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US 9,520,294 B2Granted
Atomic layer etch process using an electron beam
AssigneeApplied Materials, Inc.
InventorsAnkur Agarwal, Rajinder Dhindsa, Shahid Rauf
Life of this patent
Estimating the term…
Abstract
Atomic layer etching using alternating passivation and etching processes is performed with an electron beam plasma source, in which the ion energy is set to a low level below the etch threshold of the material to be etched during passivation and to a higher level above the etch threshold during etching but below the etch threshold of the unpassivated material.
Claims16
A method of removing an overlying film from a workpiece, comprising:
- supporting the workpiece in a chamber;
- coupling an RF bias voltage to said workpiece;
- (A) performing a passivation process for a time duration corresponding to a desired thickness of a layer of said overlying film to be passivated, said passivation process comprising:
- introducing a passivation process gas into said chamber;
- generating a plasma in said chamber for passivation, by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- controlling said RF bias voltage to set energy of ions in said chamber to a first ion energy level less than a first minimum ion energy required for etching said overlying film;
- (B) performing an etching process by:
- introducing an etching process gas into said chamber;
- generating a plasma in said chamber for etching, by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- controlling said RF bias voltage to set energy of ions in said chamber to a second ion energy level exceeding said first minimum ion energy;
- wherein said controlling said RF bias voltage to set energy of ions to a first ion energy level comprises conforming a time domain waveform of said RF bias voltage to an RF waveform in which the RF voltage is at a level corresponding to said first ion energy level for a duration of about 50% of a continuous wave RF cycle of said RF waveform;
- and
- wherein said controlling said RF bias voltage to set energy of ions to a second ion energy level comprises conforming a time domain waveform of said RF bias voltage to an RF waveform in which the RF voltage is at a level corresponding to said second ion energy level for a duration of about 50% of a continuous wave RF cycle of said RF waveform.
10 more elements
A method of performing atomic layer etching of an overlying film on a workpiece, comprising:
- coupling an RF bias voltage to said workpiece;
- passivating a predetermined thickness of a layer of said overlying film, comprising introducing into said chamber a gas containing a passivation species and generating a plasma in said chamber for passivation by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- etching the predetermined thickness of said layer, comprising introducing into said chamber a gas containing an etch species and generating a plasma in said chamber for etching by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- during said passivating, setting energy of ions in said chamber to a first ion energy level less than a first minimum ion energy for etching said layer by conforming a time domain waveform of said RF bias voltage to an RF waveform in which the RF voltage is at a level corresponding to said first ion energy level for a duration of at least 50% of an RF cycle of said RF waveform;
- during said etching, setting energy of ions in said chamber to a second ion energy level exceeding said first minimum ion energy by conforming a time domain waveform of said RF bias voltage to an RF waveform in which the RF voltage is at a level corresponding to said second ion energy level for a duration of at least 50% of an RF cycle of said RF waveform.
2 more elements
A method of removing an overlying film on a workpiece in a chamber, comprising:
- performing alternating operations of passivating and etching;
- wherein said passivating comprises:
- introducing into said chamber a gas containing a passivation species and generating a plasma in said chamber for passivation by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- wherein said etching comprises:
- introducing into said chamber a gas containing an etch species and generating a plasma in said chamber for etching by radiating gas in said chamber with an electron beam having a beam direction parallel to a plane of said workpiece from an electron beam generator;
- during said passivating, tailoring RF bias power to a waveform in which RF voltage is at a level corresponding to a first ion energy level less than an etch threshold of said overlying film for a duration of at least 50% of an RF cycle of said waveform;
- and
- during said etching, tailoring RF bias power to a waveform in which RF voltage is at a level corresponding to a second ion energy level exceeding an etch threshold of said overlying film for a duration of at least 50% of an RF cycle of said waveform.
5 more elements
Dependencies are inferred from the claim text.