Lam Research Corporation
Method for etching features in a stack

Abstract:

A method for etching features in a stack below a carbon containing mask is provided. The stack is cooled to a temperature below -20.degree. C. An etch gas is provided comprising a free fluorine providing component, a hydrogen containing component, a hydrocarbon containing component, and a fluorocarbon containing component. A plasma is generated from the etch gas. A bias is provided with a magnitude of at least about 400 volts to accelerate ions from the plasma to the stack. Features are selectively etched in the stack with respect to the carbon containing mask.