Sumaria Kaushal, Liu Tingyi Leo
Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA.
Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
Adv Mater Technol. 2025 Feb 5;10(3). doi: 10.1002/admt.202401200. Epub 2024 Sep 18.
Advancements in biomedical research have spurred the development of stretchable electronic devices. While soft insulators are readily available, soft conductors with metal-like electrical conductivity are rare. Gallium and its alloys, being non-toxic and intrinsically stretchable, are potentially ideal solutions. However, current additive liquid metal (LM) patterning methods face limitations in achieving high-throughput, high-resolution, and high-density LM wiring. Here, a subtractive LM patterning method has been developed to meet all these requirements simultaneously. The innovative method involves parallel filling a single continuous microfluidic mesh network with LM that short-circuits all the pins and pads of a circuit, followed by parallel cutting of the unwanted short-circuited interconnections using hydrochloric acid (HCl) vapor. Cutting locations are pre-defined by designing narrower intersecting channels, leveraging capillary force for precise filling and cutting. The process was characterized using a multi-dimensional parametric study with varying LM line widths and HCl concentrations, and in-situ impedance measurements to assess insulation performance. To showcase its high-throughput capabilities, a mock circuit was used to successfully generate complex LM interconnects that connected hundreds of electrical pads. Lastly, a stretchable LM circuit, fabricated using the subtractive LM patterning method, was integrated with a micro-LED array, highlighting the practical application of this new technology in creating massively parallel LM wirings in complex, heterogeneous, and stretchable electronic circuits.
生物医学研究的进展推动了可拉伸电子设备的发展。虽然软绝缘体很容易获得，但具有类似金属导电性的软导体却很少见。镓及其合金无毒且具有内在的可拉伸性，是潜在的理想解决方案。然而，目前的添加剂液态金属（LM）图案化方法在实现高通量、高分辨率和高密度LM布线方面面临限制。在此，已开发出一种减法式LM图案化方法，以同时满足所有这些要求。这种创新方法包括用LM并行填充单个连续的微流体网状网络，使电路的所有引脚和焊盘短路，然后使用盐酸（HCl）蒸汽并行切割不需要的短路互连。通过设计更窄的交叉通道来预先定义切割位置，利用毛细作用力进行精确填充和切割。使用多维参数研究对该过程进行了表征，该研究涉及改变LM线宽和HCl浓度，并进行原位阻抗测量以评估绝缘性能。为了展示其高通量能力，使用一个模拟电路成功生成了连接数百个电垫的复杂LM互连。最后，使用减法式LM图案化方法制造的可拉伸LM电路与微LED阵列集成在一起，突出了这项新技术在复杂、异构和可拉伸电子电路中创建大规模并行LM布线的实际应用。
