Area Acquisition Hardware for Pad Inspection on Wafers
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Some type of simple image processing can be an extraordinarily valuable aid for optical control in integrated circuit manufacturing. Because of its negligible load, non-destructive operation, repetitive reliable and speedy process, it can replace, with distinct advantages, human control of the tasks. Here, the objective is to apply image processing for solder pad inspection on wafers. The volume of these pads must be in a range given by the specifications of fabrication, in order to ensure good soldering between the chip and the substrate, i.e., good contact without making shorts between circuits. Previously published works have shown that there is a mathematical relation between the pad volume and its shadow when lighted with an oblique angle; the pad inspection can be done by inspecting pad shadow.