Effect of Ar/N2 Two-Step Plasma Treatments on the Interfacial Characteristics of Low-Temperature Cu-Cu Direct Bonding

IF 2.1 4区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Electronic Materials Letters Pub Date : 2025-03-17 DOI:10.1007/s13391-025-00565-9

Gahui Kim, Seonghun Choi, Yongbeom Kwon, Sarah Eunkyung Kim, Hoo-Jeong Lee, Young-Bae Park

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Abstract

The effects of Ar/N₂ two-step plasma treatments on the interfacial adhesion energies of low-temperature Cu–Cu bonding interfaces were systematically investigated with four-point bending (4-PB) test. It was confirmed that the Cu surface roughness had increased, and a Cu nitride layer was formed by the Ar/N₂ two-step plasma treatment. X-ray photoelectron spectroscopy clearly showed that the Ar/N₂ two-step plasma treatment formed less Cu oxide due to the formation of a Cu nitride layer. As a result of the 4-PB test, as the N₂ RF power was increased, the interfacial adhesion energy decreased. An analysis of the delaminated surface after the 4-PB test confirmed that a Cu nitride layer was not formed, which was thought to be due to decomposition during the bonding process. As the N₂ RF power was increased, the roughness also increased, leading to poor Cu-Cu bonding. The decrease in Cu-N bonding resulted in the progression of Cu oxidation. Additionally, the interfacial adhesion energy decreased due to the formation of a disordered Cu layer on the Cu surface.

Graphical Abstract

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Ar/N2两步等离子体处理对低温Cu-Cu直接键合界面特性的影响

采用四点弯曲（4-PB）试验系统研究了Ar/N2两步等离子体处理对低温Cu-Cu键合界面粘附能的影响。经Ar/N2两步等离子体处理后，Cu表面粗糙度增大，形成Cu氮化层。x射线光电子能谱清楚地表明，Ar/N2两步等离子体处理由于Cu氮化层的形成而形成较少的Cu氧化物。4-PB测试结果表明，随着N2 RF功率的增大，界面粘附能减小。在4-PB测试后，对分层表面的分析证实，没有形成氮化铜层，这被认为是由于键合过程中的分解。随着N2 RF功率的增加，粗糙度也增加，导致Cu-Cu键合不良。Cu- n键的减少导致了Cu氧化的进展。此外，由于Cu表面形成无序的Cu层，界面粘附能降低。图形抽象

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来源期刊

Electronic Materials Letters 工程技术-材料科学：综合

CiteScore

4.70

自引率

20.80%

发文量

审稿时长

2.3 months

期刊介绍： Electronic Materials Letters is an official journal of the Korean Institute of Metals and Materials. It is a peer-reviewed international journal publishing print and online version. It covers all disciplines of research and technology in electronic materials. Emphasis is placed on science, engineering and applications of advanced materials, including electronic, magnetic, optical, organic, electrochemical, mechanical, and nanoscale materials. The aspects of synthesis and processing include thin films, nanostructures, self assembly, and bulk, all related to thermodynamics, kinetics and/or modeling.