Patent ID: 8466547

Claim:
A manufacturing method of a substrate for a semiconductor element, the manufacturing method comprising: providing a first photosensitive resin layer on a first surface of a metal plate; providing a second photosensitive resin layer on a second surface different from the first surface of the metal plate; forming a first etching mask for forming a connection post on the first surface of the metal plate by selectively performing an exposure to the first photosensitive resin layer according to a first pattern, and by developing the first photosensitive resin layer, the first etching mask comprising the first photosensitive resin layer which was developed; forming a second etching mask for forming a wiring pattern on the second surface of the metal plate by selectively performing an exposure to the second photosensitive resin layer according to a second pattern, and by developing the second photosensitive resin layer, the second etching mask comprising the second photosensitive resin layer which was developed; after the first etching mask and the second etching mask are formed, forming the connection post by performing an etching from the first surface to a midway of the metal plate; filling in a premold resin to a portion of the first surface where the connection post does not exist; processing so that a height of the connection post of the first surface is lower than a height of the premold resin surrounding the connection post; and forming the wiring pattern by performing an etching on the second surface.