Plasma reactor having digital control over rotation frequency of a microwave field with direct up-conversion
First Claim
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1. A plasma reactor comprising:
- a cylindrical microwave cavity overlying a workpiece processing chamber, and first and second coupling apertures in a sidewall of said cylindrical microwave cavity spaced apart by an angle;
a microwave source having a microwave frequency and comprising a pair of microwave controller having respective microwave outputs coupled to respective ones of said first and second coupling apertures, each of said microwave controllers comprising;
(a) a source of first and second digital modulation signals having a frequency corresponding to a slow rotation frequency;
(b) a source of a first digital carrier signal having an intermediate frequency;
(c) a multiplier stage comprising a pair of multipliers each having a pair of inputs, said multiplier stage coupled to receive, respectively, said first digital modulation signal, said second digital modulation signal and said first digital carrier signal, respectively, said multiplier stage having respective outputs, in1 and in2;
(d) a digital-to-analog converter coupled to receive said respective outputs in1 and in2 and having analog outputs corresponding to said outputs in1 and in2; and
(e) an up-converter having inputs coupled to said analog outputs, said up-converter comprising said microwave outputs.
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Abstract
A plasma reactor for processing a workpiece has a microwave source with a digitally synthesized rotation frequency using direct digital up-conversion and a user interface for controlling the rotation frequency.
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20 Claims
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1. A plasma reactor comprising:
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a cylindrical microwave cavity overlying a workpiece processing chamber, and first and second coupling apertures in a sidewall of said cylindrical microwave cavity spaced apart by an angle; a microwave source having a microwave frequency and comprising a pair of microwave controller having respective microwave outputs coupled to respective ones of said first and second coupling apertures, each of said microwave controllers comprising; (a) a source of first and second digital modulation signals having a frequency corresponding to a slow rotation frequency; (b) a source of a first digital carrier signal having an intermediate frequency; (c) a multiplier stage comprising a pair of multipliers each having a pair of inputs, said multiplier stage coupled to receive, respectively, said first digital modulation signal, said second digital modulation signal and said first digital carrier signal, respectively, said multiplier stage having respective outputs, in1 and in2; (d) a digital-to-analog converter coupled to receive said respective outputs in1 and in2 and having analog outputs corresponding to said outputs in1 and in2; and (e) an up-converter having inputs coupled to said analog outputs, said up-converter comprising said microwave outputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A plasma reactor comprising:
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a cylindrical microwave cavity overlying a workpiece processing chamber, and first and second coupling apertures in a wall of said cylindrical microwave cavity spaced apart by an angle; a microwave source having a microwave frequency and comprising respective microwave outputs coupled to respective ones of said first and second coupling apertures, said microwave source further comprising; a source of an in-phase component 1-A and of a quadrature component 1-B of a digital modulation signal having a frequency corresponding to a slow rotation frequency; a digital-to-analog converter coupled to receive said in-phase and quadrature components 1-A and 1-B, and having corresponding analog outputs in1 and in2; and an up-converter comprising; (a) a first combiner function comprising respective inputs of said analog output in1 and an in-phase component of said microwave frequency, and a first product output corresponding to a first one of said microwave outputs; and (b) a second combiner function comprising respective inputs of said analog output in2 and an in-phase component of said microwave frequency, said second combiner function comprising a second product output. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification