Automated polarimeter–macroscope for optical mapping of birefringence, azimuths, and transmission in large area wafers. Part II. Measurement setup and results

Abstract

In the first part of this work (see preceding paper) the theory of the method lying upon a novel concept of birefringence, azimuths, and transmission mapping in large area (up to 6 in. diameter) wafers has been presented. The arrangement consisting of two HR-type linear polarizers rotated simultaneously by a stepper motor versus an immobile wafer and using a video frame grabber (VFG)/TV camera detecting system is capable of collecting data and plotting the three maps within a fraction of a minute. A detailed error analysis presented in the preceding paper has shown that in usual circumstances the VFG with 256 grey levels enables determination of birefringence with an error not greater than approximately 5×10−7, whereas errors of the azimuths and transmission are fractions of a degree and of a percent, respectively. In this part of the work the arrangement constructed is fully described and a set of polariscopic images and measured maps are presented for an exemplary 4 in. GaAs wafer.

Automated birefringence dispersion measurements

“…There is no room here to show results of other experiments carried out on these samples, also using classical polariscopes and polarimeters [6,18]. The authors, however, hereby declare that neither the plain nor circular polariscope picture, as well as the (stress-induced) birefringence map [18], resemble s any map associated with the birefringence dispersion parameters described in this paper. This, however, does not mean that these maps and pictures were not in (qualitative) agreement.…”