Design And Alignment Algorithm Study Of Pre-Aligner

With the rapid development of Integrated Circuit(IC), the market of semiconductor equipment is also booming. Cluster Tool is one of the most import semiconductor equipment. Famous for high efficiency and flexibility, cluster tool is a mechatronic system integrated several Process Module (PMs). Cooperating with cluster tool, Equipment Front End Module (EFEM) is responsible for wafer transportation&alignment.This thesis is supported by the IC Manufacturing Equipment&Process from National Science&Technology Major Project. The main target of the research is to design a wafer pre-aligner used in12-inch EFEM and study the alignment algorithm.Firstly, function and production process of pre-aligner is analyzed. According to requirement of the system, mechanical structure, driver, control system, visual detection system and vacuum system are designed.Then a comparison is made between different position algorithm, such as Radius Method, Extreme Method, Non-linear Least Square, Linear Least Squares(LLS) and Centroiding. According to the small sampling number characteristics of the system, study is made about the pros and cons of LLS&Centroiding algorithm by Matlab simulation and mathematical analysis and a suitable algorithm is chosen. The process of notch positioning is divided into coarse and fine phase to improve accuracy.Finally, experiment is held to verify the effectiveness of the algorithm and the system characteristic parameters.