Comparison of the Ablation Behavior of Polymer Films in the IR and UV with Nanosecond and Picosecond Pulses

Hahn, Ch.; Lippert, Thomas; Wokaun, Alexander

doi:10.1021/jp983609j

Cited by 24 publications

(17 citation statements)

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“…Picosecond (ps) pulses have not found many applications in structuring of polymers, as they lack the advantages of fs pulses, and perform not much better than ns pulses, at least in the UV. The effect of ps and ns pulses on PMMA has been studied in the UV (266 nm) and the near IR (1 064 nm)96 using different dopants, i.e., IR‐165 at 1 064 nm and diazomeldrum's acid (DMA) at 266 nm. With IR‐165, the polymer matrix is heated by vibrational relaxation and multi‐phonon up‐pumping 97.…”

Section: Discussionmentioning

confidence: 99%

Interaction of Photons with Polymers: From Surface Modification to Ablation

Lippert

2005

Plasma Processes & Polymers

137

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Summary: This work reviews the interaction of photons with polymers with an emphasis on UV laser ablation and surface modification using VUV lamps. Laser ablation of polymers is an established process in industrial applications, but the mechanisms of ablation are still controversial. Different polymers, such as poly(methyl methacrylate), polyimides and specially designed polymers are used as examples to show that the mechanism is a mixture of photochemical and photothermal features which are closely related to the polymer structure and properties. Different approaches to probe the ablation mechanisms and to improve ablation are discussed. Photoactive groups have been introduced into the polymer structure to improve the quality of ablation and to elucidate the ablation mechanisms. The experimental techniques to probe the ablation mechanism range from time‐resolved measurements, such as shadowgraphy, ToF‐MS, and ns‐surface interferometry to variations of the irradiation wavelengths and pulse lengths. The necessity for a critical evaluation of the experimental procedures and analysis is discussed exemplary for polyimides. The data for different types of polyimides are mixed up and some experimental procedures are possibly causing problems for the data evaluation. Various recent trends for laser ablation, such as ultrafast ablation or VUV ablation are also discussed. Surface modifications of polymers using VUV photons from lamps are discussed for oxidation and nitriding of poly dimethylsiloxane (PDMS) and polyolefines. The mechanism of the PDMS surface oxidation is presented in detail.

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Section: Discussionmentioning

confidence: 99%

Interaction of Photons with Polymers: From Surface Modification to Ablation

Lippert

2005

Plasma Processes & Polymers

137

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“…The model and all results have been developed in MATLAB. Material removal of plastics is determined using data in literature [32][33][34] and will not be discussed here.…”

Section: Single Pulse Modelmentioning

confidence: 99%

“…The first case, progressive ablation, is calculated for metals based on the single pulse model with corresponding initial temperature Tj and effective incident laser intensity /Q. Experimental data are utilized for plastics [32][33][34]. To avoid unnecessary duplicate tasks and to reduce computational time, a library of ablation depth data is produced and stored separately.…”

Section: Materials Removalmentioning

confidence: 99%

Modeling of Thin-Film Single and Multilayer Nanosecond Pulsed Laser Processing

Lutey

2013

Journal of Manufacturing Science and Engineering

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A complete model of nanosecond pulsed laser scribing of arbitrary thin multilayer structures is presented. The chain of events is separated according to time-scale; an initial simulation considers material response during the pulse; another combines this result with the much slower effects of heat flow away from the laser axis. The former considers heating, vaporization and phase explosion of metals in the course of a single pulse, accounting for variations in thermal conductivity and optical absorption as the material becomes superheated and approaches its critical temperature. The latter calculates the bidimensional heat flow in a complete multilayer structure over the course of a scribing operation, combining material properties and considering removal by both short-pulse ablation and long-term heating of the workpiece. Simulation results for the single pulse ablation of an aluminum target align well with published experimental data both in terms of phase-explosion threshold and ablation depth as a function offluence. Bidinierrsional heat flow simulations of a polypropylene-aluminum-polypropylene triplex structure reveal the progression of events toward steady state behavior; aluminum ejected due to short-pulse ablation and plastic removed due to conduction.

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“…This region is similar as the condition achieved at recalescence point in the transformation temperature curve during quenching or cooling period. It is well known that laser ablation involves photothermal and photochemical process, depending on the nature of the material used and the experimental conditions, for example laser fluence, wavelength, and pulse duration (Sato et al, 2001;Serafetinides et al, 2001;Hahn et al, 1999). A 193 nm wavelength radiation can cause a neat and clean etch region because at this wavelength the molar extinction coefficient of the material is high (~ 10 4 L mol -1 cm -1 ) so that 95% of the light is absorbed in the first 300 nm of the substrate.…”

Section: Super Lateral Growth Energymentioning

confidence: 99%