UV laser drilling hole method

Abstract

The present invention relates to an UV laser drilling method for making microconductive through-hole one printed circuit base board. Said method includes the following steps: utilizing UV laser beam to scan the position having need of making microconductive through-hole along a certain pathway, then successively making several microholes until the area of whole surface around the microconductive through-hole in covered with the made microholes all over, and then carving the whole microconductive through-hole. Said invention adopts the ring sawing process, so that it can raise the making quality of the microconductive through-hole.

Description

Technical field [0001] The invention relates to a method for laser drilling on a printed circuit substrate, in particular to a method for using UV laser drilling. Background technique [0002] With the miniaturization and portability of electronic equipment, there is an increasing demand for higher circuit density on printed circuit boards. To adapt to the above requirements, in recent years, a laminated multilayer printed circuit board with a higher density conductive layer (generally 2 to 4 layers) sequentially laminated on one or both sides of a conventional high-density printed circuit board has appeared. The board has smaller microvias, thinner insulation layer thickness and finer and shorter line width / spacing. Between the upper and lower printed circuit boards in the above-mentioned multilayer printed circuit board, it is necessary to electrically connect the conductive layer, wherein the conductive layer is generally composed of a copper pattern (pattern), and the i...

AI Technical Summary

Problems solved by technology

[0008] Microvias with these quality problems will have serious hidden dangers in subsequent processing and use. If insulating materials remain at the bottom of the holes, after the holes are electroplated with copper, there will be gaps between the electroplated copper layer and the inner copper pattern layer. The insulating layer is very easy to cause electrical disconnection, even if there is less residue and electrical conduction, but due to the small area of ​​contact between the electroplated copper layer and the inner copper pattern layer, the adhesion strength is poor, in the subsequent soldering process or product use, Due to thermal shock stress or deformation stress, the electroplated copper layer is easily broken and the electrical path is disconnected

Likewise, problems with delamination or blistering due to excessive ablation can have similar consequences

The drum-shaped hole (that is, the hole size is small and the hole waist size is large) due to side etching may easily cause poor electroplating in the subsequent metallization process of the micro-via hole. It is easy to break and fall off during use, resulting in serious poor electrical conduction

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