# 마이크로 열소자 제작을 위한 고세장비 금속채널의 레이저 가공

• Oh, Kwang-Hwan (Department of Mechatronics, Gwangju Institute of Science and Technology) ;
• Lee, Min-Kyu (Department of Mechatronics, Gwangju Institute of Science and Technology) ;
• Jeong, Sung-Ho (Department of Mechatronics, Gwangju Institute of Science and Technology)
• 오광환 (광주과학기술원 기전공학과) ;
• 이민규 (광주과학기술원 기전공학과) ;
• 정성호 (광주과학기술원 기전공학과)
• Published : 2006.10.25

#### Abstract

A fabrication method fur high-aspect-ratio microchannels in stainless steel using laser-assisted thermochemical wet etching is reported in this paper. The fabrication of deep microchannels with an aspect ratio over ten is realized by applying a multiple etching process with an optimization of process conditions. The cross-sectional profile of the microchannels can be adjusted between rectangular and triangular shapes by properly controlling laser power and etchant concentration. Excellent dimensional uniformity is achieved among the channels with little heat-affected area. Microchannels with a width ranging from 15 to $50{\mu}m$ can be fabricated with an aspect ratio of ten and a pitch of 150 m or smaller. The effects of process variables such as laser power, scan speed, and etchant concentration on the fabrication results, including etch width, depth, and cross-sectional profile are closely examined.

#### References

1. Y. Cao, M. Gao, J. E. Beam and B. Donovan, 'Experiments and analyses of flat miniature heat pipes,' Journal of Thermophysics and Heat Transfer, Vol. 11, No. 2, pp. 158-164, 1997 https://doi.org/10.2514/2.6247
2. A. V. Pattekar and M. V. Kothare, 'A microreactor for hydrogen production in micro fuel cell applications,' Journal of Microelectromechanical Systems, Vol. 13, No. 1, pp. 7-18, 2004 https://doi.org/10.1109/JMEMS.2004.823224
3. A. V. Pattekar and M. V. Kothare, 'Novel microfluidic interconnectors for high temperature and pressure applications,' Journal of Micromechanics and Microengineering, Vol. 13, No. 2, pp. 337-345, 2003 https://doi.org/10.1088/0960-1317/13/2/324
4. H. Takagi, R. Maeda, K. Ozaki, M. Parameswaran and M. Mehta, 'Phase transformation type micro pump,' Proceeding of the 5th International Symposium on Micro Machine and Human Science, pp. 199-202, 1994
5. S. J. Lee, A. Chang-Chien, S. W. Cha, R. O'Hayre, Y. I. Park, Y. Saito and F. B. Prinz, 'Design and fabrication of a micro fuel cell array with 'flip-flop' interconnection,' Journal of Power Sources, Vol. 112, No. 2, pp. 410-418, 2002 https://doi.org/10.1016/S0378-7753(02)00393-2
6. W. Shi and S. J. Lee, 'Design concepts for directed exit flow in micro fuel cells,' Fuel Cell Science, Engineering and Technology 2004, pp. 243-249, 2004
7. R. W. Haynes, G. M. Metze, V. G. Kreismanis and L. F. Eastman, 'Laser-photoinduced etching of semiconductors and metals,' Applied Physics Letters, Vol. 37, No. 4, pp. 344-346, 1980 https://doi.org/10.1063/1.91941
8. Y. -F. Lu, K. -D. Ye, 'Laser-induced etching of polycrystalline $Al_2O_3TiC$ in KOH aqueous solution,' Applied Physics. A, Vol. 62, pp. 43-49, 1996 https://doi.org/10.1007/BF01568086
9. B. W. Hussey and A. Gupta, 'Laser-assisted etching of $YBa_2Cu_3O_{7-{\delta}}$,' Applied Physics Letters, Vol. 54, No. 13, pp. 1272-1274, 1989 https://doi.org/10.1063/1.101488
10. R. Nowak, S. Metev and G. Sepold, 'Nd:YAG-laserinduced wet chemical etching of titanium and stainless steel,' Sensors and Actuators A, Vol. 51, pp. 41-45, 1995 https://doi.org/10.1016/0924-4247(96)80050-1
11. K. Piglmayer and H. Schieche, 'Laser-induced etching of tungsten,' Applied Surface Science, Vol. 109, No. 110, pp. 184-188, 1997 https://doi.org/10.1016/S0169-4332(96)00657-5
12. C. Gillot, Y. Avenas, N. Cezac, G. Poupon, C. Schaeffer and E. Fournier, 'Silicon heat pipes used as thermal spreaders,' IEEE Transactions on Components and Packaging Technologies, Vol. 26, No. 2, pp. 332-339, 2003 https://doi.org/10.1109/TCAPT.2003.815092
13. G. V. Treyz, R. Beach and R. M. Osgood, Jr., 'Rapid direct writing of high-aspect-ratio trenches in silicon,' Applied Physics Letters, Vol. 50, No. 8, pp. 475-477, 1987 https://doi.org/10.1063/1.98178
14. S. W. Son, M. K. Lee, K. H. Oh and S. H. Jeong, 'Fabrication of titanium microchannels using laser-assisted thermochemical wet etching,' Journal of Laser Applications, Vol. 18, No. 2, pp. 131-137, 2006 https://doi.org/10.2351/1.2164473
15. S. Kawata, H. -B. Sun, T. Tanaka and K. Takada, 'Finer features for functional microdevices,' Nature, Vol. 412, No. 6848, pp. 697-698, 2001 https://doi.org/10.1038/35089130
16. L. Lin, R. Ponnappan and J. Leland, 'High performance miniature heat pipe,' International Journal of Heat and Mass Transfer, Vol. 45, pp. 3131-3142, 2002 https://doi.org/10.1016/S0017-9310(02)00038-8
17. R. Hopkins, A. Faghri and D. Khrustalev, 'Flat miniature heat pipes with micro capillary grooves,' Journal of Heat Transfer, Vol. 121, pp. 102-109, 1999 https://doi.org/10.1115/1.2825922
18. R. Nowak and S. Metev, 'Thermochemical laser etching of stainless steel and titanium in liquids,' Applied Physics. A, Vol. 63, pp. 133-138, 1996 https://doi.org/10.1007/BF01567640
19. M. L. Berre, S. Launay, V. Sartre and M. Lallemand, 'Fabrication and experimental investigation of silicon micro heat pipes for cooling electronics,' Journal of Micromechanics and Microengineering, Vol. 13, pp. 436-441, 2003 https://doi.org/10.1088/0960-1317/13/3/313
20. B. W. Hussey, B. Haba and A. Gupta, 'Role of bubbles in laser-assisted wet etching,' Applied Physics Letters, Vol. 58, No. 24, pp. 2851-2853, 1991 https://doi.org/10.1063/1.104756