Intro To Coatings For Flexible Circuits

Coverlayers and covercoats are important topics as well as, because of their many ranges as well as facets, demanding of additional discussion. Flexible circuits usually call for a coating of some style over the finished circuits. At the same time, openings are nearly constantly needed to supply access to flex PCB features for interconnection to parts or ports. The finish is described as being a covercoat, coverlayer or cover film. In all cases, a typical feature of the finished protective layer is that it is flexible.

The varying terms, utilized to define products that serve a typical feature, gives away the fact that the items are likely to be different not just in name but additionally in process, which is exactly the instance. What is not clear from their names is that these items normally offer various functions in regards to the application. Some description of the modern technologies and their rationales should aid make this a little bit clearer.


Covercoats are typically liquid finishings, usually applied by screen printing. Nonetheless, various other techniques could likewise be made use of. Depending upon the sort of covercoat utilized, the display printing process can include a pattern that leaves the Flexible Circuits features open if it is a UV or thermal cure product, or it could completely cover all functions for later direct exposure as well as growth if it is a photo-imageable product. The process can be really cost-efficient with the former instance, and is best-suited to make use of with coarser features.

These products are frequently made use of in applications where the assemblies do not see much repeat flexing; nevertheless, depending upon the polymer’s specific buildings based on its formula, some covercoats can additionally serve well in some vibrant applications.


The term coverlayer has traditionally been reserved for polymer films that have a sticky layer on one side that is made use of to bond to the flex PCB. In process, the coverlayer is generally machined, most often by boring, routing or punching, to give openings for the circuit functions. After offering the openings, the coverlayer is straightened as well as laminated to the flex PCB making use of warm and stress.

While it is a lot more lengthy to create and also much more pricey than display printing, laminated coverlayers have actually been the main option for flex PCB circuits calling for high cycle life as well as vibrant flexing. This is because the buildings of the base movie and also its thickness can be made identical by placing the flexible circuits in the desired neutral axis of the bend span.


Cover movies are most much like dry movie solder mask in kind as well as use because they are laminated, subjected and created to access flex PCB features. Cover films have actually appreciated raising popularity for their capacity to define opening and accessibility very great circuit attributes. While cover films are not ideal for all vibrant applications, they can be rather functional in numerous. it offers a short summary of the various processes.

There are, obviously, variants on processing that can extend one technology over into other aspects. For example, lasers can be used with coverlayers to gain access to penalty attributes as well as chemical or plasma etching of polymer movies can be utilized to accessibility attributes when integrated with certain various other processing techniques such as using indispensable steel masks.

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