21703 CMP加工精度が実効誘電率(k_<eff>)に与える影響(配線1,OS.12 機械工学が支援する微細加工技術(半導体・MEMS・NEMS))

抄録

The effect of processing variation in CMP on effective dielectric constant (k_<eff>) of interconnect was estimated by calculation. The target structure was a hybrid type for 45nm technology node. The wiring capacitance (C) and k_<eff> were calculated by electrostatic field analysis using the finite element method. In addition, the effect on wiring resistance (R) and RC value were evaluated. The ratio of change in each electric parameter in case of polishing variations at ±5nm and ±10nm were compared with the case of the designed structure. The results indicated that the k_<eff> was relatively insensitive to the variations in CMP, while R was most sensitive. However, when the dielectric constant of the hard mask was set as high as the value of the current hard mask, the effect on k_<eff> was drastically increased. These results suggest that the processing accuracy of CMP will be even more important in the future.