PCB Optical Isolation By Nonuniform Catch Pad Stack

An apparatus comprising:

• a printed circuit board (PCB) including a first side and a second side;
• a light sensor connected to the second side of the PCB and configured to sense light incident on the light sensor from the second side of the PCB;
• a via extending through at least one layer of the PCB;
• a first catch pad connected to the via and located within a first metal layer of the PCB, wherein the first catch pad has a first size;
• and
• a second catch pad connected to the via and located within a second metal layer of the PCB, wherein the second catch pad has a second size greater than the first size, and wherein the second catch pad overlaps horizontally with a portion of a metallic feature in the first metal layer;
• and
• an enclosure disposed about the light sensor and configured to direct light from a portion of an environment onto the light sensor through an aperture.

An apparatus comprising:

• an integrated circuit (IC) device having a first side and a second side;
• a light sensor disposed on the second side of the IC device and configured to sense light incident on the light sensor from the second side of the IC device;
• a via extending through at least one layer of the IC device;
• a first catch pad connected to the via and located within a first metal layer of the IC device, wherein the first catch pad has a first size;
• and
• a second catch pad connected to the via and located within a second metal layer of the IC device, wherein the second catch pad has a second size greater than the first size, and wherein the second catch pad overlaps horizontally with a portion of a metallic feature in the first metal layer;
• and
• an enclosure disposed about the light sensor and configured to direct light from a portion of an environment onto the light sensor through an aperture.