Material Specification
Woven fiberglass fabric with a highly uniform, spread-weave structure reinforces thin printed circuit board laminates. Known as glass style 1078, this material specification balances glass and resin distribution by using flat, wide yarn bundles in both directions. This configuration restricts the size of resin-rich pockets to a minimum.
Structural Uniformity
Uniformity of the weave is achieved by mechanically spreading the glass filaments during the weaving process. Traditional fiberglass styles feature tightly bundled yarns that leave open spaces between the threads, creating areas with high resin content. The spread construction of glass style 1078 distributes the glass filaments more evenly across the sheet, closing these gaps and ensuring a consistent ratio of glass to resin throughout the laminate.
This structural density helps fabricators maintain tight thickness control during the pressing stage of multilayer board production.
Electrical Impact
Impedance consistency in high-frequency transmission lines is the main performance benefit of using this spread-glass fabric. When a differential pair of microstrip traces runs over a non-uniform glass weave, each trace experiences a different effective dielectric constant due to the variation between glass bundles and resin-rich regions. By using glass style 1078, the dielectric constant remains stable along the routing path, mitigating the phase skew that degrades signals in multi-gigabit digital designs.
This style is especially useful in thin-dielectric applications where the weave effect has a more pronounced influence on signal propagation. System designers select it to prevent timing mismatches.
