Study On Conditioner For Polishing Pad In CMP

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 deteriorate after used period of time. So the worn pad needs to be conditioned by a diamond conditioner to regenerate its rough surface and renew the performances. But the research on conditioning process is mainly based on experience, had not presented a comprehensive theoretical model.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. Establish a polishing pad conditioning removal model. In addition, make certain exploration on diamond conditioner manufacturing. The main works are as follows:(1) A removal rate model is presented for CMP pad conditioning process considering the main process parameters such as conditioning pressure, relative velocity, diamond abrasive particle size and its number on conditioner.(2) Carry on experiments with different conditioners in diamond particle size and number. Measure the pad conditioning removal rate and make contract with theoretical calculated results.(3) The process with piles of diamond abrasive particles in matrix is applied to design and manufacture a new kind of electroplate pad conditioner, and then the practicability of the conditioner is tested.Through the pad conditioning removal rate model and experiments, the effects of conditioning process parameters and conditioner parameters on material removal rate of the pad are attained. It will provide a theoretical basis on CMP conditioning process. Also, some progress is made about the design and manufacture of electroplate pad conditioner which is valuable to CMP pad conditioner manufacturing.