Angular alignment for wafer bonding

Yuan-Fang Chou; Ming-Hsun Hsieh

doi:10.1117/12.251229

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23 September 1996 Angular alignment for wafer bonding

Yuan-Fang Chou, Ming-Hsun Hsieh

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Proceedings Volume 2879, Micromachining and Microfabrication Process Technology II; (1996) https://doi.org/10.1117/12.251229
Event: Micromachining and Microfabrication '96, 1996, Austin, TX, United States

Abstract

Wafer bonding is an important fabrication step for some MEMS devices. ALignment of device patterns is vital for a successful bonding. When anisotropic wet etching is employed to fabricate microstructures on single crystal silicon wafers, the same mask may result in different etched patterns on different wafers. If the wafer pair for bonding are not matched well, the position and orientation of device patterns cannot be aligned simultaneously. This article presents a method for position and orientation alignment of the device patterns on wafer pairs. An offset angle indicating mark and a self-aligning bonding fixture are developed to satisfy the alignment requirement. The photomask for wet anisotropic etching contains patterns of indicating marks and wafer cutting targets. The indicating marks provide information of offset angles between device patterns and crystal planes after wet etching. Wafer pairs for bonding are matched with offset angles, depending on the device configuration. Simultaneously align the position and orientation is possible for the matched wafer pairs. Wafers are cut with the guide of cutting targets to ensure they have the same size. The bonding fixture consists of a steel frame and a pair of flat glass plates. The steel frame has a rectangular opening where the wafer pair are sandwiched between the glass plates. The wafer cutting process is the major source of misalignment in this bonding method.

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Yuan-Fang Chou and Ming-Hsun Hsieh "Angular alignment for wafer bonding", Proc. SPIE 2879, Micromachining and Microfabrication Process Technology II, (23 September 1996); https://doi.org/10.1117/12.251229

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