FABRICATION METHOD OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A fabrication method of semiconductor device is provided to improve an operation characteristic of a transistor by remove a tail formed into the lower portion of a sidewall insulating film. CONSTITUTION: The fabrication method of semiconductor device includes the steps of; depositing a insulating film for a sidewall insulating film(106) into a semiconductor substrate(100) formed with a gate region(104), forming the sidewall insulating film into the gate region by etch-back processing into the insulating film, undercutting the semiconductor substrate up to reach a lower side of the sidewall insulating film and, removing the sidewall insulating film isolated from the substrate by the undercutting process. Thereby, it is possible to improve operation characteristics of devices in forming the sidewall insulating film into a gate of semiconductor device.