Figure 7
From: Copper-to-copper direct bonding on highly (111)-oriented nanotwinned copper in no-vacuum ambient
Schematic drawings of the metal-to-metal direct bonding mechanism. (a) Less perfect surfaces contact during the compression process, (b) atoms diffuse from regions of high stress (where two parts touch under compression) to those of lower stress (untouched under compression) along the interface, and (c) TEM image of the bonding interface showing the bonded (strained) and unbonded (unstrained) areas.
