Method and apparatus for interferometric measurement of a large warped wafer

By using a deformable mirror to modulate the reference wavefront to be close to the measured wavefront of the wafer under test in the detection of large warped wafers, and combining it with an aperture to filter the reflected light, the problems of excessively dense interference fringes and splicing errors were solved, and efficient and accurate wafer surface shape detection was achieved.

CN122305968BActive Publication Date: 2026-07-24SHANGHAI HUIZHUO OPTICAL TECHNOLOGY CO LTD +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SHANGHAI HUIZHUO OPTICAL TECHNOLOGY CO LTD
Filing Date
2026-05-27
Publication Date
2026-07-24

AI Technical Summary

Technical Problem

When inspecting wafers with large warpage, existing interferometry techniques suffer from significant wavefront differences between the planar reference wavefront and the non-planar measurement wavefront returned by the wafer under test. This results in excessively dense interference fringes and difficulty in phase resolution. Furthermore, existing splicing measurement methods suffer from low efficiency and error accumulation.

Method used

The reference wavefront is modulated to be similar to the wavefront of the wafer being measured by a deformable mirror, and the reflected light is selectively filtered by an aperture to obtain a resolvable interference fringe pattern. By utilizing the combination of polarization beam splitting, polarization state conversion, reflection branch and imaging branch, a one-time, high-stability measurement of the large warp wafer surface shape can be achieved.

Benefits of technology

It improves the efficiency, accuracy, and stability of large warp wafer surface shape detection, reduces the number of measurements and splicing errors, ensures the resolvability and stability of interference fringes, and enhances the integrity and accuracy of detection results.

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Abstract

The present application relates to a kind of big warping wafer interference measurement method and device, belong to optical detection and semiconductor measurement technical field.Detection light is converted and diffracted after birefringence, and P light and S light are formed, and P reference light, S silicon light, S reference light and P silicon light are formed respectively;By adjusting the spatial posture of reference mirror and the wafer to be measured, and cooperating with spatial screening of diaphragm, P reference light and S silicon light enter subsequent optical path, while S reference light and P silicon light are blocked;S silicon light forms the measurement wave front carrying the wafer to be measured surface shape information, P reference light is modulated as the modulation reference wave front similar to the measurement wave front by deformable mirror, and the two form analytical interference fringe pattern at camera;Wave front sensor measures deformable mirror surface shape information, and the computing system obtains the surface shape information of the wafer to be measured according to deformable mirror surface shape information and relative surface shape variation amount.The present application can reduce the interference fringe density in the detection of big warping wafer, reduce splicing measurement error, improve detection efficiency and accuracy.
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