AVS 45th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeM

Paper PS-WeM3
Evaluation of Charging Damage Test Structures for Ion Implantation Processes

Wednesday, November 4, 1998, 9:00 am, Room 318/319/320

Session: Plasma Damage
Presenter: M.J. Goeckner, Varian Associates
Authors: M.J. Goeckner, Varian Associates
S.B. Felch, Varian Associates
J. Weeman, Varian Associates
S. Mehta, Varian Associates
J.S. Reedholm, Reedholm
Correspondent: Click to Email
Charging damage is a critical issue in both current and future ion implantation systems. In conventional ion implanters, plasma flood guns have been used successfully to reduce charging damage. However, the development of sub-0.18 µm devices will make control of wafer charging more important. In addition, sub-0.18 µm devices will require novel doping technologies such as ultra-low energy (ULE) ion implanters or plasma doping (PLAD). Throughput requirements for these new technologies, and other issues, might also make charging damage more prevalent. Because of these concerns, we are examining the efficacy of two charging test structures. They are Varian Research Center’s (VRC) proprietary charging test structures@footnote 1@ and the test structures on CHARM-2 wafers.@footnote 2,3@ These test structures operate on two very different principles. The VRC test structures use static "antenna" MOS capacitors, while the CHARM-2 uses programmable EEPROM’s. Each system has distinct limitations and advantages. For example, the CHARM-2 wafer can be used to measure the maximum induced surface voltage; however the result is influenced by the elapsed time between programming, exposure and data collection. In comparison, the VRC result is static, but the precise value of the induced surface voltage can not be measured. Both structures will be put through a series of tests on both PLAD and traditional implanters. Comparisons will be made of sensitivity, temporal and spatial variability, as well as any potential limitations or advantages each might have for examining charging in ULE and PLAD implantation environments. @FootnoteText@ @footnote 1@S.B. Felch and S. Mehta in "Materials and Process Characterization of Ion Implantation," Edited by M.I. Current and C. B. Yarling, (Ion Beam Press, Austin TX, 1997), pp 288-295. @footnote 2@W. Lukaszek in "Materials and Process Characterization of Ion Implantation," Edited by M.I. Current and C. B. Yarling, (Ion Beam Press, Austin TX, 1997), pp 296-317. @footnote 3@CHARM-2 is a registered trademark of WCM.