Forming an interconnect of a semiconductor device

Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material

Reexamination Certificate

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C438S675000

Reexamination Certificate

active

06613667

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
This invention relates generally to semiconductor fabrication and more specifically to forming an interconnect of a semiconductor device.
BACKGROUND OF THE INVENTION
Metals such as copper are typically used as interconnect material for ultra-large scale integrated circuits (ULSICs), microelectronics, opto-electronics, and other electronic devices. Known etching techniques for forming metal interconnects, however, have disadvantages. Some of the etching techniques result in poor etch uniformity or require the use of complex systems or processes. Consequently, forming metal interconnects for electronic devices has posed problems.
SUMMARY OF THE INVENTION
In accordance with the present invention, disadvantages and problems associated with previous techniques for forming an interconnect of a semiconductor device may be reduced or eliminated.
According to one embodiment of the present invention, forming an interconnect of a semiconductor device includes defining a recessed structure proximate to an outer surface of a substrate of a semiconductor device. A metal layer is deposited within the recessed structure. A region of the metal layer is exposed to a plasma operable to react with the region of the metal layer. A metal compound layer is formed from the region of the metal layer by reacting the region of the metal layer with the plasma. The metal compound layer is removed from the semiconductor structure to yield a remaining metal layer. An interconnect of the semiconductor device is formed from the remaining metal layer.
Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may be that metal is removed by exposing the metal to a plasma to form a metal compound. The metal compound may be effectively removed by an acid or base solution or by heating. Another technical advantage of one embodiment may be that the metal removal is highly selective. Typically, the acid or base solution or heating removes only the metal that has been transformed into the metal compound. Another technical advantage of one embodiment may be that the removal of metal may be performed using a conventional plasma reactor, and thus does not require building new equipment.


REFERENCES:
patent: 6260266 (2001-07-01), Tamaki
Yue Kuo and Sangheon Lee, “Plasma Process of a New Copper Dry Etching Method,” Electrochem. Soc. Extended Abst. 2000-1, #296, 1 page, 2000.
Meeting Abstracts, The 197thMeeting of The Electrochemical Society, vol. 2000-I, Spring 2000, Toronto, Ontario, Canada, ISSN 1091-8213, ISBN 1-56677-282-6, Abstract No. 296, 2 pages, May 14-18, 2000.
Chlorine Plasma/Copper Reaction in a New Cooper Dry Etching Process, Sangheon Lee and Yue Kuo,Journal of the Electrochemical Society, 148 (9) (2001), Manuscript received Feb. 14, 2001; Available electronically Aug. 10, 2001, pp. G524-G529.
Process Study Of A New Copper Dry Etching Method—The HCL Chemistry; Sangheon Lee and Yue Kuo,Plasma Processing XIII, The Electrochemical Society Proceedings, vol. 2000-6, pp. 361-367, Undated.
Room-temperature copper etching based on a plasma-copper reaction, Yue Kuo and Sangheon Lee,Applied Physics Letters, vol. 78, No. 7, Feb. 12, 2001, pp. 1002-1004.
Morphological Study of a New Copper Dry Etching Process, Y. Kuo and S. Lee, AVS 47thInternational Symposium, Paper PS-WeP24, http://www.avssymposium.org/paper.asp?abstractID=1036, Jul. 17, 2000, 1 page.
2000 Proceedings Seventeenth International VLSI Multilevel Interconnection Conference(VMIC), VMIC Catalog No. 00 IMIC—200, Library of Congress No. 89-644090, Jun. 27-29, 2000, pp. 38-44.
A Novel Plasma-Based Copper Dry Etching Method, Yue Kuo and Sangheon Lee,Jpn. J. Appl. Phys., vol. 39 (2000) Pt. 2, No. 3A/B,Express Letter, pp. 188-190, Mar. 15, 2000.
Copper dry etching with precise wafer-temperature control using CI2gas as single reactant, H. Miyazaki, K. Takeda, N. Sakuma, S. Kondo, Y. Homma, and K. Hinode, 1997 American Vacuum Society, J. Vac. Sci. Technol. B 15(2), Mar./Apr. 1997, pp. 237-240.
Copper Dry Etching with CI2/Ar Plasma Chemistry, J. W. Lee, Y.D. Park, J.R. Childress, S.J. Pearton, F. Sharifi, F. Ren,J. Electrochem. Soc., vol. 145, No. 7, Jul. 1998, The Electrochemical Society, Inc., pp. 2585-2589.
Lower temperature plasma etching of Cu using IR light irradiation, Y. Ohshita, N. Hosoi,Thin Solid Films 262, Elsevier Science S.A., SSDI 0040-6090(94)05803-2, 1995, pp. 67-72.
Reactive Ion Etching of Copper Films, G.C. Schwartz and P.M. Schaible,J. Electrochem Soc.: Accelerated Brief Communication, vol. 130, No. 8, Aug. 1983, pp. 1777-1779.
Reactive ion etching of copper in SiCI4-based plasmas, B. J. Howard and Ch. Steinbrüchel,Appl. Phys. Lett., vol. 59, No. 8, 1991 American Institute of Physics, Aug. 19, 1991, pp. 914-916.
Copper Dry Etching Technique for ULSI Interconnections, Matthias Markert, Andreas Bertz and Thomas Gessner, 1997 Elsevier Science B.V.,Microelectronic Engineering35 (1997), pp. 333-336.

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