Packaging/Interconnects: Low-Cost Flexible Circuit Substrate Supplies High Performance Levels

Low-cost high-performance flexible substrate materials are now available. Solderable up to 300°C, they come with 1 oz of copper (and other custom thicknesses) on nonpolyimide proprietary 3-mil thick flexible substrates. For super-fine-pitch applications of less than 1 mil lines/spacings and for vias, 0.25-oz or 0.375-oz copper is available. The substrates feature a low dielectric constant of 3.0 at 1 kHz with a dielectric loss of less than 0.01 and insulation strength of 1000 V dc (3-mil thickness). The non-silicone materials withstand chemical etching and treatments and maintain flexibility down to −40°C. Moisture absorption is less than 0.3%. Pricing is $1.28/ft² for 1-oz copper and $3.80 ft² for 0.5-oz copper.