Deformation Property Measurement for Single Anisotropic Conductive Adhesive Particles

Anisotropic conductive adhesives (ACAs) consist of a polymer adhesive matrix containing fine conductive particles. The primary objective of this experimental research was to establish a clearer understanding of the effects of the bonding force and load rate on the deformation of individual ACA particles. This has been achieved through measurements of the deformation against force using a specially configured nano-indenter machine, where the "indenters", instead of being a point, had a flat tip 30 mum in diameter. The merit of using this machine is that very small forces, of the order of 100 mN, can be accurately applied to the particles to a resolution of 100 nN and the resulting deformations, of less than 6 mum, can then be recorded to a resolution of 0.1 nm. The results showed that the ACA particle deformation was not linear and the force/deformation at which particle crushing occurs could be determined from the profile of the force versus deformation. The crush points and the deformation processes were affected by the load rate