Miniaturized Soft and Stretchable Multilayer Circuits through Laser-Defined High Aspect-Ratio Printing

Area of Science:

• Materials Science
• Biomedical Engineering
• Electronics Manufacturing

Background:

• Stretchable electronics are crucial for integrating wearables with the human body for biomedical applications.
• Current microfabrication methods face challenges in achieving simultaneous tissue-like softness, high resolution, and low sheet resistance in miniaturized multilayer stretchable printed circuit boards.

Purpose of the Study:

• To develop a scalable printing method for ultra-soft, high-resolution stretchable conductors with high aspect-ratio tracks and fine vertical interconnect access (VIA).
• To demonstrate the capability of this method for creating miniaturized multilayer stretchable electronics.

Main Methods:

• A scalable printing method utilizing stencil printing into laser-defined bio-masks made from lignin.
• Achieving ultra-soft conductors (<0.4 MPa) with high strain tolerance (>300%).
• Fabricating high-resolution tracks (<2.5 µm width) and high aspect-ratio features (>1) with 20 µm VIA for multilayer configurations.

Main Results:

• Demonstrated ultra-soft (<0.4 MPa) stretchable conductors with over 300% strain capacity.
• Achieved high-resolution (<2.5 µm width) and high aspect-ratio tracks (>1) with 20 µm VIA for multilayer circuits.
• Developed a miniaturized multilayer ultra-soft wireless near-field-communication temperature logger.

Conclusions:

• The developed laser-defined printing method offers a sustainable approach to create advanced stretchable conductors beyond conventional capabilities.
• This technology paves the way for the next generation of ultra-soft, miniaturized wearable devices for biomedical applications.