The majority of flex circuit constructions make use of thin, unreinforced base materials making them prone to tearing. As a result, a base product that is very immune to any tearing, both in regards to tear initiation and also tear proliferation, is liked in flex circuit manufacture. While there are design strategies to reduce tearing issues (see Chapter 7 – Practical Design Guidelines for Flex), provided the thin and also somewhat delicate nature of flexible circuit base products, tear resistance is an useful attribute.
ELECTRICAL PROPERTIES
Electric residential properties of products has actually ended up being more vital throughout the years as high frequency digital as well as analog signals (rather than DC circuits) become required for increasingly more gears, and will certainly continue to boost in relevance with the surge in signal rates. Materials for flexible circuits applications need to have electrical homes tailored to the performance demands of the design. With high data signaling speeds (higher than 100 MHz) coming to be more usual, the product’s Dielectric Constant (Dk) and also Loss Tangent or Dissipation Factor (Df) must be reduced. In addition, high insulation resistance is a desirable building for various high voltage applications. Nonetheless, for some applications the needs can be various, such as applications where greater capacitance is preferred and a high Dk is defined. Luckily there are hundreds of prospective materials to meet different needs.
One facet of design that has been forgotten because of the low rate generally used for flex circuits is that the adhesive, the product, actually touching the conductor, is also a dielectric and also contributor to the electric efficiency. The majority of design standards are based on the base dielectric movie, yet as these become thinner and the greater rate requirements or managed impedance designs for flexible circuits shown up, the glue element can be even more of an element. A reduced Dk/Df adhesive or bonding layer can minimize polyimide density while likewise decreasing cost and area.
ADAPTABILITY
An essential material function, flexibility is quite commonly an essential quality. Relying on the application, flexible
circuits can be exposed to extremes of temperature level, from cook stove hot to cryogenically chilly, making versatility over a variety of temperature vital. Of specific value is versatility at reduced temperatures where most products tend to end up being breakable. It deserves noting that numerous products are flexible if they are thin sufficient. Even silicon, as breakable as it gets on the macro scale, can be rather flexible if made incredibly slim, such as in the variety of a few microns. Versatility needs can additionally vary depending on the application as well as really could be tested differently in numerous materials areas, so defining the applications and mode of end usage, in contrast to test information offered by a supplier, are critical when selecting a material.