Multilayer flex structures offer unmatched opportunities to designers. From high reliability power distribution to high density designs, multilayer flexes get the job done. Some have enough copper inside that they retain the shape once they are bent, some have only a couple of layers in the bend area and several more in areas that stay flat.
Distributing power in tight enclosed areas and to multiple boards can be a challenge. A multilayer flex can take care of those challenges with ease. Multiple heavy copper layers to handle the high current requirements can be combined with thin shield layers for “quiet” power delivery. Thinner than a wire for the same current load and designed to fit in tight spaces, a multilayer flex may just be what your product needs.
High density interconnects
Thin substrates can be leveraged to build very small geometries. When you are able to include .001” (25 um) diameter holes in your pad-stack everything else gets smaller and easier to manufacture. Microvias are one of the features that are actually easier to manufacture in a flex substrate than in a rigid one. BGAs under 0.5 mm pitch, flip chip technology and direct wirebonding are all available options that can make your HDI design work without the extra cost.
One interesting aspect of multilayer flex boards is the ability to have different cross-sections in different areas of the board. Let’s say you need 6 layers in one section but then have to “slim down” to 2 layers to allow for a tight bend radius, it is not a problem. A single sided flex tail going to a ZIF connector coming out of a 4 layer flex? No big deal.
Not all of them need to bend
When miniaturization and weight reduction are your main objectives, multilayer flex structures allow you to design ultra-thin and ultra-light boards. At Circuits, we build many “flex” boards that do not bend at all, but they are able to achieve substantial size and weight savings. You can build a 10 layer board that is less than .023” (0.6 mm) thick, how can that impact your product?
Our aerospace customers are constantly challenged to reduce weight in flight applications, visit our Mil-Aero applications page to see more.