Development of a Vertical-spindle Rotary Surface Grinding Machine for Large Scale Silicon-wafers - Machine Specifications and Performance of Rotary Work Table

摘要

The development of a next generation surface-grinding machine for 450mm diameter silicon-wafers is required from the semiconductor industry. Loop stiffness of the grinding machine has to be high enough to sustain high grinding force because of the large contact area between the grinding wheel and the wafer. To increase the loop stiffness of the machine, each machine component should have high stiffness; the number of the components should be as small as possible and, thus, the machine construction should be simple. The authors developed a new vertical-spindle surface grinding machine equipped with a rotary work table sustained by water hydrostatic bearings, a wheel spindle equipped with a wheel infeed system and a kinematic cupping system that firmly fixes the wheel spindle head against the base of the work table1'. This paper describes the specifications of the developed grinding machine and investigates the results of static stiffness and rotational accuracy of the work table. Measured static stiffness of the work table was 2.5kN/nm under water flow rate of Q=10mL/min and rotational accuracy was 0.25 μm under 120rpm.