Fabrication of Porous Cu–Sn Microbumps for Low-Temperature Cu–Cu Bonding

IF 2.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Transactions on Semiconductor Manufacturing Pub Date : 2025-01-14 DOI:10.1109/TSM.2025.3529683

Zilin Wang;Yunfan Shi;Qingchao Zhang;Yikang Zhou;Qian Wang;Zheyao Wang

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引用次数: 0

Abstract

Cu-Cu thermocompression bonding (TCB) is widely used in 3D integration due to its excellent electrical performance, high bonding strength, and good reliability. However, TCB needs high temperature, high pressure, and complicated chemical-mechanical-planarization (CMP). We have developed a low temperature, CMP-free Cu-Cu bonding method using porous Cu-Sn microbumps. In this paper, we further report the detailed fabrication processes and the formation principles of the porous Cu-Sn bumps, as well as the characterization results of the bonded structures. A pretreatment method is developed using sequential thermal reflow and redox treatment in a gas mixture of oxygen and formic acid to form porous Cu-Sn bumps. The gas content, temperature, and duration of the pretreatment are optimized. An array of

$1000\times 800$

porous Cu-Sn bumps has been fabricated, and CMP-free Cu-Cu bonding has been achieved using Cu-Sn bumps at 250°C, 10 MPa, and 30 min. The bonding strength, the resistance, and the thermal reliability are evaluated.

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低温Cu-Cu键合用多孔Cu-Sn微凸点的制备

Cu-Cu热压键合（TCB）具有优异的电性能、高的键合强度和良好的可靠性，在三维集成中得到了广泛的应用。然而，TCB需要高温、高压和复杂的化学-机械-平面化（CMP）。我们开发了一种低温，无cmp的Cu-Cu键合方法，使用多孔Cu-Sn微凸起。在本文中，我们进一步报道了多孔Cu-Sn凸起的详细制备工艺和形成原理，以及键合结构的表征结果。提出了一种在氧气和甲酸混合气体中进行顺序热回流和氧化还原处理以形成多孔铜锡包块的预处理方法。对预处理的气体含量、温度和时间进行了优化。制备了一组$1000\ × 800$多孔的Cu-Sn凸点阵列，并在250°C、10 MPa和30 min的条件下实现了无cmp的Cu-Cu键合。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

IEEE Transactions on Semiconductor Manufacturing 工程技术-工程：电子与电气

CiteScore

5.20

自引率

11.10%

发文量

101

审稿时长

3.3 months

期刊介绍： The IEEE Transactions on Semiconductor Manufacturing addresses the challenging problems of manufacturing complex microelectronic components, especially very large scale integrated circuits (VLSI). Manufacturing these products requires precision micropatterning, precise control of materials properties, ultraclean work environments, and complex interactions of chemical, physical, electrical and mechanical processes.