Method for suppressing pattern distortion associated with BPSG reflow and integrated circuit chip formed thereby

摘要

Significant amounts of pattern distortion were found to be the result of reflowing borophosphosilicate glass (BPSG) and silicon dioxide shrinkage during high temperature junction anneals. In order to remedy this problem, a method for suppressing the pattern distortion by subjecting the wafer coated with BPSG and with silicon dioxide layers to a high temperature anneal before patterning is disclosed. The high temperature anneal densifies the undoped silicon dioxide before patterning, so that shrinkage of the undoped silicon dioxide does not affect the patterning steps.