ArF lithography

Florinated norbomane ester monomers, (V), prepared by Harada et aL (2) were effective in resist compositions when processed by ArF lithography with advantages that included improved resolution, transparency, minimal line edge roughness, and etch resistance. 

Because the NA of the optical system limits the spatial frequencies that can be transmitted to expose the resist, the NA of lens designs has migrated from 0.2 to 0.42 to 0.63 to 0.75 to 0.95. With a fundamental limit of NA 1.0 for a conventional optical system, the introduction of immersion ArF lithography has enabled the migration to hyper-NA (>1.0) optical systems. It is noteworthy that the drive toward high NA is at a cost of decreased depth of focus and increased difficulty in fabricating a lens with adequate field size. ... 

Furthermore, transesterification of hydroxyethyl ester moieties in methacrylate resists based on methacrylic acid and hydroxyethyl methacrylate resins has been demonstrated as a basis for negative-tone imaging in ArF lithography (Scheme 6.29). ... 

Remarkably, regardless of the resist technology approach used, it should be mentioned that the imaging mechanisms of resists for ArF lithography use... 

Figure 7.11 SEM images of 150-nm L/S features printed in Sumitomo s AX-210 resist, using ArF lithography.

The second platform of ester-protected positive resists designed for ArF lithography is the alicyclic polymer platform,which was first developed at the University of Texas at Austin,and involves resists in which the alicyclic units with pendant ester-protecting groups, acidic groups, and adhesion-promoting groups constitute the backbone of the polymer. Resist polymers of this platform... 

Scheme 7.38 Free radical copolymerization of various alicyclic monomers initiated by (1) azoisobutyronitrile (AIBN) in THF, and (2) di-tert-butyl peroxide (DTBP) in propylene glycol monomethylether acetate, and used in the synthesis of the alicyclic polymer resist materials for ArF lithography, pioneered at the University of Texas at Austin in 1995. Note that although only 2,3-enchainment of the cyclic olefins is shown above the scheme, 2,7-enchainement is also possible, as reported by Gaylord and co-workers. ...

Figure 7.17 SEM images of 130-nm line and space features printed in a 350-nm thick Dongjin Semichem Co. Ltd. DHA-1001 resist with ArF lithography.

The third platform of resists for ArF lithography is the ester-protected acrylate/ah-cyclic polymer hybrid platform (XLII), which was pioneered at BeU labs. The polymerization route to polymers of this platform is free radical copolymerization... 

Promising positive-tone bilayer resists based on silicon-containing methacrylate polymers bearing acid labile side groups (Scheme 7.49), and designed for ArF lithography, were reported in 1996 by researchers at Olin Ceiba-Geigy... 

Almost every single-layer resist system designed for DUV 248-nm (KrF) and DUV 193-nm (ArF lithography) needs some kind of antireflection coating to mitigate... 

U. Okoroanyanwu, H J. Levinson, C. Y. Yang, S.K. Pangrle, J. Schefske, and E. Kent, Integration considerations for 130 nm device patterning using ArF lithography, Proc. SPIE 4000, 423 (2000). 

Figure 11.25 PEB sensitivity curves for different acrylate and alicyclic/acrylate hybrid resist polymer platforms used in ArF lithography. The target CD was 120 nm L/S at 1 2 duty cycle. [Reproduced from R. Dammel, "Practical photoresist processing, SPIE Short Course No. SC616 (2005).]...

At the heart of dry ArF lithography lies an exposure tool equipped with ArF exciplex laser source (emitting 193-nm wavelength photons). The insertion of ArF (193-nm) lithography into production was originally expected to take place in... 

Some of the leading edge memory device makers actually inserted ArF lithography into limited production runs at the 130 nm half pitch around 2002. 

Okoroanyanwu, Materials and process issues delaying the Introduction of ArF lithography into production (Part 1), Future Fab Int. 12 (2002) U. Okoroanyanwu, Materials and process issues delaying the introduction of ArF lithography into production (Part 2), Future Fab. Int. 13 (2002). 

Defects in ArF lithography, as in other optical lithographic technologies, can be categorized into three broad categories, namely, (i) intrinsic defects, (ii) particle defects, and (iii) process (coat, bake, and develop unit operations)-induced defects. While process-induced and intrinsic defects make up the bulk of the... 

The physical size of some of the process-induced defects is beyond the physical resolution and detection limits of the traditional optical inspection techniques. The way in which each of the patterning processes contributes to defectivity in ArF-lithography-based device manufacture is related to the constituent materials in the photoresist and to the interaction of the photoresist with the substrate or ARC. 

Water immersion ArF lithography was deployed for the first time in large-scale fabrication of critical layers of IC devices at the 45-nm technology node in 2008,... 

Figure 13.51 Schematic showing the main physical and optical differences of water immersion and dry ArF lithographies.

Although originally developed for i-line lithography, the CARL process has been extended to ArF lithography. ... 

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