Iteratively selective gas flow control and dynamic database to achieve cd uniformity

Abstract

A method for compensating for CD variations across a semiconductor process wafer surface in a plasma etching process including providing a semiconductor wafer having a process surface including photolithographically developed features imaged from a photomask; determining a first dimensional variation of the features with respect to corresponding photomask dimensions along at least one wafer surface direction to determine a first levelness of the process surface; determining gas flow parameters in a plasma reactor for a plasma etching process required to approach a level process surface by reference to an archive of previous plasma etching process parameters carried out in the plasma reactor; carrying out the plasma etching process in the plasma rector according to the determined gas flow parameters; and, determining a second dimensional variation of the features along the at least one wafer surface direction to determine a second levelness of the process surface.