High sensitivity optical detection of oriented microdefects on silicon wafer surfaces using annular Illumination

摘要

A new optical measurement method detecting the microdefects on silicon wafer surfaces, which can be applied to in-process measurement, is presented in this paper. In our proposed method, a unique annular incident light spot is imaged by an original dark field optical system with a high-power objective lens. This annular incident light spot enables the sensitive detection of the oriented microdefects such as microscratches on the silicon wafer surface independent of its direction. In order to verify the feasibility of our proposed method, the basic and scanning experiments were performed for microgroove with sub-micrometer scale. This results showed that the proposed measurement method is effective for detecting the oriented microdefects.