Automatic impedance matching apparatus and method

52 Pages·2013·3.7 MB·English

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_US005195045A
United States Patent [19]
[11] Patent Number: 5,195,045
Keane et al. [45] Date of Patent: Mar. 16, 1993
[54] AUTOMATIC IMPEDANCE MATCHING Signetics Philips Components, Feb. 1989, pp. 2-112 to
APPARATUS AND METHOD 2-122.
Product spec. datasheet for "CMOS Dual 8-Bit Buff
[75] Inventors: Anthony R. A. Keane, Webster, N.Y.;
ered Multiplying DAC AD7528," Data Conversion
Steven E. Hauer, Berlin, NJ.
Products Databook, Analog Devices Inc., Apr., 1988,
[73] Assignee: ASTEC America, Inc., Oceanside, pp. 2-193 to 2-196.
Calif. Product speci?cation datasheet for “CMOS Low Cost
10~Bit Multiplying DAC AD7533,” Data Conversion
[21] Appl. No.: 661,813 Products Databook, Analog Devices Inc., Apr. 1988, pp.
2-197 to 2~202.
[22] Filed: Feb. 27, 1991
Product speci?cation datasheet for the “L298 Dual
Full-H Driver,” Texas Instruments, Oct., 1986, pp.
[51] Int. Cl.5 ............................................. .. H03H 7/40
5-17 to 5-18.
[52] U.S. Cl. ................................. .. 364/482; 333/17.3;
333/32; 331/36 R; 3l5/1l1.51 Primary Examiner-—Vincent N. Trans
[58] Field of Search ..................... .. 364/482, 483, 484; Attorney, Agent, or Firm-McCubbrey, Bartels, Meyer
333/173, 17.1, 17.2, 32; 3l5/lll.5l; 331/1 R, & Ward
36 R, 36 C, 36 L
[57] ABSTRACT
[56] References Cited
An automatic impedance matching apparatus for
U.S. PATENT DOCUMENTS matching an RF-signal generator to a load, such as a
plasma etching chamber, is disclosed. The matching
33,,516299,,737876 43//11997614 DBeaaluyd r. . y. . . . . . . . 3. .l. 53/2l5l/1.127l4 apparatus comprises a matching network having two
3,601,717 8/1971 Kuecken .... .. 333/l7.3 variable impedance devices, a tune detector for detect
3,648,191 3/1972 Beaudry 330/192 ing the condition of the impedance match between the
4,004,102 1/1977 Ott .......... .. 379/398 RF-signal and the load, and a controller for modifying
4,356,458 10/1982 Armitage .. 333/173 the values of the variable impedance components in
4,373,581 2/1983 Toellner 166/53
response to the measured tune condition. The present
4,375,051 2/1983 Theall ..... .. 333/17.3 invention disclosed improve reset and convergence unit
4,493,112 1/1985 Bruene 455/123
and eliminates the need for the “dead-band” provided
4,551,690 11/1985 Quist ................... .. 331/36 L
around the matching point found in prior art impedance
4,626,728 12/1986 Flackenecker et a1 ..... .. 310/316
matching controllers. Also disclosed is an improved
4,629,940 12/1986 Gagne et a1. ................. .. 315/1ll.5l
adjustment unit for adjusting the variable impedance
4,679,007 7/1987 Reese et a1. . . . . . . . . . . . . . . .. 333/173
components which is faster and more stable than found
4,763,089 8/1988 Pon . . . . . . . . . . . . . . . . . . . . .. 333/202
5,001,649 3/1991 Lo et a1 ............................ .. 364/484 in prior art controllers. Also disclosed is a normalization
unit for normalizing the input detection siganls such
OTHER PUBLICATIONS
that variations in turning performance due to variations
Product speci?cation datasheet for the in input power level from the source are substantially
“S83C552/S80C552 Single-Chip 8-Bit Microcontroller reduced.
with A/D, Capture/Compare Timer, With High-Speed
Outputs, PWM,” Signetcis Microcontroller Users’ Guide, 43 Claims, 23 Drawing Sheets
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US. Patent Mar. 16, 1993 Sheet 4 of 23 5,195,045
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US. Patent Mar. 16, 1993 Sheet 5 of 23 5,195,045
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FIG._4

US. Patent Mar. 16, 1993 Sheet 7 of 23 5,195,045
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US. Patent Mar. 16, 1993 Sheet 9 of 23 5,195,045
841
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ATUNE TUNE POINT 9c ZEJDPNET
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