Research On Key Technologies Of Wafer Lifting Mechanism

Integrated circuit (IC) is the core of the development of electronic information industry. IC manufacturing equipment is the most important support of the IC industry. Before IC manufacturing processes, wafers need to be transferred, positioned and aligned. Their speed, repeative positioning accuracy could affect the efficiency and manufacturing quality of the IC production directly or indirectly. Thus, new wafer lifting mechanism researches about high precision, high speed, high stability would promote manufacturing quality and efficiency improvement, and further positively influence IC manufacturing process as a whole.Based on studies about the domestic and international background of wafer lifting mechanism and technology development, this paper initially provides a new design of the wafer lifting mechanism, especially in structure, then discusses the analysis and optimization of key components and parameters of the structure, and further verfies the design and debugging of control system, and finally showes experimentally researches about key performance parameters of the whole system. Main contents as following:1. From the mechanism perspective, the functions and process flow are analysed, and then the overall structurally mechnism is designed, specificly including the drive system, detection system, vacuum clampling device, aerostatic bearings device. Furthermore, in order to weaken the impact during wafer transfer,a buffer device and an anti-rotation devicef are designed.2. According to the structure design, the performance of this system is descussed. On the basis of the analysis of wafer parameters, the size of the vacuum straw and the buffer parameter are optimized, then the simulation model of moving parts including the wafer to overall are established. Moreover, through the simulation analysis of statics and vibration modal of aerostatic bearings device, the structure designs are verified to performance specification.3. The control system of wafer lifting mechanism is designed, include the servo system and vacuum system. Through the construction and adjustment of the PID parameters and the optimization of system performance, precise positioning of the wafer is achieved.4. According to the principle of laser displacement measurement, experimental platform for laser measurement is established. And mechnasim performance is then examed on this platform, including movement stroke, maximum speed, and maximum acceleration. Finally, the experiments about repositioning accuracy and distinguishability are implemented successfully. Experiments indicates that the new lifting mechanism for 300mm wafer stated in this paper has achieved the required performance specifications, including minimum stroke(18mm), maximum speed (81.38mm/s), maximum acceleration (7.91m/s2), repositioning accuracy (4.9um) and resolution capability (1um).