Reinforcement Specification
Lightweight woven fiberglass fabric styles provide structural support for extremely thin printed circuit board substrates. Woven sheets of 1035 glass feature an extremely low nominal thickness and an open weave pattern that accommodates high resin percentages. This style belongs to the ultra-thin category of glass cloth, typically selected when building high-density interconnect substrates that demand minimal layer heights.
Resin Absorption
High resin content in the resulting prepreg yields a compliant dielectric layer after the pressing cycle. Because 1035 glass has a low areal weight, the ratio of polymer matrix to glass reinforcement remains exceptionally high, lowering the overall dielectric constant of the laminate. This abundance of resin helps fill the micro-vias and internal copper patterns reliably during the multi-layer lamination process, ensuring a void-free insulating boundary.
Solid flow of the resin during the gelation phase prevents dry spots, which would otherwise lead to localized electrical breakdown or delamination under thermal stress.
Mechanical Behavior
Dimensional stability represents the primary trade-off when using such open and thin fabrics. The sparse yarn count of 1035 glass provides less mechanical restraint against the thermal contraction and expansion of the epoxy or polyimide resin during soldering. Fabricators mitigate this effect by balancing the board layout and controlling the lamination cool-down rate.
