Computerized Detection/Location of Cracks in Coatings
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Silicon dioxide cracks can be located on a wafer by arranging an array of probing pads that are connected to a computer. Accordingly, the computer will say "yes" or "no" depending on whether there is a crack in the silicon dioxide layer. The pads can be made of conductive rubber, which molds or conforms through the cracks under mechanical pressure and makes contact with the aluminum underlayer, or the pads can be made of felt which was soaked in an electrolyte solution (see the preceding article). Alternatively, the probing pad can be put on a programmable x-y stepping stage with the footprint composed of the felt tip pad having the exact size of the semiconductor chip. As the sensing device is stepped across the wafer, it will locate chips that have SiO2 cracks by detecting current.