Fine grinding of silicon wafers: machine configurations for spindle angle adjustments

This paper addresses an important aspect of silicon wafer fine grinding: machine design. For any commercially available wafer grinders, spindle angle adjustments based on the wafer shape ground is almost inevitable in order to achieve flat wafers. However, there has been no commonly accepted guidance for the design of machine configurations to ensure the easiest adjustment. Practitioners doing spindle angle adjustments have been frustrated by the difficulties of achieving the adjustments on commercial wafer grinders. This paper first illustrates such difficulties with a machine configuration frequently cited in the literature. It then demonstrates the potential ease of spindle angle adjustments with a proposed machine configuration. Next, it shows mathematically that the proposed configuration (specifically, a pair of the axes for spindle angle adjustments) is uniquely determined once the wheel diameter and wafer diameter are known. It also shows that the proposed configuration is the best in terms of ease in spindle angle adjustments. The spindle angle adjustments will be more difficult with any other configurations deviating from the proposed one.