Mechanisms of acid generation from ionic photoacid generators for extreme ultraviolet and electron beam lithography

Fu, Chengbin; Du, Kun; Xue, Jie; Xin, Hanshen; Zhang, Jianhua; Li, Haoyuan

doi:10.1039/d4cp01814a

Cited by 2 publications

(1 citation statement)

References 53 publications

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“…CARs generally consist of a base polymer, a photoacid generator (PAG), and other additives (such as base quenchers for controlling the acid diffusion length). In EUV and EB lithography, the radiation-induced chemical reaction, i.e., the ionization of the base polymer, and the sensitization of secondary electrons to the PAG trigger acid generation [13][14][15]. The generated acids serve as catalysts to remove the protecting group from the polymer, generally by the application of thermal energy.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymer with tert-butoxycarbonyl-protecting group

Okamoto,

Muroya,

Kozawa

2024

Preprint

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Resist materials used for micro- and nano-patterning are formed by radiation-induced chemical reactions, with the shortening of wavelengths of the exposure light sources in lithography systems. The most widely used patterning materials in industrial lithography are chemically amplified resists (CAR). Understanding the deprotonation mechanism of ionized polymers (radical cations) is important for acid generation in CARs. In this study, the dynamics of radical cations in poly(4-hydroxystyrene) (PHS)–type resist polymers, partially and totally protected by tert-butoxycarbonyl (t-BOC) groups, are investigated using a combination of electron pulse radiolysis experiments, acid yield measurements, and quantum chemical calculations. The t-BOC(oxy) group exhibits p-electron-donating behavior in the monomer cation but changes to electron-accepting behavior in the polymer cation, owing to the interaction between substituents. The destabilization of radical cations due to decreased intramolecular charge resonance may contribute to the high deprotonation efficiency of t-BOC-capped PHS polymers.

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Section: Introductionmentioning

confidence: 99%

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymer with tert-butoxycarbonyl-protecting group

Okamoto,

Muroya,

Kozawa

2024

Preprint

View full text Add to dashboard Cite

show abstract

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymers with tert-butoxycarbonyl-protecting group

Okamoto,

Muroya,

Kozawa

2024

Sci Rep

View full text Add to dashboard Cite

The imaging reactions of resist materials used for nano-patterning have become radiation-chemical reactions, with the shortening of wavelengths of the exposure light sources in lithography systems. The most widely used patterning materials in industrial lithography are chemically amplified resists (CAR). Understanding the deprotonation mechanism of ionized polymers (radical cations) is important for acid generation in CARs. In this study, the dynamics of radical cations in poly(4-hydroxystyrene) (PHS)–type resist polymers, partially and totally protected by tert-butoxycarbonyl (t-BOC) groups, are investigated using a combination of electron pulse radiolysis experiments, acid yield measurements, and quantum chemical calculations. The t-BOC(oxy) group exhibits π-electron-donating behavior in the monomer cation but changes to electron-accepting behavior in the polymer cation, owing to the interaction between substituents. The destabilization of radical cations due to decreased intramolecular charge resonance may contribute to the high deprotonation efficiency of t-BOC-capped PHS polymers.

show abstract

Mechanisms of acid generation from ionic photoacid generators for extreme ultraviolet and electron beam lithography

Abstract: Photoacid generators (PAGs) are important components of chemically amplified resists. The properties of PAGs directly affect the sensitivity of photoresist, the line edge roughness, and resolution. Understanding the photoacid generation...

Cited by 2 publications

References 53 publications

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymer with tert-butoxycarbonyl-protecting group

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymer with tert-butoxycarbonyl-protecting group

Dynamics of ionized poly(4-hydroxystyrene)-type resist polymers with tert-butoxycarbonyl-protecting group

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