Reduction of Depth Variation in an Si Etching Process by Applying an Optimized Run-to-Run Control System

Abstract

A reduction of depth variation in a shallow trench isolation process is desired for obtaining more stable electrical performances of silicon devices. By applying an optimized run-to-run control system to a silicon trench etching process, trench depth variation of the process was reduced. Cp/Cpk of the trench depth of product wafers were improved from 1.10/0.83 to 1.39/1.34 by the control.