Simultaneous formation of electrical connection, mechanical support and hermetic seal with bump-less Cu-Cu bonding for 3D wafer stacking

• Main Authors: Peng, L., Li, H. Y., Fan, Ji, Gao, Shan, Tan, Chuan Seng
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/105523; http://hdl.handle.net/10220/17047; http://dx.doi.org/10.1109/VLSI-TSA.2012.6210174
• Institution: Nanyang Technological University

Wafer-on-wafer stacking is demonstrated successfully using bump-less Cu-Cu bonding for simultaneous formation of electrical connection, mechanical support and hermetic seal. The mechanical strength of the bonded Cu-Cu layer sustains grinding and chemical etching. Daisy chain of at least 44,000 contacts at 15μm pitch is connected successfully. Cu-Cu hermetic seal ring shows helium leak rate >;10X lower than the reject limit without under-fill. This provides robust IC-to-IC connection density of 4.4 × 105 cm-2 suitable for future wafer level 3D integration.