Monte Carlo Thermal Model of an Integrating Light Pipe for Rapid Thermal Processing

1996 ◽  
Vol 429 ◽  
Author(s):  
J. C. Thomas ◽  
D. P. Dewitt

AbstractA Monte Carlo model is developed to simulate transient wafer heating as a function of system parameters in a kaleidoscope- or integrating light-pipe type cavity with square cross-section. Trends in wafer temperature uniformity are examined as a function of length-to-width ratio, cavity width, and the number of heating lamps. The effect on temperature determination by a radiometer placed in the bottom end wall of the cavity is simulated.

Author(s):  
Hakan Erturk ◽  
John R. Howell

Light-pipe radiation thermometers are predominantly used to monitor wafer temperature during rapid thermal processing (RTP) of semiconductors. The processes used in fabrication of semiconductor devices during rapid thermal processing are extremely temperature sensitive and the errors associated with light-pipe measurements are great concerns across the industry. Modeling of the light-pipes has helped in understanding the signal transport process and errors associated with the light pipe measurements. However, due to the smaller size of the light-pipe sensor area with respect to the total system area, full scale modeling of such a system including the light pipe thermometer has not been possible due to the computational demand. In this paper, the reverse Monte Carlo method is used to model the signal transport through a light-pipe thermometer used in a RTP system. The Monte Carlo model considers the spectral and angular dependent optical properties of the chamber and quartz materials. The reverse Monte Carlo model is applied to the full scale instrumented system with characteristics of a RTP system with a quartz light pipe probe and the results are compared against previously published measurements from the same system.


2008 ◽  
Author(s):  
Hakan Erturk ◽  
Ofodike A. Ezekoye ◽  
John R. Howell

Rapid thermal processing (RTP) has been widely used by the semiconductor manufacturing industry. Light-pipe radiation thermometers are the predominant method to monitor the wafer temperature during rapid thermal processing. The errors associated with light-pipe measurements are great concerns across the industry due the extreme temperature sensitivity of the processes used to fabricate semiconductor devices during rapid thermal processing. Modeling of the light-pipes has helped understand the signal transport process and errors associated with the light pipe measurements. However, due to the smaller size of the light-pipe sensor area with respect to the total system area full scale modeling of such a system including the light pipe thermometer have not been possible due to the computational demand. In this paper, a reverse Monte Carlo method is developed to model the signal transport through a light-pipe thermometer used in a RTP system. The Monte Carlo model considers the spectral and angle dependent optical properties of the chamber and quartz materials. The reverse Monte Carlo model is applied to a simpler system with a quartz light pipe probe for verification against a model developed using a forward Monte Carlo method.


2000 ◽  
Author(s):  
Y. H. Zhou ◽  
Y. J. Shen ◽  
Z. M. Zhang ◽  
B. K. Tsai ◽  
D. P. DeWitt

Abstract This work employs a Monte Carlo method to study the radiative process in a rapid thermal processing (RTP) furnace. A “true” effective emissivity, accounting for the directional optical properties, is defined and predicted in order to determine the wafer temperature from the measured spectral radiance temperature using light-pipe radiation thermometry. The true effective emissivity is the same as the hemispherical effective emissivity for diffuse wafers, in which case the Monte Carlo model gives the same results as the net-radiation method. Deviations exist between the hemispherical effective emissivity and the true effective emissivity for specular wafers because the effective emissivity is directional dependent. This research will help reduce the uncertainty in the temperature measurement for RTP furnaces to meet the future requirements for integrated circuit manufacturing.


1995 ◽  
Vol 387 ◽  
Author(s):  
Andreas Tillmann

AbstractA new strategy based algorithm to optimize process parameter uniformity (e.g.sheet resistance, oxide thickness) and temperature uniformity on wafers in a commercially available Rapid Thermal Processing (RTP) system with independent lamp control is described. The computational algorithm uses an effective strategy to minimize the standard deviation of the considered parameter distribution. It is based on simulation software which is able to calculate the temperature and resulting parameter distribution on the wafer for a given lamp correction table. A cyclical variation of the correction values of all lamps is done while minimizing the standard deviation of the considered process parameter. After the input of experimentally obtained wafer maps the optimization can be done within a few minutes. This technique is an effective tool for the process engineer to use to quickly optimize the homogeneity of the RTP tool for particular process requirements. The methodology will be shown on the basis of three typical RTP applications (Rapid Thermal Oxidation, Titanium Silicidation and Implant Annealing). The impact of variations of correction values for single lamps on the resulting process uniformity for different applications will be discussed.


1989 ◽  
Vol 146 ◽  
Author(s):  
R. Kakoschek ◽  
E. BuβMann

ABSTRACTA complete theory of wafer heating during rapid thermal processing (RTP) is presented. Excellent agreement with experimental results of two commercial RTP systems is obtained. The temperature uniformity is limited by radiation loss at the wafer edge in the stationary state and by nonuniform illumination of the wafer during ramp-up. Structures on wafers are also potential sources for nonuniform heating. Considerable dynamic temperature inhomogeneities during rap-up might limitfu ture applications of RTPe specially when wafer sizes become larger. Possible improvements are suggested regarding adequate process cycling, chip and equipment design.


Author(s):  
Yayun Tan ◽  
He Zhang

Aiming at the necessity of torpedo detecting near field target in final stage of guidance, a non-coaxial (transmitter and receiver are not on the same axis) single beam scanning detecting and ranging system has been designed to be applied in torpedo. To study this detection system, this paper proposes a Monte Carlo simulation method for the system. The backscattering signal and target echo signal in seawater is simulated, and then the Signal-to-Backscattering-Noise (SBNR) is calculated. Furthermore, the relationship between maximum detecting distance and system parameters is calculated based on the criterion of minimum SNBR. Finally, the optimal system parameters are determined to get maximum detection range. For verifying the correctness of the theoretical models, underwater laser detection optical simulation system is designed to do target detecting experiment in a basin. The comparative analyses of the simulation and the experimental results show that the simulation results fit the experimental data well, thus the correctness of the semi-analytical Monte Carlo model is verified. The optimal parameters in single beam scanning detecting system can be determined according to the simulation and experimental results. The designed underwater laser detecting system provides a new method for the torpedo to detect underwater target in final stage of guidance.


1994 ◽  
Vol 342 ◽  
Author(s):  
Andreas Tillmann

ABSTRACTThe modelling of temperature distribution on semiconductor wafers in common RTP-equipment is described. The incident intensity distribution on the wafer is calculated using raytracing. Based on this distribution the temperature distribution on the wafer is determined solving the two-dimensional heat conduction equation. If the dependence of a considered material property on the process temperature is known, the calculated temperature distribution can be convened to a distribution of this parameter.The distinctive feature of the described algorithms is the two-dimensional treatment of the distributions using a grid of ring segments, each with equal area. This grid is identical to the usual circular test patterns of multipoint measurement equipment. This is convenient since the evaluation of temperature uniformity in RTP equipment is done mostly by mapping an appropriate temperature dependent material property. All calculated distributions can be presented by contour plots as well as 3-D plots. This results in a very suitable method to compare simulated and experimental wafer maps.The agreement between simulated and experimental temperature distributions is shown.


1995 ◽  
Vol 389 ◽  
Author(s):  
Andreas Tillmann

ABSTRACTA new strategy based algorithm to optimize process parameter uniformity (e.g. sheet resistance, oxide thickness) and temperature uniformity on wafers in a commercially available Rapid Thermal Processing (RTP) system with independent lamp control is described. The computational algorithm uses an effective strategy to minimize the standard deviation of the considered parameter distribution. It is based on simulation software which is able to calculate the temperature and resulting parameter distribution on the wafer for a given lamp correction table. A cyclical variation of the correction values of all lamps is done while minimizing the standard deviation of the considered process parameter. After the input of experimentally obtained wafer maps the optimization can be done within a few minutes. This technique is an effective tool for the process engineer to use to quickly optimize the homogeneity of the RTP tool for particular process requirements. The methodology will be shown on the basis of three typical RTP applications (Rapid Thermal Oxidation, Titanium Silicidation and Implant Annealing). The impact of variations of correction values for single lamps on the resulting process uniformity for different applications will be discussed.


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