Second generation fluids for 193 nm immersion lithography

Peng, Sheng; French, Roger H.; Qiu, Weiming; Wheland, Robert C.; Yang, Min; Lemon, M. F.; Crawford, M. K.

doi:10.1117/12.606448

Cited by 27 publications

(14 citation statements)

References 2 publications

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“…There has been a concerted effort by industry and academia to increase the refractive index ͑RI͒ of fluids 5,6 and to increase the refractive index of photoresists 7 at 193 nm. According to the Rayleigh equation ͑1͒, NA is limited by the minimum RI along the optical path, and if sufficient progress in materials for lens and immersion liquids is made, the limiter becomes the RI of the photoresist.…”

Section: Introductionmentioning

confidence: 99%

Application of quantitative structure property relationship to the design of high refractive index 193i resist

Blakey

Conley³

et al. 2008

J. Micro/Nanolith. MEMS MOEMS

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Abstract.A robust quantitative structure property relationship ͑QSPR͒ model with five parameters has been developed from 126 organic compounds for the prediction of refractive index at 589 nm. The model and the knowledge of the refractive index dispersion were used in the rational design of new materials for 193-nm immersion lithography. The significance of this model is that the structural descriptors can be readily calculated and the factors that significantly affect refractive index can be easily identified and used to guide the selection of candidates. Using this model, rapid screening of large structure databases is possible in order to find candidates. As an example of this approach, the synthesis of the copolymer of a trithiocyclane-methacrylate derivative, identified by the model, with 2-methyl adamantyl methacrylate is described. The measured refractive index of the copolymer at 589 nm agrees well with the value predicted by the model. The new polymer showed a 9.4% increase in refractive index at 193 nm compared with the standard ArF resist.

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Section: Introductionmentioning

confidence: 99%

Application of quantitative structure property relationship to the design of high refractive index 193i resist

Blakey

Conley³

et al. 2008

J. Micro/Nanolith. MEMS MOEMS

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“…5 In a double-patterning approach with high-index methods, half pitches approaching 16 nm were anticipated with the most aggressive k1 reductions. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] High-index immersion was considered as an alternative next technology until the fall of 2008, when the development of the required materials and technology was stopped by the main scanner vendors, and the focus shifted toward double patterning for 32-nm node and EUV lithography for the 22-nm node. Whereas EUV has shown the required high resolution on full wafer, its readiness to produce at acceptable cost of ownership still has to be demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Fluid-photoresist interactions and imaging in high-index immersion lithography

Tran

Hendrickx

Roey

et al. 2009

J. Micro/Nanolith. MEMS MOEMS

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Optical immersion lithography using fluids with refractive indices greater than that of water ͑1.436͒ can enable numerical apertures of 1.55 or above for printing sub-45-nm lines. Two second-generation immersion fluid candidates, IF132 and IF169, both have indices above 1.64 and have been optimized to absorb less than 0.1 cm −1 at 193.4 nm. These fluids, although meeting the requirements of index and absorption, must also be compatible with current resists and processes to image the required fine line patterns. Results of fluid-resist interactions, with water and high-index fluids on four commercial resists, are shown. Photoacid generator ͑PAG͒ leaching measurements reveal much less leaching into both high-index fluids than into water, and in two waterimmersion dedicated resists, no leaching is detected with the high-index immersion fluids. Little resist thickness change and swelling is detected by a quartz crystal microbalance ͑QCM͒ on contact with the fluids. Resist profile and line height changes due to pre-and postexposure fluid contact varies from one resist to the next, but overall the changes are minimal. Misting defects from high-index fluid-resist contact show lower counts than for water, and imaging on an immersion interference printer produces 36-nm half-pitch lines. We find no serious impediments to the use of high-index liquids based on these results.

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“…Recently, second generation fluids with a refractive index of ~ 1.6 at 193 nm have been prepared, driven by the growing interest in this area. 4,5,6 However, the developed fluids so far still present limitations such as high absorbance (> 0.4 /cm) at the working wavelength, 4 or high viscosity. 5 Recently, alkanes, base second generation fluids have been presented by some manufactures.…”

Section: Introductionmentioning

confidence: 99%

Outlook for potential third-generation immersion fluids

et al. 2007

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In a search for alkane candidates for 193 nm immersion fluids, several alkanes and cycloalkanes were synthesized, purified and screened to ascertain their absorption at 193 nm, refractive index and temperature dispersion coefficient in the context of the actual application. In general, cycloalkanes, and more specifically polycycloalkanes, possess a higher refractive index than do linear alkanes. Decalin, cyclodecane, perhydrophenanthreme (PHP), perhydrofluorene (PHF) and perhydropyrene (PHPY) are examined as potential second and third generation immersion fluids. The use of perhydropyrene, which possesses a high refractive index of 1.7014 at 193 nm, may be limited as an immersion fluid because of high absorption at 193 nm. Mixtures of cycloalkanes can lead to a higher enhancement of the refractive index together with a decrease on the viscosity. Exhaustive purification of the fluids is a critical step in determining the real absorption of the different fluids at 193 nm. Two simple purification processes of these cycloalkanes were developed that led to low absorption fluids in the VUV region. The possibility of forming the oxygen complex in aerated fluids was reduced by purging samples with argon or nitrogen. This easy elimination of the oxygen complex shows the weak bonding nature of this complex.

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Second generation fluids for 193 nm immersion lithography

Cited by 27 publications

References 2 publications

Application of quantitative structure property relationship to the design of high refractive index 193i resist

Application of quantitative structure property relationship to the design of high refractive index 193i resist

Fluid-photoresist interactions and imaging in high-index immersion lithography

Outlook for potential third-generation immersion fluids

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