Lam Research Corporation

Adrian Doe

Janet M Flanner

Prashant Gadgil

Robert P Chebi

Joel M Cook

Linda N Marquez

John P Jordan

John P Jordon

A plasma processing chamber includes a substrate holder and a gas distribution plate having an inner surface facing the substrate holder, the inner surface being maintained below a threshold temperature to minimize process drift during processing of substrates. The inner surface is cooled by adding a heat transfer gas such as helium to process gas supplied through the gas distribution plate. The chamber can include a dielectric window between an antenna and the gas distribution plate. The control of the temperature of the inner surface facing the substrate minimizes process drift and degradation of the quality of the processed substrates during sequential processing of the substrates such as during oxide etching of semiconductor wafers.

Apparatus for reducing process drift in inductive coupled plasma etching such as oxide layer

Apparatus for reducing process drift in inductive coupled plasma etching

A method in a plasma processing chamber for fabricating a semiconductor device having a self-aligned contact. The method includes the step of providing a wafer having a substrate, a polysilicon layer disposed above the substrate, a nitride layer disposed above a polysilicon layer, and an oxide layer disposed above the nitride layer. The method further includes the step of etching in a first etching step partially through the oxide layer of the layer stack with a first chemistry and a first set of process parameters. In this first etching step, the first chemistry comprises essentially of CHF.sub.3 and C.sub.2 HF.sub.5. The method also includes the step of etching the oxide layer in a second etching step through to the substrate with a second chemistry comprising CHF.sub.3 and C.sub.2 HF.sub.5 and a second set of process parameters. The second set of process parameters is different from the first set of process parameters and represents a set of parameters for etching the oxide layer with a higher oxide-to-nitride selectivity than the oxide-to-nitride selectivity achieved in the first etching step.

Methods and apparatus for etching self-aligned contacts

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Adrian Doe