Dark field detection device

Abstract

The invention provides a dark field detection device, which includes an illumination module, an optical path shaping module, an objective lens and an imaging sensor, and the optical path shaping module includes a plurality of overlapping linear illumination spots on a wafer. Branch light paths; each of the branch light paths is used to illuminate the wafer at a certain incident angle, and the plurality of branch light paths form a ring-shaped illumination; each of the branch light paths includes a uniform light structure and a critical illumination structure, and the The light provided by the light source is sequentially irradiated onto the wafer through the uniform light structure and the critical illumination structure. The invention can effectively improve the uniformity of illumination, and at the same time, it can also increase the illumination power density and suppress stray light, which is beneficial to the improvement of line scan productivity, avoids the granular distribution of illumination spots, and is more conducive to defects ( detection of particles, marked edges).

Description

technical field [0001] The invention relates to the technical field of semiconductor equipment, in particular to a dark field detection device. Background technique [0002] Dark field illumination technology is widely used in the field of instrument vision, such as the field of surface defect detection. Dark field illumination means that the illumination light is projected onto the surface of the sample at a very large incident angle. The reflected light is reflected at a very large reflection angle and cannot enter the objective lens for imaging; if there are defect features on the surface of the sample, part of the light diffusely reflected from the defect features can enter the objective lens for imaging, and these defect features appear as bright image contrasts In the dark field of view, it can finally be rendered in the CCD. The annular dark field detection device provides uniform illumination light for detecting defects such as depressions, protrusions, and scratche...

AI Technical Summary

Problems solved by technology

Because the annular dark field detection device in the prior art does not have a uniform light device, the energy difference of each optical fiber entering the annular dark field detection device is relatively large, which reduces the uniformity of the outgoing light of the annular dark field detection device, thus affecting the defect detection. quality

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