Patent ID: 6162677
Filing Date: 2000-12-19
Classification: H01L

Abstract:
A semiconductor device fabricating method for fabricating a semiconductor device having a high-density region in which transistors are arranged with a relatively high density, and a low-density region in which transistors are arranged with a relatively low density, the semiconductor device fabricating method sequentially comprising:forming transfer gates on a silicon wafer;forming a first silicon dioxide film as a protective film over an entire surface of the silicon wafer;depositing a second film on the protective film, the second film being different in kind from that of the protective film and having a high (second film)/(protective film) etch selectivity;forming side walls on the side surfaces of the transfer gates by anisotropic etching of the second film;doping regions around the transfer gates in the low-density region with impurities, using the side walls as a mask;removing the side walls by etching using the protective film as a stopper;forming a silicon nitride film of a thickness great enough to serve as a stopper over the entire surface of the silicon wafer so that regions between the transfer gates in the high density region may not be blocked up;removing parts of the silicon nitride film corresponding to at least upper surfaces of the transfer gates to be connected to wiring lines in an upper layer;depositing a second silicon dioxide film over the entire surface of the silicon wafer, the second silicon dioxide film having a thickness so as to cover the transfer gates;forming a mask for formation of contact holes in the low-density region that open to the upper surfaces of the transfer gates which are to be connected to wiring lines and for formation of contact holes in the high-density region that open to an upper surface of the silicon wafer which is to be connected to wiring lines by a photolithographic process; andforming the contact holes by etching the second silicon dioxide film through the mask by using the silicon nitride film as a stopper and by removing the silicon nitride film by etching.