The quality of PCB, the occurrence and solution of problems, and the evaluation of process improvement require slicing as the basis for objective inspection, research and judgment. The quality of slices has a great influence on the judgment of results.
Classification and Function of PCB Slices
Classification of PCB slices: General slices can be divided into longitudinal slices and horizontal slices.
1. Vertical slices are cut along the direction perpendicular to the plate surface to observe the profile condition. They are usually used to observe the quality of the hole after copper plating, the laminated structure and the condition of the internal joint surface. Vertical slice is the most commonly used method in slice analysis.
2. Horizontal slices are grinded down layer by layer along the overlapping direction of the plate to observe the condition of each layer. They are usually used to assist vertical slices in the analysis and determination of quality abnormalities, such as short or open abnormalities.
Slice making generally includes a series of means and steps such as sampling, mosaic, slicing, polishing, corrosion, observation and so on to obtain a smooth cross-section structure of pcb. Then the micro-details of the slices are analyzed by means of metallographic microscope and scanning electron microscope. Only when the slices are correctly interpreted, the correct analysis can be made and effective measures can be given. Therefore, the quality of slices is particularly important. The poor quality of slices will lead to serious misleading and misjudgement in failure analysis. Metallographic microscope is the most important analysis equipment. Its magnification varies from 50 to 1000 times, and the measurement accuracy deviation is less than 1 micron.
After the slice is made, the analysis and interpretation of the slice will follow. In order to find out the causes of adverse events, and make corresponding improvement measures, in order to improve the yield and reduce losses.