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Methods and systems for advanced ion control for etching processes

  • US 9,824,896 B2
  • Filed: 11/04/2015
  • Issued: 11/21/2017
  • Est. Priority Date: 11/04/2015
  • Status: Active Grant
First Claim
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1. A method for plasma etching of a target material in semiconductor device fabrication, comprising:

  • (a) disposing a substrate on a substrate holder within a process module, wherein the substrate includes a mask material overlying a target material with at least one portion of the target material exposed through an opening in the mask material;

    (b) generating a plasma in exposure to the substrate;

    (c) for a first duration, applying a bias voltage at the substrate holder at a first bias voltage setting corresponding to a high bias voltage level and supplying a lower primary coil power to generate the plasma in exposure to the substrate;

    (d) for a second duration, after completion of the first duration, applying a bias voltage at the substrate holder at a second bias voltage setting corresponding to a low bias voltage level and supplying a higher primary coil power to generate the plasma in exposure to the substrate, wherein the second bias voltage setting is greater than 0 V, and wherein the second bias voltage setting is sufficiently low to avoid ion-induced removal of the mask material; and

    (e) repeating operations (c) and (d) in an alternating and successive manner for an overall period of time necessary to remove a required amount of the target material exposed on the substrate, such that when the bias voltage transitions from the low bias voltage level to the high bias voltage level, the higher primary coil power also transitions to the lower primary coil power.

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