Ultrathin film imaging at 157 nm

Rottstegge, Joerg; Herbst, W.; Hien, Stefan; Fuetterer, Gerald; Eschbaumer, Christian; Hohle, Christoph; Schwider, Johannes; Sebald, Michael

doi:10.1117/12.474249

Cited by 3 publications

(2 citation statements)

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“…Signal B is a representative signal of a resist material showing the aforementioned problems. We suspected that development problems could be due to surface segregation (similar to what has been observed for random fluorine-containing copolymers) or even self-organization phenomena. , To clarify whether surface segregation was present, we used XPS analysis 1 Typical DRM signals of two POSS-based resists with optimized (signal A, AC−POSS-2-71) and nonoptimized (signal B, AC−POSS-2-69) development processes. …”

Section: Resultsmentioning

confidence: 99%

“…In the present paper we report our group work on the capabilities POSS monomers offer for high resolution lithography. In the case of 157-nm lithography, the use of thin films has been employed in order to meet the low absorbance criterion and achieve high-resolution imaging. , Incorporating the POSS cage as a pendant group in the traditionally used methacrylate platform presents the advantage of enhanced etch resistance and the possibility of employing the bilayer scheme. Nevertheless, several requirements such as low absorbance, adhesion, controlled dissolution behavior, aqueous base development, and high-resolution imaging remain to be satisfied.…”

Section: Introductionmentioning

confidence: 99%

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Polyhedral Oligomeric Silsesquioxane (POSS) Based Resists: Material Design Challenges and Lithographic Evaluation at 157 nm

et al. 2004

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In this paper we describe the lithographic behavior and related material properties of a new class of chemically amplified, positive tone, silicon-containing methacrylate photoresists incorporating the polyhedral oligomeric silsesquioxane (POSS) group as the etch-resistant component. POSS-bearing monomers were copolymerized with methacrylic acid (MA), tertbutyl methacrylate (TBMA), tert-butyl trifluoro methacrylate (TBTFMA), itaconic anhydride (IA), and 2-(trifluoromethyl) acrylic acid (TFMA), in various compositions. A perfluorooctylsulfonate-based photoacid generator (PAG) was used to deprotect TBMA (or TBTFMA) to base soluble carboxylic acid by heating after exposure. XPS and angular XPS analysis were used to examine possible surface segregation phenomena. It was proven that POSS surface enrichment occurs for the POSS-TBMA copolymers while surface segregation may be reduced if suitable additional resist components are selected. The POSS-based resists were studied for 157-nm lithographic applications and found to have high sensitivity (<10 mJ/cm 2 under open field exposure), no silicon outgassing, and sub-100-nm resolution capabilities. Ninety nanometer patterns in 100-nm thick films were resolved. At present, their absorbance is high (∼4 µm -1 ) for single-layer lithographic applications at 157 nm; however, high etch resistance in oxygen plasma makes them suitable for bilayer schemes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyhedral Oligomeric Silsesquioxane (POSS) Based Resists: Material Design Challenges and Lithographic Evaluation at 157 nm

et al. 2004

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Etching silicon-containing bilayer resists in ammonia-based plasmas

Panda¹,

Wise²,

Mahorowala³

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The need to print smaller feature sizes has led to the shift from 248nmto193nm lithography. The disadvantages of 193nm ArF single-layer resist materials, such as lower depth of focus and lower etch resistance, have made thin-film imaging (TFI) techniques an attractive alternative. In the bilayer (comprised of an image layer and an underlayer) approach, a form of TFI, O2-based plasma chemistries are used for the transfer etches whereby oxidation of silicon in the image layer provides the required etch resistance. However, use of oxygen results in profile and critical dimension (CD) control issues. While gas additives have helped minimize these problems, there are other accompanying disadvantages. In this work, the feasibility of a non-O2-containing NH3-based plasma etch chemistry was evaluated. Effects of additive gases, such as N2, H2, and C2H4, were investigated. Surface analysis of the resist showed that nitrogen from the gas phase was incorporated in the surface of the image layer during the etch, and the etch resistance increased with this nitrogen content. Gas phase analysis showed that the relative N2H species density in the system was correlated with the nitrogen incorporated in the image layer, and is thus believed to govern the etch resistance of the image layer. The underlayer etch behavior was correlated with that of the atomic hydrogen species density. The effect of the additives on the cross section profiles and line edge roughness were studied. The highest CD biases were obtained with H2 as the additive, while near-zero CD biases were attained with C2H4 as the additive. Also, with the C2H4 additive, minimum line edge roughness and smoothest profiles were obtained.

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