Optics and Precision Engineering, Volume. 22, Issue 8, 2180(2014)
Spin coating of UV-curable resist for imprinting long-wave infrared subwavelength structures
The ultraviolet-curing imprinting resist on Si substrates was explored by spin coating method, and the long wave subwavelength structures were imprinted. The surface topography of the coated resist layers was observed by a Laser Scanning Co-focal Microscope (LSCM), and their surface roughnesses(Ra) were tested. The thicknesses of the resist layers were tested by an ellipsometer, then the surface morphology and the structure heights of the imprinted patterns were tested by a Scanning Electron Microscope (SEM) and a Scanning Probe Microscopy(SPM), respectively. Results show when spin velocities are as low as 300 r/min, the resist layers have negligible defects, such as gas bubbles, pinholes and very low Ra, meanwhile, it shows a bad uniformity. The uniformity can be improved by increasing spin velocity, however, the bubbles and pinholes in the resist layers are also increased and cannot be decreased by extending the spin time at elevated velocities. A four-spin-velocity coating method was proposed to eliminate the bubbles and pinholes and obtain the resist layers with high uniformity. The obtained resist layers show the roughness to be 317 nm, lower than that of the Si substrate (324 nm) and its uniformity is 89.17%, mean thickness is 626 nm. These results well satisfy the requirement of UV imprinting of long-wave infrared antireflective subwavelength structures and imprinted patterns have the advantages of good uniformity, integrity, and higher fidelity.
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WANG Zhi-jun, LI Yang-ping, ZHOU Xiao-yi, LI Jun, LIU Zheng-tang. Spin coating of UV-curable resist for imprinting long-wave infrared subwavelength structures[J]. Optics and Precision Engineering, 2014, 22(8): 2180
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Received: Nov. 1, 2013
Accepted: --
Published Online: Sep. 15, 2014
The Author Email: Zhi-jun WANG (wzjun2010@126.com)