Title: Application of the Taguchi method in the optimization of laser micro-engraving of photomasks

Authors: Y. H. Chen, S. C. Tam, W. L. Chen, H. Y. Zheng

Addresses: Gintic Institute of Manufacturing Technology, Nanyang Technological University, 71 Nanyang Drive, 638075 Singapore. ' School of Electrical & Electronic Engineering, Nanyang Technological University, Nanyang Avenue, 639798 Singapore. ' Gintic Institute of Manufacturing Technology, Nanyang Technological University, 71 Nanyang Drive, 638075 Singapore. ' Gintic Institute of Manufacturing Technology, Nanyang Technological University, 71 Nanyang Drive, 638075 Singapore

Abstract: Photomasks are needed to generate various design patterns in the fabrication of liquid crysral displays (LCDs). This paper discusses the use of the Taguchi method of experimental design in optimising process parameters for micro-engraving of iron oxide coated glass using a Q-switched Nd:YAG laser. The effects of five key process parameters – beam expansion ratio, focal length, average laser power, pulse repetition rate and engraving speed – have been explored. The primary response under study is the engraving linewidth. An L16 orthogonal array was used to accommodate the experiments. The study indicated that a minimum linewidth of 18 pm could be obtained with beam expansion ratio of 5x, focal length of 50 mm, laser average power of 0.4 W, pulse repetition rate of 5 kHz, and engraving speed of 5000 mm/min.

Keywords: laser engraving; parameter optimisation; photomasks; Taguchi methods; microengraving; liquid crysral displays; LCD fabrication; iron oxide coatings; coated glass; beam expansion ratio; focal length; average laser power; pulse repetition rate; engraving speed.

DOI: 10.1504/IJMPT.1996.036336

International Journal of Materials and Product Technology, 1996 Vol.11 No.3/4, pp.333 - 344

Published online: 02 Nov 2010 *

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