Fraunhofer IPMS, Dresden carries out customer specific developments in the field of micro systems technology and organic light emitting diodes serving as a business partner, that supports the transition of innovative ideas into new products. In addition to R&D services the Fraunhofer IPMS offers ramp-up within a pilot production.

With modern equipment and about 200 scientists and engineers, the range of projects and expertise covers sensor and actuator systems, microscanners, spatial light modulators, wireless microsystems as well as organic materials and systems.

At VISION 2011 Fraunhofer IPMS presents for the first time ever

Automatic Optical Inspection (AOI) of Microsystem Dies

The Fraunhofer Institute for Photonic Microsystems IPMS exploits digital image processing for optically inspecting the quality of micro systems that are fabricated for key accounts. The microsystems are made with silicon wafer processing technologies similar to semiconductor production in a cleanroom, where however, particles cannot be completely eliminated and changes of process parameters impair the yield of well prepared »pass« chips.

Since the microsystem chips of Fraunhofer IPMS act as optical elements or sensors, regions of their surface should be free from particles, scratches and inhomogeneities. This can be checked visually under a microscope, however, human control allows not enough throughput and is too dependent on subjective impacts. Therefore, the Fraunhofer IPMS has tooled up a prober for chip testing with a digital camera, and has developed specific image capturing, analysis and benchmarking algorithms that check the optical quality of each chip. Hence, combined to the results of electrical tests the quality of each microsystem chip is fully checked, which gives feedback for technology optimization and is usable as proof of quality to the customers.

The complete test equipment consists of a prober of Cascade Microtech Inc., a high resolution digital camera of BASLER Vision Technologies, and a standard computer with a MATROX framegrabber. The optical test software called VITool (Visual Inspection Tool) has been developed at Fraunhofer IPMS and can be flexibly configured for processing a variety of microsystem chips and can be adapted easily for customers requests.

All works and investments have been financed by means of the Fraunhofer-Gesellschaft. The Fraunhofer IPMS offers its competence for projecting, programming and starting-up suchlike equipments as a service to other companies.

At the VISION 2011 show, the action of the prober is shown as video clip since the prober cannot be moved out of the cleanroom. The simulation of the optical inspections process by VITool software can be watched directly at the booth.