[54] SEMICONDUCTOR WAFER CLEANING SYSTEM
[75] Inventors: Michael B. Olesen, Yorba Linda;
Mario E. Bran. Garden Grove, both of
Calif.
[73] Assignee: Verteq, Inc., Santa Ana, Calif.
[21] Appl. No.: 361,139
[22] Filed: Dec 21,1994
Related U.S. Application Data
[63] Continuation-in-part of Ser. No. 140,290, Oct 20, 1993, abandoned.
[51] Int CI.6 B08B 3/08; B08B 3/12;
B08B 7/02; C23G 1/02 [52] U.S. CI 134/1; 134/2; 134/3; 134/26;
134/28; 134/34; 134/41
[58] Field of Search 134/1. 2. 3, 26.
134/28, 34, 41
[56] References Cited
U.S. PATENT DOCUMENTS
2,961,354 11/1960 Cleveland 134/1
3,690,333 9/1972 Kiemer 134/95
3,893,869 7/1975 Mayer etal 134/1
4,193,818 3/1980 Young et al 134/1
4,409,999 10/1983 Pediziwiatr 134/95
4,577,650 3/1986 McConnell 134/59
4,633,893 1/1987 McConnell et al 134/95
4,736,760 4/1988 Coberly et al 134/134
4,738,272 4/1988 McConnell 134/59
4,740549 4/1988 McConnell 134/25.4
4,778,532 10/1988 McConnell et al 134/10
4,795,497 1/1989 McConnell etal 134/18
4.856,544 8/1989 McConnell 134/95
4,899,767 2/1990 McConnell et al 134/56 R
4,911,761 3/1990 McConnell et al 134/11
4,917,123 4/1990 McConnell et al 134/95
4,984,597 1/1991 McConnell et al 134/95
5,100,476 3/1992 Maseetal 134/1
5,143,103 9/1992 Basso et al 134/1
5,308,400 5/1994 Chen 134/2
OTHER PUBLICATIONS
Singer, "Trends in Wafer Cleaning", Semiconductor International, Dec. 1992.
Verhaverbeke et al., "Advanced Wet Cleaning Technology for Highly Reliable Thin Oxides", Nov. 1993. An article by Werner Kern, "The Evolutioin of Silicon Wafer Cleaning Technology". J. Electrochem. Soc.. vol. 137, No. 6. Jun. 1990.
Primary Examiner—Zeinab El-Arini
Attorney, Agent, or Firm—Knobbe, Martens, Olson & Bear,
LLP
[57] ABSTRACT
Semiconductor wafers are positioned in a cleaning tank and subjected to sequential flows of one or more highly diluted cleaning solutions that are injected from the lower end of the tank and allowed to overflow at the upper end. One solution contains one part ammonium hydroxide, two parts hydrogen peroxide, and 300-600 parts deionized water together with a trace of high purity surfactant. Rinsing water is flowed through the tank after the first solution is dumped. A second solutions contains highly dilute hydrofluoric acid. A third solution is more dilute than the first solution. A fourth solution contains hydrochloric acid greatly diluted with deionized water. The cleaning tank is provided with a megasonic generator in its lower portion for selective application of megasonic energy. Quick dump valves in the tank bottom enable the solutions to be quickly dumped followed by one or more rinse steps, including a quick refill while spraying and then dumping of the rinsing water.
63 Claims, 9 Drawing Sheets
