A standard metallographic microscope is designed to observe embedded and unembedded samples generally not larger than 50 x 50 mm.
An 8" wafer is a round sample with a size of 200mm. This would mean having the ability to move the microscope from its optical axis along the four directions of the microscope (forward, backward, right and left) by 100 mm.
With standard microscopes this is not possible. Specific models for the semiconductor industry are designed for such samples and can also observe 14x12" (350x300mm) samples.

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