US Patent 10453697 Methods of measuring electrical characteristics during plasma etching

Wafers processed by methods of plasma etching are disclosed. In one embodiment, a wafer is prepared by a process including positioning the wafer within a chamber of a plasma etcher, generating plasma ions using a radio frequency power source and a plasma source gas, directing the plasma ions toward the wafer using an electric field, focusing the plasma ions using a plasma focusing ring to increase a flux of plasma ions arriving at a surface of the wafer, and etching a plurality of through-wafer vias in the wafer.