Spread Glass Prepreg Performance in Ultra Low Skew Multilayer Stackups
Spread glass prepregs eliminate dielectric permittivity gaps across differential traces, suppressing signal skew below 1 ps/inch in 112G PAM4 stackups.
1035 Weave Fabric
Material Classification
Lightweight glass reinforcement provides the thin substrate structure needed for high-density multi-layer printed circuit boards. For very thin rigid laminates, 1035 weave fabric offers a nominal thickness of approximately twenty-eight micrometres, which allows designers to reduce overall board thickness. Fabricators select this style to achieve tight dielectric spacing.
Laminate properties of such thin boards are heavily driven by the glass itself because the thin yarn restricts the physical space available for resin.
Dielectric Performance
Signal integrity in high-frequency circuits depends on the consistency of the dielectric constant across the board area. When using 1035 weave fabric, the relatively large open spaces between the fine glass yarns can create localized variations in the dielectric constant, a phenomenon known as the fiber weave effect. Designers must route differential traces at specific angles or use multiple ply offsets to mitigate this variation.
Modern fabricators often combine this style with resin systems formulated for low loss, which helps stabilize the propagation velocity of high-speed digital signals across the signal tracks.
Manufacturing Characteristic
Lamination processing of thin fiberglass sheets requires careful control of resin rheology to prevent voids. Because 1035 weave fabric has a very low basis weight, it is susceptible to mechanical distortion during handling and prepreg treating.