MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To conform a mask accurately, and to improve yield by partially exposing the pattern of a buried diffusion region and precisely confirming the position of the whole buried diffusion region from the exposed section. CONSTITUTION:The section not formed m of an epitaxial layer 4 is left in a substrate 2 to which the buried diffusion regions 3 are shaped selectively, and one part or the whole of a buried region 3m is exposed. An insulating film 8 and a photo-resist film 11 are laminated, and the mask 12 is executed. When two positions of the opaque film 14 of the mask 12 are conformed to the region 3m, all are conformed accurately because the patterns of the opaque film 14 and the diffusion regions 3 are constant, the mask is conformed positively with eyes without being affected by the scattering, etc. of the thickness of the epitaxial layer 4, and the pattern can be exposed. It is advantageous that the section not formed m of the epitaxial layer is shaped to the fringe of the substrate. According to such constitution, the yield of the device obtained from one substrate is improved.