Yamamoto Michitaka, Okuda Shinji, Takamatsu Seiichi, Itoh Toshihiro
Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8563, Japan.
Micromachines (Basel). 2022 Jul 29;13(8):1210. doi: 10.3390/mi13081210.
Metal interconnects with a vertical wavy structure have been studied to realize high-density and low-electric-resistance stretchable interconnects. This study proposed a new method for fabricating vertical wavy structured metal interconnects that comprises the pre-stretch method and the micro-corrugation process. The pre-stretch method is a conventional method in which a metal film is placed on a pre-stretched substrate, and a vertical wavy structure is formed using the return force of the substrate. The micro-corrugation process is a recent method in which a metal foil is bent vertically and continuously using micro-gears. In the proposed method, the pitch of the vertical wavy structured interconnect fabricated using the micro-corrugation process is significantly narrowed using the restoring force of the pre-stretched substrate, with stretchability improvement of up to 165%, which is significantly higher than that of conventional vertical wavy structured metal interconnects. The electrical resistance of the fabricated interconnect was low (120-160 mΩ) and stable (±2 mΩ or less) until breakage by strain. In addition, the fabricated interconnect exhibits durability of more than 6500 times in a 30% strain cycle test.
为实现高密度、低电阻的可拉伸互连，人们对具有垂直波浪结构的金属互连进行了研究。本研究提出了一种制造垂直波浪结构金属互连的新方法，该方法包括预拉伸法和微波纹工艺。预拉伸法是一种常规方法，即将金属膜放置在预拉伸的基板上，并利用基板的回复力形成垂直波浪结构。微波纹工艺是一种最近的方法，即使用微齿轮将金属箔垂直连续弯曲。在所提出的方法中，利用预拉伸基板的回复力，显著缩小了采用微波纹工艺制造的垂直波浪结构互连的间距，拉伸性提高了165%，这明显高于传统的垂直波浪结构金属互连。所制造互连的电阻较低（120 - 160 mΩ），并且在因应变而断裂之前电阻稳定（±2 mΩ或更小）。此外，所制造的互连在30%应变循环测试中表现出超过6500次的耐久性。
