Design of Protective Topcoats for Immersion Lithography

Allen, Robert D.; Brock, Phillip J.; Sundberg, Linda K.; Larson, Carl E.; Wallraff, Gregory M.; Hinsberg, William D.; Meute, Jeff; Shimokawa, Tsutomu; Chiba, Takashi; Slezak, Mark

doi:10.2494/photopolymer.18.615

Cited by 17 publications

(9 citation statements)

References 5 publications

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“…Ideally, the topcoat would dissolve in the same aqueous base developer (TMAH) used in the resist development step, but some topcoat versions were designed for nonaqueous solvent development, which adds an extra processing step. Many topcoats incorporate fluorinecontaining functional groups for their increased hydrophobicity, as well as the same compound 112 French · Tran types used effectively for absorbance reduction in 157-nm technology (88,(96)(97)(98)(99)(100)(101). These fluoropolymers have also been used in water immersion resist materials-either as additives to current 193-nm materials or as block copolymers (102)(103)(104).…”

Section: Topcoats and Topcoatless Photoresistsmentioning

confidence: 97%

Immersion Lithography: Photomask and Wafer-Level Materials

French

Tran

2009

Annu. Rev. Mater. Res.

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Optical immersion lithography utilizes liquids with refractive indices >1 (the index of air) below the last lens element to enhance numerical aperture and resolution, enabling sub-40-nm feature patterning. This shift from conventional dry optical lithography introduces numerous challenges requiring innovations in materials at all imaging stack levels. In this article, we highlight the recent materials advances in photomasks, immersion fluids, topcoats, and photoresists. Some of the challenges encountered include the fluids' and photomask materials' UV durability, the high-index liquids' compatibility with topcoats and photoresists, and overall immersion imaging and defectivity performance. In addition, we include a section on novel materials and methods for double-patterning lithography-a technique that may further extend immersion technology by effectively doubling a less dense pattern's line density. 93 Annu. Rev. Mater. Res. 2009.39:93-126. Downloaded from www.annualreviews.org by Otterbein University on 09/17/13. For personal use only.

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Section: Topcoats and Topcoatless Photoresistsmentioning

confidence: 97%

Immersion Lithography: Photomask and Wafer-Level Materials

French

Tran

2009

Annu. Rev. Mater. Res.

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“…16 It was proposed that the longer spacer group limited hydrogen bonding of the fluoroalcohols to the methacrylate backbone, increasing their accessibility to base, and thereby increasing the rate of dissolution. Intramolecular hydrogen bonding to the methacrylate backbone would also conceivably limit the accessibility of the fluoroalcohol group to water, thereby increasing contact angles.…”

Section: Spacer Lengthmentioning

confidence: 99%

“…16 Coated wafers were set in contact with water in a controlled reproducible manner (time, speed, volume, contact area etc.). The water was thereafter collected and analyzed for extractables by Exygen Research using LC/MS/MS.…”

Section: Pag Leachingmentioning

confidence: 99%

“…[14][15] However, the combination of the moderately low pK a and the large amount of fluorine in the hexafluoroisopropanol structure also make fluoroalcohol-based methacrylate polymers very attractive for immersion topcoat materials. 16 Previously, we showed that minor structural changes in fluoroalcohol-based methacrylate copolymers can have large effects in both dissolution rate and receding contact angle. 17 As shown in Figure 2, the two isomers of the norbornyl hexafluoroalcohol methacrylate demonstrate very different contact angle behavior.…”

Section: Introductionmentioning

confidence: 99%

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Fluoro-alcohol materials with tailored interfacial properties for immersion lithography

et al. 2007

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Immersion lithography has placed a number of additional performance criteria on already stressed resist materials. Much work over the past few years has shown that controlling the water-resist interface is critical to enabling high scan rates (i.e. throughput) while minimizing film pulling and PAG extraction (i.e. defectivity). Protective topcoat polymers were developed to control the aforementioned interfacial properties and emerged as key enablers of 193 nm immersion lithography. Achieving the delicate balance between the low surface energies required for high water contact angles (generally achieved via the incorporation of fluorinated groups) and the base solubility required for topcoat removal is challenging. More recently, additional strategies using fluoropolymer materials to control the water-resist interface have been developed to afford topcoat-free resist systems. In our explorations of fluoroalcohol-based topcoat materials, we have discovered a number of structure-property relationships of which advantage can be taken to tailor the interfacial properties of these fluorinated materials. This paper will address the effect of structure on immersion specific properties such as water contact angle, aqueous base contact angle, and dissolution rate.

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“…He also led the IBM team on the studies of diffusion and distributions of photoacid generators [7], supercritical processing [8], non-polymeric macromolecular resists [9], and polymer-bond several leading chemical companies, JSR and Central Glass to explore, develop and ultimately manufacture water immersion-specific materials. Possibly the most important material type developed to enable worldwide volume manufacturing of semiconductors using water immersion lithography were the invention and development of aqueous base-soluble polymers via the HFA (hexafluoro-alcohol) functional group [11]. Methacrylate monomers were developed with varying "spacer" groups that gave tremendous control over desirable properties [12].…”

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confidence: 99%