Laser microfabrication using nano-particles dispersed polymer resist

A new laser microfabrication technique to realize a high aspect ratio microstructure with free shaped wall using newly developed resist was proposed. The resist is made of ethylcellulose in which nano-particles with average diameter of 3.4 nm was dispersed. Since this resist has a strong absorption at wavelength of about 530 run, it can be processed using focused low power output Nd:YVO4-SHG laser. From the experiments, it was confirmed that the cross-sectional shape of processed resist microstructure can be controlled by the gold (Au) concentration (1-50 wt%) and the laser beam power. The processed depth showed a strong dependency on Au concentration and showed maximum at 17 wt% Au concentration. From analysis of the processed resist surface, it was revealed that the Au aggregation at the bottom of the processed channel played an important role for the resultant processed depth.