Method for manufacturing a substrate for mounting a semiconductor element

摘要

A method for manufacturing a substrate for mounting a semiconductor element includes: a step for forming a predetermined resist pattern by affixing resists on both faces of a base material including a metallic thin plate and using the resist of one of the faces as a masking for plating; a step for performing an etching of a predetermined position on a base material exposed from the resist pattern; a step for forming a plating layer having at least three layers including a lower, a middle, and an upper layer on the etched base material; a step for separating the resists affixed to both faces of a base material; and a step for performing an etching of the middle plating layer to make the middle plating layer narrower than the upper and lower plating layers.