With the fast development of integrated circuit (IC) fabrication technology, the demands for precision and surface quality of wafer become higher and higher. Chemical mechanical polishing (CMP) technology has been considered as the most effective local and global planarization technology for wafer and widely used in ULSI fabrication. The polishing pad is main consumables of the CMP system, the structure and surface roughness of pad have great effects on the material removal rate and surface roughness of wafer. However, the polishing pad will wear and often become smooth and glazed. After used period of time, it lead to decrease of the material removal rate (MRR) on the wafer surface and increase of the within-wafer non-uniformity (WIWNU). The worn pad needs to be conditioned by a diamond conditioner. The conditioned pad can regenerate the rough surface and renew the performances by removing the glazed area. On the other hand, comparing with the wear of the pad in CMP, most of the pad material is consumed in the conditioning, so the suitable conditioning can prolong the life of the polishing pad so as to save the time of replacing and adjusting the pads and improve stability of CMP process.The suitable structure parameters of the conditioner and the applied process parameter of conditioning pad are studied in this thesis in order to reduce the pad consume due conditioning and achieved the desired performances of the pad. The main works are as follows:(1) Through simulating the trajectories of diamond grain on the pad conditioned by conditioners with different arrangements of diamond grain, the effects on conditioning uniformity of the rotation speed ratio of conditioner to pad and arrangements form of diamond grain are studied.(2) According to the simulation results of diamond grain arrangement and trajectories, some new rational diamond conditioners are designed.(3) The conditioning tests of the diamond conditioners are conducted on a polishing machine. Through analyzing the relationships between pad performances and conditioning parameters, the conditioning parameters are optimized.Through simulation and experiments, the effects of conditioning process parameters including conditioning pressure, rotation speed ratio, time on the surface roughness and material removal rate of the pad are attained. The effects of the conditioner parameters such as size and arrangement form of diamond grain are also analyzed.