The effect of substrate characteristics on droplet spreading of liquid metal alloys

The field of soft- and stretchable electronics is trending in research and industry due to the growing number of applications. The prospects of using soft electronics in medical devices, such as smart-patch physiological monitors, are interesting due to the potential quality of life benefits, as well as decreased cost of production. Previous work has used liquid metal alloys (LMA) using gallium [1,2] to create electrical circuits with exceptional electrical qualities and mechanical conformability. Contact dispensed patterns produced linewidths down to 50±5 um [1], but it was too slow for any sort of mass production. To decrease production time, a non-contact dispensing method, Jet-printing, was used successfully. However, it increased linewidth and variance by a factor of ten. Factors, such as capillary action and surface tension, prevent feature sizes to the degree typical of the IC industry while regular PCB technology might be possible to imitate. In a study by Guo et al. [3], they show a technique to decrease linewidth and variance compared to regular contact dispensing by manipulating the substrate. This study will investigate the change in deposition results with respect to line width and quality by altering the surface characteristics of the substrate. The experimental results will focus on non-contact deposition.

[1] Maslik, J. et al. 2022 IMAPS (NordPac). IEEE.

[2] Maslik, J. et al. 2024 IMAPS (NordPac). IEEE.

[3] Guo, H. et al. 2023. Adv. Mat. Tech.