IMEC thins chip for fully flexible circuit
Belgian research lab IMEC has demonstrated a mechanically-flexible circuit, including a bendable silicon chip thinned to 30µm.
“The resulting circuitry can be embedded in medical and lifestyle applications where user comfort and unobtrusiveness is key, such as wearable health monitors or smart clothing,” said the lab.
For the demonstration, researchers thinned a commercially available microcontroller, then embedded the die in a polyimide package 40-50µm thick.
The flexible PCB is also polyimide, supporting two-dimensional spring wires that meander to allow flexure without conductor fracture. The horseshoe meander pattern was developed and optimised at the lab.
Lastly, the assembly is embedded in polydimethylsiloxane (PDMS) or similar elastomer.
“This achievement demonstrates that flexible ultra-thin chip packages [UTCP] can be integrated with stretchable wiring,” said project researcher Jan Vanfleteren, of IMEC’s Ghent lab. “Future electronic circuitry will stretch and bend like rubber or skin while preserving its conductivity. We anticipate the first appliances will be used in intelligent clothing, with medical applications following later. Once commercial products are introduced, I expect to see clothing with signalisation by using LEDs and sensors to track movements.”
The work was presented at ESTC, the Electronics System Integration Technology Conference in Amsterdam this week.