New challenges in design and understanding of chip-on-glass (COG) for LCD packaging by FEA

The chip-on-glass (COG) technique using flip chip technology has been developed for excellent resolution and high quality liquid crystal display (LCD) panels for several years. In the industry, LCD glass of 0.3 mm thickness will soon be used in real products. However, many serious manufacturability and reliability issues were observed in previous studies. In those, ACF (anisotropic conductive film) delamination is a critical issue, which causes mechanical and electrical failures. The investigation of local stress/strain behavior is an important problem in predicting and preventing delamination initiation and propagation. By means of the finite element analysis (FEA) tool, Abaqus, we have established global and local numerical models of the LCD cell by taking the detailed interconnect structure into consideration to simulate the ACF bonding process and investigate the temperature and stress/strain distributions under thermal-stress load. We also explored the effects of bonding temperature and stage temperature on local fracture behaviors.