Dry micro-grooving on Si wafer using a coarse diamond grinding

Abstract

A novel micro-grooving approach of Si wafer is proposed using a coarse diamond grinding without any coolant. In the dry micro-grooving with micro grain cutting edges, the coarse diamond grains on wheel working surface may easily exclude cutting chips and heat with their high protrusion space and outstanding thermal conductivity. The objective is to explore the dry micro-grooving with a mechanical approach instead of general chemical etchings. First, a dressed #60 diamond grinding wheel was used in grinding for the dry micro-grooving on Si wafer surface with coarse diamond grain edges; then the transition from brittle-mode grooving to ductile-mode grooving was observed; finally, groove angle, groove tip radius and groove aspect ratio were investigated with reference to grain protrusion parameters and micro-grooving conditions. It is shown that the dry micro-grooving depends on the ductile-mode grain cutting depth less than 73nm, the high grain protrusion height up to 86μm and the large negative grain rake angle up to 82°. The dressing may reduce top grain angle, but it increases top grain tip radius. In the case of high wheel speed of 33.3m/s, the groove tip radius approaches grain tip radius, and the change of groove aspect ratio with grooving depth is identical to the theoretical result. This is because high wheel speed may lower grain cutting depth to critical ductile depth. High wheel speed and low feed speed are required for a deep micro-grooving in ductile-mode. It is confirmed that the dry micro-grooving on Si wafer may be performed through a coarse diamond grinding by controlling grain protrusion parameters and micro-grooving parameters.