Flash step preparatory to dielectric etch

A dielectric etch process for etching a via or contact hole through an inter-level dielectric layer formed in a substrate and overlaid by an anti-reflection coating a patterned mask overlying said anti-reflection coating, said process comprising to steps of:

• placing said substrate in a plasma reactor;
• a first step of flowing a first etching gas into said reactor and exciting it into a plasma to etch through said anti-reflection coating;
• and
• a second step of flowing into said reactor a second etching gas comprising a perfluorocarbon having a F/C ratio of no more than 1.6 to etch said dielectric layer, said plasma not being extinguished between said first and second steps, said first etching gas being less polymerizing than said second etching gas.

A dielectric etching method for etching holes into an upper dielectric layer overlying a lower dielectric layer of a substrate having a plurality of conductive features formed in an upper surface of said lower dielectric layer, said method comprising the steps of:

• placing into a plasma etch reactor said substrate having a mask formed on a surface thereof patterned with a plurality of first apertures overlying respective ones said conductive features and at least one second aperture not overlying any of said conductive features;
• processing said substrate in a plasma of a first gas;
• and
• without extinguishing said plasma, then etching said upper dielectric layer in a plasma of a second gas comprising a first perfluorocarbon having an F/C ratio of no more than 1.6, wherein said first gas is less polymerizing than said second gas.