Wafer level proximity sensor

A method, comprising:

• forming a plurality of light sensors on an upper surface of a silicon substrate;
• forming a plurality of contact pads on the upper surface of the silicon substrate;
• forming openings in a lower surface of a silicon cap wafer;
• aligning the openings to the light sensors and the contact pads;
• bonding the silicon cap wafer to the silicon substrate;
• removing material from an upper surface of the silicon cap wafer to expose the light sensors and the contact pads;
• attaching a plurality of light emitters to respective ones of the contact pads;
• thinning the silicon substrate;
• filling the openings with a transparent material;
• forming through-silicon vias extending from the upper surface of the silicon substrate to a lower surface of the silicon substrate;
• forming a ball grid array on the lower surface of the silicon substrate, the ball grid array including a plurality of solder balls electrically connected with respective ones of the through-silicon vias;
• and
• singulating the bonded silicon wafers into individual sensor modules.