A copper-embedded multilayer board defect detection method and system based on eddy current thermography and impedance spectrum fusion

By combining eddy current thermal imaging with impedance spectroscopy, the problem of detecting latent defects such as microcracks and delamination in copper-embedded multilayer boards has been solved, achieving non-destructive full inspection and high-sensitivity detection, thus improving the accuracy and efficiency of detection.

CN122109203BActive Publication Date: 2026-07-24SUINING BAIFANG ELECTRONICS CO LTD
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Patent Information

Application Number
CN202610595336.X
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2026-04-30
Publication Date
2026-07-24
Estimated Expiration
2046-04-30

AI Technical Summary

Technical Problem

Existing technologies are insufficient to effectively detect latent defects such as microcracks, delamination, or poor connections that occur during the lamination, welding, or thermal cycling processes of copper-embedded multilayer boards. In particular, they cannot achieve non-destructive full inspection and high-sensitivity detection.

Method used

A method combining eddy current thermal imaging and impedance spectroscopy is adopted. A high-frequency alternating pulsed magnetic field is applied by an array of excitation coils, and thermal field images are acquired simultaneously using an infrared thermal imager. Combined with multi-frequency impedance spectroscopy analysis, a multi-dimensional feature fusion judgment model is constructed to determine defects.

Benefits of technology

It achieves non-destructive full inspection, increases the microcrack detection rate to 97%, and accurately detects copper embedding offset and interlayer short circuit defects with 100% accuracy, thereby improving the sensitivity and accuracy of detection.

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Abstract

The application discloses a copper-embedded multilayer board defect detection method and system based on eddy current thermal imaging and impedance spectrum fusion, relates to the technical field of multilayer board defect detection, and comprises the following steps: applying a high-frequency alternating pulse magnetic field to a copper-embedded multilayer board to be detected; continuously collecting thermal field cooling sequence images after pulse excitation, then extracting thermal diffusion coefficients of copper-embedded regions a and thermal field isotheral line distribution characteristics; using test probes of an automatic machine to contact copper-embedded blocks and corresponding network test points on the copper-embedded multilayer board to be detected, injecting a wideband sweep signal, obtaining impedance spectrum and extracting characteristic parameters; and a , thermal field isotheral line asymmetry, Z LF , R HF and Δ θ are constructed into a multi-dimensional feature vector, input into a fusion judgment model, and a judgment result of the copper-embedded multilayer board defect is output according to a preset multiple threshold. The application realizes non-destructive defect detection, and the micro-crack detection rate is about 97%, and the copper-embedded offset and interlayer short-circuit detection rate is 100%.
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