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Proceedings Paper

Key techniques of laser direct writing of fine lines on the spherical surface
Author(s): Fengchao Liang; Jun Hu
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Paper Abstract

The main principles of laser direct writing (LDW) system for lines on the spherical surface (SS) are discussed. It is pointed out that line profile is determined by the exposure dose distribution, which lies on the light intensity distribution of focus plane and the scanning speed. To improve the quality of line profile on the SS, several key techniques as follows are introduced. Firstly, the unique system configuration, four axes mutually intersecting at the center of the SS, is adopted, which ensures the shape of the focus be maintained circular during the writing period. Secondly, an automatic focus system (AFS) with the function of automatic focus in a certain range is introduced. Thirdly, to guarantee the linear velocity to accord with the exposure character of the photoresist all the time, an efficient arithmetic that controls motors run at appropriate angular velocity in different latitude is developed. Finally, to achieve a stable and well-behaved system so as to compensate the velocity instability resulting from unavoidable errors of mechanical and electronics factor, a powerful programmable multi-axis controller (PMAC) is utilized as the kernel element of the servocontrol system, and the curves of step response and parabolic response achieved by feedforward and PID loop tuning indicate that the location precision and velocity stability have reached a high level. The experimental results of LDW of lines on the SS work piece with a diameter 30 mm and a radius equal to 100 mm are given. The section analysis of the lines on the photoresist by the atomic force microscope (AFM) after exposure and development is performed. The results show that line width is about 3.0 μm, and the steep sides of the lines are parallel to each other.

Paper Details

Date Published: 1 February 2006
PDF: 7 pages
Proc. SPIE 6034, ICO20: Optical Design and Fabrication, 60340G (1 February 2006); doi: 10.1117/12.668100
Show Author Affiliations
Fengchao Liang, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Chinese Academy of Sciences (China)
Jun Hu, Changchun Institute of Optics, Fine Mechanics and Physics (China)


Published in SPIE Proceedings Vol. 6034:
ICO20: Optical Design and Fabrication

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