Effect of Co-W and Co-Fe-W Diffusion Barriers on the Reliability of the Solder/Cu Interface during Reflow Conditions

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

Electronic Materials Letters Pub Date : 2024-04-13 DOI:10.1007/s13391-024-00491-2

Yuexiao Liu, Chongyang Li, Peixin Chen, Jinyang Liu, Anmin Hu, Ming Li

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Abstract

Efficient diffusion barriers are necessary to prevent the formation of copper-tin intermetallic compounds (IMCs) in advanced packaging for Sn/Cu micro-bumps. This study investigated the interfacial properties of solder and Ni, Co-9W, Co-20W, Co-20Fe-10W, and Co-36Fe-17W barriers and determined the thickness of IMCs formed between Sn and these barriers after up to 15 reflows. Among the five barriers, Co-36Fe-17W proved to be the most effective in inhibiting the reaction of liquid Sn solder. At the Sn/Co-W interface, CoSn₃ IMC was formed, while at the Sn/Co-Fe-W interface, CoSn₃ IMC and FeSn₂ IMC were observed. The contact angles of these layers were measured and found to be 18°, 22°, 25°, 29°, and 27°, respectively. The results showed that an increase in W content in Co-W led to an increase in the contact angle, while the intrinsic wettability of Co-Fe-W decreased with an increase in Fe content. The shear strengths of the five joints were 27 MPa, 31 MPa, 25 MPa, 25 MPa, and 26 MPa, respectively, with different fracture modes observed. The Co-Fe-W-Sn layer was partially peeling from the diffusion barriers in SAC305/Co-20Fe-10W, and the fracture surfaces exhibited an irregular and rough state, which was attributed to the increasing Fe and W contents. These findings offer valuable insights for enhancing the reliability of electronic packages.

Graphical Abstract

Abstract Image

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Co-W 和 Co-Fe-W 扩散屏障对回流条件下焊料/铜界面可靠性的影响

在先进的锡/铜微凸块封装中，要防止形成铜锡金属间化合物 (IMC)，必须要有高效的扩散屏障。本研究调查了焊料与 Ni、Co-9W、Co-20W、Co-20Fe-10W 和 Co-36Fe-17W 隔离层的界面特性，并测定了锡与这些隔离层之间在多达 15 次回流后形成的 IMC 厚度。事实证明，在五种阻挡层中，Co-36Fe-17W 在抑制液态锡焊料反应方面最为有效。在 Sn/Co-W 界面形成了 CoSn3 IMC，而在 Sn/Co-Fe-W 界面则观察到了 CoSn3 IMC 和 FeSn2 IMC。测量发现，这些层的接触角分别为 18°、22°、25°、29° 和 27°。结果表明，Co-W 中 W 含量的增加会导致接触角的增加，而 Co-Fe-W 的固有润湿性会随着 Fe 含量的增加而降低。五个接头的剪切强度分别为 27 兆帕、31 兆帕、25 兆帕、25 兆帕和 26 兆帕，并观察到不同的断裂模式。在 SAC305/Co-20Fe-10W 中，Co-Fe-W-Sn 层与扩散屏障部分剥离，断裂表面呈现出不规则的粗糙状态，这归因于铁和 W 含量的增加。这些发现为提高电子封装的可靠性提供了有价值的见解。

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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.