Line edge roughness reduction for EUV self-aligned double patterning by surface modification on spin-on-carbon and tone inversion technique
Line edge roughness reduction for EUV self-aligned double patterning by surface modification on spin-on-carbon and tone inversion technique
复制标题
通过旋涂碳表面改性和色调反转技术降低 EUV 自对准双图案的线边缘粗糙度
DOI：
10.1117/1.jmm.20.2.024901
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
G. Denbeaux
中科院分区：
文献类型：
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作者：
E. Liu;Katie Lutker;Qiaowei Lou;Ya;Angélique Raley;P. Biolsi;K. Yu;G. Denbeaux
抽象的。为了制造先进的逻辑器件，极紫外光刻(EUVL)已被应用于大批量生产。由于互连制造对尺寸的连续要求，形成自对准双图案(SADP)的EUVL引起了广泛的研究兴趣。EUV SADP目前面临的挑战是从光刻到芯棒形成的图形转移过程。在该步骤中，在蚀刻过程中，特征的目标临界尺寸(CD)需要从光刻CD缩小一半。在此刻蚀过程中增加的长宽比潜在地恶化了图案的有效性和线边缘粗糙度(LER)。除了这些挑战外，由于随机效应，EUVL还有一个根本的瓶颈，它可能会因缺陷形成和边缘放置误差(EPE)而导致器件退化。线条和空间图案的LER是EPE的主要贡献者之一。为了减少图案变化和提高器件性能，需要在工艺和集成两个方面采取有效的降低误码率的方法。在我们的研究中，我们研究了一种减少EUV SADP线条图案上的LER的技术。这项技术包括在图案化堆叠和色调反转过程中对旋转碳(SOC)层进行表面修饰。我们发现了SOC表面疏水性与EUV SADP LER性能之间的趋势。SOC疏水性越强，反转色调后的LER性能越差。试验条件包括与氢气等离子体、氟碳等离子体的直流叠加作用，以及与氢气等离子体和三甲基硅烷二甲胺沉积的组合。在20 nm间距的EUV SADP上，该技术显示了从光刻到SADP形成的26%的LER改进。在关联长度为200 nm和200~30 nm时，PSD分析分别记录了约6%和30%的LER改善。这项技术的进一步缩放到15 nm间距的演示也显示出从光刻到SADP形成的LER减少了30%。
Abstract. Extreme ultraviolet lithography (EUVL) has been adopted into high volume production for advanced logic device manufacturing. Due to the continuous size scaling requirement for interconnect fabrication, EUVL with self-aligned double patterning (SADP) formation has attracted substantial research attention. The current challenge in EUV SADP is the pattern transfer process from lithography to mandrel formation. In this step, the target critical dimension (CD) of the feature needs to shrink by half from the lithography CD during the etch process. The increasing aspect ratio during this etch potentially deteriorates the pattern validity and the line edge roughness (LER). In addition to these challenges, EUVL has a fundamental bottleneck due to stochastic effects, which can lead to device degradation by defect formation and edge placement error (EPE). LER of the line and space pattern is one of the main contributors to EPE. Effective methods of LER reduction in both process and integration are needed in order to reduce pattern variation and boost device performance. In our study, we examine a technique to reduce LER on the EUV SADP line pattern. This technique involves the surface modification on the spin-on carbon (SOC) layer in the patterning stack and tone inversion process. We had found a trend between surface hydrophobicity of the SOC and the EUV SADP LER performance. The condition that increased the hydrophobicity of the SOC resulted in a lower LER performance after tone inversion. The tested conditions include direct current superposition (DCS) function with H2 plasma, fluorocarbon plasma, and the combination of DCS with H2 plasma and trimethylsilane dimethylamine deposition. On 20-nm pitch EUV SADP, this technique shows 26% of LER improvement from lithography to SADP formation. PSD analysis recorded about 6% and 30% of the LER improvement at the correlation length of >200 nm and 200 to 30 nm, respectively. A demonstration of this technique for a further scaling to 15-nm pitch also shows an LER reduction of 30% from lithography to SADP formation.