SEMICONDUCTOR DEVICE MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a manufacturing method which avoids the occurrence of failure and which can manufacture a surface-mounted semiconductor device stably and with excellent mass productivity.SOLUTION: A semiconductor device manufacturing method sequentially performs: a process of preparing a base substrate in which a second metal layer is formed on a first metal layer; a process of forming a patterned resist mask layer on the second metal layer; a process of forming a plurality of semiconductor element mounting parts and electrode terminal parts by electrocasting on the second metal layer exposed from the resist mask layer; a process of removing the rest mask layer; a process of mounting semiconductor elements on the semiconductor element mounting parts and electrically connecting the semiconductor elements and the electrode terminal parts; a process of resin encapsulating the semiconductor element mounting parts, the semiconductor elements and the electrode terminal parts to form a resin encapsulated body; and a process of peeling and removing the base substrate including the second metal layer.