Feed forward spacer width control in semiconductor manufacturing

Abstract

A feed-forward method and apparatus for controlling spacer width measures spacer width during processing then further processes the spacers in a spacer width adjustment operation to achieve a desired final spacer width. Silicon nitride spacers may be measured after plasma etching and the measured spacer width is automatically compared to the final desired spacer width and a time for further processing is calculated based on a correlation between processing time and spacer width loss. Using computer interface manufacturing, the measured spacer width data is provided to a computer that performs the calculation and provides the further processing time or a recipe to the tool used for the spacer width adjustment operation. The spacer width adjustment operation may be wet processing in an SPM solution that oxidizes the spacers and an HF clean operation may be used to remove the oxidized portion and yield spacer widths within acceptable specification limits.