Sponsored by: EMPMD Thin Films & Interfaces Committee
Program Organizers: N.M. Ravindra, New Jersey Institute of Technology, Newark, NJ; R.K. Singh, University of Florida, Gainesville, FL
Wednesday, AM Room: Grand J
February 7, 1996 Location: Anaheim Marriott Hotel
Session Chairman: Krishna C. Saraswat, Stanford, University, Stanford, CA; Walter F. Kosonocky, New Jersey Institute of Technology, Newark, NJ
8:30 am Invited
MANUFACTURING FEASIBILITY OF RIPPLE PYROMETRY IN RAPID THERMAL ANNEALING (RTA): Minseok Oh, Anthony T Fiory, AT&T Bell Laboratories, 600 Mountain Ave., Murray Hill, NJ 07901; Binh Nguyenphu AT&T Microelectronics, 9333 S. John Young Parkway, Orlando, FL 32819
Single wafer processing of RTA requires a temperature sensing method that is independent of wafer-to-wafer process variations. Ripple pyrometry utilizes an AC ripple component of radiation produced by heating lamps and converts it to a temperature in situ. Therefore, it can compensate for the wafer-emissivity variations induced by batch processes prior to an RTA step. A method based on AC lamp ripple was tested extensively for a long-term period at process temperatures of 650 C to 950[[ring]]C. Device wafers as well as blanket-film wafers were examined to study the accuracy and repeatability of the temperature measurement. Statistical analysis with sheet resistance data will be presented to confirm the feasibility of pyrometry using AC lamp ripple in microelectronics manufacturing.
9:00 am Invited
DEVELOPMENT OF A NON-CONTACT SENSOR FOR SiO2 LAYER THICKNESS AND TEMPERATURE IN A RAPID THERMAL OXIDATION REACTOR: Stuart Farquharson and Peter A. Rosenthal of Advanced Fuel Research, Inc. 87 Church Street, East Hartford, CT 06108; Peter R. Solomon, On-Line technologies, Inc., 87 Church Street, East Hartford, CT 06108; Nuggehalli M. Ravindra, F.M. Tong, New Jersey Institute of Technology, Department of Physics, 323 Martin Luther King Blvd., Newark, NJ 07102
Recently, rapid thermal reactors have been identified as ideal modules for building a programmable factory capable of flexible production of submicron ultra large scale integration devices. Critical to the development and employment of these reactors is the real-time measurements of process parameters to institute process control. Recently, Advanced Fuel Research Inc. and On-Line Technologies, Inc., have developed a Fourier transform infrared system capable of determining film temperature, thickness and composition within process reactors. The system was interfaced to a rapid thermal oxidation reactor at the New Jersey Institute of Technology, to monitor temperature and layer formation rate for one of the most important steps in integrated circuit manufacturing, the formation of thin, high quality silicon dioxide layers on silicon. A matrix method employing the complex dielectric functions for the SiO2 layer and the Si substrate allowed the first known determination of SiO2 layer thickness AND interstitial (intrinsic) oxygen in the substrate from infrared reflectance spectra, independent of back-side wafer roughness. Absorption bands allowed layer thickness measurements to 0.2 nm (2A) and intrinsic oxygent concentration simultaneous measurement of infrared spectral radiance allowed real-time wafer temperature measurements (200 to 800 +- 2 C). Integration of real-time temperature and layer formation rate into process models to control final product properties will be presented.
9:30 am Invited
MULTI-WAVELENGTH IMAGING PYROMETER FOR NON-CONTACT TEMPERATURE MONITORING: M.B. Kaplinsky, J. Li, N.J. McCaffrey, W.F. Kosonocky, E.S.H. Hou, N.M. Ravindra, Electronic Imaging Center, New Jersey Institute of Technology, University Heights, Newark, NJ 07102
Abstract not available.
10:00 am BREAK
10:15 am
REAL-TIME PROCESS CONTROL OF MOLECULAR BEAM EPITAXIAL GROWTH OF MERCURY CADIMIUM TELLURIDE FILMS BY FOURIER TRANSFORM INFRARED SPECTROSCOPY: Stuart Farquharson, Martin D. Carangelo, James R. Markham, Advanced Fuel Research. Inc., 87 Church Street, East Harford, CT 06108; Peter R. Solomon, John R. Haigis, On-Line technologies, Inc., 87 Church Street, East Hartford, CT 06108; Nuggehalli M. Ravindra, Fei-Ming Tong, New Jersey Institute of Technology, Department of Physics, 323 Martin Luther King Blvd., Newark, NJ 07102; Glenn Wesphal, Texas Instruments Incorporated, 13536 North Central Expressway, Dallas, TX 75265
The ternary semiconductor mercury cadmium telluride (Hg1-xCdxTe) has become the most widely used material in infrared detection devices. This is primarily due to the ability to tailor its spectral response (band gap energy or cut-off wavelength) and efficiency to the desired application. This is accomplished by controlling the relative alloy concentration (x) of mercury and cadmium. Nevertheless, stringent process control of film temperature and film growth rate is necessary to attain the required alloy concentrations. Recently, Advanced Fuel Research Inc. and On-Line Technologies, Inc., have developed a Fourier transform infrared system which performs real-time measurement of these properties, and interfaced it to a molecular beam epitaxial growth reactor at Texas Instruments for dedicated process control. The system performs simultaneous measurement of the film infrared reflectance and emittance. The former is used to determine film thickness, the latter to determine the cut-off wavelength, and the combination to determine the film temperature. Instrument design, spectral analysis, and implementation of process control will be presented.
10:35 am
ESTIMATION OF TRANSPORT LOSSES IN RTP SYSTEMS: R.K. Singh, Department of Materials Science & Engineering, University of Florida, Gainesville, FL 32611
Abstract not available.
10:55 am
THREE DIMENSIONAL MODELLING OF RTP SYSTEMS: R.V. Nagabhusnam, R.K. Singh, Department of Materials Science & Engineering, University of Florida, Gainesville, FL 32611
Abstract not available.
11:15 am
REAL-TIME IMPLEMENTATION OF AN ADAPTIVE CONTROL SYSTEM FOR A 3-ZONE RTP STATION: Sergey Belikov, David Hur, Bernard Friedland, N.M. Ravindra, New Jersey Institute of Technology, Newark, NJ 07102
This presentation concerns with real-time implementation of a model-based adaptive RTP control algorithm developed in NJIT. An adaptive controller with measured temperatures of the wafer as the inputs and control voltages for the heating lamps as the outputs was designed and implemented on a transputer parallel computing system. An intermediate step of the process of installation of the controller into the 3-zone RTP station, under investigation at NJIT, involves its testing with an RTP simulator, which has the same inputs and outputs as the actual RTP station. Due to natural and artificial noise of the RTP simulator, the simulated inputs for the controller become close to actual real-time outputs of temperature sensors used for RTP. Using the RTP simulator allowed us to solve various real-time implementation problems before the actual installation of the controller into the RTP station. During this step, we also improved quality and robustness of parameter estimation. Instrumental wafers with embedded thermocouples have been used for testing the adaptive control system on real-time RTP processes. 2-dimensional infrared and fiber optic sensors are planned to be used for the controller after its successful testing with thermocouples. This investigation was supported by the National Science Foundation under Grant ERSC-9312451 and ARPA under contract F33615-92-C-5817.
11:35 am
COMPUTER WORKSTATION FOR MULTIWAVELENGTH IMAGING PYROMETER: J. Li, E.S.H. Hou, M.B. Kaplinsky, N.J. McCaffrey, W.F. Kosonocky, Electronic Imaging Center, New Jersey Institute of Technology, University Heights, Newark, NJ 07102
Abstract not available.
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