Lee Jun-Myeong, Lee Jong-Chan, Kim Seong-In, Lee Seung-Jae, Bae Jae-Yung, Park Jin-Hyung, Park Jea-Gun
Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul 04763, Korea.
Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea.
Nanomaterials (Basel). 2022 Mar 15;12(6):969. doi: 10.3390/nano12060969.
To scale down semiconductor devices to a size less than the design rule of 10 nm, lithography using a carbon polymer hard-mask was applied, e.g., spin-on-carbon (SOC) film. Spin coating of the SOC film produces a high surface topography induced by pattern density, requiring chemical-mechanical planarization (CMP) for removing such high surface topography. To achieve a relatively high polishing rate of the SOC film surface, the CMP principally requires a carbon-carbon (C-C) bond breakage on the SOC film surface. A new design of CMP slurry evidently accomplished C-C bond breakage via transformation from a hard surface with strong C-C covalent bonds into a soft surface with a metal carbon complex (i.e., C=Fe=C bonds) during CMP, resulting in a remarkable increase in the rate of the SOC film surface transformation with an increase in ferric catalyst concentration. However, this surface transformation on the SOC film surface resulted in a noticeable increase in the absorption degree (i.e., hydrophilicity) of the SOC film CMP slurry on the polished SOC film surface during CMP. The polishing rate of the SOC film surface decreased notably with increasing ferric catalyst concentration. Therefore, the maximum polishing rate of the SOC film surface (i.e., 272.3 nm/min) could be achieved with a specific ferric catalyst concentration (0.05 wt%), which was around seven times higher than the me-chanical-only CMP.
为了将半导体器件缩小到小于10纳米的设计规则尺寸，采用了使用碳聚合物硬掩膜的光刻技术，例如旋涂碳（SOC）膜。SOC膜的旋涂会产生由图案密度引起的高表面形貌，这需要化学机械平面化（CMP）来去除这种高表面形貌。为了实现SOC膜表面相对较高的抛光速率，CMP主要需要在SOC膜表面打破碳-碳（C-C）键。一种新设计的CMP浆料在CMP过程中通过从具有强C-C共价键的硬表面转变为具有金属碳络合物（即C=Fe=C键）的软表面，明显实现了C-C键的断裂，随着铁催化剂浓度的增加，SOC膜表面转变速率显著提高。然而，SOC膜表面的这种表面转变导致在CMP过程中，SOC膜CMP浆料在抛光后的SOC膜表面的吸收程度（即亲水性）显著增加。随着铁催化剂浓度的增加，SOC膜表面的抛光速率显著降低。因此，在特定的铁催化剂浓度（0.05 wt%）下，可以实现SOC膜表面的最大抛光速率（即272.3纳米/分钟），这比仅机械CMP高出约七倍。
