© Fraunhofer ISIT / photocompany, Itzehoe
Glass wafers are often used to determine placement accuracy by visual inspection. Typical use cases are calibration marks for camera systems, and placement accuracy verification of die placing equipment.
In addition to custom specific designs, Fraunhofer ISIT offers two standard layouts, each consisting of a chip and a substrate wafer.
Besides miscellaneous alignment marks for camera systems each design features several grid structures, which form a Vernier scale when chip and substrate are combined. This way lateral displacement and rotational error can be measured easily by visual inspection without need of image recognition software or other optical measurement systems.
Fraunhofer Institute for Silicon Technology