Patent ID: 7733499

Claim:
A method for optically testing and displaying internal stresses of semiconductor devices or wafers while being manufactured, the device or wafer under test being comprised a semiconductor conductor material having an interior surface and interior structures, comprising: using a holographic optical interference system with at least one light source providing at least one light beam of coherent wavelength with a wavelength to which the semiconductor material is at least semi-transparent or transparent, splitting the light beam into a pair of beams, comprising a reference beam and an object beam, imposing the object beam on the exterior surface of the semiconductor material to generate a reflected object beam reflected from the interior structures of the semiconductor material, to generate a reflected beam reflected from the interior structures of the semiconductor material, adjusting the angle of incidence of the reference beam relative to the object beam between a plurality of angles with the semiconductor material being in a different state for each angle of the reference beam, imposing the reflected object beam and the reference beam onto a one or more detection devices to create a plurality of interference patterns of the reflected object beam with the reflected reference beam, one interference pattern at each of the plurality of angles of the reference beam, wherein the detection device or devices physically records or digitally stores the plurality of interference patterns, and comparing the plurality of interference patterns to one another to determine and display stress and interior structure characteristics within the semiconductor material, device or wafer.