A plasma etch process for forming a high aspect ratio contact opening through a silicon oxide layer is disclosed. The silicon oxide layer is plasma etched using etch gases that include at least one organic fluorocarbon gas. At least one etch gas is used that includes one or more nitrogen-comprising gases to deposit a surface polymeric material during the etching for maintaining a masking layer over the silicon oxide layer. The method of the invention achieves a complete and anistropic etching of a contact opening having a high aspect ratio and the desired dimensions.