Direct-write, microfiber-based template for pattern transfer of aligned metallic microwires

Abstract

We have demonstrated a fiber-based template process for fabricating site-specific and highly aligned platinum (Pt) microwires (MWs) with a polymeric core utilizing near-filed electrospinning (NFES) and soft transferring technology. Eliminating the indispensably expensive submicron lithographic and metal catalyst/lift-off as well as the extensive etching processes, the proposed method is direct-write, lithography-free, and low cost. As a demonstration, Pt sputtering deposition on top of a 500-μm length of microfibers for 5/10/15 min is sufficient to produce highly conductible Pt MWs with a sheet resistance measured to be 1.46/1.09/0.83 kΩ/sq, with good adhesion between the sputtered MWs and the underlying layers. The measured total resistances were found to increase almost linearly with the length of the MWs and are comparatively more conductive than polypyrrole films. Furthermore, the reliable and repeatable nanofiber arrays can be speedily fabricated, while various patterns and dimensions are predominantly controllable by NFES in a direct-write, addressable manner.