In order to reduce the interconnect resistance and capacitance (RC) time delay of a semiconductor integrated circuit, a more porous dielectric material is used in recent interconnection for lower dielectric constant. However, it is difficult to use highly porous low-k dielectric materials at the narrow pitch because it is easily damaged during the plasma etching processes. In this study, as one of the plasma induced damage reduction methods in the etching of porous low-k dielectric, RF pulsed plasma methods have been investigated by using a dual frequency capacitively coupled plasma etching system. RF pulsed plasmas generated more polymerizing species and less UV compared to continuous wave plasmas and showed reduced damaged layer compared to the conventional continuous wave plasma etching. Porous SiCOH dielectric patterned with a TiN hard mask was etched using the RF pulsed plasmas and the results showed more anisotropic etching profiles with less sidewall damages, which was estimated by the thickness loss of sidewall low-k material after dipping into a diluted HF solution. Therefore, it is believed that the RF pulsed plasma etching process of ultra low-k dielectric materials can improve the RC time delay related to plasma damage for the next interconnect manufacturing technology.

中文翻译：

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通过使用源脉冲等离子体蚀刻来减少超低 k 电介质的等离子体诱导损伤，用于下一个 BEOL 互连制造

为了减少半导体集成电路的互连电阻和电容（RC）时间延迟，在最近的互连中使用了更多多孔的介电材料以降低介电常数。然而，由于在等离子蚀刻过程中容易损坏，因此难以以窄间距使用高度多孔的低k介电材料。在这项研究中，作为多孔低 k 电介质蚀刻中的等离子体诱导损伤减少方法之一，RF 脉冲等离子体方法已经通过使用双频电容耦合等离子体蚀刻系统进行了研究。与连续波等离子体相比，射频脉冲等离子体产生更多的聚合物质和更少的紫外线，并且与传统的连续波等离子体蚀刻相比，显示出减少的损坏层。使用 RF 脉冲等离子体蚀刻用 TiN 硬掩模图案化的多孔 SiCOH 电介质，结果显示更多的各向异性蚀刻轮廓和更少的侧壁损伤，这是通过浸入稀释的 HF 溶液后侧壁低 k 材料的厚度损失来估计的。因此，相信超低k介电材料的RF脉冲等离子体蚀刻工艺可以改善与等离子体损伤相关的RC时间延迟，用于下一个互连制造技术。