Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-30T18:50:54.306Z Has data issue: false hasContentIssue false
  • English
  • Français

The Reliability of Aluminum/Tungsten Technology for VLSI Applications

Published online by Cambridge University Press:  29 November 2013

Yosi Shacham-Diamand
Get access

Extract

Interconnects technology and back-end processing moved to the center stage of very large-scale integration (VLSI) technology in the mid-1980s. At that time, the critical dimensions dropped below 1 μm while the chip size and complexity increased to a level where interconnects were recognized to be a limiting factor. As dimensions decreased, the step coverage of sputtered aluminum inside contacts and via-contact holes decreased and alternative technologies were studied. The increasing cost of ownership (COO) of single-wafer Al sputtering processes also supported the search for alternative technologies, such as tungsten chemical vapor deposition (CVD) for via contacts and plugs (Figure 1). Only recently have all the W CVD process steps been optimized to lower cost without loss of reliability and/or performance. The development of cluster tool technology and multiwafer process modules also allowed reliable and cost-effective utilization of the W/Al technology.

Tungsten technology for VLSI circuits became complementary to that of aluminum. Tungsten thin-film resistivity ρw = 7–8 μΩ cm is much higher than that of aluminum ρAl = 3–4 μΩ cm, introducing large W interconnect resistance-capacitance (RC) delays compared to Al. Therefore, tungsten is not favorable for high-speed global-interconnect schemes. However, tungsten is suitable for local interconnects where the impedance of the driving transistors is dominant and the RC interconnect delay is less significant. Tungsten is also suitable for contact filling, in which the via resistance is negligible. For these applications, tungsten became a dominant technology and was integrated with the aluminumalloy-based technology used for global interconnects.

Type
Metallization for Integrated Circuit Manufacturing
Information
MRS Bulletin , Volume 20 , Issue 11 , November 1995 , pp. 78 - 82
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. See, for example, Blewer, R.A., Solid State Technology 11 (1986) p. 117 and Proc. Workshops on Tungsten and Other Adv. Met. for VLSI/ULSI Applications (Materials Research Society, Pittsburgh, 1984–1994).Google Scholar
2.Railey, P.A., Peng, S.S., Fang, L., Solid State Technology 36 (1993) p. 47.Google Scholar
3.Moy, D., Schadt, M., Hu, C-K, Kaufman, F., Ray, A., Mazzeo, N., Baran, E., and Pearson, D.J., Proc. VMIC 26 (1989).Google Scholar
4. K. Ishira, Yamadai, T., Onishi, S., Matsuda, K., and Sakiyama, K., Proc. VMIC 185 (1991).Google Scholar
5.Kajiyana, K., Oyama, K., Tsunenari, K., Kunio, T., Koh, R., and Haysahi, Y., Proc. VMIC 185 (1991).Google Scholar
6.Constitution of Binary Alloys (1987).Google Scholar
7.Mayer, J. and Lau, S.S., Electronic Material Science (Macmillan, New York, 1992).Google Scholar
8.Li, J., PhD dissertaion, Cornell University (1992).Google Scholar
9.Wang, S.Q., Proc. Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1993) p. 31.Google Scholar
10.Yano, K., Murkami, T., and Nomura, N., Proc. Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1993) p. 361.Google Scholar
11.Schulz, S.E., Hintze, B., Wurzbacher, C., W. Grunewald, and Gessner, T., Proc. of the Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1993) p. 465.Google Scholar
12.Leusnik, G.J., Oosterlaken, T.G.M., Jamsen, G.C.A.M., and Radelaar, S., Proc. Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1993) p. 335.Google Scholar
13.Joshi, R.V., Int. Conf. on Solid State Dev. and Mat. (Makubari, Japan, 1993) p. 164.Google Scholar
14.Sullivan, T.D. and Miller, L.A., in Materials Reliability in Microelectronics III, edited by Rodbell, K., Filter, B., Frost, H., and Ho, P. (Mater. Res. Soc. Symp. Proc. 309, Pittsburgh, 1993).Google Scholar
15.Arena, C., Faguet, J., Foster, R.F., Hillman, J.T., and Srinivas, D., Proc. Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1993) p. 173.Google Scholar
16.Onoda, H., Kageyama, M., Tatara, Y., Harada, Y., Nakamura, A., and Fukuda, Y., Proc. Adv. Met. for ULSI Applications in 1993 (Materials Research Society, Pittsburgh, 1992) p. 19.Google Scholar
17.Joshi, R.V. and Brodsky, S., “Collimated Sputtering for Ti/TiN Liners Using High Aspect Ratio Contacts/Lines,” Appl. Phys. Lett. 61 (19) (1992) p. 2613.CrossRefGoogle Scholar
18.Rathore, H.S., Fillip, R.G., Wachnik, R.A., Estabil, J.J., and Kwok, T., Proc. of the SPIE Meeting on Submicrometer Metallization, vol. 1805 (San Jose, 1992).Google Scholar
19.Kwok, T., Proc. of the SPIE Meeting on Metallization: Performance and Reliability Issues for VLSI and ULSI, vol. 1595 (San Jose, 1991).Google Scholar
20.Estabil, J.J., Rathore, H.S., and Levine, E.N., Proc. of the VMIC (Santa Clara, June 11–12, 1991).Google Scholar
21.Fillip, R.G., Biery, G.A., and Wood, M.H., in Materials Reliability in Microelectronics III, edited by Rodbell, K., Filter, B., Frost, H., and Ho, P. (Mater. Res. Soc. Symp. Proc. 309, Pittsburgh, 1993) p. 141.Google Scholar
22.Blech, I., J. Appl. Phys. 47 (1976) p. 1203; J. Appl. Phys. 448 (1977) p. 473.CrossRefGoogle Scholar
23.Gadepally, K., Reddy, P.K., Hiew, S., Merrill, R., Lahri, R., and Biswal, M., Materials Reliability in Microelectronics III (Mater. Res. Soc. Symp. Proc. 309, Pittsburgh, 1993) p. 161.Google Scholar
24.Kim, M.M.J., SPIE, vol. 1597, edited by Gildenblat, G.S. and Schwartz, G.P. (San Jose, 1991) p. 161.Google Scholar
25.Small, M.B. and Pearson, D.J., IBM J. Res. Dev. 34 (1990) p. 858.CrossRefGoogle Scholar
26.Trattles, J.T., O'Neill, A.G., and Mecrow, B.C., Proc. of the VMIC (Santa Clara, June 11-12, 1991).Google Scholar
27.Kahn, H. and Thompson, C.V., “A Statistical Characterization of Electromigration-Induced Open Failures in 2-Level Metal Structures,” in Materials Reliability Issues hi Microelectronics (Mater. Res. Soc. Symp. Proc. 225, Pittsburgh, 1991).Google Scholar