Abstract: A semiconductor device having a silicon resistor element is disclosed. The silicon resistor element includes a first polycrystalline silicon film containing oxygen atoms with a low density, and a second polycrystalline silicon film disposed on the first polycrystalline silicon film and containing oxygen atoms with a high density. A silicon oxide film converted from polycrystalline silicon is attached to the top surface of the second polycrystalline silicon film.

Abstract: A semiconductor device comprises a semiconductor substrate, an insulating film formed on a major surface of the substrate a lower wiring layer formed on the insulating film, a borophosphosilicate glass film covering the lower wiring layer and the insulating film, a phosphosilicate glass film having a low phosphorus concentration and provided on the borophosphosilicate glass film, and a polycrystalline silicon layer doped with an impurity and provided on the phosphosilicate glass. According to the structure, the polycrystalline silicon layer maintains the normal state. Therefore, the silicon layer can be precisely etched for patterning and a wiring layer made of the silicon layer is never moved in a following process step such as thermal step. Further, even if another wiring layer of aluminum is formed on the phosphosilicate glass film, the aluminum wiring layer is not broken above the corner of the lower wiring layer, and is hardly corroded by invaded water into a plastic package.