Patent ID: 6992773
Filing Date: 2006-01-31
Classification: G01N

Abstract:
1. For a semiconductor device that includes a semiconductor die having a circuit side and bulk silicon in a back side opposite the circuit side, a method for detecting a defect at a surface in the die, comprising: locating a first beam splitter for optical manipulation relative to the back side of the semiconductor die; directing light of a known wavelength at the beam splitter, wherein the first beam splitter is adapted to direct a first beam of light into the back side of the semiconductor die which reflects a second beam of light back to the first beam splitter; redirecting the second beam to a second beam splitter, the second beam splitter generating third and fourth beams of light; analyzing the third and fourth beams of light, including comparing a relational factor that is a function of the two beams of light and is a function of a time differential, or intensity, between the third and fourth beams of light with a reference and detecting therefrom a surface defect in the die; and using the first and second beam splitters to generate different third and fourth beams from a nondefective semiconductor and analyzing the different third and fourth beams of light to develop the reference.