Parallelized laser-direct patterning of nanocrystalline metal thin films by use of a pulsed laser-induced thermo-elastic force.
Thin film patterning by the conventional lithographic technique requires a number of steps including the deposition, development, and removal of the photoresist layer. Here we demonstrate that metal thin films evaporated on glass can be directly patterned by a spatially modulated pulsed Nd-YAG laser beam (wavelength = 1064 nm, pulse width = 6 ns) incident from the backside of the substrate. This method utilizes a pulsed laser-induced thermo-elastic force exerted on the film which plays a role in detaching it from the substrate. High-fidelity patterns at the micrometer scale have been fabricated over a few square centimeters by a single pulse with pulse energy of 850 mJ. This is attributed to the fact that deposited metal films are polycrystalline with nano-sized grains, and thus localized etching of the material is possible with shearing along the weakly bonded grain boundary regions. We have also developed a nano-block model to simulate the laser-direct patterning of nanocrystalline thin films. Experimental results could be well described with this simulation model. The patterning process presented here provides a simple photoresist-free route to fabricate metal thin film patterns on transparent substrates.
Yoo
Hyeonggeun
H
Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea.
Shin
Hyunkwon
H
Sim
Boyeon
B
Kim
Sangtae
S
Lee
Myeongkyu
M
D003460:Crystallization / Q000379:methods*; D055119:Elastic Modulus; D007834:Lasers; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008670:Metals / Q000737:chemistry* / Q000528:radiation effects*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature
D046911:Macromolecular Substances; D008567:Membranes, Artificial; D008670:Metals