Plasma etching apparatus, plasma etching method, and semiconductor device manufacturing method

摘要

There is provided a plasma etching apparatus provided for performing an etching in a desirable shape. The plasma etching apparatus includes a processing chamber 12 for performing a plasma process on a target substrate W; a gas supply unit 13 for supplying a plasma processing gas into the processing chamber 12; a supporting table positioned within the processing chamber 12 and configured to support the target substrate thereon; a microwave generator 15 for generating a microwave for plasma excitation; a plasma generation unit for generating plasma within the processing chamber 12 by using the generated microwave; a pressure control unit for controlling a pressure within the processing chamber 12; a bias power supply unit for supplying AC bias power to the supporting table 14; and a control unit for controlling the AC bias power by alternately repeating supply and stop of the AC bias power.

主权项

1. A plasma etching method for performing an etching process on a target substrate with generated plasma by using a plasma etching apparatus including a processing chamber configured to perform therein a plasma process on the target substrate; a gas supply unit configured to supply a plasma processing gas into the processing chamber; a supporting table positioned within the processing chamber and configured to support the target substrate thereon; a microwave generator configured to generate a microwave for plasma excitation; a plasma generation unit configured to generate plasma within the processing chamber by using the microwave generated by the microwave generator; and a pressure control unit configured to control a pressure within the processing chamber, the plasma etching method comprising:
forming a gate insulating film layer, a gate electrode layer and a gate side wall on a silicon substrate, forming a spacer layer to cover the gate insulating film layer, the gate electrode layer and the gate side wall, the spacer layer including an upper region formed on the gate electrode layer, a side region formed on a side surface of the gate side wall, and an end region formed on a horizontal side of the side region on the silicon substrate, performing a first etching process on the spacer layer until just before the spacer layer on the end region is completely removed, and performing a second etching process on the spacer layer so that the spacer layer is completely removed from the end region, wherein in the second etching process, an AC bias power is controlled by alternately repeating supply and stop of the AC bias power, a protective film is formed on the spacer layer when the AC bias power is in an OFF state, a thickness of the protective film is about 100 Å or less, a duty ratio (a/b) of a supply time (a) of the AC bias power to a total time (b) of the AC bias power in the second etching process is in a range of from about 0.18 to about 0.75, and an ON/OFF frequency of the AC bias power in the second etching process is in a range of from about 5 Hz to about 100 Hz.