AGY reports that S-3 HDI glass fibre is designed to meet the demanding technical requirements of high-density interconnect (HDI) technology in PCBs – especially integrated circuit (IC) package substrates.

“As miniaturisation of electronic devices continues, and functionality of those devices increase, the need for higher performing substrates has emerged,” explains Drew Walker, Vice President Marketing and Sales at AGY. “In response to this need, AGY has introduced S-3 HDI glass fibre for use in very thin high performance laminates.”

Containing a patent-pending glass composition, S-3 HDI glass fibre was developed with specific performance criteria in mind.

“As laminates become thinner and circuit density increases, PCBs become more prone to warping,” says Walker. “S-3 HDI glass fibre has a tensile modulus of 82 GPa (11.9 msi), which is 17% higher than the traditional E-glass used in PCBs, and provides improved stiffness and excellent dimensional stability.”

“In the case of IC package substrates, finer pitch circuitry and the elevated processing temperature of lead-free soldering have magnified the need for a closer match of the laminate CTE with that of the IC component,” reports Walker.

“S-3 HDI fibre addresses this need with a CTE of 3.5 ppm/°C (1.9 ppm/°F), versus 5.4 ppm/°C (3.0 ppm/°F) for traditional E-glass, yielding laminates with CTEs in the range of 10 ppm/°C (5.6 ppm/°F) versus E-glass laminates at 15 ppm/°C (8.33 ppm/°F), depending on the choice of resin. This improves thermal stability and reduces stress at solder joints, resulting in higher reliability.”

AGY, headquartered in Aiken, South Carolina, USA, is a global producer of glass fibre yarns and high-strength glass fibre reinforcements.