AVS 62nd International Symposium & Exhibition
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP22
VUV Curing Process for Low-k Organosilicate Dielectrics

Tuesday, October 20, 2015, 6:30 pm, Room Hall 3

Session: Electronic Materials and Processing Poster Session
Presenter: Huifeng Zheng, University of Wisconsin-Madison
Authors: H. Zheng, University of Wisconsin-Madison
X. Guo, University of Wisconsin-Madison
S.W. King, Intel Corporation
E. Ryan, GLOBALFOUNDRIES
Y. Nishi, Stanford University
J.L. Shohet, University of Wisconsin-Madison
Correspondent: Click to Email
Porous SiCOH films are of great interest in semiconductor fabrication due to their low-k properties. Post-deposition treatments of SiCOH thin films are required to decompose the labile pore generator (porogen) and ensure optimum network formation to improve the electrical and mechanical properties of low-k dielectrics. The currently used UV curing method has some weaknesses such as the required high curing temperature (400-425oC) and the time for curing (several minutes). Vacuum ultraviolet (VUV) irradiation over specific energy ranges was found to overcome some of these drawbacks by efficiently decreasing the dielectric constant and increasing the hardness and elastic modulus of low k dielectrics at room temperature. Specifically, photon energies equal to or larger than 6.0 eV were found to decrease the k value of SiCOH films while lower energies did not have this effect. 6.2 eV photons were found to be most effective. [1] In addition, photons with energies equal to or larger than 8.3 eV enhanced the mechanical properties of SiCOH films significantly. Fourier Transform Infra-red Spectroscopy (FTIR) shows that the breaking of C-Hx stretching bonds (3050-2850 cm-1) in organic porogens and transitioning of Si-O-Si stretching bonds (1250-1000 cm-1) from cage-like to network-like structures contribute to the decrease of dielectric constant and increase of hardness and elastic modulus of SiCOH films. [2] [#_edn2] These investigations show that the optimum photon energies for post-deposition treatment of SiCOH might exist in the VUV range and a VUV-involved curing process could be utilized as a post treatment method in low-k material deposition technologies.

This work was supported by the Semiconductor Research Corporation under Contract 2012-KJ-2359 and by the National Science Foundation under Grant CBET-1066231.

[1] H. Zheng, E.T.Ryan, Y. Nishi and J.L. Shohet, “Effect of vacuum-ultraviolet irradiation on the dielectric constant of low-k organosilicate dielectrics,”Appl. Phys. Lett. 105, 202902 (2014).

[2] [X. Guo, J. E. Jakes, S. Banna, Y. Nishi and J. L. Shohet, “Effects of plasma and vacuum- ultraviolet irradiation on the mechanical properties of low-k porous organosilicate glass”, J. Appl. Phys. 116, 044103 (2014).