Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing, 100871, China.
Adv Mater. 2018 Dec;30(50):e1805408. doi: 10.1002/adma.201805408. Epub 2018 Oct 11.
Electronic systems on ultrathin polymer films are generally processed with rigid supporting substrates during fabrication, followed by delamination and transfer to the targeted working areas. The challenge associated with an efficient and innocuous delamination operation is one of the major hurdles toward high-performance ultrathin flexible electronics at large scale. Herein, a facile, rapid, damage-free approach is reported for detachment of wafer-scale ultrathin electronic foils from Si wafers by capillary-assisted electrochemical delamination (CAED). Anodic etching and capillary action drive an electrolyte solution to penetrate and split the polymer/Si interface, leading to complete peel-off of the electronic foil with a 100% success rate. The delamination speed can be controlled by the applied voltage and salt concentration, reaching a maximum value of 1.66 mm s at 20 V using 2 m NaCl solution. Such a process incurs neither mechanical damage nor chemical contamination; therefore, the delaminated electronic systems remain intact, as demonstrated by high-performance carbon nanotube (CNT)-based thin-film transistors and integrated circuits constructed on a 5.5 cm × 5.0 cm parylene-based film with 4 µm thickness. Furthermore, the CAED strategy can be applied for prevalent polymer films and confers great flexibility and capability for designing and manufacturing diverse ultrathin electronic systems.
在制造过程中，通常将电子系统加工在超薄聚合物薄膜上，然后在刚性支撑基底上进行分层，再转移到目标工作区域。高效且无害的分层操作的挑战是实现大规模高性能超薄柔性电子产品的主要障碍之一。在此，我们报道了一种简便、快速、无损的方法，通过毛细辅助电化学分层（CAED）从 Si 晶片上分离晶圆级超薄电子箔片。阳极刻蚀和毛细作用驱动电解质溶液渗透并分裂聚合物/Si 界面，从而使电子箔以 100%的成功率完全剥落。通过施加的电压和盐浓度可以控制分层速度，在使用 2 m NaCl 溶液时，在 20 V 下达到最大 1.66 mm s 的速度。该工艺既不会造成机械损伤，也不会造成化学污染；因此，分层后的电子系统保持完整，这一点通过构建在厚度为 4 µm 的 5.5 cm×5.0 cm 聚对二甲苯基底薄膜上的高性能基于碳纳米管（CNT）的薄膜晶体管和集成电路得到了证明。此外，CAED 策略可适用于常见的聚合物薄膜，并为设计和制造各种超薄电子系统提供了极大的灵活性和能力。
