The development of soft electronics requires methods to connect flexible and stretchable circuits. With conventional rigid electronics, vias are typically used to electrically connect circuits with multilayered architectures, increasing device integration and functionality. However, creating vias using soft conductors leads to additional challenges. Here we show that soft vias and planar interconnects can be created through the directed stratification of liquid metal droplets with programmed photocuring. Abnormalities that occur at the edges of a mask during ultraviolet exposure are leveraged to create vertical stair-like architectures of liquid metal droplets within the photoresin. The liquid metal droplets in the uncured (liquid) resin rapidly settle, assemble and then are fully cured, forming electrically conductive soft vias at multiple locations throughout the circuit in a parallel and spatially tunable manner. Our three-dimensional selective stratification method can also form seamless connections with planar interconnects, for in-plane and through-plane electrical integration.

软电子的发展需要连接柔性和可拉伸电路的方法。在传统的刚性电子设备中，通孔通常用于对具有多层架构的电路进行电气连接，从而提高器件的集成度和功能。然而，使用软导体创建通孔会带来额外的挑战。在这里，我们展示了软通孔和平面互连可以通过编程光固化对液态金属液滴进行定向分层来创建。利用紫外线照射期间在掩模边缘发生的异常，在光刻胶内创建液态金属液滴的垂直阶梯状结构。未固化（液态）树脂中的液态金属液滴迅速沉降、组装，然后完全固化，以平行和空间可调的方式在整个电路的多个位置形成导电软通孔。我们的三维选择性分层方法还可以与平面互连形成无缝连接，实现面内和面内电气集成。