Dual facing BSI image sensors with wafer level stacking

A device comprising:

• a first image sensor element having a first photosensitive region and a first surface that includes a first dielectric portion;
• a second image sensor element having a second photosensitive region and a second surface that includes a second dielectric portion;
• an interconnect structure disposed on a substrate between the first and second image sensor elements, the interconnect structure including a third surface that includes a third dielectric portion and the substrate having a fourth surface that includes a fourth dielectric portion, the third dielectric portion directly interfacing with the first dielectric portion and the fourth dielectric portion directly interfacing with the second dielectric portion;
• and
• a first conductive feature extending from one of the first and second photodiode regions to the interconnect structure.

A device comprising:

• a first image sensor, wherein the first image sensor includes a first conductive portion and a first dielectric portion;
• a second image sensor, wherein the second image sensor includes a second conductive portion and a second dielectric portion;
• and
• a third element disposed between the first image sensor and the second image sensor, the third element having a first surface and a second surface, the first surface including a third conductive portion and a third dielectric portion and the second surface including a fourth conductive portion and a fourth dielectric portion, wherein the third conductive portion directly interfaces with the first conductive portion and the fourth conductive portion directly interfaces with the second conductive portion, wherein the third dielectric portion directly interfaces with first dielectric portion and the fourth dielectric portion directly interfaces with the second dielectric portion.