Kla Tencor Corporation

Samuel Ngai

Ady Levy

Mehdi Vaez-Iravani

Guoheng Zhao

Geordie Zapalac

Vineet Dharmadhikari

Methods and systems for determining the quality of a substrate are disclosed. One or more substrates may be examined to determine whether bending is present at the edge of a substrate. The substrate may be accepted if it is determined that bending is not present at the edge of the substrate. The substrate may be rejected if it is determined that bending is present at the edge of the substrate.

Priori crack detection in solar photovoltaic wafers by detecting bending at edges of wafers

To increase inspection throughput, the field of view (FOV) of an IR camera can be moved over the sample at a constant velocity. Throughout this moving, a modulation (e.g. optical or electrical) can be provided to the sample and IR images can be captured using the IR camera. Moving the FOV, providing the modulation, and capturing the IR images can be synchronized. The IR images can be filtered to generate the time delay LIT, thereby providing defect identification. In one embodiment, this filtering accounts for the number of pixels of the IR camera in a scanning direction. For the case of optical modulation, a dark field region can be provided for the FOV throughout the moving, thereby providing an improved signal-to-noise ratio (SNR) during filtering.

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San Francisco, CA, United States of America

Samuel Ngai