Original article: https://doi.org/10.3390/nano15110830
Directly writing tiny copper circuits on glass with laser precision—without needing traditional steps like lithography, vacuum coating, or chemical etching—is a major breakthrough for the future of microfabrication.
In this work, we introduce a high-resolution, mask-free method to add metal onto glass. It uses ultrashort-pulse Bessel beam lasers to prepare the glass surface, followed by silver ion treatment and copper plating.
Here’s how it works:
- The laser creates tiny chemical changes (nanoscale defects) on the glass surface.
- When the surface is exposed to a silver nitrate (AgNO₃) solution, the silver ions are reduced to metallic silver (Ag⁰) directly on the glass.
- These silver spots become strong seeds for copper growth during electroless plating.
With this method, we successfully created copper circuit lines as narrow as 0.7 micrometers, showing excellent smoothness and strong adhesion to the glass.
Why it matters:
Compared to traditional methods like redistribution layers (RDL) and under-bump metallization (UBM), this new process:
- Skips many complex steps
- Doesn’t require masks or vacuum systems
- Saves time and simplifies production
It’s also scalable and flexible, making it ideal for use in transparent electronics, advanced packaging (like fan-out), and high-density electronic connections.