In this study, we have successfully demonstrated the 1μm pitch Cu-Cu hybrid bonding technology with remarkable electrical properties and reliabilities. 1μm pitch is world's finest class and is 3 times smaller than the connection pitch of our conventional Cu-Cu hybrid bonding technology. Moreover, the impacts of misalignment between upper Cu pad and lower Cu pad on contact resistance, electro-migration (EM) performance, leakage current and breakdown voltage were also investigated in such ultra-fine Cu-Cu hybrid bonding system.