Production of semiconductor device

A method of producing a semiconductor device, which comprises the steps of:

• forming a recess on a first side of a metal substrate;
• forming a metal film, made of a metal that is not dissolved by an enchant solution which dissolves the metal substrate, on an inner surface of the recess;
• punch-pressing a region of the metal substrate that corresponds to an area of the metal film, from a second side of the metal substrate, so that the area of the metal film formed on the inner surface of the recess becomes substantially flush with said first side of the metal substrate, thereby to form a bonding pad from an extending portion of the metal film that extends from the inner surface of the recess over the first side of the metal substrate;
• mounting a semiconductor chip on a portion of said first side of the metal substrate where the bonding pad is formed;
• wire-bonding electrodes on the semiconductor chip and the bonding pads together with bonding wires;
• sealing with resin said first side of the metal substrate that includes the semiconductor chip, the bonding wires and the metal film;
• and
• dissolving and removing the metal substrate by etching thereby to expose the metal film formed on the inner surface of the recess.