Yeom Hee-Jung, Yoon Min Young, Choi Daehan, Lee Youngseok, Kim Jung-Hyung, You Shin-Jae, Lee Hyo-Chang
Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea.
Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea.
ACS Omega. 2023 Aug 31;8(36):32450-32457. doi: 10.1021/acsomega.3c02438. eCollection 2023 Sep 12.
In the current and next-generation Si-based semiconductor manufacturing processes, amorphous carbon layer (ACL) hard masks are garnering considerable attention for high-aspect-ratio (HAR) etching due to their outstanding physical properties. However, a current limitation is the lack of research on the etching characteristics of ACL hard masks under plasma etching conditions. Given the significant impact of hard mask etching on device quality and performance, a deeper understanding of the etching characteristics of ACL is necessary. This study aims to investigate the role of oxygen in the etching characteristics of an ACL hard mask in a complex gas mixture plasma etching process. Our results show that a small change of oxygen concentration (3.5-6.5%) can significantly alter the etch rate and profile of the ACL hard mask. Through our comprehensive plasma diagnostics and wafer-processing results, we have also proven a detailed mechanism for the role of the oxygen gas. This research provides a solution for achieving an outstanding etch profile in ACL hard masks with sub-micron scale and emphasizes the importance of controlling the oxygen concentration to optimize the plasma conditions for the desired etching characteristics.
在当前及下一代基于硅的半导体制造工艺中，非晶碳层（ACL）硬掩膜因其出色的物理性能，在高深宽比（HAR）蚀刻方面受到了广泛关注。然而，目前的一个局限性在于缺乏对ACL硬掩膜在等离子体蚀刻条件下蚀刻特性的研究。鉴于硬掩膜蚀刻对器件质量和性能有重大影响，深入了解ACL的蚀刻特性是必要的。本研究旨在探究氧气在复杂气体混合等离子体蚀刻工艺中对ACL硬掩膜蚀刻特性的作用。我们的结果表明，氧气浓度的微小变化（3.5 - 6.5%）会显著改变ACL硬掩膜的蚀刻速率和轮廓。通过我们全面的等离子体诊断和晶圆加工结果，我们还证明了氧气作用的详细机制。本研究为在亚微米尺度的ACL硬掩膜中实现出色的蚀刻轮廓提供了一种解决方案，并强调了控制氧气浓度以优化等离子体条件以获得所需蚀刻特性的重要性。
