Fabric Architecture
Woven fiberglass reinforcers establish the structural rigidity and dimensional stability of composite circuit board laminates. The 3313 glass style is a medium-weight, balanced glass weave commonly used in prepregs to build stable dielectric layers with reliable thickness. It utilizes yarns that are spread flatly during manufacturing to create a uniform fabric sheet.
This style bridges the gap between thin, flexible prepregs and thick, heavy core fabrics, offering a versatile option for high layer count laminates.
Moisture Resistance
Moisture absorption occurs more slowly in laminates containing spread-weave fabrics. The 3313 glass style has a flat bundle structure that minimizes the size of open resin pockets within the laminate. Because the glass yarns are tightly and flatly woven, the completed laminate provides fewer interstitial spaces where water molecules can collect.
This characteristic reduces the likelihood of delamination during thermal assembly processes such as reflow soldering or wave soldering.
Skew Minimization
Differential signal skew decreases when signal lines run across spread-glass weaves. In PCBs made with 3313 glass style, the flattened glass bundles create a highly uniform dielectric constant across the plane of the board. High-frequency signals traveling over this substrate encounter a consistent mix of glass and resin rather than alternating between dense glass yarns and resin-only pockets.
Consequently, propagation delays remain identical on both conductors of a differential pair, which preserves signal integrity. This consistency is highly valued in backplanes and high speed digital circuits operating at frequencies where phase differences would otherwise distort the digital waveforms.
