Direct optical polymer patterning
As a platform for electronic devices, polymeric materials offer the advantages of intrinsic flexibility and stretchability relative to hard material devices. However, unlike materials such as silicon, there are few tools for large-scale patterning of monolithic devices. Zheng et al. developed an optical lithography technique for the high-throughput fabrication of transistor circuitry on stretchable substrates. In this method, ultraviolet light is used to control the local solubility of the polymer, which makes it possible to fabricate transistors on the micrometer scale. These devices can be made with high yield and excellent uniformity without compromising their electronic and mechanical characteristics.
Science, abh3551, this issue p. 88
Abstract
Polymeric electronic materials have enabled soft and stretchable electronics. However, the lack of a universal micro/nanofabrication method for skin-like and elastic circuits results in low device density and limited parallel signal recording and processing ability relative to silicon-based devices. We present a monolithic optical microlithographic process that directly micropatterns a set of elastic electronic materials by sequential ultraviolet lightтАУtriggered solubility modulation. We fabricated transistors with channel lengths of 2 micrometers at a density of 42,000 transistors per square centimeter. We fabricated elastic circuits including an XOR gate and a half adder, both of which are essential components for an arithmetic logic unit. Our process offers a route to realize wafer-level fabrication of complex, high-density, and multilayered elastic circuits with performance rivaling that of their rigid counterparts.
