Laser machining of specially designed photopolymers: photochemical ablation mechanism

Thomas K. Lippert; J. Thomas Dickinson; Steve C. Langford; H. Furutani; H. Fukumura; Hiroshi M. Masuhara; Thilo Kunz; Alexander J. Wokaun

doi:10.1117/12.308615

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26 May 1998 Laser machining of specially designed photopolymers: photochemical ablation mechanism

Thomas K. Lippert, J. Thomas Dickinson, Steve C. Langford, H. Furutani, H. Fukumura, Hiroshi M. Masuhara, Thilo Kunz, Alexander J. Wokaun

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Proceedings Volume 3404, ALT'97 International Conference on Laser Surface Processing; (1998) https://doi.org/10.1117/12.308615
Event: ALT '97 International Conference on Laser Surface Processing, 1997, Limoges, France

Abstract

Photopolymers based on the triazeno chromophore group (-NequalsN-N<) have been developed. The absorption properties can be tailored for a specific irradiation wavelength (e.g. 308 cm XeCl laser). The photochemical exothermic decomposition yields high energetic gaseous products which are not contaminating the surface. The polymer can be structured with high resolution. No debris has been found around the etched corners. Maximum ablation rates of about 3 micrometers / pulse were achieved due to the dynamic absorption behavior (bleaching during the pulse). No physical or chemical modifications of the polymer surface could be detected after irradiation at the tailored absorption wavelength, whereas irradiation at different wavelengths resulted in modified (physical and chemical) surfaces. The etching of the polymer starts and ends with the laser pulse, shown by ns-interferometry, confirming that the acting mechanism is mainly photochemical. TOF-MS revealed fragments which are also totally compatible with a photochemical decomposition mechanism.

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Thomas K. Lippert, J. Thomas Dickinson, Steve C. Langford, H. Furutani, H. Fukumura, Hiroshi M. Masuhara, Thilo Kunz, and Alexander J. Wokaun "Laser machining of specially designed photopolymers: photochemical ablation mechanism", Proc. SPIE 3404, ALT'97 International Conference on Laser Surface Processing, (26 May 1998); https://doi.org/10.1117/12.308615

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