Abstract: A method of forming a thin film stack on a substrate, wherein the thin film stack includes at least a polysilicon layer and an oxide layer; forming a hardmask layer on the thin film stack; forming an anti-reflective coating (ARC) layer on the hardmask layer; patterning the ARC layer; etching the hardmask layer using the patterned ARC layer as a mask; and etching the thin film stack using the hardmask layer as a mask.

Abstract: The invention relates to a method of etching a feature in an oxide layer using a photoresist mask, the oxide layer being disposed above an underlying layer of a substrate inside an inductively-coupled plasma processing chamber. The method includes flowing an etchant source gas that includes CH2F2,C4F8 and O2 or C3H3F5,C4F8 and O2 into the plasma processing chamber. The method further includes forming a plasma from the etchant source gas. The method additionally includes etching through the oxide layer of the substrate with the plasma, wherein the etching substantially stops on the underlying layer, the underlying being one of a silicon layer, a tungsten-based layer or a TiN layer.

Abstract: In a plasma processing chamber, a method for etching through a selected portion of an oxide layer of a wafer's layer stack to create a self-aligned contact opening is described. The wafer stack includes a substrate, a polysilicon layer disposed above the substrate, a nitride layer disposed above said polysilicon layer and the oxide layer disposed above the nitride layer. The method for etching includes etching through the oxide layer of the layer stack with a chemistry and a set of process parameters. The chemistry essentially includes C.sub.2 HF.sub.5 and CH.sub.2 F.sub.2 and the set of process parameters facilitate etching through the oxide layer without creating a spiked etch and etching the oxide layer through to the substrate without substantially damaging the nitride layer.

Abstract: A plasma, formed from a mixture of C.sub.4 F.sub.8 and CH.sub.2 F.sub.2, is used to etch a self-aligned contact, the self-aligned contact being an opening in the oxide layer, the opening being aligned with an opening in an underlying nitride layer and extending to a substrate underlying the nitride. The mixture of C.sub.4 F.sub.8 and CH.sub.2 F.sub.2 provides a high ratio of oxide etch rate to nitride etch rate so that the etching is completed without substantially damaging the nitride layer. For thicker oxide layers a preliminary etch step using C.sub.2 F.sub.6 and C.sub.2 HF.sub.5 may be performed prior to using the mixture of C.sub.4 F.sub.8 and CH.sub.2 F.sub.2.

Abstract: 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.