Utilizing simultaneous masking and diffusion of peripheral substrate areas

Claim 1

In a method of producing silicon gate-type MOS integrated circuit devices having polycrystalline silicon resistance, comprising: a step for forming a field oxide on the main surface of a silicon semiconductor substrate so as to surround areas where transistors are to be formed; a step for forming a gate oxide having a thickness smaller than that of said field oxide; a step for forming an elongated strip of polycrystalline silicon which extends from an area selected from said areas onto said field oxide; a step for forming a first masking layer on the surface of said elongated strip thereby to form a resistor region in said elongated strip; a step for introducing impurities of a conductivity type opposite to that of said semiconductor substrate into the surface of said elongated strip exposed from said first masking layer and into the selected surfaces of said areas; and a step for forming a first metal layer which comes into contact with said areas into which are introduced said impurities; the improvement characterized by; forming a second masking layer on the peripheral surface of said silicon semiconductor substrate such that said impurities will not be introduced into said peripheral surfaces, said second masking layer being formed during said step for forming said first masking layer; and forming a second metal layer on said peripheral surfaces of said silicon semiconductor substrate into which are not introduced said impurities, said second metal layer being formed during said step for forming said first metal layer, thereby to form a substrate electrode of said silicon semiconductor substrate.

Claim 6

A method according to any one of claims 1 to 4, wherein said semiconductor substrate is scribed on the peripheral surface of said semiconductor substrate on the outer side of said second metal layer.