A method and apparatus of inspecting a surface of a specimen for the presence of defects, foreign substance and the like are disclosed. The surface has a mark such as a cutting mark formed thereon and composed of fine grooves or recesses extending in a predetermined direction. The surface is scanned...http://www.google.com/patents/US4423331?utm_source=gb-gplus-sharePatent US4423331 - Method and apparatus for inspecting specimen surface
