Influence of base and photoacid generator on deprotection blur in extreme ultraviolet photoresists and some thoughts on shot noise

A contact-hole deprotection blur metric has been used to monitor the deprotection blur of an experimental open platform resist (EH27) as the wt % of base and photoacid generator (PAG) were varied. A six times increase in base wt % is shown to reduce the size of successfully patterned 1:1 line-space features from 52 to 39 nm without changing deprotection blur. Corresponding isolated line edge roughness is reduced from 6.9 to 4.1 nm. A two times increase in PAG wt % is shown to improve 1:1 line-space patterning from 47 to 40 nm without changing deprotection blur or isolated line edge roughness. A discussion of improved patterning performance as related to shot noise and deprotection blur concludes with a speculation that the spatial distribution of PAG molecules has been playing some role, perhaps a dominant one, in determining the uniformity of photogenerated acids in the resists that have been studied. © 2008 American Vacuum Society

Microwave Assisted Synthesis of Py-Im Polyamides

Microwave synthesis was utilized to rapidly build Py-Im polyamides in high yields and purity using Boc-protection chemistry on Kaiser oxime resin. A representative polyamide targeting the 5′-WGWWCW-3′ (W = A or T) subset of the consensus Androgen and Glucocorticoid Response Elements was synthesized in 56% yield after 20 linear steps and HPLC purification. It was confirmed by Mosher amide derivatization of the polyamide that a chiral α-amino acid does not racemize after several additional coupling steps

Active Site Mapping of Xylan-Deconstructing Enzymes with Arabinoxylan Oligosaccharides Produced by Automated Glycan Assembly

Xylan-degrading enzymes are crucial for the deconstruction of hemicellulosic biomass, making the hydrolysis products available for various industrial applications such as the production of biofuel. To determine the substrate specificities of these enzymes, we prepared a collection of complex xylan oligosaccharides by automated glycan assembly. Seven differentially protected building blocks provided the basis for the modular assembly of 2-substituted, 3-substituted, and 2-/3-substituted arabino- and glucuronoxylan oligosaccharides. Elongation of the xylan backbone relied on iterative additions of C4-fluorenylmethoxylcarbonyl (Fmoc) protected xylose building blocks to a linker-functionalized resin. Arabinofuranose and glucuronic acid residues have been selectively attached to the backbone using fully orthogonal 2-(methyl)naphthyl (Nap) and 2-(azidomethyl)benzoyl (Azmb) protecting groups at the C2 and C3 hydroxyls of the xylose building blocks. The arabinoxylan oligosaccharides are excellent tools to map the active site of glycosyl hydrolases involved in xylan deconstruction. The substrate specificities of several xylanases and arabinofuranosidases were determined by analyzing the digestion products after incubation of the oligosaccharides with glycosyl hydrolases.Fil: Senf, Deborah. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Ruprecht, Colin. Max Planck Institut für Kolloid und Grenzflächenforschung; AlemaniaFil: de Kruijff, Goswinus H. M.. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; Alemania. University Mainz. Institute of Institute of Organic Chemistry, Johannes Gutenberg; AlemaniaFil: Simonetti, Sebastián Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Max Planck Institut für Kolloid und Grenzflächenforschung; AlemaniaFil: Schuhmacher, Frank. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Seeberger, Peter H.. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Pfrengle, Fabian. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; Alemani

Asymmetric synthesis of γ-chloro-α,β-diamino- and β,γ-aziridino-α-aminoacylpyrrolidines and -piperidines via stereoselective Mannich-type additions of N-(diphenylmethylene)glycinamides across α-chloro-N-sulfinylimines

The asymmetric synthesis of new chiral gamma-chloro-alpha,beta-diaminocarboxylamide derivatives by highly diastereoselective Mannich-type reactions of N-(diphenylmethylene) glycinamides across chiral alpha-chloro-N-p-toluenesulfinylaldimines was developed. The resulting (S-S,2S,3S)-gamma-chloro-alpha,beta-diaminocarboxylamides were formed with the opposite enantiotopic face selectivity as compared to the (S-S,2R,3R)-gamma-chloro-alpha,beta-diaminocarboxyl esters obtained via Mannich-type addition of analogous N-(diphenylmethylene) glycine esters across a chiral alpha-chloro-N-p-toluenesulfinylaldimine. Selective deprotection under different acidic reaction conditions and ring closure of the gamma-chloro-alpha,beta-diaminocarboxylamides was optimized, which resulted in N-alpha-deprotected syn-gamma-chloro-alpha,beta-diaminocarboxylamides, N-sulfinyl-beta,gamma-aziridino-alpha-aminocarboxylamide derivatives, a trans-imidazolidine, and an N-alpha,N-beta-deprotected syn-gamma-chloro-alpha,beta-diaminocarboxylamide

Exchange reactions of poly(arylene ether ketone) dithioketals with aliphatic diols: formation and deprotection of poly(arylene ether ketal)s

The dithioketal derivatives of industrially important, semi-crystalline poly(arylene ether ketone)s undergo facile exchange with aliphatic diols in the presence of N-bromo-succinimide to give a range of novel poly(arylene ether ketal)s. These are amorphous and readily soluble in a wide range of organic solvents. Although generally stable under ambient conditions, they undergo rapid and quantitative hydrolysis in the presence of acids to regenerate the original polyketones. The poly(ether ketal)s reported here are not accessible from ketal-type monomers, nor can they be obtained by direct reaction of poly(ether ketone)s with aliphatic diols. The starting polyketones are essentially unchanged after sequential dithioketalization, dithioketal-ketal exchange, ketal hydrolysis, and re-dithioketalization. Poly(arylene ether ketal)s provide a new approach to the processing of poly(arylene ether ketone)s into carbon fiber composite materials

Novel Fmoc-Polyamino Acids for Solid-Phase Synthesis of Defined Polyamidoamines

A versatile solid-phase approach to sequence-defined polyamidoamines was developed. Four different Fmoc-polyamino acid building blocks were synthesized by selective protection of symmetrical oligoethylenimine precursors followed by introduction of a carboxylic acid handle using cyclic anhydrides and subsequent Fmoc-protection. The novel Fmoc-polyamino acids were used to construct polyamidoamines demonstrating complete compatibility to standard Fmoc reaction conditions. The straightforward synthesis of the building blocks and the high efficiency of the solid-phase coupling reactions allow the versatile synthesis of defined polycations

Studying resist stochastics with the multivariate poisson propagation model

Progress in the ultimate performance of extreme ultraviolet resist has arguably decelerated in recent years suggesting an approach to stochastic limits both in photon counts and material parameters. Here we report on the performance of a variety of leading extreme ultraviolet resist both with and without chemical amplification. The measured performance is compared to stochastic modeling results using the Multivariate Poisson Propagation Model. The results show that the best materials are indeed nearing modeled performance limits

Synthesis of 1 alpha,25-Dihydroxyvitamin D Analogues Featuring a S-2-symmetric CD-ring Core

Three analogues of 1 alpha,25-dihydroxyvitamin D-3 (calcitriol), featuring a transfused decalin C, D-core with local S-2-symmetry, and possessing identical side-chain and seco-B,A-ring structures, have been synthesized starting from readily available (4aR, 8aS)octahydronaphthalene-1,5-dione(7). The very short sequences involve the simultaneous introduction of the side-chain and seco-B, A-ring fragments via Suzuki and Sonogashira coupling reactions. The analogues are devoid of relevant biological activity

Synthesis of biodegradable polyesteramides with pendant functional groups

Morpholine-2,5-dione derivatives having substituents with benzyl-protected carboxylic acid, benzyloxycarbonyl-protected amine and p-methoxy-protected thiol groups, respectively, were prepared in 29-58% yield by cyclization of the corresponding N-[(2RS)-bromopropionyl]-L-amino acids. Polyesteramides with protected pendant functional groups were obtained by ring-opening copolymerization of either ε-caprolactone or DL-lactide with morpholine-2,5-dione derivatives having protected functional substituents. The copolymerizations were carried out in the bulk at 130°C using stannous octoate as an initiator and using low mole fractions (0,05, 0,10 and 0,20) of morpholine-2,5-dione derivatives in the feed. The molecular weight of the resulting copolymers ranged from 1,4 to 8,3 · 104. The ring-opening homopolymerization of morpho-line-2,5-dione derivatives with protected functional substituents was not successful. Polyesteramides with either pendant carboxylic acid groups or pendant amine groups were prepared by catalytic hydrogenation of the corresponding protected copolymers. Treatment of copolymers having pendant p-methoxybenzyl-protected thiol groups with trifluoromethanesulfonic acid resulted not only in the removal of the p-methoxybenzyl group but also in severe degradation of the copolymers, due to acidolysis of main-chain ester bonds