Skip to main content Accessibility help
×
Home

Fabrication of Air-Gaps Between Cu Interconnects for Low Intralevel k.

  • Dhananjay M. Bhusari (a1), Michael D. Wedlake (a1), Paul A. Kohl (a1), Carlye Case (a2), Fred P. Klemens (a2), John Miner (a2), Byung-Chan Lee (a3), Ronald J. Gutmann (a3), J.J. Lee (a4), Robert Shick (a5) and L. Rhodes (a5)...

Abstract

We present here a method for fabrication of air-gaps between Cu-interconnects to achieve low intralevel dielectric constant, using a sacrificial polymer as a ‘place holder’. IC compatible metallization and CMP processes were used in a single damascene process. The air-gap occupies the entire intralevel volume between the copper lines with fully densified SiO2 as the planer interlevel dielectric. The width of the air-gaps was 286 nm and the width of the copper lines was 650 nm. The effective intralevel dielectric constant was calculated to be 2.19. The thickness of the interlevel SiO2 and copper lines were 1100 nm and 700 nm, respectively. Further reduction in the value of intralevel dielectric constant is possible by optimization of the geometry of the metal/air-gap structure, and by use of a low k interlevel dielectric material.

In this method of forming air-gaps, the layer of sacrificial polymer was spin-coated onto the substrate and formed into the desired pattern using an oxide or metal mask and reactive-ion-etching. The intralevel Cu trench is then inlaid using a damascene process. After the CMP of copper, interlevel SiO2 is deposited by plasma-CVD. Finally, the polymer place-holder is thermally decomposed with the decomposition products permeating through the interlevel dielectric material. The major advantages of this method over other reported methods of formation of air-gaps are excellent control over the geometry of the air-gaps; no protrusion of air-gaps into the interlevel dielectric; no deposition of SiO2 over the side-walls, and no degradation of the interlevel dielectric during the formation of air-gap.

Copyright

References

Hide All
1. Meindl, J.D., Proc. IEEE, 83, 619 (1995).10.1109/5.371970
2. The National Technology Roadmap for Semiconductors, Semiconductor Industry Association, San Jose, CA, 1997.
3. Grove, N.R., Kohl, P.A., Bidstrup-Allen, S.A., Shick, R.A., Goodall, B.L. and Jayaraman, S., Mater. Res. Soc. Symp. Proc. 476, 3 (1997).10.1557/PROC-476-3
4. Townsend, P.H., Martin, S.J., Godschalx, J., Romer, D.R., Smith, D.W. Jr., Castillo, D., DeVries, R., Buske, G., Rondan, N., Froelicher, S., Marshall, J., Shaffer, E.O. and Im, J-H., Mater. Res. Soc. Symp. Proc. 476, 9 (1997).10.1557/PROC-476-9
5. Theil, J.A., Mertz, F., Yairi, M., Seaward, K., Ray, G. and Kooi, G., Ibid, 31 (1997).
6. Kohl, P.A., Zhao, Q., Patel, K., Schmidt, D., Bidstrup-Allen, S.A. Shick, R. and Jayaraman, S., Electrochem. and Solid State Lett. 1, 49 (1998).10.1149/1.1390631
7. Shieh, B., Saraswat, K.C., McVittie, J., List, S., Nag, S. and Islamraja, M., IEEE Electron Device Letters 19, 16 (1998).10.1109/55.650339
8. Anand, M.B., Yamada, M. and Shibata, H., IEEE Trans. Electron Devices 44, 1965 (1997).10.1109/16.641367
9. Shieh, B., Saraswat, K., Deal, M. and McVittie, J., Solid State Technol.(February), 51 (1997).
10. Shick, R.A., Goodall, B.L., McIntosh, L.H., Jayaraman, S., Kohl, P.A., Bidstrup-Allen, S.A. and Grove, N.R., Proc. IEEE Multichip Module Conf., 182 (1996).
11. Zhao, Q. and Kohl, P.A., J. Electrochem Soc. 145, 1257 (1998).10.1149/1.1838448
12. Steigerwald, J.M., Murarka, S.P. and Gutmann, R.J., Chemical Mechanical Planarization of Microelectronic Materials (John Wiley & Sons Inc.), p.150 (1997).10.1002/9783527617746

Fabrication of Air-Gaps Between Cu Interconnects for Low Intralevel k.

  • Dhananjay M. Bhusari (a1), Michael D. Wedlake (a1), Paul A. Kohl (a1), Carlye Case (a2), Fred P. Klemens (a2), John Miner (a2), Byung-Chan Lee (a3), Ronald J. Gutmann (a3), J.J. Lee (a4), Robert Shick (a5) and L. Rhodes (a5)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed