Development of vertical-spindle rotary surface grinding machine for large-scale silicon-wafers - static stiffness of grinding spindle and worktable

摘要

The development of the next generation, large-scale silicon-wafer surface grinding machine for the semiconductor industry is necessary. High loop stiffness is indispensable for putting the grinding machines into practical use for large-scale silicon wafers. The authors developed a vertical spindle rotary surface grinding machine, as shown in Fig.1, and investigated its performance. Hydrostatic water bearings are used for the worktable and wheel spindle to enhance loop stiffness. Further more, the number of machine components and its guide-ways have been minimized as much as possible to eliminate losing loop stiffness. A grinding head is not used, so the wheel spindle shaft creates both rotary and axial infeed motion. In addition, the worktable and the wheel spindle components are rigidly connected using kinematic couplings. This results in the measured loop stiffness of the developed grinding machine being 163N/μm.