Patent ID: 6955990
Filing Date: 2005-10-18
Classification: H01L

Abstract:
1. A method to form a gate in a semiconductor device comprising: forming a gate insulation film on a semiconductor substrate; forming a gate polysilicon layer on the gate insulation film; performing a first dry etching process on the gate polysilicon layer under first process conditions, wherein upper sidewall polymers are formed on an upper portion of the gate polysilicon layer; performing a second dry etching process on the gate polysilicon layer under second process conditions, wherein lower sidewall polymers are formed on sidewalls of a lower portion of the gate polysilicon layer by sidewall polymerization, the lower sidewall polymers being thinner than the upper sidewall polymers; and performing a third dry etching process on the gate polysilicon layer to remove the upper and lower sidewall polymers, wherein the lower portion of the gate polysilicon layer is over etched so that a CD of the upper portion of the gate is greater than a CD of the lower portion of the gate.