A kind of electroless copper backlight test method

Abstract

The invention relates to a hole metallization of a printed circuit board, in particular to a test method for electroless copper backlighting, which uses a copper-clad epoxy resin glass cloth laminate to etch into a light board and then presses it into a 12-layer board with a thickness of 2.0mm. board; drill two backlight test holes with diameters of 0.3mm, 0.8mm, and 1.0mm respectively; process the backlight standard sheet into a standard backlight test sheet with a size of 100mm×100mm; after electroless copper deposition on the standard backlight test board , and then perform cold buried resin potting, cut and grind after 5 minutes, and finally judge the backlight level under a microscope. The damage caused by the sandpaper rotating at medium and high speeds to the hole wall greatly reduces the influencing factors in the backlight level determination process, reducing the unqualified backlight level from 8.9% to 0.40%, which improves the pass rate of backlight detection.

Description

technical field [0001] The invention relates to hole metallization of printed circuit boards, in particular to a method for testing chemical immersion copper backlight. Background technique [0002] The backlight test is used to test the coverage of chemical copper on the hole wall. It is a destructive test. It is necessary to cut the through hole from the section, pass a strong light through the back of the hole, and observe it from the front under a low magnification glass. The deposition of the copper layer on the hole wall, the place where the copper has been deposited will not transmit light, and the area where the copper is not deposited will have light passing through, so it can be graded by the number of bright areas seen to identify chemical The quality of copper deposition. [0003] 4.2.3 of QJ2860-96 "Technical Requirements for Metallization of Printed Circuit Board Holes" stipulates the backlight inspection method: drill no less than 3 process holes with a diame...

AI Technical Summary

Problems solved by technology

Whether it is the method stipulated by the standard or the industry practice, it is not difficult to see that: 1) The thickness, number of layers, aperture, number of holes and other information of the printed board used in the backlight test are not specified in detail, and there are inconsistencies in the backlight samples, which affect the backlight determination process. Too many factors

2) The method of grinding with sandpaper after cutting is adopted, and the cutting hole is not protected, and there is a phenomenon that the backlight level is unqualified due to damage to the electroless copper layer during the grinding process of the sandpaper

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