New electrically conductive adhesives (ECAs) for flexible interconnect applications

Abstract

By blending flexible epoxy with rigid epoxy or using epoxies with different chain lengths, the mechanical properties of the resulting polymer matrices could be tuned to meet different requirements. With the introduction of nanoparticles into the formulation, better electrical properties of the resulting flexible ECAs (FECAs) have been achieved via particle-particle interface enhancement. Moreover, adhesion strength of FECAs on a Au surface has been significantly improved by using conjugated difunctional molecules. With optimized material properties of FECAs, device level test indicated that the FECAs can be used for flexible electronics. In addition, conductive thin films with certain transparency have been developed using Ag-coated glass fiber as filler.

Soft Bioelectronics Based on Nanomaterials

“…The strategies to modify the filler materials include controlling the dimension of fillers and modifying their surface properties. Using filler materials with a high-aspect ratio can enhance conductivity 517 because the electrical conduction through a filler moiety increases but the conduction from contacts between filler moieties is minimized at the same time. Since the contact resistance between the filler moieties is much higher than the resistance of a filler moiety itself, the overall conductance increases.…”

Materials for heterogeneous integration

“…In general, various types of TIMs are available, for example, in the form of grease (silicone-based matrix filled with thermal fillers/boron nitride (hexagonal-BN) 40 or alumina-Al 2 O 3 ), 41,42 phase change materials (PCM, utilizing latent heat during melting, polyolefin and low Mw polyester), [43][44][45] gels and adhesives (silicon-nitride 46 or silver-filled epoxy). 47,48 The h-BN and exfoliated h-BN nanosheets (BNNS) have been extensively studied as thermal filler in polymer or ceramic composites with high thermal conductivity and electrical resistivity. [49][50][51][52][53][54][55][56][57][58][59][60][61][62] h-BN is a z-direction stacking structure that uses van der Waals bonding of covalently bonded 2D hexagonal boron-nitrogen (h-BN) atoms, which is very similar to the structure and thermal properties of graphite.…”