AVS 58th Annual International Symposium and Exhibition
    Plasma Science and Technology Division Tuesday Sessions
       Session PS+MN+TF-TuM

Paper PS+MN+TF-TuM4
Evaluation of Alternative Passivation Chemistries for TSV Applications

Tuesday, November 1, 2011, 9:00 am, Room 202

Session: Plasma Processing for Disruptive Technologies
Presenter: Nicholas Fuller, IBM T.J. Watson Research Center
Authors: E.A. Joseph, IBM T.J. Watson Research Center
G. Matsuura, ZEON Chemicals L.P.
S. Engelmann, IBM T.J. Watson Research Center
M. Nakamura, ZEON Chemicals L.P.
N.C.M. Fuller, IBM T.J. Watson Research Center
E.M. Sikorski, IBM T.J. Watson Research Center
M. Gordon, IBM T.J. Watson Research Center
B.N. To, IBM T.J. Watson Research Center
H. Matsumoto, Zeon Corporation
A. Itou, Zeon Corporation
Correspondent: Click to Email
With the current advent of 3D integration for advanced interconnect and packaging applications, there has been a renewed focus on deep silicon etch technology to satisfy the need for Through Silicon Via (TSV) patterning. The most common etch method used to fabricate said devices is a time-muliplexed (BoschTM) process, based on years of maturity in the MEMS field.[i] However, issues such as scalloping, mask undercut and limited etch rates are becoming more pronounced as feature sizes scale to meet the ITRS roadmap requirements. This has prompted efforts to attempt to either develop a more conventional etch process[i][ii]or to modify the Bosch process to circumvent these issues.[iii][iv] [v] In this work, we explore a novel polymerizing feedgas chemistry for the deposition step of the Bosch process to improve mask undercut while simultaneously increasing TSV etch rate. Initial results indicate a 5x larger deposition rate as compared to C4F8 (under nominal conditions) and under optimized conditions, enables a 50% decrease in undercut along with 10% increase in TSV etch rate. Optical emission spectra also differ substantially between the two feed gases, indicating different dissociation pathways and radical densities. Further results and a detailed characterization of the deposition properties of the novel chemistry will also be discussed leading to a proposed mechanism for the profile improvements as compared to C4F8. [i] B. Wu, A. Kumar and S. Pamarthy, J. of Applied Physics 108, 051101 (2010) [ii] I. Sakai, N. Sakurai and T. Ohiwa, J. Vac. Sci. Technol. A 29(2), Mar/Apr 2011 [iii] N. Ranganathan et al, Proceedings of the Electronics Components and Technology Conference, 2005 [iv] H. Rhee et al, J. Vac. Sci. Technol. B 27(1), Jan/Feb 2009 [v] S.-B. Jo et al, J. Vac. Sci. Technol. A 23(4), Jul/Aug 2005