Abstract

Power semiconductors require a large bonding area for die attachment. For this purpose, transient liquid phase bonding (TLPB) was applied using fabricated interlayers, namely Sn–3Cu and Sn–10Cu, to study the intermetallic compound (IMC) formation, and the results were compared with those obtained with a pure-Sn interlayer. The Sn–3Cu and Sn–10Cu interlayers exhibited primary IMC fraction of 0.06 and 0.24, respectively, before the TLPB. For a Cu/interlayer/Cu sandwich structure, the TLPB was applied at 250 °C over various time periods (1–4 h). A reduction in the bonding time was more significant for a Sn–10Cu interlayer with a larger amount of primary IMCs than for the Sn–3Cu interlayer. The time exponent of the IMC fraction with respect to the bonding time was approximately 0.3 for all interlayers. This implies that the IMC growth mechanism is governed by a liquid channel or wet grain boundary diffusion. The nearly constant fraction and increasing size of the primary IMCs produced during the TLPB indicate that the primary IMCs coalesced during this process. The primary IMCs preferentially coalesced with the interface IMCs produced during the TLPB when they had the same crystalline orientation.

Graphic Abstract

抽象的

功率半导体需要较大的键合面积以进行管芯连接。为此，使用制造的中间层Sn–3Cu和Sn–10Cu进行了瞬态液相键合（TLPB），以研究金属间化合物（IMC）的形成，并将结果与​​纯Sn中间层的结果进行了比较。在TLPB之前，Sn-3Cu和Sn-10Cu中间层的主IMC分数分别为0.06和0.24。对于Cu /中间层/ Cu夹层结构，TLPB在250°C的不同时间段（1-4小时）内使用。对于具有较大IMC数量的Sn-10Cu中间层，与Sn-3Cu中间层相比，键合时间的减少更为显着。对于所有中间层，IMC分数相对于键合时间的时间指数约为0.3。这意味着IMC的生长机制受液体通道或湿晶粒边界扩散的支配。TLPB期间生成的主要IMC的比例几乎恒定且大小不断增加，这表明主要IMC在此过程中合并了。当主IMC具有相同的晶向时，它们优先与TLPB期间生成的界面IMC合并。

图形摘要