Y. Moon, L. Qin, D. Koli, C. Snow
GlobalFoundries, United States
pp. 108 - 111
Keywords: planarization, GCIB
In sub-14nm advanced CMOS logic technology, controlling wafer-scale planarization or uniformity became tremendously critical. This is mainly due to the CMOS integration scheme where chemical mechanical polishing (CMP) is used to create the transistor gate. The precise gate height control is extremely important since any within wafer or within chip non-uniform gate height can cause degradation in device performance and yield. Especially, the technology requirement in the wafer-scale planarization at the advanced CMOS technology is beyond the capability a conventional CMP process can deliver. This technology limitation initiated the need for alternative integration scheme or planarization technology. The wafer-scale planarization using location specific gas cluster ion beam (GCIB) is considered as a potential technology to meet this stringent requirement. GCIB is a focused beam enabled by clusters of gas molecules and can remove surface material in molecular scale. The gas clusters bombard into the molecules of the wafer surface and remove the surface by physical and chemical means. The amount of material removed is controlled by the total energy applied on the gas cluster and the composition of gas cluster molecules.