POS7-0897
Rheological flow engineering of h-BN/epoxy fluids for semiconductor packaging
Topic
S7. Innovations in Polymeric Composites: From Design and Processing to Industrial Applications
When and Where
Oct 1, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Jinkee HONG
Ki Su KIM
Presenter(s)
Hansam Park (HANYANG UNIVERSITY)
Co-Author(s)
Abstract
Hexagonal boron nitride (h-BN) is an attractive filler for semiconductor packaging materials such as molded underfills (MUF) and epoxy molding compounds (EMC), owing to its high thermal conductivity and electrical insulation. However, the platelet morphology of h-BN sharply increases suspension viscosity and yield stress, making the packing design of highly filled systems challenging. In this study, epoxy-BN suspensions with BN contents ranging from 1 to 31 vol% were prepared, and their rheological behavior was correlated with the actual filling performance in a chip-scale geometry. Depending on the shear frequency, the rheological evaluation revealed three percolation thresholds at approximately 7, 13, and 21 vol% BN, at which the suspensions underwent distinct structural transitions. The first threshold (7 vol%) was characterized by an increase in viscosity accompanied by a peak in the storage modulus (G′), indicating the formation of an h-BN network structure. The second threshold (13 vol%) exhibited the most pronounced increase in viscosity, while G′ showed a plateau over a specific shear frequency range. Although the yield stress increased at the first and second thresholds, it decreased sharply with increasing BN concentration beyond the third threshold (21 vol%). To connect these rheological regimes to real processing, epoxy-BN suspensions of varying BN content are injected into a dummy chip equipped with a defined bump array, and the flow is visualized in situ. Key filling parameters(fill time, flow-front morphology, and void content) are extracted and interpreted within each percolation regime to reveal how the network structure and yield stress govern the filling behavior. Linking these process-relevant indicators to the underlying rheological characteristics provides a rational basis for packing design and the development of high-performance electronic packaging materials.
