SEMICONDUCTOR DEVICE AND ITS MANUFACTURE

摘要

PURPOSE:To prevent a lowering in resolution of a resist pattern and dimensional accuracy by a method wherein the surface of in Si substrate where a memory cell is formed is excavated directly and is made low with respect to a peripheral circuit including its neighborhood. CONSTITUTION:An opening of a resist pattern 2 formed on an Si substrate 1 is used as a region 3 to form a memory cell; the Si is dry-etched by making use of a resist as a mask. An etching depth is about one half of a difference between average heights in a finished state of the memory cell part and a peripheral circuit part. The resist 2 is removed; an Si substrate 1' whose region to form the memory cell is recessed is formed. Memory circuits 4 and peripheral circuits 5 are formed by using an ordinary method. If the surface of a semiconductor to form the memory cell is dug down with reference to a region of the peripheral circuit, an average difference between a memory cell region whose average height has become high and a region of the peripheral circuit is limited; both regions can be set within the allowable depth of the focus of an aligner.