Resist outgassing as a function of differing photoadditives

Houlihan, Francis M.; Rushkin, Ilya L.; Hutton, R. S.; Timko, Allen G.; Nalamasu, Omkaram; Reichmanis, Elsa; Gabor, Allen H.; Medina, Arturo N.; Malik, Sanjay; Neiser, Matthew; Kunz, Roderick R.; Downs, D. K.

doi:10.1117/12.350209

Cited by 13 publications

(3 citation statements)

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“…Since virtually no moisture is present in the high-vacuum environment of an e-beam exposure system, the subsequent acid-catalyzed hydrolysis is delayed until the external post-exposure processing, in which ambient moisture is allowed to participate in the deprotection reactions. The results of these findings have been published in detail elsewhere but are generally summarized by the data in Table 2, which demonstrates the low degree of resist outgassing in KRS-XE with a lithographically relevant dose of e-beam radiation as compared to more conventional highactivation-energy materials [46]. It should be noted that in all cases the primary outgassing products are not attributable to the products of deprotection, but rather are the consequence of PAG photolysis.…”

Section: Resist Outgassingmentioning

confidence: 89%

Recent progress in electron-beam resists for advanced mask-making

et al. 2001

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Resists for advanced mask-making with highvoltage electron-beam writing tools have undergone dramatic changes over the last three decades. From PMMA and the other early chain-scission resists for micron dimensions to the aqueous-base-developable, dry-etchable chemically amplified systems being developed today, careful tuning of the chemistry and processing conditions of these resist systems has allowed the patterning of photomasks of increasing complexity containing increasingly finer features. Most recently, our research efforts have been focused on a low-activation-energy chemically amplified resist based on ketal-protected poly(hydroxystyrene). These ketal resist systems, or KRSs, have undergone a series of optimization and evaluation cycles in order to fine-tune their performance for advanced mask-fabrication applications using the 75-kV IBM EL4؉ vector scan e-beam exposure system. The experiments have led to an optimized formulation, KRS-XE, that exhibits superior lithographic performance and has a high level of processing robustness. In addition, we describe advanced formulations of KRS-XE incorporating organometallic species, which have shown superior dry-etch resistance to novolak-based resists in the Cr etch process while maintaining excellent lithographic performance. Finally, current challenges facing the implementation of a chemically amplified resist in the photomask manufacturing process are outlined, along with current approaches being pursued to extend the capabilities of KRS technology.

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Section: Resist Outgassingmentioning

confidence: 89%

Recent progress in electron-beam resists for advanced mask-making

et al. 2001

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“…The relationship between molecular weight, boiling point, and vapor pressure of various photoproducts and their outgassing characteristics at 157 nm was reported earlier. 64 However, emission of volatile products at EUV wavelengths is an important concern, and it has been shown that changing the resist composition and PAG chromophores can reduce the concentration of volatile of products. 53,63 3.2.4.…”

Section: Oil-water Partition Coefficientmentioning

confidence: 99%

Arylonium Photoacid Generators Containing Environmentally Compatible Aryloxyperfluoroalkanesulfonate Groups

Ayothi

Cao

et al. 2007

Chem. Mater.

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Photoacid generators (PAGs) producing environmentally benign 2-phenoxytetrafluoroethanesulfonate fluoroorganic sulfonic acids were synthesized. Synthesis and characterization of the new PAGs composed of 2-phenoxytetrafluoroethanesulfonate with diphenyliodonium or triphenylsulfonium units are described. Characteristics of the onium PAGs were evaluated and compared with perfluorobutanesulfonate (PFBS)-based onium PAGs. The newly synthesized compounds efficiently produced sulfonic acid photochemically upon exposure to selected radiation (254 nm, e-beam, and 13.4 nm wavelengths). The sulfonic acid generated from the new PAGs contains far fewer perfluorinated carbon atoms than those found in widely used perfluorooctanesulfonate (PFOS) PAGs and successfully catalyzed deprotection of the acid-labile tert-butoxycarbonyl, methyladamantyl ester, and tert-butyl ester groups present in model positive tone chemically amplified resists (CARs). Their influence on the lithographic performance of chemically amplified resists was investigated using e-beam and extreme ultraviolet (EUV or 13.4 nm) radiation. For the first time, the capability of PFOS-free PAGs for EUV lithographic application in a CAR was demonstrated by comparing resist sensitivity, resolution, and line-edge roughness (LER) with resist formulations containing PFBS-based diphenyliodonium and triphenylsulfonium PAGs. These new PAGs are attractive for lithographic applications as alternatives to the widely used PFOS PAGs because environmental and performance issues require the availability of strong acid PFOS-free photoacid generators.

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“…9,[10][11][12][16][17][18][19][20] Many of these studies have focused on the outgassing (including photo-induced outgassing) of organic contaminants from photoresists. 10,12,[16][17][18] These organic contaminants reduce system transmittance by partially absorbing the light energy at the specific radiation wavelength by being in the beam path or adsorbed to the lens surface (see inset Figure 1). Basic (e.g.…”

Section: Introductionmentioning

confidence: 99%

New concerns with the design of filters for the protection of lithography optics

et al. 2003

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The optimal medium in which DUV resists are exposed is becoming increasingly under investigation by lithography tool manufacturers. These medium requirements have created even more design restrictions for effective filtration methods. Traditional airborne molecular contamination control in tracks and exposure tools has focused on the removal of weak bases that poison the resist. Newer concerns, including; the degradation of optics, changes in resist sensitivity, the index of refraction and the demands of tighter geometry's, all contribute to the need for quantification and control of gas-phase contamination within exposure tools. As a result, filter manufacturers are required not only to remove a broader spectrum of contaminants (e.g. organic and acid gases), but to supply removal efficiency data, under a variety of conditions including; variable challenge concentrations, mixed stream contamination, humidity (dew points), flow rates, and temperatures. The paper will address these new concerns focusing on the efficiency effects of relative humidity for various contaminant streams using a variety of filter media. In addition, the removal of hydrophilic compounds such as ammonia and sulfur dioxide when drying an air stream will also be considered. This ongoing study has contributed to the design of a point-of-use air-shower filter used to protect lithography lenses. Preliminary field tests by a major manufacturer indicate that the removal of the specified bases, acids and total organics is below detection limits of <0.1 ppb.

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Resist outgassing as a function of differing photoadditives

Cited by 13 publications

References 0 publications

Recent progress in electron-beam resists for advanced mask-making

Recent progress in electron-beam resists for advanced mask-making

Arylonium Photoacid Generators Containing Environmentally Compatible Aryloxyperfluoroalkanesulfonate Groups

New concerns with the design of filters for the protection of lithography optics

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