Measurement of local contact zone forces in rotational grinding of silicon wafers

Abstract

For a first-time assessment of the local process forces in rotational grinding, a three-component piezo senor is integrated under a segment of a resin-bond D3 cup grinding wheel. The signals are amplified in the rotating system and telemetrically transferred to an external receiver. Industrially, common spindle speeds of up to 5,000 min –1 were achieved by conclusive optimisation of the tool’s static-dynamic behaviour. The system can detect even minute force variations in dependence on the process parameters and the relative position of the cutting speed to the crystal main axes. 200 mm (100)-oriented Si wafers are used due to its importance for IC fabrication. The normal and tangential forces increase with an increase in feed rate and radius and decrease with cutting speed. A direction dependence of the process forces can be determined, with force maxima and minima occurring for cutting directions parallel to and , respectively. Areas with high and low process forces coincide well with the areas of high and low subsurface damage (SSD) depths, respectively.