Simultaneous formation of electrical connection, mechanical support and hermetic seal with bump-less Cu-Cu bonding for 3D wafer stacking
Li, H. Y.
Tan, Chuan Seng
Date of Issue2012
International Symposium on VLSI Technology, Systems and Application (2012 : Hsinchu, Taiwan)
School of Electrical and Electronic Engineering
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.
DRNTU::Engineering::Electrical and electronic engineering