Collaborative Research: Solid-Liquid Interactions during Transient Liquid Phase Bonding

先进的热力学和相场模型的结合，再加上实验，将有助于理解瞬态液相 (TLP) 键合过程中的固/液相互作用。 对固/液界面现象的更好理解有望使 TLP 键合变得可行，并为电子焊接提供一种环保的替代方案。 本研究将研究控制界面相互作用的新方法，以减少接头宽度、缩短粘合时间并改善 TLP 接头特性。 这些包括通过不可润湿氧化物层的去稳定来改善低温下的成分润湿性，以及通过施加瞬态扩散阻挡层来维持平面固/液界面。 金属间化合物的沉淀将通过工艺参数和扩散势垒来解决。 所探索的现象也适用于凝固、液相烧结和其他毛细管驱动的连接工艺。该提案目标的成功实现将有助于开发更好、环保的电子制造技术。 含铅合金广泛用作电子产品的焊接材料。 不幸的是，可回收性差使得电子废物成为土壤/水铅污染的主要来源。 因此，使用更环保的替代品具有强大的推动力。 尽管取得了相当大的进步，但大多数无铅焊料需要更高的键合温度，导致残余热应力增加，从而降低互连可靠性。 预计从这项研究中获得的理解将有助于最终逐步淘汰危险的含铅微电子元件。

The combination of advanced thermodynamic and phase-field models, coupled with experiments will allow the understanding of solid/liquid interactions during Transient Liquid Phase (TLP) bonding. Better understanding of the solid/liquid interfacial phenomena is expected to make TLP bonding viable and will provide an environmentally-friendly alternative for electronic soldering. This research will study new approaches to control interfacial interactions to reduce joint width, shorten the bonding time, and improve the TLP joint characteristics. These include improving the compositional wetting at low temperatures through the de-stabilization of non-wettable oxide layers and maintaining a planar solid/liquid interface by applying transient diffusion barrier layers. The precipitation of Intermetallic Compounds will be addressed through processing parameters and diffusion barriers. The explored phenomena apply also to solidification, liquid phase sintering and other capillary-driven joining processes.The successful attainment of the objectives of this proposal will contribute to the development of better, environmentally-friendly electronic manufacturing techniques. Lead-containing alloys are extensively used as soldering materials for electronics. Unfortunately, poor recyclability makes electronic waste a major source for soil/water lead contamination. There is thus a strong driving force for the utilization of more environmentally-friendly alternatives. Despite considerable progress, most Pb-free solders require higher bonding temperatures, resulting in increased residual thermal stresses that reduce interconnect reliability. It is expected that understanding gained from this study will contribute to the ultimate phase-out of hazardous, lead-containing microelectronics components.