PURPOSE: To enhance the quality of a semiconductor device by composing at least wiring structure of a bonding pad region of one type of metal of alloy layer of a wiring layer.

CONSTITUTION: An insulating film 102 of silicon oxidized film having desired thickness is covered, for example, on an N type epitaxial substrate 101. A photoresist 104 having a desired hole 103 is covered on the film 102, and P type impurity ions are implanted through the film 102 into the hole 103, thereby forming a base region 105 in the substrate 101. The film 102 on the region which becomes an emitter N+ part 106 and collector electrode 107 is removed, and phosphorus atoms are introduced into the substrate. The film 102 on the region which becomes the base electrode and metal-semiconductor diode anode electrode 108 of an N-P-N type transistor is removed, platinum is deposited on the entire surface, is heat treated, platinum silicide 109 is formed on the holes 106a, 107a, 108a, aqua regia is immersed with the entirety, thereby removing only the platinum except the part of silicide 109. Ti/W12 is covered on the overall surface of the substrate. Ti/W of the part which becomes bonding pad region is removed, and aluminum 113 of upper layer wiring metal is further covered.