SBIR Phase I: Stable Undercooled Metal Materials for Soldering Heat-Sensitive Components and Substrates

该SBIR第一阶段项目将使柔性和印刷电子技术能够用于塑料，纸张和有机电子等热敏材料，这些材料由于温度，成本和/或性能限制而无法使用传统的焊接或导电粘合剂。这项研究的基础是一种无热量添加的焊膏，由液态金属颗粒制成，这些颗粒就像填充的气球，在爆裂时释放出液态金属，然后变成固体。印刷电子产品为美国的主要制造业增长提供了潜力，因为设备结构适合在国内制造，提供了运输优势和整体较低的拥有成本。该技术可能应用于商用柔性显示器、可穿戴生物医学传感器、军用设备的轻型电子产品以及用于供应链连接的射频识别标签。该技术支持的产品的开发预计将使美国公民，机构，军队和政府机构更高效，更有效地进行库存/废物跟踪，生物识别收集，减轻重量和对象网络。启用新的美国技术为物联网和远程医疗创造了市场机会，以及在美国制造电子产品的制造机会，创造大量的就业机会、企业和税收。该项目的重点是开发独特的过冷金属微粒，用于印刷/柔性电子产品的无加热焊接。这项研究将使加热与金属的接合分离。显著地降低了处理温度，从而保持了热敏电子器件和衬底的功能。创新的关键？一个氧化物封装壳防止了具有薄氧化物壳层的异质形核以及在微米和纳米尺度上的过冷增强。它可以被机械剪切或通过化学熔剂作用去除，使内部的液态金属首先流动和聚结，然后固化。 这种金属合金在室温下可以保持液体状态数月。研究将提高在139°C熔化的铋合金的生产良率和可靠性，以降低在217°C熔化的锡/银/铜SnAgCu焊料的脆性。 目标是：1）开发一种材料，可以在不增加热量的情况下用固体金属连接/涂覆材料，2）与导电粘合剂和传统焊接相比，展示接头的性能，3）展示惠斯通电桥和柔性微机电系统（MEMS）原型器件。过冷焊料将使用助焊剂策略来应用，以在室温下在电子设备中制造机械和电气坚固的接头。

This SBIR Phase I project will enable the use of flexible and printed electronic technologies for heat-sensitive materials such as plastics, papers, and organic electronics that cannot employ traditional soldering or conductive adhesives because of temperature, cost, and/or performance limitations. The foundation for the proposed research is a no-heat-added solder paste made from liquid-metal particles that act like filled balloons, releasing a liquid metal when popped and then turning solid. Printed electronics offer potential for major manufacturing growth for the United States, because the device structure lends itself to being manufactured domestically, offering transportation advantages and overall lower costs of ownership. This technology may have applications in commercial flexible displays, wearable biomedical sensors, lightweight electronics for military equipment, and radio frequency identification tags for supply-chain connectivity. The development of the products enabled by this technology is expected to make U.S. citizens, institutions, military, and government agencies more efficient and effective with better inventory/waste tracking, biometrics collection, weight reduction, and object networking. Enabling new U.S. technologies creates market opportunities for the Internet of Things and telemedicine, as well as manufacturing opportunities to make electronics in the U.S., creating significant jobs, businesses, and tax revenue. This project focuses on developing unique undercooled metal microparticles for use in no-heat-added soldering of printed/flexible electronics. The research will decouple the heating from the joining of the metal?significantly lowering the processing temperature and thus preserving function for heat-sensitive electronics and substrates. The key to the innovation?an oxide encapsulating shell?prevents heterogeneous nucleation with a thin oxide shell and undercooling's enhancement on the micro- and nanoscale. It can be mechanically sheared or removed by chemical flux action to enable the liquid metal inside to first flow and coalesce, and to then solidify. The metal alloys can remain as liquids at room temperature for months. Research will increase the production yield and reliability of bismuth alloys that melt at 139°C to less brittle tin/silver/copper SnAgCu solder that melts at 217°C. Objectives are to 1) develop a material that can join/coat materials with solid metal without adding heat, 2) demonstrate the properties of the joint compared to conductive adhesives and traditional soldering, and 3) demonstrate a Wheatstone bridge and flexible Micro Electro Mechanical Systems (MEMS) prototype device. Undercooled solders will be applied using flux strategies to make mechanically and electrically robust joints in an electronic device at room temperature.