Study Of Control Technology Of Temperature Field In Rapid Thermal Processing System

Rapid thermal processing is an advanced art of single silicon wafer thermal processing which is more appropriate for the miniaturization of integrate circuit feature size, comparing with the traditional batch type thermal processing art. In the early time, it came out for the need of materials science research. But now it has been abroad applied in the production art of integrate circuit, MEMS and so on, the classical application of which concluding RTA(rapid thermal annealing),RTO(rapid thermal oxidation)and RTCVD(rapid thermal chemical vapor deposition) and so on.The RTP device is always the fundamental art of thermal processing. Since the first commercial device of RTP showed up in1970, it has been keeping updating. The uniformity of temperature field and temperature measurement have always been the research spot. It is the temperature field of the RTP device directly determines the quality of production art, so the better performance of temperature uniformity and rising speed is essential.In the paper the research of temperature field control has been proposed in the platform of RTP device developed in our own lab. First of all, heat transfer theory analysis has been taken which contains radiative transfer, heat conduction and heat convection. After the radiant power distribution rule of halogen tungsten lamp torus has been clear, the silicon wafer was divided into several zones and the calculation formula of heat conduction between all the zones has obtained. According to the law of conservation of energy, the differential equation of silicon wafer temperature and heat power has been got and the control model of its temperature also has been obtained through the linear processing.After the analysis of control model, a temperature controller based Fuzzy-PID has been designed, whose Fuzzy controller and PID controller are parallel structure and they control the temperature in the rising phase and holding phase. Finally, the algorithmic effectiveness has been tested in Matlab simulation. An temperature controller hardware based on FPGA has been designed which has the function of three ways temperature real-time sampling,USB2.0dates communication PWM signal driving and so on. The design model of Fuzzy-PID controller and other interface logic which are based on Verilog HDL and QuartusⅡ has been done. At last, it has been tested that all the setting functions work.