Murata Manufacturing Co., Ltd.

Senju Metal Industry Co., Ltd.

Shigeo Nishimura

Minoru Ueshima

Hidekiyo Takaoka

Yasuyuki Sekimoto

Katsuro Hirayama

Tohru Kurushima

A solder bump formed on an Ni electrode with the use of a solder ball containing Bi as a main component and Sn as a sub component. The solder ball contains Sn from 1.0 to 10.0 mass % and at most 1.0 mass % of at least one of Cu and Ag. A solder joint portion obtained by use of the solder bump has at least one of Sn and an SnBi eutectic alloy.

Method of forming solder bump, and solder bump

A method for manufacturing a substrate having built-in components prevents a short circuit caused by the spread of solder or conductive adhesive. Land regions to connect a circuit component and a wetting prevention region surrounding the land regions are formed on one primary surface of a metal foil. Terminal electrodes of the circuit component are electrically connected to the land regions using solder, and an uncured resin is disposed on and pressure bonded to the metal foil and the circuit component, so that a resin layer in which the circuit component is embedded is formed. Subsequently, a wiring pattern is formed by processing the metal foil. The wetting prevention region is a region obtained by roughening or oxidizing one primary surface of the metal foil so as to reduce solder wettability.

Method for manufacturing substrate having built-in components

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Nagaokakyo, Japan

Shigeo Nishimura