Fabric Specification
Lightweight glass fabric specifications provide a standardized reinforcement density for the production of ultra-thin pre-pregs. Fabricating boards with style 1035 allows for a finished dielectric thickness as low as 0.04 millimeters. This weave is composed of fine yarns in a plain weave pattern, offering a balance between mechanical strength and resin capacity for multi-layered designs.
Resin Absorption
Chemical bonding between the glass and the polymer depends on the openness of the weave. Style 1035 has a relatively high resin-to-glass ratio, which ensures that the laminate remains flexible and well-filled during the pressing cycle. This high resin content provides a consistent dielectric environment, although it also increases the coefficient of thermal expansion compared to heavier fabrics.
The openness of the weave allows for easy penetration of the epoxy, reducing the risk of voids or dry spots in the finished board. Manufacturers use this style in mobile devices and advanced packaging where space is extremely limited and thinness is a primary requirement.
Layer Thickness
Precision in the final stackup height is achieved by selecting specific glass styles. Because style 1035 is so thin, it is often used as a cap layer or in conjunction with other fabrics to hit an exact thickness target. Designers must account for the lower stiffness of this fabric when planning the mechanical handling of the panels during production.
The use of this style is common in HDI boards that require small via diameters and high density routing.
