| Aiming at the present condition of the local semiconductor profession, the diffusion/oxidize system of semiconductor enterprise can be choosed as research object. The traditional diffusion furnace's temperature control always use regular temperature control instruments, it has many problems such as lower process control ability and efficiency. And the foreign advanced diffusion/oxidize control system do not adapt to the national conditions of our country in function and price. Therefore, from the actual applied aspect, design and manufacture a kind of diffusion/oxidize process control system, which can attain the actual applied request, imperatively.This topic in depth research and development includes the temperature detecting, components and implementation of the control system and the development of management software of the upper computer.(1) According to the actual application requirements of the diffusion/oxidize control, This thesis presents the detailed study on the integrated design of diffusion/oxidize process control system based on fieldbus, research mechanism and diffusion/oxidize process flow in the semiconductor manufacturing processes.(2) In the diffusion/oxidize process control flow, the temperature control is critical, which affects quality of the semiconductor diffusion/oxidize process. To ensure the accuracy of temperature control, first of all to ensure the accuracy of temperature detection. In accordance with the requirements of temperature measurement accuracy, develop JC-9 temperature detection module, on which built Modbus-RTU slave protocol.(3) The design of temperature control algorithm. According to the temperature characteristics of diffusion furnace, an improved expanded response curve is presented, which can be used to achieve self-tuning of PID parameters.(4) Constituting the diffusion/oxidize process control system based on fieldbus. This control system has Two-tier bus architecture; one is between JC-9 temperature detection module, gas mass flowmeter and the PLC, the other is between PLCs and one computer. Each tier communicates via to Modbus protocol each other.(5) The development of management software of the upper computer. This software can monitor multiple devices simultaneously, get all kinds of parameters, and control these devices.Operation result on site shows that the diffusion/oxidize process control system based on fieldbus is feasible. The system improves the quality of semiconductor and the efficiency of semiconductor production effectively. Hence, studying and developing this system by this method has excellent meanings. |
