Patent ID: 7829465

Claim:
A method of etching features in a substrate comprising: placing said substrate on a support member in a vacuum chamber; introducing at least one polymer containing gas into said vacuum chamber; igniting a plasma from said polymer containing gas; depositing a polymer on said substrate using said plasma of said polymer containing gas; pulsing said depositing of said polymer, said pulsing having a process on-time of less than about two seconds; repeating said pulsing of said depositing of said polymer; introducing an etchant containing gas, a polymer containing gas and a scavenger containing gas into said vacuum chamber; igniting a plasma from said etchant containing gas, said polymer containing gas and said scavenger containing gas; etching said substrate using said plasma of said etchant containing gas, said polymer containing gas and said scavenger containing gas; and adjusting parameters of the deposition step and adjusting parameters of the etching step until a predetermined trench depth and a predetermined sidewall angle are achieved.