Micro-Transfer Printing - Flexible and Stretchable Electronics
The Center has developed an adhesiveless transfer printing process of micro/nanoscale wafer-based devices (LED's, sensors, TFT's, FET's, etc), wires, and ribbons which, with controlled undercut etching, are made very thin (100-200 nm) and flexible allowing transfer to other substrates. In the process, the wafer produced devices/structures are undercut with a controlled etch that leaves them attached with only small tags. A soft PDMS stamp is then brought in contact with the wafer in a step and repeat process which can disperse the devices on a receiving substrate.
This undercut etching followed by pick-and –place process can also be applied to micro and nanowires/ribbons, SWNT, and other structures formed on a silicon substrate to create new products and potential applications. When the receiving substrate is a pre-stressed elastomer, the process can create stretchable form of printed silicon electronics. The process can also be used to "print" multi-layered active silicon devices to produce integrated electronic devices.
This process is being employed by the Center to assemble or integrate nano- and micro-structures into functional devices. It can combine structures produced by different Nano-CEMMS patterning processes as well as other well-established micro/nano manufacturing processes into complete, heterogeneously integrated systems.
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