Electronics Packaging substrates with fin-line circuitry, such as those used in laminated multichip modules (MCM-Ls) and plastic ball grid arrays (PBGAs), are generally fabricated with layers of copper clad composite laminates. The conducting copper provides electrical interconnections and power distribution for the system, while the composite laminates furnish mechanical support for the structure along with insulative resistance.

Most laminates are comprised of several plys of glass fabrics embedded in a polymeric resin, where the fabric acts as a structural reinforcement by offsetting the resin's inherent mechanical and thermomechanical weaknesses. A popular fabric fiber material used in the electronics industry for laminate reinforcement is E-glass due to cost, high strength, water resistance, and bond stability with resins.