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Sensor Solution For Wafer Back Grinding Process Control

Wafer thinning is always a critical process. The chips are already present on the wafer and any failure in the process affects the production yield and costs. Tight in-line control on the thinning in-process operation is possible using contact gauges or non-contact sensors, even in the presence of DI water. Marposs sensors helps in obtaining a repetitive final thickness of the wafer.

The thinning operation is usually performed in two steps: rough grinding and finish grinding. The first one is used to remove most of the silicon amount during the finish operation just a small amount is removed until the desired final thickness, normally less than 100µm, is achieved. Marposs contact gauge control the rough thinning phase and because of its robust design, can survive in DI water without adding unwanted contaminants that could be dangerous to the wafer.

The same is for the Marposs series of non-contact gauges that are particularly useful in the finish phase where particular care has to be taken in order not to damage the wafer. Contactless measurement is not easy inside the dirty and wet environment of a back grinding machine, however, due to Marposs gauge, this is possible, almost independently of the wafer roughness and type of material to be thinned.

Along with ensuring that productivity levels are met, it is crucial to maintain the production equipment in service through ‘preventive’ alarms Using Marposs Machine Monitoring products. It is possible to monitor wheel dressing and other vibrations in the machine to insure the machine is operating properly.

The early detection of mechanical problems is essential in keeping machine and spindle vibrations under control, reducing consequential costs, improving quality and efficiency. This can be achieved through the precise evaluation of sensor signals (vibration, temperature, and optional gravity). Alarm limits can be set individually and if exceed or drop below these limits, a defined reaction can be taken promptly.

Marposs offers a complete product portfolio that helps keep under control machines working semiconductor materials.

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