Expertise of the raw material components of flexible circuits (i.e., base movie, glue layer and also metal foil) and also exactly how they are combined makes it possible to examine them in more deepness and, much more specifically, to learn about the available mate- rial options as well as their homes. This procedure makes it possible for designers making knowledgeable choices based on the result of each decision on the end product

FLEXIBLE BASE FILMS

Various products have actually been utilized as base movies or substratums for flexible circuits manufacture, including:

– Fluoropolymer movies, such as Teflon ®
. – Aramid fiber-based papers and fabrics, such as Nomex ®
. – Formable composites, such as those stood for by Bend/Flex ®.
– Various flexible epoxy-based compounds.
– Thermoplastic movies, such as polyethylene, polyvinyl chloride, polyvinyl fluoride, and also polyetherimide.

All these film as well as slim compounds have been used in flexible circuits manufacture at one time or another and a lot of them continuously be utilized in certain applications. The expense of materials could vary widely.

The most popular and most commonly defined flexible base materials are polyester (PET) as well as polyimide (PI). The selection substratum polymer to use is figured out by a combo of economics, output application and also assembly processing temperature levels, which are progressively crucial to please EU-legislated lead-free requirements, Polyimide and also polyester may control existing applications, however there are different film modern technologies that can see enhanced usage for a number of strong factors. Polyethylenenaphthalate (PEN), for instance, looks like an attractive inter mediate choice in terms of cost as well as efficiency.

Another material of increasing passion as the industry transfers to greater frequency digital electronic devices is fluid crystal polymer (LCP). This product has a number of eye-catching physical and electrical buildings. For instance, LCP products have naturally low dampness absorption homes (0.02% to 0.1%) that ought to prevent the requirement for the cooking that is commonly part of the polyimide manufacturing procedure due to its even more hygroscopic nature. The reduced wetness uptake is also an essential factor in producing a low signal loss atmosphere. With a loss tangent of 0.003 and also a dielectric constant of around 2.9 LCP is quite appealing for high-speed applications. An additional attractive feature of LCP is that it is chemically etchable, a feature it shares with polyimide. This ability is something that can be made use of to advantage in creating both exotic and reasonably ordinary buildings.

Slim fluoropolymer laminates are also candidate products to offer future flex circuit interconnection demands. While not necessarily fit to vibrant applications, PTFE companion- rials could discover usage in applications where reduced loss as well as low dielectric constant are required. Common loss tangent worths for PTFE materials are less than 0.001 as well as the dielectric consistent frequently comes in the 2.0 to 2.4 array. Companies such as Taconic are targeting just such applications for products they are creating for the flex circuit market. The laminate friend- rial is based on PTFE. FEP is a by-product of PTFE with a much reduced melt point of 550 ° F vs. 640 ° F for
PTFE. As kept in mind earlier, the selection of material is additionally mostly influenced by the assembly technology to be made use of for components on the completed product. This is where designers need to seriously consider the trade-offs connected with product and also product option. It is feasible making an educated choice that would certainly not, under normal scenarios, be considered appropriate. Such choices are normally based on unique understanding of ways to prevent troubles connected with the friend- rial residential property limitations of the chosen substratum.