Ultrahigh-solid-content silica/epoxy composite for high-performance semiconductor packaging

Packaging materials are crucial for chip performance, directly impacting heat dissipation, warpage, and signal quality. However, balancing flowability and solid content often limits their effectiveness. Herein, a novel methodology is developed for creating ultrahigh-solid-content liquid molding compounds (LMCs) with low viscosity and exceptional properties. By establishing a mathematical model that accurately predicts composites’ viscosity and optimal maximum packing density based on binary size-distributed samples, achieving 78.0 vol% LMC. Its excellent flowability enables superior processability, with precise thickness control and low surface roughness on wafer coatings. The low thermal expansion coefficient (α₁ = 11.4 ppm °C⁻¹) ensures minimal warpage and strong adhesion. Dielectric properties (Dk/Df = 2.62/0.0062) significantly lower than commercial FR-4 materials are reached. Besides a high flexural strength of 142.2 MPa, the 78 vol% LMC demonstrates thermal conductivity (1.33 W m⁻¹ K⁻¹) closely approaching pure silica. These outstanding properties highlight the practicality of the ultrahigh-solid-content LMCs for advanced wafer-level packaging applications.