This fully functional 3D-IC was manufactured as part of Tezzaron’s “Orion” project in 2004. It is a prototype image sensor built in two layers that were manufactured on two separate wafers.
The first layer contains the sensor arrays, which are illuminated from the back. There are six different arrays, each with a different type of sensor cell. The two largest arrays each have over 9000 cells; these arrays are visible as the blue and yellow rectangles in this picture. The other four arrays are very small, and not easily distinguished here.