The Design And Development Of Three-station CMP Control System

Currently, chemical mechanical Polishing (CMP) is the most effective technology for global and local planarization of the wafer in IC manufacturing. The CMP machine is a hardware foundation of CMP technology, and safeguards the realization of CMP technology. The CMP control technology is the important constituent of CMP machine and provides the technical support for the CMP machine of high surface processing accuracy.The analysis and design of control system hardware is made in line with the function of three-station CMP machine.Every station has the same function and is divided into three units which are designed and developed independently .The function of the polishing pressure monitoring and control uint is to carry out the PID operation to acquired data and to pass on the result to polishing pressure via D/A port so that closed-loop control of polishing pressure is formed. The vacuum absorption and recoil uint monitors the real-time vacuum pressure, absorbs and recoils wafer .The polishing head motion control unit adopts control system of open style, which consists of "PC+ motion control card+servo controller" to realize the rise,drop,reciprocation and rotation of polishing head and rotation of polishing disk.The control software is analyzed and designed according to the function requirement of three-station CMP machine. Based on the detailed analysis of control system's function structure, modeling of control system is realized using UML, then the translation from model to C++ code is realized by using Forward Engineering of Rational Rose 2003, and the control system is developed with Visual C++ finally. Object-oriented method is adopted to divide monitoring system software and encapsulate control function modules by means of class. The key technologies for control software such as the realization of multi-view communications and the use of OpenGL to achieve visualization are analyzed in this paper.The hardware system is assembled and tested. Based on the result of experiment, the software and hardware is consummated. The result of experiment shows that the three-station CMP control system has achieved the anticipated control requirement, which lays the foundation for the development of three-station CMP machine and its control system.