Methods for selective plasma etch

摘要

Disclosed is a method for improving the selectivity of dielectric layers to photoresist layers and base layers. The method is performed in a plasma processing chamber, and the photoresist layer is coated over the dielectric layer. The method includes introducing an etchant source gas into the plasma processing chamber, which consists essentially of a CxFy gas and an N2 gas. The method further includes striking a plasma in the plasma processing chamber from the etchant source gas. The method additionally includes etching at least a portion of the dielectric layer with the plasma through to a base layer that underlies the dielectric layer. The method is also well suited for anisotropically etching an oxide layer with very high selectivities to Si, Si3N4, TiN, and metal silicides.