Abstract

To reduce bonding time in the die bonding process of power devices, we propose a novel technique based on the melting and reactions of Sn shells in Sn-coated Cu dendritic particles during heating. In this study, transient liquid phase (TLP) die bonding was performed at 250 °C in air under 10 MPa of pressure. Sn coating content was considered as a main process parameter. During the immersion Sn plating (coating) of Cu dendritic particles, excessive Cu₆Sn₅ and Sn were formed in situ. Coating the Cu dendritic particles significantly reduced the oxidation of core Cu during heating in air. When the average Sn coating content was 18 wt%, abundant Cu remained based on Sn shortages, even after 10 min of reaction. However, pure Cu was virtually eliminated in the bondlines following an identical reaction when the Sn content was 45 wt%. A paste containing 45 wt% Sn-coated Cu dendritic particles provides more effective TLP bondability, resulting in average shear strengths of bondlines of 19.6 and 21.4 MPa following die bonding for 3 and 5 min, respectively.

Graphical Abstract

中文翻译：

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镀锡铜树枝状颗粒的瞬态液相键合工艺

摘要

为了减少功率器件的芯片键合过程中的键合时间，我们提出了一种基于加热过程中镀锡铜树枝状颗粒中锡壳的熔化和反应的新技术。在这项研究中，瞬态液相（TLP）芯片键合是在250°C的空气中在10 MPa的压力下进行的。Sn涂层含量被认为是主要的工艺参数。铜树突状颗粒的浸镀（镀层）过程中，过量的Cu ₆ Sn ₅和锡是原位形成的。在空气中加热期间，涂覆铜树枝状颗粒可显着减少核心铜的氧化。当平均Sn涂层含量为18wt％时，即使在反应10分钟后，基于Sn的短缺，仍保留大量的Cu。然而，当Sn含量为45wt％时，经过相同的反应，实际上在键合线中消除了纯Cu。含45％（重量）Sn涂层的Cu树突状颗粒的糊料提供了更有效的TLP粘结性，在芯片粘结3分钟和5分钟后，粘结层的平均剪切强度分别为19.6和21.4 MPa。

图形概要