Wafer level proximity sensor and method of making same

A method, comprising:

• at each integrated circuit area of a plurality of integrated circuit areas for a silicon integrated circuit substrate wafer, forming at least one photosensitive region and at least one front connection pad;
• covering each photosensitive region with a protective layer before wafer-to-wafer bonding;
• forming a plurality of first trenches and a plurality of second trenches in a silicon cap wafer;
• providing an opaque light barrier at the silicon cap wafer to block light transmission through the silicon cap wafer between the first and second trenches;
• wafer-to-wafer bonding of the silicon cap wafer to the silicon integrated circuit substrate wafer to form a bonded wafer sandwich, where an opening of each first trench in the silicon cap wafer faces a corresponding photosensitive region of the silicon integrated circuit substrate wafer and wherein an opening of each second trench in the silicon cap wafer faces a corresponding front connection pad of the silicon integrated circuit substrate wafer;
• then, performing a back grind to thin the silicon integrated circuit substrate wafer of the bonded wafer sandwich;
• then, performing a back grind to thin the silicon integrated circuit substrate wafer of the bonded wafer sandwich;
• forming through silicon vias in the thinned silicon integrated circuit substrate wafer, wherein at least some of the through silicon vias are electrically connected to said at least one photosensitive region in each of the plurality of integrated circuit areas;
• then, performing a back grind to thin the silicon cap wafer and expose the openings of the first and second trenches;
• removing the protective layer after performing the back grind to thin the silicon cap wafer;
• installing a light emitter integrated circuit die in the opening for each second trench, the light emitter integrated circuit die mounted to the thinned silicon integrated circuit substrate wafer and electrically connected to said at least one front connection pad;
• filling the openings of the first and second trenches with a transparent material;
• and
• cutting through the bonded wafer sandwich between adjacent integrated circuit areas in a singulation operation to produce a plurality of individual wafer level micro-sensor modules.

A method, comprising:

• at each integrated circuit area of a plurality of integrated circuit areas for a silicon integrated circuit substrate wafer, forming at least one photosensitive region and at least one front connection pad;
• forming a plurality of first trenches and a plurality of second trenches in a silicon cap wafer;
• providing an opaque light barrier at the silicon cap wafer to block light transmission through the silicon cap wafer between the first and second trenches;
• wafer-to-wafer bonding of the silicon cap wafer to the silicon integrated circuit substrate wafer to form a bonded wafer sandwich, where an opening of each first trench in the silicon cap wafer faces a corresponding photosensitive region of the silicon integrated circuit substrate wafer and wherein an opening of each second trench in the silicon cap wafer faces a corresponding front connection pad of the silicon integrated circuit substrate wafer;
• then, performing a back grind to thin the silicon integrated circuit substrate wafer of the bonded wafer sandwich;
• forming through silicon vias in the thinned silicon integrated circuit substrate wafer, wherein at least some of the through silicon vias are electrically connected to said at least one photosensitive region in each of the plurality of integrated circuit areas;
• then, performing a back grind to thin the silicon cap wafer and expose the openings of the first and second trenches;
• installing a light emitter integrated circuit die in the opening for each second trench, the light emitter integrated circuit die mounted to the thinned silicon integrated circuit substrate wafer and electrically connected to said at least one front connection pad;
• filling the openings of the first and second trenches with a transparent material;
• after filling the openings of the first and second trenches with the transparent material, covering an upper surface of the thinned silicon cap wafer with a patterned layer of opaque material that includes apertures over each of the transparent material filled openings of the first and second trenches;
• and
• cutting through the bonded wafer sandwich between adjacent integrated circuit areas in a singulation operation to produce a plurality of individual wafer level micro-sensor modules.