A Photochemical Approach toward High‐Fidelity Programmable Transfer Printing. Issue 9 (5th July 2019) - Zhang, Ying
Abstract: Transfer printing is a critically important process toward assembling a wide range of materials and fabricating high‐performance flexible and stretchable electronics. It is still challenging to directly integrate transfer printing techniques into current semiconductor processing technologies via a low‐cost, scalable, and programmable manner. Here, a photochemical approach is proposed to transfer microelectronic components and functional materials onto soft substrates. This approach relies on the photoinduced modulation of the adhesive strength of stamps, leading to faithfully pick up and release inks upon UV irradiation. Moreover, by coupling with a photomask, this method could be further utilized to print inks via a spatially selective manner which is difficult to realize in conventional approaches. Micrometer‐sized Si inks, thin‐film metal electrodes, and polystyrene colloidal particles are transferred from their corresponding donor substrates to polydimethylsiloxane substrates to demonstrate the potential of this versatile approach. Considering that UV light is widely used in current semiconductor industry (e.g., photolithography), this method could be potentially compatible with large‐area, high‐throughput manufacturing processes. This newly developed photochemical approach toward programmable transfer printing provides a promising solution for high‐volume production of flexible and stretchable electronics in the near future. Abstract : High‐fidelity programmable transfer printing is successfully achieved by a photochemical approach. This approach relies on a newly synthesized photoresponsive polymer adhesive which undergoes light‐induced solid‐state degradation to become adhesiveless with high efficiency. This approach addresses a critically important issue in precisely controlling adhesion switchability during transfer printing.