小径工具を用いた揺動制御ラッピングに関する研究

抄録

The development of recent semiconductor industry depends greatly on the innovation of the technology. Silicon chips used as semiconductor element, etc. require higher accuracy. Presently silicon wafers with diameter as large as 300mm are generally used. On the other hand, the improvement in flatness and roughness is required in order to use lapping process in large diameter wafers. Generally, the lapping is performed using a “4 way lapping” system. In 4 way system, several wafers can be lapped simultaneously by rotating and revolving the several wafers and rotating the lapping plate. However, various problems are pointed out when large diameter wafers are lapped in 4 way system. Therefore, the single wafer lapping method which uses the small diameter tool has been discussed, recently. This paper describes the basic characteristics of the oscillation controlled lapping method based on a series of experiment and the computation results. Besides, the consideration of traction expressed by the Preston's equation is used to the computation. Moreover, the method in this paper uses the genetic algorithms for deciding the oscillation controlled conditions. As the results, we can get the good agreement between the theoretically aimed profiles and the experimental results.