The Development Of The High-precision Semiconductor Diffusion/oxidation Process Control System

Semiconductor and IC equipment manufacturing is the basis to support the development of the Semiconductor and integrated circuit.Among the various Semiconductor equipment,Diffusion/oxidation equipment is one of the most important process equipment in the integrated circuit manufacturing.The control system is the core of this equipment,at the same,whose performance index can reflect the performance level of such equipment.Aiming at the problems of the existing control system,especially in the temperature control,the diffusion/oxidation process control system is developed from actual use.The detection and control of the temperature is the key indicator in this system, the precision of the temperature measurement and detection and the stability of operating are the decisive factor in the level of accuracy which will eventually affect the quality of the products.Firstly,redesign the structure of the temperature detection and control system.This system consists of temperature detection unit and control unit.The detection unit is connected with the PLC of the control unit by RS485 Communication interface,through which,the detected temperature will be put into the PLC.The PLC uses the data, together with the application of the diffusion/oxidation process of the temperature control algorithm to achieve temperature control.Secondly,on the basis of the temperature measurement accuracy of better than 0.5‰of the performance indicators,from the selection of circuit component type,circuit design,circuit board production,design of the detection software,expound the design and production of the detection unit.Temperature detection unit was made by cost-effective components,with full considering of the circuit design and circuit board production so as to ensure the temperature measurement accuracy and stability.Finally,according to the precision of temperature control is better than 1‰of the performance indicators,taking into account the temperature control system of diffusion/oxidation process is typically large inertia,pure time-delay system,and it is difficult to establish accurate mathematical model for controlled device and so on.we educe the temperature control algorithm which adapt the system,set up reasonable control parameters and complete the production of temperature control unit. Experiments shows that the temperature detection and control system with a high degree of automation is credible,and stable.It is of significance to research and develop this system for the semiconductor manufacturers.