Interface adhesion study of Cu interconnection and low-k organic materials

For microelectronic applications, it is important to have good interfacial properties between copper and dielectric layers. To prevent Cu diffusion issue, Ti and Ta are commonly used as barrier layers. In redistribution layer (RDL) process, Parylene-C (PC) and Polybenzoxazoles (PBO) are applied to dielectric organic materials. Therefore, it is necessary to study the adhesion of Cu/barrier layer (Ta, Ti)/low-k organic dielectric (PBO/PC) system. In this paper, adhesion effect of barrier layer (Ta, Ti) between Cu and low-k organic material (PBO/PC) system was investigated by peeling test, transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). The result shows poor adhesion of Cu/PC can be improved by either Ti or Ta, while the adhesion of Cu/PBO can be only enhanced by Ti.