Fabrication of smart card using UV curable anisotropic conductive adhesive (ACA) part II: reliability performance of the ACA joints

For mobile electronic products, there are different mechanical or environmental attacks like warps, stretching, changing in humidity and temperature, which may affect the performance and reliability of the electronic products. In this work, the reliability of the smart cards fabricated by chip-on-flex (COF) bonding using UV curable anisotropic conductive adhesive (ACA) was investigated. Based on the aforementioned attacks, successfully fabricated contactless smart card samples were subjected to autoclave testing to investigate the failure mechanisms. The reading distance between card reader and sample was measured and compared at each test interval. In addition, a shear test was performed to determine the shear strength and the effect of autoclave test on ACA joints. Fracture surfaces were then analyzed using a scanning electron microscope (SEM). ACA joints selected from the aged samples were cross-sectioned and examined using the SEM. Bare ACA specimens that were cured under the same curing conditions were also put into the autoclave test chamber simultaneously. Chemical analyses were performed using FTIR-ATR analysis to investigate the chemical structure change in these UV curable ACA samples. These results were then collaborated to have a better understanding of the failure mechanism of ACA joints of the smart card that have undergone autoclave testing.