Patent ID: 8829660

Claim:
A resin-sealed semiconductor device comprising: a semiconductor chip including a silicon substrate; a die pad on which the semiconductor chip is secured via a solder layer; a sealing resin layer sealing the semiconductor chip; and a plurality of lead terminals connected electrically with the semiconductor chip, one end portion of the plurality of lead terminals being covered by the sealing resin layer, wherein the die pad and the lead terminals are formed of copper or a copper alloy, wherein the die pad has a curved side surface so as to have a gradually varying thickness, wherein the die pad has a plan area larger than a plan area of the semiconductor chip, wherein, in the die pad, only in a predetermined region other than a region in which the semiconductor chip is arranged, an open part that penetrates from one main surface side to the other main surface side of the die pad is provided, wherein outer edges of the open part along a longer-side direction thereof are formed of two sides extending continuously in a direction along an edge line of the semiconductor chip, wherein the curved side surface has a center of curvature in a direction of a bottom surface of the die pad, and wherein the open part is in a vicinity of the semiconductor chip so as to prevent accumulation of moisture near the semiconductor chip.