Regression analysis of photodecomposable quencher concentration effects on chemical gradient in chemically amplified extreme ultraviolet resist processes

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Understanding the dissolution kinetics of resist materials is essential for their efficient development. In this study, we investigated the dissolution kinetics of poly(4-hydroxystyrene) (PHS) with a weight-average molecular weight (M w) of 8000–30 000 and a polydispersity index (M w /M n) of 1.07–1.20. The dissolution kinetics of PHS films was observed in tetramethylammonium hydroxide (TMAH) aqueous developers by a quartz crystal microbalance (QCM) method. The TMAH concentration was changed from 0 to 2.38 wt%. The formation of a thick transient swelling layer at these M w /M n values was suppressed compared with that at M w /M n > 2. QCM data were analyzed using the polynomial regression to clarify the effects of M w and M w /M n on the dissolution kinetics in a narrow polydispersity region. Both dissolving and swelling kinetics largely depended on M w/M n. M w had little effect in 2.38 wt% TMAH developer; however, it had a large effect on the swelling when 2.38 wt% TMAH developer was diluted.

Section: Introductionmentioning

confidence: 99%

Analysis of dissolution kinetics of narrow polydispersity poly(4-hydroxystyrene) in alkaline aqueous solution using machine learning

Tanaka¹,

Watanabe²,

Matsuoka³

et al. 2021

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“…In this study, the protected unit distributions after PEB were compared at a constant sensitizer concentration, because the PAG and PDQ both function as the information receiver in the sensitization process. 44,45) Figure 3 shows the dependence of the average decomposed sensitizer concentration on the film thickness in Pattern II. The graph shows the depth profile of average decomposed sensitizer concentrations upon exposure to 90 μC cm −2 EB.…”

Section: Resultsmentioning

confidence: 99%

Theoretical study of interfacial effects on low-energy electron dynamics in chemically amplified resist processes of photomask fabrication

Kozawa¹,

Tamura²

2021

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The resist thickness has decreased with the miniaturization of transistors. In chemically amplified electron beam resists used for photomask fabrication, thermalized electrons play an important role in acid generation. The interfacial effects of low-energy electrons strongly affect the latent image formation in thin resist films. In this study, we investigated the relationships between the boundary conditions of low-energy electrons at interfaces and the protected unit distribution in terms of resist thickness, concentrations of photoacid generators and photodecomposable quenchers (PDQs), and sensitivity. The dependences of chemical gradient and optimum PDQ concentration on the boundary conditions at the interfaces for low-energy electrons were clarified. It was found that the PDQ concentration should be optimized, depending on not only the boundary conditions but also the resist film thickness. That is, the resist depth profile can be controlled by the boundary conditions at the interfaces for low-energy electrons.

“…The protected unit distributions after PEB were compared at a constant sensitizer concentration, because PAG and PDQ both function as the information receiver in the sensitization process. 43,44) The ratio of PAG concentration to PDQ concentration was optimized to maximize the chemical gradient (minimize LER) for each case. Figures 3-5 show the dependence of the average decomposed sensitizer concentration on the film thickness in Pattern II.…”

Section: Resultsmentioning

confidence: 99%

Relationship between blurring factors and interfacial effects in chemically amplified resist processes in photomask fabrication

Kozawa¹,

Tamura²

2021

Self Cite

Chemically amplified resists are an indispensable technology for photomask fabrication. The formation of latent images near interfaces in resist films is strongly affected by low-energy electron dynamics at the interfaces. On the other hand, the latent images are blurred by low-energy electron migration and acid diffusion in latent image formation. In this study, the relationship between blurring factors and interfacial effects was investigated by simulating the latent image formation on the basis of the sensitization and reaction mechanisms of chemically amplified electron beam resists. For low-energy electron dynamics, the interfacial effects on the protected unit distribution was reduced and the chemical gradient slightly increased with decreasing thermalization distance. For acid diffusion, the decrease in exposure pattern width significantly reduced the interfacial effects on the protected unit distribution in the depth direction because the acid diffusion length can be increased without sacrificing resolution.