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Wafer Warpage Radius of Curvature R Highly Accurate and Fast Measurement Solution

2023-07-19

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In the chip manufacturing process, when the coefficient of thermal expansion of the film is different from that of the wafer substrate, stress will be generated, resulting in wafer warpage, which can be calculated by measuring the radius of curvature R of the wafer warpage to see if the stress is too great and to determine whether it affects the quality of the chip.

When a single field of view measurement does not cover the entire wafer, high precision splicing with an Atometrics AM-7000 series white light interferometer can be used to solve this problem.

Dr. Yoshi is sharing with you today a practical example of white light interferometer measurement of radius of curvature of a wafer.


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Figure 1 - 3D shape of wafer (stitching range: 18mmx13mm)


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Figure 2 - Measurement of the radius of curvature R of a cross section of a wafer


Nanoscale seamless splicing
More than 3 times more efficient than traditional white light interferometers
Easy measurement of the curvature R-value at a glance.

Such excellent results are achieved thanks to the high precision and high speed moving platform equipped with the AM-7000 white light interferometer.




I. High precision

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Figure 3-High-precision motorized stage



The splicing accuracy of the mobile platform directly affects the splicing effect and the authenticity of the three-dimensional topography. Insufficient precision of the platform will result in picture faults, 

overlapping, and discontinuous transition, leading to unreliable data of measurement results.

Different from ordinary moving platforms, AM-7000 white light interferometer adopts a high-precision motorized platform with a resolution of 0.01μm and an accuracy of 1μm+0.01L, which can realize seamless and high-precision splicing.





II. High speed

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Figure 4 - Splice Settings Screen


① Splice speed up to 60mm/s;

② Splice path optimization, automatically select the shortest moving path;

③ The XY axis can be customized to the range that needs to be spliced without invalid splicing;

④ The Z-axis can set the scanning height of each field of view individually, and the splicing speed is improved again.





III. Customization



In addition, Atometrics white light interferometers offer customized services such as wafer adsorption tables, PCB ceramic adsorption plates, and more.





Want to continue to learn more about white light interferometer measurement cases.

Stay tuned to Dr. Younger, and let's continue to share it with you in the next issue!


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