Researchers from Xerox PARC have developed a new micro-transfer printing technique that can be used to mass-transfer microLED devices. This technology offers high performance, simple and robust structure, and high process scalability and flexibility.

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The new technology uses thermally induced adhesion modulation of shape memory polymer (SMP) materials. The idea is to use a print head that uses an individually-addressable micro-fabricated resistive heater array, which locally delivers heat for transfer of single microLED devices.

The researchers demonstrated the new technology, and have transferred chips with a size of 50x50 um, with a pixel pitch of 100 um. The transfer head can be dynamically configured to assemble micro-objects in arbitrary patterns, allowing digital manufacturing, object sorting, or in-line assembly correction of defects.

The transfer-printing head (shown above) comprises of a glass substrate, a micro-heater array, and a controllable adhesion layer, which is made of SMP.