Contactless 3D contour reconstruction method based on spectral confocal sensors

Laser processing of micro-via arrays is a critical technology in the electronic packaging industry, essential for the rapid, non-destructive inspection of the geometric shape and depth of blind vias. As chip packaging processes trend towards higher density and miniaturization, the demands on blind via array detection technology are increasing. This paper proposes a fast blind via array inspection method based on dispersive spectroscopy confocal technology. By mounting the probe on a three-axis kinematic stage, auto-focusing is achieved, enabling rapid scanning imaging over a 10 mm × 10 mm area to acquire 3D point cloud data. We have developed an effective algorithm to filter noise from the 3D point cloud data and align the line scan data, reconstructing accurate geometric profile information of the blind vias with sub-micron inspection accuracy. Tested on copper-clad board blind via arrays, this method quickly and accurately detects the geometric parameters of blind vias, providing a powerful tool for real-time monitoring of blind via processing quality and a novel solution for quality control in electronic packaging, including BGA packaging. The method offers advantages such as fast measurement speed, wide measurement range, and non-destructive, non-contact operation, with broad application prospects in the electronics manufacturing industry. Compared to existing technologies, our proposed measurement method is faster, offers higher resolution, and covers a wider measurement range, meeting the increasing requirements for blind via detection in future chip packaging processes. Furthermore, this technology can be extended to size and morphology inspection in other micro-nano processing fields, offering significant theoretical and practical value.