(April 13, 2009) AIKEN, SC &#151 L-Glass low-loss glass fiber yarn for printed wiring board (PWB) applications has low dielectric constant (Dk) and low dissipation factor (Df) properties for designs requiring increased signal speeds and better signal integrity than traditional E-Glass/epoxy substrate materials.

L-Glass fiber overcomes limitations of E-Glass/epoxy substrates and low Dk/Df resins with ceramic filler and lower E-Glass content by allowing epoxy resin systems to achieve much lower Dk/Df properties, and the PTFE-based systems to use a higher glass loading. At 10 GHz L-Glass fiber has a dielectric constant of 4.86 and a dissipation factor of 0.0050 whereas E-Glass has a dielectric constant of 6.81 and a dissipation factor of 0.0060.

The CTE of L-Glass fiber is 3.9 ppm/&#176C compared to 5.4 ppm/&#176C for E-Glass. This makes L-Glass fiber an attractive material for use in IC packaging, where CTE mismatches with silicon are magnified due to the thermal environment and can cause defects. AGY’s L-Glass fibers will be available in a variety of yarn counts, that will allow production of low-loss fabrics analogous to styles 106, 1080, 2113/2313, and 2116. Additional yarn counts can be produced as needed.

AGY, www.agy.com.