Focal plane measuring device and defect detection equipment

Abstract

The invention provides a focal plane measuring device and defect detection equipment. The focal plane measuring device comprises a focus measuring light source, a focus measuring marking plate, an optical assembly, an imaging unit, a focal plane compensation structure and a control unit; the focus measuring light source is used for providing a first illumination light beam which is obliquely incident, the focus measuring marking plate comprises at least one group of focus measurement patterns, each group of focus measurement patterns comprises at least three sub-marks, and after the first illumination light beam is projected to the focus measuring marking plate, the focus measurement patterns are projected to the surface of a test sample piece and generate a reflection light beam; the focal plane compensation structure is located on one side of the imaging plane of the imaging unit and used for changing the transmission path of the reflected light beam, so that the imaging plane of the reflected light beam converged by the optical assembly is located on the receiving plane of the imaging unit to form at least one group of signal images, and each group of signal images comprises at least three sub-patterns; and the control unit acquires the vertical height of the test sample piece according to the position of the at least one sub-pattern. According to the invention, coaxial measurement of the focus measurement point and the defect detection point is realized, and the precision of focal plane measurement is improved.

Description

technical field [0001] The invention relates to detection technology, in particular to a focal plane measurement device and defect detection equipment. Background technique [0002] With the deepening and popularization of industrial automation and intelligence, the use of automatic optical inspection equipment (Auto Optical Inspection, AOI) to replace traditional manual visual inspection has become a technological development trend. AOI equipment is widely used in automobiles, medicine, transportation, semiconductors and other fields due to its fast and accurate defect identification and positioning capabilities. [0003] At present, existing AOI equipment usually includes an optical imaging system, an object stage, a material transfer system, and the like. The optical imaging system includes an illumination unit, an imaging objective lens, and a detector. The illumination unit is responsible for providing the required radiant light, the objective lens is used to collect ...

AI Technical Summary

Problems solved by technology

The off-axis focal plane test point 41 of the off-axis focal plane measurement device 40 is not in the same position as the focal plane 42 of the defect detection objective lens 20. When the test sample 50 is tilted, the off-axis focal plane test point 41 cannot truly represent the defect detection The focal plane 42 of the objective lens 20, resulting in defocusing during defect detection

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