Uniaxial ratchetting behavior of anisotropic conductive adhesive film under cyclic tension

Polymer-based conductive adhesive materials have become widely used in many electronic packaging interconnect applications. Uniaxial ratchetting behavior of anisotropic conductive adhesive film (ACF) was studied by uniaxial cyclic tension experiments. The effects of mean stress, stress amplitude and loading history on the ratchetting response of ACF material were analyzed. Results show that (1) the ratchetting strain amplitude and ratchetting strain rate of the ACF material increase with increasing stress amplitude or mean stress; (2) the ACF material has a strong memory of loading history. Prior stress cycling with higher mean stress or stress amplitude restrains the ratchetting strain in subsequent cycling with lower mean stress or stress amplitude. Prior stress cycling with higher stress rate will accelerate the plastic deformation of subsequent cycling with lower stress rate for the ACF material.