Direct laser drilling method for processing blind hole of circuit board

Abstract

The invention discloses a direct laser drilling method for processing a blind hole of a circuit board and aims to provide a laser drilling method which has the advantages that the minimum-value aperture of the processed blind hole reaches 0.002 inch, i.e. 50[mu]m, and the laser drilling production efficiency is relatively high. The production process is improved so as to be more simplified, and the modified process comprises laminating, copper etching and thinning, blackening and laser drilling, wherein the copper etching and thinning process is characterized in that a mixed solution of hydrogen peroxide and sulfuric acid is utilized for thinning and etching a copper layer of a laminated product from the general thickness of about 18[mu]m to the thickness of 4-6[mu]m, and the blackening process is characterized in that the surface of the copper is treated to enable the surface to form a layer of black copper oxide film. Due to the adoption of the copper etching and thinning method, the laser output quantity is reduced, and the smaller processing aperture can be obtained; and the blackening treatment can be used for effectively absorbing laser emitted by a laser drilling machine, so that the waste of light sources is reduced, and the laser drilling efficiency is improved.

Description

technical field [0001] The invention relates to a manufacturing process of a printed circuit board, in particular to a laser drilling process in the manufacturing process of the circuit board. Background technique [0002] In the manufacturing process of printed circuit board (PCB) or flexible circuit board (FPC), mechanical drilling is basically used when the hole diameter is larger than 0.008 inches (200μm). Mechanical drilling is a mature technology. With the trend of miniaturization, light weight, and thinning of electronic products, high-density interconnect (HDI) printed boards have appeared on the market, and traditional mechanical drilling methods can no longer meet the requirements for processing smaller apertures. At present, the processing of the above-mentioned small apertures is mainly realized by laser drilling, and the apertures of laser drilling are relatively small, generally the standard apertures are 0.004 inches (100 μm) to 0.008 inches (150 μm). [0003...

AI Technical Summary

Problems solved by technology

The disadvantages of the above process are: 1. Affected by negative film and dry film analysis, the minimum diameter of the copper window is 0.006 inches (150 μm), and the minimum diameter is about 0.008 inches (200 μm) after the hole is expanded during the laser process; 2. Production process Long, more auxiliary materials are used; 3. Due to the limitation of manufacturing process capacity, it cannot meet the needs of more and more refined circuit layout in the industry