Surface inspection using the ratio of intensities of s- and p-polarized light components of a laser beam reflected a rough surface

摘要

A surface inspection device irradiates a laser beam onto the surface of a sample, scans the surface two-dimensionally, and detects the intensities of the s-polarized light component and p-polarized light component of the reflected laser beam. RR (reflectance ratio), which is the ratio of the reflective intensities of the s- and p-polarized light components, is calculated for each position of the surface of the sample, and the two-dimensional distribution of RR on the surface of the sample is detected. The distribution width of this measured RR is compared with the natural width for a clean sample, and the surface of the sample is determined to be contaminated when, as the result of comparison, the RR distribution width diverges from the natural width. The absence or presence of contamination on the microscopically rough surface of a sample can therefore be quickly and easily determined based on the RR of the reflective intensities of the s- and p-polarized light components.