Browsing by Author "Henn-Lecordier, Laurent"
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Item A NEW APPROACH TO SPATIALLY CONTROLLABLE CVD(2004) Choo, Jae-Ouk; Adomaitis, Raymond A.; Rubloff, Gary W.; Henn-Lecordier, Laurent; Cai, Yuhong; Adomaitis, Raymond A.; ISRThis paper describes the continuing design evolution of a new approach to spatially controllable chemical vapor deposition for electronic materials manufacturing. Based on the success of a previous prototype reactor, we describe construction of a newer version of the prototype reactor system to assess its performance and identify its key operational characteristics. This new design includes a fully automated feed gas control system, allowing the reprogramming of reactor operation without hardware modifications and a time-shared gas sampling mass spectrometer for spatially resolved across-wafer gas composition analysis.Item Real-Time Growth Rate Metrology for a Tungsten CVD Process by Acoustic Sensing(2000) Henn-Lecordier, Laurent; Kidder, John N., Jr.; Rubloff, Gary W.; Gogol, C. A.; Wajid, A.; ISRAn acoustic sensor, the Leybold Inficon ComposerTM, was implemented downstream to a production-scale tungsten chemical vapor deposition (CVD) cluster tool for in-situ process sensing. Process gases were sampled at the outlet of the reactor chamber and compressed with a turbo-molecular pump and mechanical pump from the sub-Torr process pressure regime to above 50 Torr as required for gas sound velocity measurements in the acoustic cavity. The high molecular weight gas WF6 mixed with H2 provides a substantial molecular weight contrast so that the acoustic sensing method appears especially sensitive to WF6 concentration.By monitoring the resonant frequency of exhaust process gases, the depletion of WF6 resulting from the reduction by H2 was readily observed in the 0.5 Torr process for wafer temperatures ranging from 300 to 350 C. Despite WF6 depletion rates as low as 3-5%, in-situ wafer-state metrology was achieved with an error less than 6% over 17 processed wafers.
This in-situ metrology capability combined with accurate sensor response modeling suggests an effective approach for acoustic process sensing in order to achieve run-to-run process control of the deposited tungsten film thickness.
Item Simulator Development for a Spatially Controllable Chemical Vapor Deposition System(2002) Choo, Jae-Ouk; Adomaitis, Raymond A.; Rubloff, Gary W.; Henn-Lecordier, Laurent; Liu, Yijun; ISRMost conventional chemical vapor deposition systems do not have the spatial actuation and sensing capabilities necessary to control deposition uniformity, or to intentionally induce nonuniform deposition patterns for single-wafer combinatorial CVD experiments. In an effort to address this limitation, we began a research program at the University of Maryland focusing on the development of a novel CVD reactor system that can explicitly control the (2-dimensional) spatial profile of gas-phase chemical composition across the wafer surface.This reactor is based on a novel segmented showerhead design in which gas precursor composition can be individually controlled in the gas fed to each segment. Because the exhaust gas is recirculated up through the showerhead though the individual segments, the gas flow pattern created eliminates convective mass transfer between the segment regions. The effect of this design is a CVD system in which across-wafer composition gradients can be accurately predicted and controlled.
This paper discusses the development of a simulator for a three-segment prototype that has recently been constructed as a modification to an Ulvac ERA1000 CVD cluster tool. A preliminary set of experiments has been performed to evaluate the performance of the prototype in depositing tungsten films for a range of wafer/showerhead spacing and segment gas compositions. We discuss the simulation approach taken to developing the simulator for this system focusing on a one-dimensional simulation of transport through the segments and exhaust mixing region, a model valid in the limit of close showerhead/wafer spacing. The use of simulation in the prototype system design, interpreting experimental data, and its ultimate use in controlling the CVD process to achieve true programmable CVD operation all will be discussed. Further information can be found at the project website, http://www.isr.umd.edu/Labs/CACSE/research/progrxr