TEAR RESISTANCE
A lot of flex circuit buildings utilize slim, unreinforced base materials making them vulnerable to tearing. Because of this, a base material that is highly resistant to any tearing, both in terms of tear initiation and tear breeding, is chosen in flex circuit manufacture. While there are design methods to mitigate tearing concerns (see Chapter 7 – Practical Design Guidelines for Flex), given the thin as well as rather delicate nature of flexible circuit base materials, tear resistance is a valuable characteristic.
ELECTRIC PROPERTIES
Electrical residential properties of products has actually become more important throughout the years as high frequency digital and analog signals (rather than DC circuits) end up being required for an increasing number of gears, and also will certainly continue to raise in significance with the increase in signal speeds. Materials for flexible circuit applications should have electrical buildings tailored to the performance needs of the design. With high data signaling rates (greater than 100 MHz) coming to be most typical, the material’s Dielectric Constant (Dk) as well as Loss Tangent or Dissipation Factor (Df) must be low. On top of that, high insulation resistance is a preferable home for different high voltage applications. However, for some applications the requirements can be different, such as applications where greater capacitance is desired as well as a high Dk is defined. Thankfully there are lots of potential products to satisfy divergent requirements.
One facet of design that has been neglected due to the reduced speed generally used for flex circuits is that the glue, the product, actually touching the conductor, is additionally a dielectric and factor to the electrical efficiency. Most design standards are based on the base dielectric film, however as these ended up being thinner and also the higher speed needs or controlled resistance layouts for flex turned up, the adhesive component can be more of an element. A reduced Dk/Df adhesive or bonding layer can minimize polyimide density while also decreasing price and also space.
FLEXIBILITY
A basic product function, adaptability is extremely usually a critical feature. Depending upon the application, flexible
circuits can be revealed to extremes of temperature, from chef range hot to cryogenically chilly, making flexibility over a large variety of temperature level important. Of certain importance is adaptability at low temperature levels where most products tend to become fragile. It is worth keeping in mind that lots of materials are flexible if they are thin enough. Also silicon, as fragile as it is on the macro scale, can be fairly flexible if made exceptionally thin, such as in the varix of a couple of microns. Versatility demands can likewise differ relying on the application and really may be examined in different ways in numerous materials locations, so specifying the applications and method of end use, as opposed to examine information supplied by a provider, are essential when selecting a product.