The influence of wavelength, temporal sequencing, and pulse duration on resonant infrared matrix-assisted laser processing of polymer films

Understanding the mechanism of and how to improve the laser processing of polymer films have been important issues since the advent of the procedure. Due to the important role of a photothermal mechanism in the laser ablation of polymer films, especially in transparent polymer films, it is both important and effective to adjust the evolution of heat and temperature in time and space during laser processing by simply adjusting the ambient environment so as to improve and understand the mechanism of this procedure. In this work, studies on the pyrolysis of PET film and on temperature field-assisted ultraviolet nanosecond (UV-ns) pulse laser processing of polyethylene terephthalate (PET) film were performed to investigate the photothermal ablation mechanism and the effects of temperature on laser processing. The results showed that the UV-ns laser processing of PET film was dominated by the photothermal process, in which PET polymer chains decomposed, melted, recomposed and reacted with the ambient gases. The ambient temperature changed the heat transfer and temperature distribution in the laser processing. Low ambient temperature reduced the thermal effect and an increase in ambient temperature improved its efficiency (kerf width: 39.63 μm at −25 °C; 48.30 μm at 0 °C; 45.81 μm at 25 °C; 100.70 μm at 100 °C) but exacerbated the thermal effect.

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Matrix Assisted Laser Processing of Organic Thin Films with an Er:YAG Laser

Journal of Laser Micro/Nanoengineering ◽

10.2961/jlmn.2006.01.0015 ◽

2006 ◽

Vol 1 (1) ◽

pp. 79-83 ◽

Cited By ~ 7

Author(s):

D. Bubb

Keyword(s):

Thin Films ◽

Laser Processing ◽

Er:Yag Laser ◽

Organic Thin Films ◽

Matrix Assisted Laser

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Long-Pulse Duration Excimer Laser Processing in the Fabrication of High Performance Polysilicon TFTs for Large Area Electronics

MRS Proceedings ◽

10.1557/proc-685-d7.1.1 ◽

2001 ◽

Vol 685 ◽

Cited By ~ 1

Author(s):

E. Fogarassy ◽

B. Prévot ◽

S. de Unamuno ◽

C. Prat ◽

D. Zahorski ◽

...

Keyword(s):

Pulse Duration ◽

Excimer Laser ◽

Laser Processing ◽

High Performance ◽

Microstructural Analysis ◽

Neutral Atmosphere ◽

Large Area ◽

Electrical Stress ◽

Si Films ◽

Long Pulse

AbstractIn this work, was investigated both numerically and experimentally, the excimer laser processing of a-Si films deposited on SiO2-coated glass substrates, using the very large area (∼ 20 cm2) and long pulse duration (200 ns) excimer source from SOPRA Company. Experiments were carried out in air or in neutral atmosphere, using both the single- and multi-shot mode. From the microstructural analysis of the laser irradiated area the formation of a large-grained material through the so-called SLG regime was evidenced. In addition, the application of a multi-shot process was demonstrated to be very efficient to prepare uniform polysilicon layers with enlarged grain sizes (up to 1.5 µm after 20 shots). Finally, poly-Si TFTs prepared in the optimized conditions (multi-shot, neutral ambience) exibited field effect mobilities up to 235 cm2/V.s (for N-type) and 84 cm2/V.s (for P-type), with fairly uniform device characteristics over large area and excellent stability under electrical stress.

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