A Superhydrophobic Bilayer Anisotropic Conductive Film with Improved Reliability for Electronic Interconnects

Abstract

Anisotropic conductive films (ACFs) are essential interconnect materials in flexible, high-density electronics but suffer from low functional reliability under humid or contaminated conditions. A superhydrophobic bilayer ACF (S-ACF) is developed to address this limitation through a scalable spray-coating process that deposits a composite of vapor-phase SiO 2 nanoparticles and styrene-ethylene-butylene-styrene (SEBS) onto a conventional epoxy-based ACF. The resulting film exhibits a dual-layer architecture in which the SiO 2 /SEBS topcoat forms a micro-nano hierarchical texture with low surface energy, yielding a static water contact angle of 150° compared to 64° for the pristine ACF. Despite the surface modification, the bonding strength (17.1 MPa) and Z-axis contact resistance (1.64 Ω) remained nearly identical to those of the unmodified counterpart (17.2 MPa, 1.58 Ω). Additionally, the minimum lateral insulation distance of the S-ACF was approximately 60 μm, confirming that both the mechanical and electrical integrity were preserved. The superhydrophobic surface endures over 200 abrasion and tape-peel cycles while retaining ≥145° contact angle and exhibits a twofold reliability enhancement in humid-heat stability (85 °C/85% RH, resistance inflection shifted from ~150 to ~300 hours). The design in this work offers a practical route toward durable, moisture-resistant interconnects for next-generation flexible electronics.