Abstract
This paper presents a novel particle detection method for evaluating a defect on patterned wafer surface by detecting “Scattered Evanescent Light Fringe Pattern (SELFP)”. In order to apply this optical measurement method to in-process measurement at high speed, scanning measurement is proposed. The scanning measurement process is performed by identifying defect position and evaluating SELFPs.
The scanning basic experiments are performed using a tip of AFM probe with the size of 110nm. It is found that P-polarized evanescent light is better applied to illumination light than S-polarized evanescent light and that the defect position can be identified according to the peak value of intensity variation at scanning area. The measurement of defect with a size of 170nm on the patterned wafer surface comprising about 180nm Half Pitch is conducted, under the condition that illumination light has P-polarized evanescent light. The results suggest that the proposed scanning method can be effective for in-process measurement.
