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The continued miniaturization of integrated circuit features has been made possible through multilayer patterning processes where different etch steps transfer the patterned photoresist image through various hardmasks and ultimately to the underlying substrate. Spin-on carbons (SOCs) are a type of a solution-dispensable carbon hardmask that can offer excellent resistance to various etch gases for good pattern transfer fidelity, while simultaneously conferring desirable gap fill and planarization properties onto the underlying substrate. We recently reported on the development of a new SOC platform with excellent etch resistance, having a relative reactive ion etch (RIE) rate of 1.08 compared to amorphous carbon. However, one drawback we observed for this polymer was its relatively high absorbance between 400-700 nm which can complicate lithographic alignment. Here we report our work on reducing the absorbance of our SOC platform while maintaining its excellent etch resistance. We identify that the origin of high absorbance is from side reactions that occur during curing and discuss the various polymer modifications or additives that prevent these unwanted processes. We additionally look at any trade-offs that are observed between decreasing absorbance and etch resistance and optimize the SOC’s composition to minimize absorbance while having a minimal effect on its etch resistance.

As part of our efforts toward the discovery of new late transition metal catalysts, we synthesized [(o-(Ph2P)C6H4)2(o-C6Cl4O2)SbPh)Au]+ (3+) and [(o-(iPr2P)C6H4)2(o-C6Cl4O2)SbPh)Au]+ (4+), two cationic bis(phosphino)gold stiborane complexes, which were isolated as their hexafluorophosphate salts and fully characterized. Structural and computational studies indicate that the cores of these two complexes are almost structurally and electronically identical. Despite these similarities, these two complexes exhibit different catalytic activities in the hydroamination of phenylacetylene using anilines or in the cyclization of N-(prop-2-yn-1-yl)benzamide. Indeed, whereas 3+ catalyzes both reactions, we found that 4+ is inactive. The data collected on these two complexes suggest that the origin of this contrasting behavior is steric, rather than electronic, with the relatively bulky iPr2P ancillary ligands blocking access to the reactive gold center.

We report direct evidence of living anions of 2-vinylpyridine and 4-vinylpyridine for the first time to the authors' knowledge on the basis of in situ Raman spectral observations during a living anionic polymerization reaction. The former is characterized by a band at 1607 cm−1 and the latter at 1622 cm−1. A titration experiment was carried out by adding multiple aliquots of 4-vinylpyridine into a solution containing 2-vinylpyridine anions. Systematic spectral changes for the aforementioned bands provided convincing evidence for such spectral assignments. These assignments are supported by electronic structure calculations of the monomers and anions. Both anions showed large Raman cross sections, which allowed them to be detected at relatively low concentrations. Such Raman bands will enable facile in situ monitoring of the anionic species and thus can be useful for process development and optimization. Copyright © 2017 John Wiley & Sons, Ltd.

As the critical dimension (CD) in semiconductor devices continues to shrink, the multilayer patterning process to transfer fine line patterns into an underlying substrate is becoming increasingly important. The trilayer processes consist of a photoresist film, a silicon-containing layer and a carbon rich underlayer. The distinctive difference in etch selectivity toward fluorine and oxygen based reactive ion etching (RIE) chemistry is critical to provide highly selective pattern transfer to the substrate. In response to the need for high etch resistant underlayers, we have developed carbon rich spin-on carbon (SOC) materials with good solubility in preferred casting solvents, high thermal stability and high dry etch resistance. To better understand structure-property relationships of high etch resistant SOC films, cured SOC films were analyzed by Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The design considerations for high etch resistance SOC underlayers, such as Ohnishi parameter, crosslinking and film density, will be discussed in this paper.

As part of our continuing interest in redox-active, anion-responsive main-group transition-metal platforms, we have investigated the effect of chloride by fluoride anion substitution on the core structure of a dinuclear AuSb platform. Starting from [(o-(iPr2P)C6H4)2Cl2SbPh]AuCl (2) in which the antimony-bound phenyl group is positioned trans to the gold atom, we found that the introduction of fluoride anions, as in [(o-(iPr2P)C6H4)2F2SbPh]AuCl (3) and [(o-(iPr2P)C6H4)2ClFSbPh]AuCl (4), produces structures in which the phenyl group switches to a perpendicular direction with respect to the gold atom. Replacement of the gold-bound chloride anion in 3 by a fluoride anion can be achieved by successive treatment with TlPF6 and [nBu4N][Ph3SiF2]. These reactions, which proceed via the intermediate zwitterionc gold antimonate complex [o-(iPr2P)C6H4)2F3SbPh]Au (6), trigger migration of the phenyl group to gold and afford [(o-(iPr2P)C6H4)2F3Sb]AuPh (7). Because the phenyl group in 7 is orthogonal to that in 3 and opposite to that in 2, the title AuSb platform can be regarded as a molecular analogue of a mechanical three-way switch in which the switching element is a phenyl group. Finally, while all complexes involved retain a Au → Sb interaction, this interaction is no longer present in the zwitterionic derivative 6 because of the neutralization of the Lewis acidity of the antimony center.

Miniaturization of lithographic feature sizes via shrink technologies is under development in order to extend 193nm immersion lithographic capabilities and achieve sub-20nm critical dimensions (CD) in integrated circuit manufacturing before extreme ultraviolet lithography comes online. It was found that precisely controlled polymers comprising a grafting unit and a shrink unit are capable of reducing pattern dimensions formed in negative tone development (NTD) photoresists. Fundamental studies were pursued regarding the type of grafting chemistry, the shrink monomer and polymer backbone choice, and differences between polymer architectures. Mechanistic studies demonstrated that shrink amount could be tuned by choice of monomer, polymer molecular weight, and choice of grafting unit. These studies permitted the development of several generations of grafting polymer platforms to meet a range of desired CD shrink targets from less than 10nm shrink to 30nm shrink on contact hole or line/space patterns. The shrink technology further exhibits improved process window compared to optical lithography at the same CD and low defectivity, highlighting the use of this technology in advanced semiconductor processing nodes.

The use of multilayer processes in advanced ArF patterning schemes continues to increase as device critical dimensions shrink. In a multilayer stack, underlayer materials play a critical role in terms of gap fill, planarization and etch resistance to enable high resolution and high aspect ratio patterning. The emerging quadlayer imaging process requires a unique spin on carbon (SOC) layer with high thermal stability to withstand subsequent deposition of an inorganic hard mask layer, commonly deposited via chemical vapor deposition (CVD). The thermal stability requirement associated with CVD compatibility largely limits the options of organic materials, which mostly decompose in the 300-450°C range. Thermal shrinkage and coefficient of thermal expansion (CTE) differences between layers are other key considerations in designing a high temperature stable, CVD compatible SOC material. Furthermore, the SOC polymer resin must be compatible with solvents and spin on products commonly used in the FAB. This paper highlights the development of a novel CVD compatible HT-SOC platform with excellent thermal stability (>500°C) and good FAB drain line compatibility. In addition, this polyaromatic SOC platform shows various improvements compared to traditional Novolacbased SOC, including reduced shrinkage, good gap fill, improved planarization, and low defectivity. Robust formulation design, high quality raw materials, and advanced metal removal technique synergistically enabled manufacturing of multigallon HT-SOC product with high quality. Application specific versions are available for more demanding planarization requirement and applications that require good adhesion to metal substrate. In addition, a newly developed method for quantitative measurement of long-range planarization was used to validate new material designs aimed at improving planarization.

A trilayer stack of spin-on-carbon (SOC), silicon anti-reflective coating (SiARC) and photoresist (PR) is often used to enable high resolution implant layers for integrated circuit manufacturing. Damage to substrates from SiARC removal using dry etching or aqueous hydrogen fluoride has increased the demand for innovative SiARC materials for implant lithography process. Wet strippable SiARCs (WS-SiARCs) capable of stripping under mild conditions such as SC1 (ammonium hydroxide/hydrogen peroxide/water) while maintaining key performance metrics of standard SiARCs is highly desirable. Minimizing the formation of Si-O-Si linkages by introducing organic crosslink sites was effective to impart SC1 solubility particularly after O2 dry etching. Incorporation of acidic groups onto the crosslinking site further improved SC1 solubility. A new siloxane polymer architecture that has SC1 active functionality in the polymer backbone was developed to further enhance SC1 solubility. A new SiARC formulation based on the new siloxane polymer achieved equivalent lithographic performances to a classic SiARC and SC1 strip rate >240A/min under a relatively low concentration SC1 condition such as ammonium hydroxide/hydrogen peroxide/water=1/1/40.

BiZness as usual? Not exactly! The bismuth atom of the tridentate diphosphinobismuthine (o-(Ph(2)P)C(6)H(4))(2) BiCl behaves as a Z rather than L ligand when in the coordination sphere of late transition metals such as gold. The σ-acceptor behavior of Bi is supported by its disphenoid coordination geometry and theoretical studies, which show a Au→Bi interaction.

Turn on the lantern! The stibine donor ligand of a cationic palladium complex acts as a Lewis acid and reacts with a fluoride anion to afford the corresponding fluorostiboranyl-palladium species (see scheme). Bindung of the fluoride anion to the antimony center induces a change in denticity of the triphosphine unit and leads to a bright-orange trigonal-bipyramidal d(8) lantern complex.

Hexagonal mesoporous silicas containing tungsten complexes have been synthesized through the condensation of tetraethoxysilane templated by an amphiphilic diblock copolymers modified with tungsten isocyanide complexes under acidic conditions. Upon calcination, the tungsten complex was transformed into its oxide, which was deposited inside the channels. This material is illustrated to be a good catalyst on the allylic oxidation of cyclohexene in the presence of hydrogen peroxide under mild conditions. In addition, this catalyst could be easily recovered after the reaction and re-used without any significant loss of its activity.

The tetravalent platinum stiboranyl complex [(o-(Ph2P)C6H4)2(o-C6Cl4O2)Sb]PtCl2Ph (2) has been synthesized by reaction of [(o-(Ph2P)C6H4)2SbClPh]PtCl (1) with o-chloranil. In the presence of fluoride anions, the stiboranyl moiety of 2 displays non-innocent behavior and is readily converted into a fluorostiborane unit. This transformation, which is accompanied by elimination of a chloride ligand from the Pt center, results in the formation of [(o-(Ph2P)C6H4)2(o-C6Cl4O2)SbF]PtClPh (3). Structural, spectroscopic, and computational studies show that the conversion of 2 into 3 is accompanied by a cleavage of the covalent Pt-Sb bond present in 2 and formation of a longer and weaker Pt→Sb interaction in 3. These results show that this new Pt-Sb platform supports the fluoride-induced metamorphosis of a stiboranyl X ligand into a stiborane Z ligand.

The 9-anthryltriphenylstibonium cation, [1](+), has been synthesized and used as a sensor for the toxic fluoride anion in water. This stibonium cation complexes fluoride ions to afford the corresponding fluorostiborane 1-F. This reaction, which occurs at fluoride concentrations in the parts per million range, is accompanied by a drastic fluorescence turn-on response. It is also highly selective and can be used in plain tap water or bottled water to test fluoridation levels.

The tetradentate stibine and bismuthine ligands (o-(iPr2P)C6H4)3Sb (LSbP3) and (o-(iPr2P)C6H4)3Bi (LBiP3) react with CuCl and AgCl in THF at room temperature to afford (o-(iPr2P)C6H4)3SbCu3(μ2-Cl)3 (1), (o-(iPr2P)C6H4)3SbAg3(μ2-Cl)3 (2), (o-(iPr2P)C6H4)3BiCu3(μ2-Cl)3 (3), and (o-(iPr2P)C6H4)3BiAg3(μ2-Cl)3 (4), respectively. These complexes, which have been fully characterised, feature a central M3(μ2-Cl)3 cluster (M = Cu or Ag) supported by coordination of a LSbP3- or LBiP3-phosphino group to each group 11 metal ion. The heavy pnictogen atom (Pn) interacts simultaneously with the three group 11 metal ions of the M3(μ2-Cl)3 cluster leading to formation of a tetrahedral PnM3 core. Bonding analysis using the Natural Bond Orbital method indicates the presence of a four-centre two-electron Pn→M3 interaction whose strength is the highest in 1 and the lowest in 4. The triply bridging bonding mode of the stibine and bismuthine ligands observed in these complexes is, to our knowledge, unprecedented. We also note that the central M3(μ2-Cl)3 clusters found in these complexes are related to the cyclo-trimers observed in vapours of CuCl and AgCl.