ICD (Internal Connection Defect) detection method for PCB

Abstract

The invention discloses an ICD detection method for a PCB. The method comprises the flowing steps that a vertical slice of a PCB sample is made, and a metallographic microscope is used to observe whether there is a crack between an electro-coppering layer and an internal copper ring in the vertical slice; if there is, an outside force is used to separate the whole electro-coppering layer from the internal copper ring, an unthreaded hole is formed in the PCB; if there is not, it is shown that no residual glue exists between the electro-coppering layer and the internal copper ring, and no detection is needed any longer; and a scanning electron microscope is used to detect the internal copper ring to observe whether residual glue exists on the internal copper ring. Vertical slicing and copper wire pulling are carried out on the circuit board sample, the electro-coppering layer is directly separated from the internal copper ring, and the scanning electron microscope is used to directly observe whether residual glue exists on the electro-coppering layer; and thus, the detection method can be used to detect whether cracks and residual glue exist between the electro-coppering layer and the internal copper ring is a more direct, effectively and accurate manner, and the ICD detection efficiency of the PCB is greatly improved.

Description

technical field [0001] The invention relates to a method for detecting interconnection defects in PCB inner layers. Background technique [0002] The metal through hole plays the role of connecting the lines of each layer in the PCB, and connects the inner layer lines with the hole copper. The production process of the metal through hole is: making the inner layer circuit → laminating → drilling → deburring → sinking copper → electroplating copper. During the drilling process, due to high heat and large stress, the copper ring of the inner layer circuit will be There is a large amount of glue (epoxy resin), and the glue removal step in the sinking copper removes the remaining glue on the copper ring. After the step, an electroplated copper layer with conduction effect is formed between the inner wall of the through hole and the copper ring, and there is residual glue between the electroplated copper layer and the inner copper ring. Poor, resulting in cracks in the hole wal...

AI Technical Summary

Problems solved by technology

[0003] The traditional analysis method for internal layer interconnection defects is: first make a vertical section to observe whether there are cracks between the electroplated copper layer and the copper ring of the memory, if there is, then make a horizontal section, and then use a microscope to observe whether there is any residual glue between the electroplated copper layer and the copper ring , but this method has high requirements on the analyst's slice level, and it is difficult to make horizontal slices, and the image of cracks obtained by this method is black under the microscope, and it is still difficult to judge the difference between the electroplated copper layer and the inner copper ring. Whether there is residual glue in the space and the approximate amount of residual glue. In the process of using horizontal slice detection, the through hole needs to be ground, and the detection result is also easily affected by the grinding debris.

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