Photosensitive coating resin of auxiliary plates for drilling and application thereof

Abstract

A photosensitive resin composition and auxiliary plates for drilling are introduced. The auxiliary plates are made by coating the photosensitive resin composition on aluminum foil and photocuring the coated resin to make the resin bonded on the aluminum foil. The resin composition comprises a first polymer formed by the reaction of 1,2,4,5-pyromellitic dianhydride and polyetheramine; and a second polymer formed by the reaction of polyetheramine and vinyl chloride, wherein the second polymer is a photosensitive polymer. The novel resin composition provided by the present invention can be coated on drilling auxiliary plates. When the drilling auxiliary plates coated with the resin composition are used in a drilling process, it can avoid the coated resin being cracked due to the heat caused by friction of high speed drilling, so it can further enhance the stability, accuracy, and precision of drilling.

Description

FIELD OF THE INVENTION[0001]The invention relates to a resin composition, especially a coating resin composition that is applied to auxiliary plates used in a drilling process.BACKGROUND OF THE INVENTION[0002]Printed circuit boards (PCBs) provide electronic connection among electronic components and have been developed for about a hundred years. PCBs are made by using insulating plates as substrates, which are cut to a certain size, and having at least one conductive pattern and holes (such as component holes, fastening holes, or metallizing holes) on the substrates to connect electronic components. A common method of manufacturing multilayer PCBs is stacking copper-plated laminates, placing a cover plate on the obtained stack, drilling small holes from the top of the stack, and then connecting holes by electroplating. Therefore, selecting proper materials of cover plates can usually prevent irregular holes, reduce burrs, and improve positioning accuracy.[0003]Recently, because elec...

AI Technical Summary

Benefits of technology

The patent text describes a resin composition and drilling auxiliary plate for PCBs. The drilling auxiliary plate has a lubricating resin layer made by coating the resin composition on a substrate and curing it using illuminating or baking. The technical effects of this invention include improving the drilling process of PCBs by reducing friction and wear, and achieving better hole quality. The invention also provides a better understanding of the purpose, features, and effects of the invention through the detailed description of its composition and use in different examples.

Problems solved by technology

However, due to low melting point, the lubricating resin coated on the covers has problems of flowing over, residue, or even blocking holes.

During drilling process, an instantaneous temperature reaches approximately 200° C. due to friction between drill bits and PCBs to be drilled, but the melting point of known lubricating resin is about 60° C. Secondly, because lubricating resin does not adheres well to aluminum foil, resin with high hardiness is often chosen to be the undercoat.

This method is complicated, and if the undercoat resin remains in the holes on PCBs, it will cause problems such as broken copper or diffusion of coating during electroplating process.

Although the methods mentioned above improved drilling quality, low melting points of the coating resin cause curling problems, which lead to tilting problems of drill bits and decreasing positioning accuracy.

However, the method mentioned above must have an additional thermosetting resin layer, which increases complexity of the manufacturing process, and the high hardness of the resin may lead to drill bits slipping, which causes shifting of holes, or drill bits breaking.

In addition to extending manufacturing time, the baked resin layer may have problems of inconsistent functions and uneven coating thickness due to inconsistent molecular weights of the resin and different evaporation rates of solvent, which may hinder the following drilling application.

The concern of inconsistent molecular weights may lead to problems of drill bit getting stuck, degumming of coating layers, and contaminating walls of the drilled holes.