CONTROLLING SYSTEM FOR GATE FORMATION OF SEMICONDUCTOR DEVICES

A method of controlling gate formation of semiconductor devices includes determining the correlation between the step heights of isolation structures and the over-etching time by measuring step heights of isolation structures, determining an over-etching time based on the step heights, and etching gates using the over-etching time. The method may include an after-etching-inspection to measure the gate profile and fine-tune the gate formation control. Within-wafer uniformity can also be improved by measuring the step height uniformity on a wafer and adjusting gate formation processes.