Semiconductor device

Claim 1

A semiconductor device, which is subjected to a thermal oxidation treatment process at a temperature of over 900° C. during manufacture of the device, comprising: a wafer having a semiconductor substrate comprised of one conductivity type semiconductor material and having a main surface divided into a plurality of chip forming areas, each chip forming area including (1) at least one insulation layer of silicon dioxide, (2) at least one semiconductor region insulated from said semiconductor substrate by said insulation layer, and (3) a main surface substantially in the same plane as the main surface of said semiconductor substrate; an array of semiconductor memory elements formed in said semiconductor substrate included in said chip forming area, said array of semiconductor memory elements formed in said semiconductor substrate constituting a semiconductor memory; semiconductor elements formed in said semiconductor region, said semiconductor elements formed in said semiconductor region constituting a data processing unit for processing data stored in said semiconductor memory; and means for preventing warping of said wafer resulting from said thermal oxidation treatment process, said means comprising (1) the total area of the main surface of said wafer which is occupied by semiconductor regions insulated from said semiconductor substrate by insulation layers in said chip forming areas being less than 30% of the area of the main surface of said wafer which wafer area includes the total area of the main surfaces of said semiconductor regions and the total area of the main surfaces of said insulation layers in said chip forming areas, and (2) those portions of said semiconductor substrate in each of said chip forming areas which lie under at least part of said insulation layers and at least part of said array of semiconductor memory elements in said semiconductor substrate being integrally formed of said one conductivity type semiconductor material.