Modeling Slip Velocity and Pressure Gradients across Smooth Copper Foils
Modelling slip velocity and pressure gradients across smooth copper foils prevents resin starvation and locks dielectric thickness tolerances during lamination.
Silica Filler Loading
Composite Composition
Adding inorganic particles to an epoxy resin alters the physical and electrical characteristics of a printed circuit substrate. High levels of silica filler loading reduce the coefficient of thermal expansion to match the copper and the components more closely. This adjustment is necessary to prevent the failure of micro-vias during the extreme heat of the soldering process.
The particles also increase the stiffness of the board and improve its dimensional stability.
Thermal Expansion
Resin content decreases as the amount of inorganic material rises. In a laminate with high silica filler loading, the reduced polymer volume leads to lower moisture absorption and better signal stability. However, the material becomes more abrasive and harder to drill.
Mechanical Property
Manufacturing challenges arise when the filler concentration exceeds sixty percent by weight. At this point, the silica filler loading makes the prepreg more brittle and prone to cracking during handling. The increased viscosity of the molten resin also makes it harder to fill the gaps around internal copper features.
Fabricators must use specialized drill bits and slower feed rates to avoid excessive tool wear and maintain hole wall quality. Balancing the filler amount is a critical task for material suppliers to ensure both reliability and processability.