Stretchable Multilayer Printed Circuit Boards: Fabrication, Surface Mount Challenge, Fundamental Research, and Applications

背景与动机：本提案是电子技术与材料科学的交叉领域。它描述了为实现可伸缩电子组件而进行的研究。该团队认为，目前已知的许多电子系统都可以在未来设计成新的形状。最常见的技术方法是使用“单片”晶圆规模工艺来制造可拉伸的波浪电子产品。虽然很有趣，但这个提议将遵循一个非单一的、更异构的替代方案。所提出的方法建立在电路板级连接和组装方法的基础上，该方法对来自各种来源的各种尺寸的设备开放。-支持研究：研究人员的切入点来自先前的研究，该团队已经(i)学会了生产和加工芯片规模的功能设备段，（ii）在独特的放置和连接技术方面的开创性工作，该技术基于流体自组装和转移，能够在非常规基板上放置和连接功能芯片规模和微观设备段。研究人员在拟议的研究领域内收集了支持性的结果；支持结果包括实现(i)可伸缩和可充气的照明结构，（ii）变形为球体的麦克风阵列，以及（iii）球形触摸板。-获得的见解总结：支持研究表明，瓶颈不是应用程序，而是一些技术限制和对系统级故障模式的理解滞后，我们建议在本提案中研究和克服。-第一个目标和挑战解决了这样一个事实，即研究仅限于单一金属化层的设计；制造可拉伸的多金属化层之间的通孔，目前是不可能的。这就限制了可以生成的系统的路由和复杂性。此外，还没有对其交流和高频特性进行研究，这是另一个重要的任务。第二个目标和挑战涉及有源设备的组装和电气连接。提出了潜在的解决方案，使组装不仅宏观而且微观芯片。将产生有关机械和电气故障的元件尺寸相关比例律的新知识。第三个目标和挑战涉及系统级故障类型的研究。已经确定了几个关键区域。失效机制和使用计算模型的更深层次的理解需要推导。建立计算指导设计和设计规则。-将获得的知识连续应用，并提出合适的示范。提出的演示包括一个变形贴片天线，一个球形触摸板，以及一个有源矩阵LED阵列。复杂性一年比一年增加。

BACKGROUND AND MOTIVATION: This proposal is at the cross-section of electronics technology and material science. It describes research to enable the realization of stretchable electronic assemblies. The team believes that many electronic system known today can be designed to morph to take on new shapes in the future. The most common technical approach is to use "monolithic" wafer scale processes to fabricate stretchable wavy electronics. While interesting, this proposal will follow a non-monolithic and more heterogeneous alternative. The proposed approach builds on a board level connection and assembly methodology which are open to devices from various sources with various dimensions. -SUPPORTING STUDIES: The points of entry for the investigators comes from prior research where the team has (i) learned to produce and process chip scale functional device segments and (ii) pioneering work on a unique placement and interconnection technology, which is based on fluidic self-assembly and transfer to enable the placement and interconnection of functional chip scale and microscopic device segments on unconventional substrates. The investigators gathered supporting results within the proposed field of research; the supporting results include the realization of (i) a stretchable and inflatable lighting structure, (ii) a microphone array which morphs into a sphere, and (iii) a spherical touchpad. -SUMMARY OF GAINED INSIGHTS: The supporting studies have shown that the bottlenecks are not the applications but a number of technical limitations and a lag of understanding of system level failure modes, which we propose to study and overcome in this proposal. -The FIRST GOAL and challenge addresses the fact that the research has been limited to designs with a single metallization layer; the fabrication of stretchable multiple metallization layers with vias in between, is presently not possible. This puts constraints on the routing and complexity of the systems that can be produced. Moreover, AC and HF properties have not been studid, which is another important task.-The SECOND GOAL and challenge deals with the assembly and electrical connection of active devices. Potential solutions are proposed to enable the assembly of not only macroscopic but also microscopic chips. New knowledge on component-size dependent scaling-laws concerning mechanical and electrical failure will be generated.-The THIRD GOAL and challenge deals with the study of system level failure types. Several critical regions have been identified. Failure mechanisms and a deeper understanding using computational models need to be derived. Computational guided designs and design rules are to be established.-The gained knowledge will be applied consecutively and suitable demonstrators are proposed. The proposed demonstrators include a metamorphic patch antenna, a spherical touch pad, as well as an active matrix LED array. The complexity increases from one year to the next.