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Mechanistic Study of the Deposition of Metals from HF Solutions onto Silicon Wafers

Published online by Cambridge University Press:  21 February 2011

H.G. Parks ,
J.B. Hiskey  and
K. Yoneshige
H.G. Parks
Affiliation:
Electrical and Computer Engineering Department, The University of Arizona, Tucson, AZ 85721
J.B. Hiskey
Affiliation:
Materials Science and Engineering Department, The University of Arizona, Tucson, AZ 85721
K. Yoneshige
Affiliation:
Electrical and Computer Engineering Department, The University of Arizona, Tucson, AZ 85721
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Abstract

Process chemicals in use today are quite pure, depending on the grade used but can easily be contaminated with metal ions through improper handling or storage techniques. Such metal impurities, if deposited on wafer surfaces during processing can increase reverse-bias junction leakage, degrade oxide breakdown strength and increase metal oxide semiconductor capacitor leakage which in turn can adversely affect the function of ultra large scale integrated (ULSI) circuits. Because of these device effects and since metal contamination can come from several sources it is important to know the deposition level and mechanism on Si wafers from a given process solution. HF based process solution have been investigated due to their historical use in patterning, etching, and their increased use in advanced wafer cleaning processes.

Multi-contaminant experiments have been designed to study the probability of, and mechanism for deposition. It is shown that in general single element deposition is predicted by electrochemical considerations based on redox reactions, however, potential complex synergistic interactions can cause deviations from the simple theory. Specifically, Sn is shown to inhibit the deposition of Ag, and Mo does not deposit in proportion to the amount of Mo in solution, but does deposit on wafers in the presence of Cu and/or Ag. Detailed analysis of Cu and Ag from BOE and Cu from HF shows the deposition: is statistically uniform over bare Si wafers, is independent of substrate doping and rinse time, does not occur on SiO2 is linear with time (up to 25 min) and solution concentration ( up to 500 ppb), shows an Arrhenius behavior with temperature (15 - 55°C) and increases surface micro-roughness. Interpretation of these results with an Evans diagram indicates the deposition is mass transport limited, allowing a first order quantitative theoretical interpretation of the deposition process.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 318: Symposium Ca – Interface Control of Electrical, Chemical, and Mechanical Properties , 1993 , 245
Copyright
Copyright © Materials Research Society 1994

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References

REFERENCES

1 Sze, S. M., “Physics of Semiconductor Devices,” p. 21, pp. 35–38, John Wiley and Sons, New York (1981).Google Scholar
2 Jastrzebski, L., “An Overview of Effects of Heavy Metal Contamination, Wafer Characteristics and Gettering on Device/Circuit Performance,” Proceedings of the Sixth International Symposium on Silicon Materials Science and Technology: Semiconductor Silicon 1990, pp 614, Electrochemical Society (1990).Google Scholar
3 Hattori, T., “Contamination Control: Problems and Prospects,” Solid State Technology, pp.51–58, July (1990).Google Scholar
4 Schmid, J., Craigin, R., Damianou, C., Hohl, J., Schrimpf, R., Parks, H. G., Ramberg, J., Brown, N., Jones, R., “A Simple Model for Estimating Allowable Transition Metal Contamination Levels in DRAM's,” TECHCON '90 Extended Abstract Volume, pp. 263–266 (1990).Google Scholar
5 Miki, N., Kikuyama, H., Saka, K., Takano, J., Kawanabe, I., Miyashita, M., Ohmi, T., “Optimization of Wet Processing with Advanced Surface Active BHF for ULSI Manufacturing,” Akins, V. E., Harada, H., Editors, PV 91-5, p. 133, Proceedings of the Sixth Symposium on Automated Integrated Circuits Manufacturing, Pennington, NJ (1991).Google Scholar
6 Kern, F.W. Jr., Itano, M., Kawanabe, I., Miyashita, M., Rosenberg, R., and Ohmi, T., “Metallic Contamination of Semiconductor Devices from Processing Chemicals the Unrecognized Potential”, presented at the 37th Annual IES Meeting, San Diego, CA, May 6–10, 1991.Google Scholar
7 Mahan, B.H., University Chemistry, Second Edition, Addison Wesley, Reading, MA, 1969 Google Scholar
8 Craigin, R. et-al; “Metal Contaminant Deposition on Silicon Surfaces from Solutions”, SRC Technical Report, Contract 90-MC-501, ID #C91581, June 1991.Google Scholar
9 Montgomery, D. C., “Design and Analysis of Experiments,” 2nd ed., p.329, John Wiley and Sons, New York (1990).Google Scholar
10 Hsu, E., Parks, H.G., Craigin, R., Tomooka, S., Ramberg, J.S., Lowry, R.K., “Deposition Characteristics of Transition Metal Contaminants From HF-Based Solutions onto Wafer Surfaces,” The Electrochemical Society Extended Abstracts, Vol. 91–2, Abstract No. 523, pp. 779–780, October 1991.Google Scholar