Patent ID: 7369905

Claim:
A method of controlling a graded plasma enhanced chemical vapor deposition (PECVD) process, comprising the steps: determining a desired dynamic profile for a first output process parameter of a graded PECVD process; and determining a dynamic profile for a first input process parameter that produces the desired dynamic profile for the first output process parameter during the graded PECVD process wherein the step of determining a dynamic profile for a first input process parameter includes iteratively optimizing an initial dynamic profile for a first input process parameter to converge on the desired dynamic profile for the first output process parameter; wherein the step of iteratively optimizing includes: forming the initial dynamic profile for a first input process parameter; performing a first production run in accordance with the initial dynamic profile for a first input process parameter; measuring an actual dynamic profile for the first output process parameter; comparing the actual dynamic profile for the first output process parameter with the desired dynamic profile for the first output process parameter; and adjusting the initial dynamic profile for a first input process parameter based on the results of the comparing to generate an adjusted dynamic profile for the first input process parameter.