Fundamental Study on Nanoremoval Processing Method for Microplastic Structures Using Photocatalyzed Oxidation

Abstract:

Micro plastic structures, typified by photoresists for semiconductor devices or various MEMS devices, photosensitive resins of microstereolithography, and so on, play one of the most important roles in the microdevices manufacturing. In order to process finer plastic structures with higher reliability for more complexly-modulated microdevices in the next generation micromanufacturing field, a nano removal processing method, which can be applied to a corrective machining process with the removal resolution less than 10nm in both lateral and vertical direction, is strongly required. In this study, we propose a novel nano removal processing method for micro plastic structures with photocatalyzed oxidation. Here, we apply photocatalysts micro particles as a specially designed material removal tool tip. Since a light energy is not directly used for processing the material, a material removal resolution does not depend on the diffraction limit. Further, using photocatalysts is free from micro tool wear problem. As the first report, in order to verify the fundamental feasibility of the proposed method, we performed basic experiments using TiO₂ micro particles with the diameter of 500nm for cured photosensitive resin surface. An AFM observation of the processed surface showed that a vertical removal resolution of 8nm was achieved.

• Periodical: Key Engineering Materials (Volumes 523-524)
• Pages: 610-614
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.523-524.610
• Online since: November 2012
• Authors: Takahiro Sekino, Satoru Takahashi, Kiyoshi Takamasu
• Keywords: Micro Machining, Nano-Processing, Photocatalyst, Removal Processing

References

[1] A. Ashkin, Acceleration and trapping of particles by radiation pressure, Phys. Rev. Lett. 25 (1970) 156-159

DOI: 10.1103/physrevlett.24.156

[2] A. Suzuki, et al., Nano-structures fabrication using local electrophoretic deposition associated with laser trap, Proc. JSPE (2008, spring), 12p-G-21

[3] H. Shimizu, et al., Study on micro-machining using a small particle controlled by optical pressure, Proc. JSPE (1996, autumn), 483

[4] A. Fujishima, K. Honda, Electrochemical photolysis of water at a semiconductor electrode, Nature 238 (1972) 37-38

DOI: 10.1038/238037a0

[5] S. Horikoshi, et al., Photocatalyzed degradation of polymers in aqueous semiconductor suspensions. 1., Environ. Sci. Technol. 32 (1998) 4010-4016

DOI: 10.1021/es9710464

[6] H. Hidaka, et al., Photocatalyzed degradation of polymers in aqueous semiconductor suspensions. 1., J. Polym. Sci.: Part A Polym. Chem. 34 (1996) 1311-1316

DOI: 10.1002/(sici)1099-0518(199605)34:7<1311::aid-pola18>3.0.co;2-c

[7] J. Shang, et al., Photocatalystic degradation of polystyrene plastic under fluorescent light, Environ. Sci. Technol. 37 (2003) 4494-4499

DOI: 10.1021/es0209464

[8] X. Zhao, et al., Enhancement of photocatalystic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation, Appl. Surf. Sci. 254 (2008) 1825-1829

DOI: 10.1016/j.apsusc.2007.07.154