Alberto Piqué: Laser-direct write process enables printing of functional devices
Laser direct-write techniques are being used to print hybrid electronics.
20 January 2017, SPIE Newsroom. DOI: 10.1117/2.3201701.06
Dr. Alberto Piqué and his group at the U.S. Naval Research Laboratory (NRL) are working on techniques for printing the next generation of 3D hybrid electronics. The process, known as laser direct-write (LDW), is a printing technique where small amounts of functional materials are propelled forward onto a receiving substrate by a laser pulse. In addition, LDW can transfer and place entire functional microcomponents and devices (such as bare dies) onto a receiving substrate. Moreover, the LDW process can also operate in a subtractive mode by removing material via laser micromachining.
Most electronics today are printed using lithographic or chemical processes that were developed over decades resulting in the cheap and mass-produced devices of today. The techniques being developed at NRL's LDW lab are non-lithographic and much closer to additive manufacturing or 3D printing. They are able to print using many different types of materials and suspensions with low (i.e. water) to high (i.e. toothpaste) viscosities. They have demonstrated LDW of functional devices such as interconnects, antennas, sensors and microbatteries. These advances in printing have created a new tool for rapid prototyping and device fabrication not limited by traditional design protocols.
Printed examples with very high resolutions were on display when SPIE visited the lab late last year. The team has printed freestanding structures, as small as several micrometers wide, as well as stacked layers that are transferred concurrently to a substrate. Although the process is serial in nature, it can be combined with a spatial light modulator to operate in a parallel mode to print at the much higher speeds required in a production environment.
The team is working predominately on mastering the technique and developing the materials that will be used for future devices. But as Dr. Piqué explains, they are also working on pushing the limits of the field as well.
"We're pursuing different applications, for example printing different types of materials that can be co-located and jointly processed and this has been challenging. The processing conditions to deposit a metal may be different than the processing conditions for a polymer or a ceramic. It's an area that we are investigating to make more advanced structures. For example, if you can combine an insulator material with a conducting material, then you can start making other types of devices beyond interconnects."