Patent ID: 8187483

Claim:
A method for improving a critical dimension performance during a plasma etching process of a photolithographic substrate, comprising: providing a photomask comprising, in order, a photolithographic reticle having a thin film that has been previously deposited on said photolithographic reticle, an etch mask that has been previously patterned on said thin film; placing said patterned etch mask on a support member in a vacuum chamber; introducing a process gas into said vacuum chamber, at least some portion of the process gas is introduced coplanar to said patterned etch mask; depositing a passivation film on non-horizontal surfaces and horizontal surfaces of said patterned etch mask using a first set of process conditions, said first set of process conditions including the use of said introduced process gas and said introduced portion of coplanar process gas; clearing the deposited passivation film from the horizontal surfaces of said patterned etch mask using a second set of process conditions while some of the deposited passivation film remains on at least some of the non-horizontal surfaces of said patterned etch mask; etching an exposed surface of the thin film using a third set of process conditions; monitoring the critical dimension performance of said patterned etch mask using in-situ metrology; and adjusting the deposition step in-situ based on the monitoring step to achieve a desired critical dimension performance.