An image sensor structure that includes a first semiconductor substrate having a plurality of imaging sensors; a first interconnect structure formed on the first semiconductor substrate; a second semiconductor substrate having a logic circuit; a second interconnect structure formed on the second semiconductor substrate, wherein the first and the second semiconductor substrates are bonded together in a configuration that the first and second interconnect structures are sandwiched between the first and second semiconductor substrates; and a backside deep contact (BDCT) feature extended from the first interconnect structure to the second interconnect structure, thereby electrically coupling the logic circuit to the image sensors.