the simultaneous formation of electrical connection, mechanical support, and hermetic frame
for 3-D IC application. The ohmic behavior of the Cu-Cu bond is verified. A daisy chain of at
least 44 000 contacts at a 15-μm pitch is connected successfully and sustains thermal
cycling. Postbonding delamination is found to be strongly affected by the wafer curvature
and bond strength. The Cu-Cu hermetic seal ring shows a helium leak rate more than ten …