Hostname: page-component-8448b6f56d-t5pn6 Total loading time: 0 Render date: 2024-04-16T04:07:50.564Z Has data issue: false hasContentIssue false
  • English
  • Français

Nanoindentation Analysis of Mechanical Properties of Low to Ultralow Dielectric Constant SiCOH Films

Published online by Cambridge University Press:  01 August 2005

Lugen Wang ,
M. Ganor ,
S.I. Rokhlin  and
Alfred Grill
Lugen Wang
Affiliation:
The Ohio State University, Laboratory for Multiscale Materials Processing and Characterization, Edison Joining Technology Center, Columbus, Ohio 43221
M. Ganor
Affiliation:
The Ohio State University, Laboratory for Multiscale Materials Processing and Characterization, Edison Joining Technology Center, Columbus, Ohio 43221
S.I. Rokhlin*
Affiliation:
The Ohio State University, Laboratory for Multiscale Materials Processing and Characterization, Edison Joining Technology Center, Columbus, Ohio 43221
Alfred Grill
Affiliation:
IBM—Thomas J. Watson Research Center, Yorktown Heights, New York 10598
*
a) Address all correspondence to this author. e-mail: rokhlin.2@osu.edu
Get access

Abstract

Carbon-doped oxide SiCOH films with low to ultralow dielectric constants were prepared on a Si substrate by plasma-enhanced chemical vapor deposition (PECVD) from mixtures of SiCOH precursors with organic materials. The films have different levels of nanoscale porosity resulting in different dielectric constants and mechanical properties. The mechanical properties of the films have been characterized by continuous-stiffness nanoindentation measurements. To study the effect of film thickness, each group of samples with the same dielectric constant was composed of samples prepared with different film thicknesses. It is shown that the effective hardness and modulus of the SiCOH/Si substrate system depends significantly on indentation depth due to substrate constraint effects. The “true” film properties were determined using both an empirical formulation of the effective modulus and direct inversion based on a finite element model. The hardness and modulus of three groups of samples with different degrees of dielectric constants have been measured. The hardness increases from 0.7 to 2.7 GPa and modulus from 3.6 to 17.0 GPa as the dielectric constants change from 2.4 to 3.0. While for stiffer films the modulus measured at an indentation depth 10% of the film thickness is close to the “true” value for films thicker than 0.5 μm, the measured value can give an overestimate of up to 35% for softer films. Thin film cracking and film–substrate debonding have been observed with scanning electron and atomic force microscopy at the indentation sites in softer films. The damage initiation is indicated by pop-in events in the loading curve and sharp peaks in the normalized contact stiffness curves versus indentation depth.

Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 8 , August 2005 , pp. 2080 - 2093
Copyright
Copyright © Materials Research Society 2005

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

REFERENCES

1Grill, A.: Plasma enhanced chemical vapor deposited SiCOH dielectrics: From low-k to extreme low-k interconnect materials. J. Appl. Phys. 93, 1785 (2003).Google Scholar
2Grill, A. and Neumayer, D.A.: Structure of low dielectric constant to extreme low dielectric constant SiCOH films: Fourier transform infrared spectroscopy characterization. J. Appl. Phys. 94, 1 (2003).Google Scholar
3Grill, A. and Patel, V.: Ultralow-k dielectrics prepared by plasma-enhanced chemical vapor deposition. Appl. Phys. Lett. 79, 803 (2001).CrossRefGoogle Scholar
4Edelstein, D., Davis, C., Clevenger, L., Yoon, M., Cowley, A., Nogami, T., Rathore, H., Agarwala, B., Arai, S., Carbone, A., Chanda, K., Cohen, S., Cote, W., Cullinan, M., Dalton, T., Das, S., Davis, P., Demarest, J., Dunn, D., Dziobkowski, C., Filippi, R., Fitzsimmons, J., Flaitz, P., Gates, S., Gill, J., Grill, A., Hawken, D., Ida, K., Klaus, D., Klymko, N., Lane, M., Lane, S., Lee, J., Landers, W., Li, W-K., Lin, Y-H., Liniger, E., Liu, X-H., Madan, A., Malhotra, S., Martin, J., Molis, S., Muzzy, C., Nguyen, D., Nguyen, S., Ono, M., Parks, C., Questad, D., Restaino, D., Sakamoto, A., Shaw, T., Shimooka, Y., Simon, A., Simonyi, E., Tempest, S., Van Kleeck, T., Vogt, S., Wang, Y-Y., Wille, W., Wright, J., Yang, C-C., and Ivers, T.: Reliability, yield, and performance of a 90 nm SOI/Cu/SiCOH technology, in Proceedings of the IEEE 2004 Intern. Interconnect Technol. Conference, (IEEE, Piscataway, NJ, 2004), pp. 214–216.Google Scholar
5Grill, A., Patel, V., Rodbell, K.P., Huang, E., Baklanov, M.R., Mogilnikov, K.P., Toney, M. and Kim, H.C.: Porosity in plasma enhanced chemical vapor deposited SiCOH dielectrics: A comparative study. J. Appl. Phys. 94, 3427 (2003).CrossRefGoogle Scholar
6Oliver, W.C. and Pharr, G.M.: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).CrossRefGoogle Scholar
7Oliver, W.C. and Pharr, G.M.: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19, 3 (2004).CrossRefGoogle Scholar
8Li, X. and Bhushan, B.: A review of nanoindentation continuous stiffness measurement technique and its applications. Mater. Charact. 48, 11 (2002).Google Scholar
9Nix, W.D.: Elastic and plastic properties of thin films on substrates: Nanoindentation techniques. Mater. Sci. Eng., A 234, 37 (1997).CrossRefGoogle Scholar
10Saha, R. and Nix, W.D.: Effects of the substrate on the determination of thin film mechanical properties by nanoindentation. Acta Mater. 50, 23 (2002).CrossRefGoogle Scholar
11Shen, L., Zeng, K., Wang, Y., Narayanan, B. and Kumar, R.: Determination of the hardness and elastic modulus of low-k thin films and their barrier layer for microelectronic applications. Microelectron. Eng 70, 115 (2003).CrossRefGoogle Scholar
12Volinsky, A.A., Vella, J.B. and Gerberich, W.W.: Fracture toughness, adhesion and mechanical properties of low-K dielectric thin films measured by nanoindentation. Thin Solid Films 429, 201 (2003).CrossRefGoogle Scholar
13Tsui, T.Y., Ross, C.A. and Pharr, G.M.: A method for making substrate-independent hardness measurements of soft metallic films on hard substrates by nanoindentation. J. Mater. Res. 18, 1383 (2003).CrossRefGoogle Scholar
14Tsui, T.Y. and Pharr, G.M.: Substrate effects on nanoindentation mechanical property measurement of soft films on hard substrates. J. Mater. Res. 14, 292 (1998).Google Scholar
15King, R.B.: Elastic analysis of some punch problems for a layered medium. Int. J. Solids Struct. 23, 1657 (1987).CrossRefGoogle Scholar
16Nix, W.D. and Gao, H.: Indentation size effects in crystalline materials: A law for strain gradient plasticity. J. Mech. Phys. Solids 46, 411 (1998).CrossRefGoogle Scholar
17Saha, R., Xue, Z.Y., Huang, Y. and Nix, W.D.: Indentation of a soft metal film on a hard substrate: Strain gradient hardening effects. J. Mech. Phys. Solids 49, 1997 (2001).CrossRefGoogle Scholar
18Xu, Z.H. and Rowcliffe, D.: Deriving mechanical properties of soft coatings using nanoindentation: An application of mechanism-based strain gradient plasticity. Surf. Coat. Technol. 157, 231 (2002).Google Scholar
19Wang, L. and Rokhlin, S.I.: Universal scaling functions for continuous stiffness nanoindentation with sharp indenters. Int. J. Solids Struct. 42, 3807 (2005).CrossRefGoogle Scholar
20Wang, L., Ganor, M. and Rokhlin, S.I.: Inverse scaling functions in nanoindentation with sharp indenters: Determination of material properties. J. Mater. Res. 20, 987 (2005).CrossRefGoogle Scholar
21Knapp, J.A., Follstaedt, D.M., Myers, S.M., Barbour, J.C. and Friedmann, T.A.: Finite element modeling of nanoindentation. J. Appl. Phys. 85, 1460 (1999).Google Scholar
22Grill, A., Edelstein, D., Restaino, D., Lane, M., Gates, S., Liniger, E., Shaw, T., Liu, X-H., Klaus, D., Patel, V., Cohen, S., Simonyi, E., Klymko, N., Lane, S., Ida, K., Vogt, S., Van Kleeck, T., Davis, C., Ono, M., Nogami, T., and Ivers, T.: Optimization of SiCOH dielectrics for integration in a 90 nm CMOS technology, in Proc. IEEE 2004 Int. Interconnect Technol. Conference, (IEEE, Piscataway, NJ, 2004), pp. 54–56.Google Scholar
23Zhang, T.Y., Xu, W.H. and Zhao, M.: The role of plastic deformation at a rough surface in the size-dependent hardness. Acta Mater. 52, 57 (2004).CrossRefGoogle Scholar
24Qu, S., Huang, Y., Nix, W.D., Jiang, H., Zhang, F. and Hwang, K.C.: Indenter tip radius effect on the Nix-Gao relation in micro- and nanoindentation hardness experiments. J. Mater. Res. 19, 3423 (2004).CrossRefGoogle Scholar
25Vella, J.B., Adhihetty, I.S., Junker, K. and Volinsky, A.A.: Mechanical properties and fracture toughness of organo-silicate glass (OSG) low-k dielectric thin films for microelectronic applications. Int. J. Fracture 119/120, 487 (2003).CrossRefGoogle Scholar
26Morris, D.J., Myers, S.B. and Cook, R.F.: Sharp probes of varying acuity: Instrumented indentation and fracture behavior. J. Mater. Res. 19, 165 (2004).Google Scholar
27Toivola, Y., Stein, A. and Cook, R.F.: Depth-sensing indentation response of ordered silica foam. J. Mater. Res. 19, 260 (2004).CrossRefGoogle Scholar
28Czernuszka, J.T. and Page, T.F.: Characterizing the surface-contact behavior of ceramics. 1. Hardness response of glass-bonded alumina and titania. J. Mater. Sci. 22, 3907 (1987).Google Scholar
29Hommel, M. and Kraft, O.: Deformation behavior of thin copper films on deformable substrates. Acta Mater. 49, 3935 (2001).CrossRefGoogle Scholar
30von Blanckenhagen, B., Gumbsch, P. and Arzt, E.: Dislocation sources and flow stress of polycrystalline thin metal films. Philos. Mag. Lett. 83, 1 (2003).CrossRefGoogle Scholar