Effect of Hydrogen on Vacancy Formation in Sputtered Cu Films Studied by Positron Annihilation Spectroscopy
Effect of Hydrogen on Vacancy Formation in Sputtered Cu Films Studied by Positron Annihilation Spectroscopy
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DOI：
10.7567/jjap.52.046501
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发表时间：
2013-03
影响因子：
1.5
通讯作者：
A. Yabuuchi;T. Kihara;D. Kubo;M. Mizuno;H. Araki;T. Onishi;Y. Shirai
中科院分区：
文献类型：
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作者：
A. Yabuuchi;T. Kihara;D. Kubo;M. Mizuno;H. Araki;T. Onishi;Y. Shirai
作为大规模集成电路互连制造工艺的一部分，提出了一种用于将铜嵌入到沟槽结构中的后沉积高压退火法。在溅射的Ar气体中加入氢气可以改善溅射的铜膜的包埋性。为了阐明氢对溅射铜膜中空位形成的影响，用正电子湮没谱对正常的Ar溅射和Ar-H溅射的铜膜进行了研究。结果表明，在Ar-H溅射的铜膜中观察到了浓度大于10-4的单空位，而在普通的Ar-H溅射的铜膜中只检测到一个对应于晶界的正电子寿命分量。这一结果意味着通过向溅射的气体中添加氢气来稳定单胞菌。在热处理过程中，稳定的单空位在300℃左右开始聚集，这表明单空位-氢键解离。引入的单空位可能促进高压退火过程中的蠕变变形。
As a part of the LSI interconnect fabrication process, a post-deposition high-pressure annealing process is proposed for embedding copper into trench structures. The embedding property of sputtered Cu films has been recognized to be improved by adding hydrogen to the sputtering argon gas. In this study, to elucidate the effect of hydrogen on vacancy formation in sputtered Cu films, normal argon-sputtered and argon–hydrogen-sputtered Cu films were evaluated by positron annihilation spectroscopy. As a result, monovacancies with a concentration of more than 10-4 were observed in the argon–hydrogen-sputtered Cu films, whereas only one positron lifetime component corresponding to the grain boundary was detected in the normal argon-sputtered Cu films. This result means monovacancies are stabilized by adding hydrogen to sputtering gas. In the annealing process, the stabilized monovacancies began clustering at around 300 °C, which indicates the dissociation of monovacancy-hydrogen bonds. The introduced monovacancies may promote creep deformation during high-pressure annealing.