi

Hiroto Iida

Kazuhiro Yoshikawa

A method-of producing a printed wiring board comprises: forming a via-hole for interlayer connection in a laminate in which a copper foil for laser processing comprises a copper foil and an easily soluble laser absorption layer provided on a surface of the copper foil which has a higher etching rate to a copper etchant than the copper foil and absorbs an infrared laser beam and another conductor layer is laminated through an insulating layer, directly irradiating the infrared laser beam on the easily soluble laser absorption layer; and removing the easily soluble laser absorption layer from the surface of the copper foil in a desmear step of removing a smear in a via-hole and/or a microetching step as a pretreatment of an electroless plating step is adopted.

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Tokyo, Japan

Joji Fujii