Patent ID: 9437544
Filing Date: 2016-09-06
CPC Classification: H01L

Claim Text:
1. A semiconductor device comprising: a semiconductor chip; a wiring formed on the semiconductor chip; an insulating film, coating the wiring and having an opening for partially exposing the wiring from the insulating film; a first film made of Ti and W, formed on a portion of the wiring facing the opening; a Cu layer, formed by plating on the first film and on a portion of the wiring exposed through the insulating film such that an upper surface of the Cu layer is a uniform distance from an upper surface of the wiring, and having a peripheral edge portion thereof protruding away from the opening more than a peripheral edge of the first film in a direction parallel to a surface of the insulating film; and a solder ball bonded to the Cu layer, wherein a distance between the surface of the insulating film and the Cu layer is fixed, a protrusion amount of the peripheral edge portion of the Cu layer with respect to the peripheral edge of the first film is greater than a thickness of the first film, the Cu layer is stacked high enough that a surface of the first film does not vertically surpass the upper surface of the Cu layer in the center of the opening, and an interface between the Cu layer and the solder ball is arc-shaped on both sides of the upper surface of the Cu layer in a cross section taken perpendicularly to the upper surface of the Cu layer.