Patent ID: 7476968

Claim:
A semiconductor device comprising: a semiconductor substrate that has an electrode; a protective insulating layer that protects the electrode; a buffer layer that is formed over the protective insulating layer, the buffer layer having a first surface and a second surface, the first surface facing the protective insulating layer, the second surface being opposite to the first surface; a hole that is provided over the electrode in such a manner as to penetrate the protective insulating layer and the buffer layer; an under electrode that has a first portion and a second portion, the first portion being formed on the second surface of the buffer layer, the second portion being formed on the inner surface of the hole and the surface of the electrode, the first portion having a third surface facing the buffer layer and a fourth surface opposite to the third surface; a conductive layer that is formed in the hole, the conductive layer being formed of an electrically conductive material, the conductive layer having a fifth surface facing the electrode and a sixth surface opposite to the fifth surface; and a bump electrode formed on the under electrode and on the conductive layer, wherein the conductive material is a material that is more flexible than a material of the bump electrode, wherein the sixth surface of the conductive layer and the fourth surface of the first portion of the under electrode are in the same plane.