Patent ID: 7227262

Claim:
A semiconductor device including a protrusion electrode for flip chip connection, comprising; a semiconductor substrate; electrodes formed on the semiconductor substrate, the electrodes being made of a metal; a passivation film that covers the surface of the semiconductor substrate on which the electrodes are formed, in which an opening is formed so as to expose a predetermined electrode from among the electrodes; a diffusion prevention plug that is formed in the vicinity of the opening of the passivation film, and that is electrically connected to the predetermined electrode; a seed layer formed on and over the diffusion prevention plug, the seed layer being in contact with the passivation film; and a protrusion electrode formed on the seed layer, wherein a width of the protrusion electrode is greater than a width of the diffusion prevention plug. the diffusion prevention plug is substantially completely covered by the seed layer so that the diffusion prevention plug is not exposed, and the diffusion prevention plug is made of a metal material that prohibits an occurrence of diffusion between the metal forming the electrodes formed on the semiconductor substrate and a metal forming the protrusion electrode.