02 Jun 2016
European research project examining micro-transfer printing to boost large-scale integration of diverse materials, devices.Tyndall National Institute, Cork, Ireland is leading a European consortium, called TOP-HIT, to develop novel technology designed to address the challenge of integrating components of different materials in large volumes at the semi-conductor scale.
The TOP-HIT (“Transfer-print operations for heterogeneous integration”) consortium uses micro-transfer printing (μTP), a technology that allows device developers to take a set of devices out of one semiconductor wafer and print these sparsely onto another wafer, transferring potentially many thousands of devices in a single transfer operation.
One potential application of the TOP-HIT technique could be to take a small platelet of a relatively costly semiconductor material, pick it up with a stamp and transfer it (by printing it) with the same stamp onto a larger surface of a cheaper substrate, then perform all the electrical and optical waveguide interconnections on the second material. Printed platelets are typically a few microns thick, and can be printed with a placement precision of about 1 µm.
Alternatively, light-emitting devices, such as LEDs or lasers, could be printed onto a material more suitable for electronic signal processing. It could even be possible to print several types of devices onto the same substrate to combine light sources, detectors and signal processing on the same platform; Tyndall says a “system-on-a-chip”, based on a complex photonic integrated circuit combining devices of different materials, could be constructed in this way.
Brian Corbett, Principal Investigator at Tyndall and coordinator of the project, explained, “The transfer print process, by combining diverse optical, electronic and other functional materials, opens up an enormous range of possibilities for new devices with embedded functionality.
"This will lead to more compact chips and systems for a variety of applications, such as telecommunications, smart sensing, biomedical sensing and data storage, but the key breakthrough will be the application of micro-transfer-printing to address the challenge of integrating non-compatible components in large volumes at the wafer level.”
The TOPHIT project is funded under the European Union’s Horizon 2020 programme for Smart System Integration: it is to run from 2015 to 2018 and is worth over €5 million. The partners, which are located across Europe, provide complementary expertise:
X-Celeprint (Ireland) is a manufacturer of transfer printing equipment and provides the printing expertise. Its equipment is capable of printing many devices simultaneously.
IMEC (Belgium) is a large micro-electronics research centre, employing over 1,500 people. It provides the silicon photonics platforms that form the basis for the photonic products.
Caliopa Huawei (Belgium) is a photonics company that develops optical components and circuits for telecommunications.
Centre for Integrated Photonics (UK) develops indium phosphide-based components and circuits for telecommunications applications.
X-Fab (Germany), a leading analog/mixed-signal and MEMS foundry, will develop new processes to provide wafers with components that can be transfer printed.
Seagate (UK) manufactures harddisk drives and storage solutions. The Seagate facility in N-Ireland ships more than 500 million read-write heads annually.
Tyndall (Ireland) co-ordinates the project, and provides designs and components that can be transfer printed by X-Celeprint onto platforms provided by IMEC and X-Fab.
Schematic view of the micro-transfer print (µTP) process.
About the Author
Matthew Peach is a contributing editor to optics.org.