Locos isolation process using a layered pad nitride and dry field oxidation stack and semiconductor device employing the same

摘要

The present invention provides methods of manufacturing a field oxide isolation structure over a semiconductor. One of the methods includes the steps of: (1) depositing a first stack-nitride sublayer over the semiconductor at a first deposition rate and (2) subsequently depositing a second stack-nitride sublayer over the first stack-sublayer at a second deposition rate that is either greater or less than the first deposition rate. The first and second deposition rates provide first and second stack-nitride sublayers that cooperate to form a relatively thin, uniform thickness of the field oxide isolation structure over the semiconductor and provide a stress-accommodating system within the semiconductor. The varying rates of deposition and accompanying changes in mixture ratio, produce a stack that is better able to absorb stress, has greater uniformity and is far less subject to the disadvantageous phenomenon of stack-lifting, particularly encountered in semiconductor having a PADOX layer deposited thereon.