Ab initio photodynamics of model EUV photoresists

Chalabala, Jan; Dvořák, Ondřej; Slavı́ček, Petr

doi:10.1016/j.chemphys.2018.06.009

Cited by 9 publications

(11 citation statements)

References 83 publications

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“…Inclusion of counteranions, as we will demonstrate later, does not explain the difference. There is an apparent discrepancy between our BDFE and multireference bond strength 39 (0.09 vs 0.96 eV), but they are not directly comparable as the multireference calculation only provides the electronic contribution. By ignoring the vibrational (zero point and finite temperature) and entropic contributions to the BDFE, the PBE0-D3(BJ) contribution to this reaction is 0.67 eV.…”

Section: Resultscontrasting

confidence: 67%

“…The presence of a dealkylated cage with charge 3+ reported is therefore intriguing. 22 Multireference calculations on Sn(CH 3 ) 3 OH suggested the presence of multiple dissociative excited state potential energy surfaces, 39 which could explain the observation.…”

Section: Resultsmentioning

confidence: 98%

“…The drastic reduction in bond energy and change in methyl geometry is consistent with multireference calculations performed on ionized Sn(CH 3 ) 3 OH. 39 Atomic displacements subsequent to ionization are magnified by 10 times and shown in red arrows in the bottom left panel of Figure 2. The involved tin atom moves toward the center and is coplanar with the surrounding oxygen atoms.…”

Section: Resultsmentioning

confidence: 99%

“…In a bond-breaking process the single determinant description of the electronic structure often breaks down, rendering multireference methods such as complete active space self-consistent field (CASSCF) necessary. 39 Such methods, albeit accurate, are impractical for Sn 12 R 12 (A) 2 . A state-of-the-art CASSCF algorithm can efficiently compress the determinant space to enable an active space of (50,50).…”

Section: Computation Methodologymentioning

confidence: 99%

See 3 more Smart Citations

Mechanistic Advantages of Organotin Molecular EUV Photoresists

Heidkamp

Needham

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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The Extreme Ultraviolet(EUV)-induced radiation exposure chemistry in organotinoxo systems, represented by the archetypal [(R Sn) 12 O 14 (OH) 6 ](A) 2 cage, has been investigated with density functional theory. Upholding existing experimental evidence of Sn-C cleavage dominant chemistry, computations have revealed either electron attachment or ionization can single-handedly trigger tin-carbon bond cleavage, partially explaining the current EUV sensitivity advantage of metal oxide systems. We have revealed that tin atoms at dierent parts of the molecule react dierently to ionization and 1 electron attachment, and have identied such selectivity as a result of local coordination chemistry instead of the macro geometry of the molecule. An ionizationdeprotonation pathway has also been identied to explain observed evolution of anion conjugate acid upon exposure and anion mass dependence in resist sensitivity.

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Section: Resultscontrasting

confidence: 67%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Computation Methodologymentioning

confidence: 99%

See 2 more Smart Citations

Mechanistic Advantages of Organotin Molecular EUV Photoresists

Heidkamp

Needham

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…We have therefore complemented the experiments with ab initio simulations, providing both various molecular data and the insight into the ultrafast photochemistry. Techniques of nonadiabatic dynamics started to be used recently as an almost standard tool in photochemistry, and the same methods can be used for ionization induced dynamics. − …”

Section: Introductionmentioning

confidence: 99%

Photochemistry of Amylene Double Bond in Clusters on Free Argon Nanoparticles

et al. 2020

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We have investigated reactivity of double bond in 2methyl-2-butene (also trimethylethylene or amylene) in the excited and ionized states. In a combined experimental and theoretical study, we focused on both the intermolecular and intramolecular reactions. In a molecular beam experiment, we have sequentially picked up several amylene molecules on the surface of argon nanoparticles Ar M , M̅ ≈ 90, acting as a cold support. Ionization with 70 eV electrons yields mass spectra strongly dominated by amylene cluster ions Am(Am) n + . Interestingly, upon multiphoton ionization with 193 nm (6.4 eV) photons, a new strong fragment series appears in the spectra, nominally corresponding to an addition of two carbon atoms, i.e., (Am) n C 2 + . This difference between electron and photoionization suggests a reaction in an excited state of amylene with a neighboring amylene molecule. We used techniques of nonadiabatic molecular dynamics to study the reactivity of amylene molecules both in the excited and in ionized states. Possible reaction pathways are proposed, substantiating the observed differences between the electron ionization and photoionization mass spectra.

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Particle-Breaking Hartree–Fock Theory for Open Molecular Systems

2023

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In this work we present the particle-breaking Hartree–Fock (PBHF) model which is a mean-field approach to open molecular systems. The interaction of a system with the environment is parametrized through a particle-breaking term in the molecular Hamiltonian. The PBHF wave function is constructed through an exponential unitary transformation of a Slater determinant with a given number of electrons. We consider only the closed-shell formalism. The parametrization results in a linear combination of Slater determinants with different numbers of electrons, i.e., the PBHF wave function is not an eigenfunction of the number operator. As a result, the density matrix may have fractional occupations which are, because of the unitary parametrization, always between 0.0 and 2.0. The occupations are optimized simultaneously with the orbitals, using the trust-region optimization procedure. In the limit of a particle-conserving Hamiltonian, the PBHF optimization will converge to a standard Hartree–Fock wave function. We show that the average number of electrons may be decreased or increased depending on whether the particle-breaking term affects occupied or virtual orbitals.

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Ab initio photodynamics of model EUV photoresists

Cited by 9 publications

References 83 publications

Mechanistic Advantages of Organotin Molecular EUV Photoresists

Mechanistic Advantages of Organotin Molecular EUV Photoresists

Photochemistry of Amylene Double Bond in Clusters on Free Argon Nanoparticles

Particle-Breaking Hartree–Fock Theory for Open Molecular Systems

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