Synchronous embedded radio frequency pulsing for plasma etching
First Claim
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1. A method of etching a substrate, comprising:
- generating a plasma by providing only a first RF signal having a first frequency and a first duty cycle;
applying only a second RF signal to bias the plasma towards the substrate, wherein the second RF signal has the first frequency and a second duty cycle different than the first duty cycle, and wherein an “
on”
portion of the second RF signal is entirely embedded with an “
on”
portion of the first RF signal and does not overlap an “
off”
portion of the first RF signal;
adjusting a phase variance between the first and second RF signals to control an ion energy distribution in the plasma, wherein adjusting the phase variance further includes controlling a phase lag of the second RF signal relative to the first RF signal to reduce ion bombardment damage on the substrate, and wherein the “
on”
portion of the second RF signal remains entirely embedded within the “
on”
portion of the first RF signal and does not overlap the “
off”
portion of the first RF signal after the phase lag of the second RF signal has been adjusted; and
etching the substrate with the plasma.
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Abstract
Methods for etching a substrate are provided herein. In some embodiments, a method of etching a substrate may include generating a plasma by providing only a first RF signal having a first frequency and a first duty cycle; applying only a second RF signal to bias the plasma towards the substrate, wherein the second RF signal has the first frequency and a second duty cycle different than the first duty cycle; adjusting a phase variance between the first and second RF signals to control an ion energy distribution in the plasma; and etching the substrate with the plasma.
17 Citations
18 Claims
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1. A method of etching a substrate, comprising:
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generating a plasma by providing only a first RF signal having a first frequency and a first duty cycle; applying only a second RF signal to bias the plasma towards the substrate, wherein the second RF signal has the first frequency and a second duty cycle different than the first duty cycle, and wherein an “
on”
portion of the second RF signal is entirely embedded with an “
on”
portion of the first RF signal and does not overlap an “
off”
portion of the first RF signal;adjusting a phase variance between the first and second RF signals to control an ion energy distribution in the plasma, wherein adjusting the phase variance further includes controlling a phase lag of the second RF signal relative to the first RF signal to reduce ion bombardment damage on the substrate, and wherein the “
on”
portion of the second RF signal remains entirely embedded within the “
on”
portion of the first RF signal and does not overlap the “
off”
portion of the first RF signal after the phase lag of the second RF signal has been adjusted; andetching the substrate with the plasma. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of etching a substrate disposed on a substrate support in the processing volume of an inductively coupled plasma etching reactor having one or more inductive coils disposed above the substrate support and external of the processing volume and an electrode disposed in the substrate support, comprising:
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generating a plasma by providing only a first RF signal having a first frequency and a first duty cycle; applying only a second RF signal to bias the plasma towards the substrate, wherein the second RF signal has the first frequency and a second duty cycle different than the first duty cycle, wherein an “
on”
portion of the second RF signal is entirely embedded within an “
on”
portion of the first RF signal and does not overlap an “
off”
portion of the first RF signal;adjusting a phase variance between the first and second RF signals to control an ion energy distribution in the plasma, wherein adjusting the phase variance further includes controlling a phase lag of the second RF signal relative to the first RF signal to reduce ion bombardment damage on the substrate, and wherein th “
on”
portion of the second RF signal remains entirely embedded within the “
on”
portion of the first RF signal and does not overlap the “
off”
portion of the first RF signal after the phase lag of the second RF signal has been adjusted; andetching the substrate with the plasma. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification