Fluorescence studies of the vacuum ultraviolet, synchrotron radiation-induced photochemistry of polystyrene

Simons, J. K.; Chen, J. M.; Taylor, Joshua P.; Rosenberg, R. A.

doi:10.1021/ma00065a003

Cited by 18 publications

(24 citation statements)

References 4 publications

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“…Corresponding thickness and density of the films were considered as dry thickness and density of the films. 6 To study the dynamics of change in film thickness it is important to understand the response of the films as a function of annealing at various temperature and time. In order to investigate the change in film thickness with temperature, we have performed X-ray reflectivity study of a particular film as a function of temperature.…”

Section: Sample Preparationmentioning

confidence: 99%

Study of structural evolution during controlled degradation of ultrathin polymer films

Mondal

Mukherjee

2010

Polymer

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The structural aspects of polyacrylamide thin films annealed at degradation threshold temperature have been studied as a function of annealing time using in situ X-ray reflectivity technique in vacuum. We observe significant decrease of thickness and increase of density with annealing time for all the films. The dynamical behavior of the changes was modeled in terms of two distinct exponential decay functions, following our earlier observation of two different time scales for the chemical modification pathways, and was found to be in excellent agreement with the data. The diffusion coefficients of the polymer chains corresponding to the two modes are found to be different by an order of magnitude. It was found that the two dynamical modes correspond to the formation of two degradation products at two different rates. The larger time constants for both the modes in case of thickness reduction compare to the chemical changes was explained in terms of inter-chain entanglement and attachment of the polymer with the substrate.

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Section: Sample Preparationmentioning

confidence: 99%

Study of structural evolution during controlled degradation of ultrathin polymer films

Mondal

Mukherjee

2010

Polymer

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“…The reaction of dehydrogenation of the molecular chain is the major step in chemical conversions of polystyrene leading to formation of π-conjugated systems when the polymer is exposed to UV light or ionizing radiation [2,11] and when it is heat-treated. An analogous process also occurs in the case of poly-p-xylylene [12].…”

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confidence: 99%

Fluorescence and absorption of polystyrene exposed to UV laser radiation

2006

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We show that when polystyrene is exposed (for 15-60 sec) to a UV laser light beam (λ = 248 nm), its absorption and luminescent properties change significantly. In the irradiated polymer, optical centers are formed with absorption bands in the 280-460 nm region and fluorescence bands in the 330-520 nm region. We have established the chemical structure of the optical centers for fluorescence of polystyrene.

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“…This results in a decrease in fluorescent signal over time. Prior photobleaching kinetics literature [22][23][24][25] indicates that this decay process is not a simple first order or second order reaction, but instead can be modeled by a sum of exponential terms:…”

Section: Fluorophore Reaction Kineticsmentioning

confidence: 99%

Studying electron-PAG interactions using electron-induced fluorescence

et al. 2016

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In extreme ultraviolet (EUV) lithography, 92 eV photons are used to expose photoresists. Typical EUV resists are organic-based and chemically amplified using photoacid generators (PAGs). Upon exposure, PAGs produce acids which catalyze reactions that result in changes in solubility. In EUV lithography, photo-and secondary electrons (energies of 10-80 eV) play a large role in PAG acid-production. Several mechanisms for electron-PAG interactions (e.g. electron trapping, and hole-initiated chemistry) have been proposed. The aim of this study is to explore another mechanism -internal excitation -in which a bound PAG electron can be excited by receiving energy from another energetic electron, causing a reaction that produces acid. This paper explores the mechanism of internal excitation through the analogous process of electron-induced fluorescence, in which an electron loses energy by transferring that energy to a molecule and that molecule emits a photon rather than decomposing. We will show and quantify electron-induced fluorescence of several fluorophores in polymer films to mimic resist materials, and use this information to refine our proposed mechanism. Relationships between the molecular structure of fluorophores and fluorescent quantum yield may aid in the development of novel PAGs for EUV lithography.

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Fluorescence studies of the vacuum ultraviolet, synchrotron radiation-induced photochemistry of polystyrene

Cited by 18 publications

References 4 publications

Study of structural evolution during controlled degradation of ultrathin polymer films

Study of structural evolution during controlled degradation of ultrathin polymer films

Fluorescence and absorption of polystyrene exposed to UV laser radiation

Studying electron-PAG interactions using electron-induced fluorescence

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