| AVS 60th International Symposium and Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM+AS+PS+TF-ThM |
| Session: | Materials and Process for Advanced Interconnects I |
| Presenter: | H. Zheng, University of Wisconsin-Madison |
| Authors: | H. Zheng, University of Wisconsin-Madison D. Pei, University of Wisconsin-Madison M. Nichols, University of Wisconsin-Madison S. Banna, Applied Materials Inc. Y. Nishi, Stanford University J.L. Shohet, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
Charging during plasma processing of VLSI/ULSI devices can cause degradation of dielectrics and is a leading cause of damage in semiconductor devices. Thus, a search for a proper method to limit and deplete charge in dielectric materials, especially low-k dielectric materials, (SiCOH) has received great interest. In this work, the temporary increase in the surface conductivity of SiCOH during exposure to vacuum-ultraviolet radiation is investigated and compared with similar measurements for SiO21. To measure this, patterned titanium “comb structures” were deposited on thin SiCOH films and exposed to synchrotron radiation. VUV-induced currents along the surface of the layer between the titanium fingers of the comb structure were measured by biasing the comb structure through electrical connections from the test structure to outside circuitry. By measuring the I-V characteristics of the comb test structure under a constant flux of VUV light, we determined that, for low electric fields, the measured current density and applied electric field are linearly proportional. However, because the SiCOH samples used here are relatively thin, as the electric field increases, the photoinjection current from the substrate becomes large and then dominates the measured VUV-induced current. Hence, it is possible to generate a self-consistent VUV-induced IV characteristic only by using low applied electric fields. Based on these measurements, the surface conductivity can be found. Specifically, under VUV radiation with photon energies between , the surface conductivity of the SiCOH films materials increases by at least one order of magnitude compared with the surface conductivity in the absence of radiation. This increase can be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge, which holds the potential to decrease processing-induced plasma damage to semiconductor devices significantly.
1 C.Cismaru, J.L. Shohet and J.P. McVittie, Applied Physics Letters, 71 2191 (2000).
This work was supported by the Semiconductor Research Corporation under Contract 2012-KJ-2359 and by the National Science Foundation under Grant CBET-1066231.