TSV-less 3D stacking of MEMS and CMOS via low temperature Al-Au direct bonding with simultaneous formation of hermetic seal

• Main Authors: Tan, Chuan Seng, Razzaq, A., Wee, K. H., Li, K. H., Yu, H., Chua, S. L.
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electronic systems
• Online Access: https://hdl.handle.net/10356/103614; http://hdl.handle.net/10220/24544
• Institution: Nanyang Technological University

3D integration has been widely recognized as the next generation of technology for integrated microsystems with small form factor, high bandwidth, low power consumption, and possibility of heterogeneous More-than-Moore integration. Heterogeneous integration of MEMS and CMOS is critical in future development of multi-sensor data fusion in a low-cost chip size system. MEMS/CMOS integration was primarily done using monolithic and hybrid/package approaches until recently. In this work, 3D CMOS-on-MEMS stacking without TSV using direct (i.e. solder-less) metal bonding is demonstrated. This MEMS/CMOS integration leads to a simultaneous formation of electrical, mechanical, and hermetic bonds, eliminates chip-to-chip wire-bonding, and hence presents competitive advantages over hybrid or monolithic solutions. We present the fabrication flow and verify the performance of the stacked MEMS/CMOS microsystem in this paper.