Rapid sintering of printed silver microstructures via projection of spatiotemporally focused femtosecond light sheet

Abstract

Due to the poor electrical conductivity of printed silver microstructures, it is often necessary to improve their conductivity via sintering. Although thermal sintering is effective, it is incompatible with thermally sensitive substrates. Sintering with femtosecond laser is a promising low-temperature technique, but it is slow due to the point-by-point scanning mechanism. Here, we present a projection-based femtosecond sintering technique that overcomes this challenge by sintering areas as large as 0.25 mm × 0.25 mm in <1.5 ms. Our technique is 50 times faster, and it improves conductivity by 20 times. Thus, it is a scalable and substrate-friendly sintering technique.