irscope is a microscope with a computer-connected camera sensitive to both visible and infrared light. The microscope has visible light illumination for the top side of the sample, and infrared for the back. This can be used to look through silicon wafers.

2 Nov 2021, Daniel: I took the following pictures of an 550-2-40um SOI wafer with an inchworm motor etched into the 40um frontside after patterning ~300nm Cr/Au. The first picture shows the microscope looking through the wafer at the inchworm motor, the second picture is the original design (green is frontside silicon, yellow is the metal deposited on top of that frontside), and the third is the microscope looking at the closer side of the wafer (the wafer backside), which had a trench etched in it, under visible light. The height of the area in both pictures is about 650um.