Patent ID: 9711555
Date: 2017-07-18
CPC Classifications: H01L

Claim:
1. A method for fabricating a dual facing BSI image sensor assembly, comprising: receiving a first BSI image sensor element, a second BSI image sensor element, and a third element, wherein: bonding the first side of the first metal stack to the first side of the third metal stack using a first hybrid bond process, wherein the first hybrid bond process includes a direct bond process and an annealing process, wherein the direct bond process uses a first temperature, wherein the annealing process includes a first stage and a second stage, the first stage uses a second temperature that is higher than the first temperature; and the second stage uses a third temperature that is higher than the second temperature; thinning the first substrate from the second side of the first substrate to a first thickness; forming a passivation layer over a second side of the third substrate, wherein a first side of the passivation layer includes a fourth plurality of conductive features that is electrically coupled to the third metal stack; bonding the first side of the second metal stack to the first side of the passivation layer using a second hybrid bond process; and thinning the second substrate from the second side of the second substrate to a second thickness.