Bond pad structure for bonding improvement

A method of fabricating a semiconductor device includes receiving a device substrate; forming an interconnect structure on a front side of the device substrate; and etching a recess into a backside of the device substrate until a portion of the interconnect structure is exposed. The recess has a recess depth and an edge of the recess is defined by a sidewall of the device substrate. A conductive bond pad is formed in the recess, and a first plurality of layers cover the conductive bond pad, extend along the sidewall of the device substrate, and cover the backside of the device substrate. The first plurality of layers collectively have a first total thickness that is less than the recess depth. A first chemical mechanical planarization is performed to remove portions of the first plurality of layers so remaining portions of the first plurality of layers cover the conductive bond pad.