A method for fast three-dimensional topography reduction of thin-film laser etched surface

With the improvement of the precision and yield of laser etched film, the key to evaluating the processing technology and judge the processing quality is how to restore the three-dimensional information of the etched film surface. However, due to the small thickness, low reflectivity, and small etching linewidth of the film, it is difficult to clearly present the three-dimensional surface morphology of the machined surface by traditional machine vision. In this paper, a method of three-dimensional surface topography reduction of PET film by combining parallel object differential confocal technology and image processing is proposed. Firstly, the differential signal curve representing the relationship between the defocusing amount u and the light intensity difference ID is calibrated, and the confocal images of the etched sample before and after focusing are obtained. The three-dimensional shape information of the sample surface at the submicron level is restored by using the functional relationship between the gray level difference and the height of the confocal image. Finally, the bubbles and bubbles on the PET film are eliminated by image processing techniques such as two-dimensional adaptive filtering Impurities and other components that affect the reduction results, the three-dimensional reduction experiment of transverse 1 um and axial 0.1 um etched morphology is completed. The method only takes 65 ms to complete a three-dimensional morphology reduction and measurement, which has the characteristics of simple operation, high resolution, and fast measurement speed. This work provides quality evaluation reference and mechanism support for high-quality thin film laser etching.