Single crystalline sapphire wafers are used as a substrate for semiconductor and
optoelectronic applications like gallium nitride-based LED light sources. In the
optimization of the manufacturing chain, rotational grinding plays a mayor role by
substituting the conventional lapping process in order to reduce cost intensive efforts
in downstream polishing steps. Due the material properties of the sapphire and in
particular its hardness of 9 on the Mohs Scale however, it is difficult to establish a
stable finishing process. For this reason, the detection of in-process variables like the
grinding temperature distribution in the contact zone between the wafer and the
grinding wheel are of significant interest. On the one hand, the acquired data increase
process understanding, enhancing grinding wheel and process development. On the
other hand, real-time processing of the measurement data enables direct control of the
process in order to achieve optimum stability. Within this paper, a novel chuck
system for the measurement of contact zone temperatures is presented. The general
behaviour of the realized system is examined in preliminary calibration tests and
grinding tests are performed to prove the feasibility of the chuck system under
common machining conditions.
