Silicon wafer surface topography reconstruction method based on B-spline

Abstract

The invention provides a silicon wafer surface topography reconstruction method based on B-spline. The silicon wafer surface topography reconstruction method based on the B-spline comprises firstly fitting an input triangular mesh boundary, and then giving a boundary curve to perform surface fitting of an interpolation, and generating a first level B-spline surface; secondly, performing local adaptive refinement fitting on an error transfinite portion in an upper level B-spline surface and repeatedly performing local refinement fitting in this way until a given error is met; and finally, adding the multilevel B-spline surface with the offset to a base plane to obtain a fitting result. The silicon wafer surface topography reconstruction method based on the B-spline can simultaneously meet overall fitting and local adaptation of surface reconstruction, and effectively avoids data redundancy; and is strong in robustness and has significant effects for solving non-linear problems and restraining fuzzy noises; and the reconstructed surface is smooth and burr-free, so that the method can better meet response frequency requirements of actual motion of a motor.

Description

technical field [0001] The invention relates to a silicon chip surface topography reconstruction method, in particular to a silicon chip surface topography reconstruction method based on B-splines, which is applied to a focus detection system in a projection lithography system and belongs to the field of VLSI manufacturing and optics. The field of nano-device manufacturing and detection technology in microfabrication technology. Background technique [0002] The sharp improvement in the performance of lithography machines requires the use of larger numerical apertures and shorter wavelengths, resulting in a reduction in the depth of focus. The depth of focus of the widely used immersion lithography machine can only be maintained at the order of hundreds of nanometers, which has greatly exceeded the changes caused by vacuum adsorption warpage and substrate flatness, so it is required to improve the focus detection accuracy, and the silicon wafer Topography reconstruction is ...

AI Technical Summary

Problems solved by technology

[0007] The technical problem of the present invention is to overcome the shortcomings of low precision and low responsiveness in the prior art, and provide a method for reconstructing the surface topography of silicon wafers based on B-splines. The method ① has a high degree of fitting to the original appearance of silicon wafers and has Self-adaptive, satisfying overall fitting and local self-adaptiveness at the same time; ②The reconstructed surface is smoother than the original appearance, and more in line with the actual motion requirements of the motor; ③Multi-level surface fitting can greatly improve the calculation speed and accuracy; ④While satisfying high-definition, the distribution of control points based on B-spline is optimal, effectively avoiding data redundancy; ⑤Strong robustness, effectively dealing with complex nonlinear optimization problems

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