Flexible silicon electronics by laser processing

Sara Ver-Bruggen - 25 Oct 2011

Researchers in the US have developed a process for assembling very thin silicon chips on flexible substrates, to create conformal circuits.

The process developed by the team at the North Dakota State University (NDSU) Centre for Nanoscale Science and Engineering uses laser processing to enable non-contact assembly of thin semiconductor chips onto a substrate, achieving higher throughput and reducing manufacturing costs.

Since working on the laser-enabled advanced packaging technology in 2008, NDSU has filed for a patent on parts of the technique, described as the Thermo-Mechanical Selective Laser Assisted Die Transfer (tmSLADT) process.

Laser processing

The process can place active, passive and other types of ultra-thin chips under 50µm, at specific orientations and sites, on a flexible substrate. The process can produce flexible electronic and photonic devices that are conformal for different shapes, and can be bent or rolled.

The tmSLADT process is compatible with commercial micro-assembly and microelectromechanical system (MEMS) fabrication processes. The technique could be used to produce devices for defence and security applications, but commercial possibilities include smartcards, RFID labels, banking cards, smart currency, antennas shaped around devices, sensor arrays, and smart textiles.

Healthcare

In September 2011, Massachusetts-based start-up MC10 announced it would be targeting medical device and healthcare markets as early adopters of its flexible silicon circuit technology. The company raised almost $15 million (€10.8 million) in series B financing.

One of MC10's investors has strong connections with the healthcare industry through funding companies, which could help accelerate the commercialisation.

MC10 has demonstrated a small translucent device, about the size of a stamp, which attaches to skin to measure vital body signs and processes, such as heart rate and perspiration.

MC10 is working with Massachusetts General Hospital to integrate its stretchable circuits with cardiac catheters, for monitoring irregular heartbeats. There are also plans, with the US military, to develop its technology as power sources for vehicles.

Enjoyed reading this article? For even more high-value content on the plastic electronics industry, subscribe to +Plastic Electronics magazine.