Fabricating patterned polyelectrolyte brushes by dynamic microprojection lithography for selective electroless metal deposition

Abstract

The emerging need for flexible and wearable electronics has been pushing the edge of the traditional electroless deposition (ELD) technique. With the rapid development of polymer‐assisted ELD (PAELD), its time‐consuming and possess‐complicated procedures have hindered the application of the technique. Here, for purpose of addressing the challenge, the work demonstrates a highly efficient and versatile method, based on the procedure consisting of the customized polyelectrolyte brushes patterns fabrication with the assistance of mask‐free dynamic microprojection lithography and sequential selective ELD (DML‐ELD), for the fabrication of arbitrary electrode on the silicon dioxide/silicon (SiO2/Si) substrate. The resistivity of the patterned copper electrode maintained around 0.062 Ω∙mm at room temperature, indicating the high reproducibility and stability of the method. Furthermore, an interdigital copper electrode fabricated with the DML‐ELD method was coated with a poly(vinyl alcohol) sensing layer, forming a sandwich structure for the ambient humidity detection. The sensitivity of the lab‐made humidity sensor achieves 0.82 pF/%RH (<80%RH) and 19.3 pF/%RH (>80%RH). The work has demonstrated the broad prospect of the proposed DML‐ELD method in the rapid and customized manufacturing of microcircuit fabrication for electronic devices.