Self-conditioning of encapsulated abrasive pad in chemical mechanical polishing

Chemical mechanical polishing (CMP) is the process of planarization which was achieved by both chemical reaction and mechanical force. The polishing consists of moving wafer to be polished against the polyurethane pad, carrying slurry between wafer and polyurethane pad. There have been, however, some problems including dishing, erosion, high cost of consumables, environmental problems and scratches due to diamonds dropped out of conditioner. In particular, the slurry used in CMP not only increases the cost of consumables, but also interferes with the environmentally benign semiconductor manufacturing. This paper introduces the encapsulated abrasive pad to achieve the environmentally benign CMP and self-conditioning mechanism of pad. The self-conditioning just means that additive conditioning process on pad is not necessary between polishing wafers. Hydrophilic polymers were used to develop the encapsulated abrasive pad. When these polymers keep in contact with water, they have soluble and swelling characteristics. The removal rate of the encapsulated abrasive pad showed higher than that of general CMP process using slurry and polyurethane pad. The self-conditioning of pad was verified through experiment, which showed the possibility of environmentally benign process only using de-ionized water in interlayer dielectric CMP.