I found this, which could help someone like me in the future :
A wafermap (generated after test the wafer) categorizes the passing and non-passing dies by making use of bins. A bin is then defined as a good or bad die. This wafermap is then sent to the die attachment process which then only picks up the passing circuits by selecting the bin number of good dies. The process where no ink dot is used to mark the bad dies is named substrate mapping. When ink dots are used, vision systems on subsequent die handling equipment can disqualify the die by recognizing the ink dot.
https://en.wikipedia.org/wiki/Wafer_testing
