Epoxy-based siloxane composites for electronic packaging: Effect of composition and molecular structure of siloxane matrix on their properties

Epoxy-based composites are widely used in electronic packaging because of their excellent moldability and insulation properties. However, commercial epoxy-based materials have low thermal stability and high thermal expansion. Herein, we report epoxy siloxane/silica composites that improve the thermal, mechanical, and insulating properties of epoxy resin by introducing a sol–gel-synthesized siloxane hybrid and silica particles. We develop two types of epoxy-based composites with different siloxane molecular structures (branch and linear) and investigate the changes in their properties with different compositions and siloxane structures. Branched siloxane structure leads to hard and low insulating properties, whereas linear siloxane structure results in soft and high insulating properties. Both epoxy siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are greatly improved by the incorporation of silica particles. Finally, we confirm the feasibility of the use of developed composites in electronic packaging, wherein two types of epoxy-based siloxane/silica composites are coated onto a commercial metallic substrate without any deformation. Our epoxy-based composites have significant potential as high-performance and robust electronic packaging materials. In addition, our composite-design approach can easily control the composite characteristics of mechanics and insulation, and improve both these properties by employing silica particles with a homogeneous distribution.