Patent ID: 9711364
Date: 2017-07-18
CPC Classifications: H01J,H01L

Claim:
1. A method of wafer etching, the method comprising: positioning a wafer on a feature plate 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 that is spaced apart from the feature plate to increase a flux of plasma ions arriving at a surface of the wafer; clamping the wafer against the feature plate using a clamp that is positioned over the wafer and the feature plate; measuring an electrical bias of the feature plate based on passing a portion of the plasma ions through one or more electrical measurement holes of the clamp to impact the feature plate; adjusting a power provided to the radio frequency power source based at least in part on the measured electrical bias; and etching a plurality of through-wafer vias in the wafer.