Precise measurement of surface topography with microstructures based on differential confocal and spiral scanning. (November 2021)

• Record Type: Journal Article
• Authors: Ying, Ronghui; Cui, Yuguo; Huang, Jun; Liang, Dan; Wang, Yiqiang
• Is Part Of: Measurement. Volume 184(2021)
• Publication Date: 2021-11
• Subjects: Topography measurement -- Differential confocal -- Spiral scanning -- Wavelet denoising; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2021.110004
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: A new method for topography measurement of microstructure surfaces. The relationship between alignment deviation and image distortion is described. Spiral-scanning sampling strategy can eliminate the image sawtooth distortion. A wavelet denoising algorithm is proposed to eliminate the noise disturbance. Abstract: This paper proposes a new topography measurement method combining laser differential confocal and spiral-scanning measurements together (TM-DCSS), which can realize large-area, fast and high-accuracy measurement of microstructure topography. Firstly, the mapping relationship between probe centering deviation and reconstructed topography distortion is analyzed, and a wedge rotation alignment method is proposed to make the probe precisely aligned with the rotating stage. Secondly, a sampling strategy of spiral trajectory is designed to eliminate the sawtooth distortion. Thirdly, a threshold-tunable wavelet denoising algorithm based on translation-invariant and particle swarm optimization is proposed in order to effectively eliminate the noise disturbance. Finally, an experimental platform based on TM-DCSS principle is constructed. The measurement results show that the centralization deviation of the proposed system is within 1.94 μm, and the maximum relative error is less than 0.78% when compared with the commercial microscope. The proposed method shows great potentials in various non-contact precision measurement applications.