Precision Identification of the Major Crystal Orientation of the Silincon Wafer
Jia Chenping，Qu Liangsheng
(School of Mechanical Engineering,Xi'an　Jiaotong　University,Xi'an 710049,China)

Abstract：To accurately identify the major crystal orientation of the silicon wafer, which is frequently used in the manufacturing of various micro electro and mechnical system devices, a precise alignment scheme was proposed. By using a group of elablrately designed calibrating patterns and ensuing pre-etching process, the major crystal orientation of the wafer was explicitly exposed. To pick out the pattern that represents the major crystal orientation, digital image processing technology was used to analyze the metallograph. Experimental result showed that instead of the original ±1°~±2° alignment precision provided by the alignment flat, an improved precision of ±0.1° could be achieved by the proposed method, which is accurate enough in the production of most MEMS devices. The effectiveness of the above-mentioned method was verified by a special designed wet chemical etching experiment.
Keywords：MEMS；bulk micro machining；crystal orientation