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The dissolution inhibition mechanism for tert-butylcarboxylate (e.g. tert-butyl cholate) dissolution inhibitors and onium salt photoacid generators (PAG's) were examined in terpolymers of poly(norbornene-maleic anhydride-acrylic acid) (P(NB/MA/AA)). For tert-butyl carboxylates, increasing hydrophobicity increased the dissolution inhibition ability. Dissolution promotion tracked with the number of carboxylic acid moieties and the hydrophobicity of carboxylic acids moieties released upon acidolytic cleavage of the tert-butyl carboxylate. For onium salt PAG's, increasing the hydrophobicity and size of fluorinated anions decreased dissolution inhibition.

The intense absorption of aromatic molecules at 193 nm severely limits the use of conventional matrix aromatic resins such as novolac, poly vinyl phenol for 193 nm lithography. This paradigm shift in resist design provides opportunities for new chemistries and process schemes to provide the required aqueous base solubility, etch resistance, resolution, photospeed and process latitude. In addition, regulatory constraints on the volatile organic emissions (VOC) also provide opportunities to design revolutionary resist schemes that not only address the lithographic performance requirements but also alleviate the environmental safety and health (ES&H) aspects of resist technology. In this paper, we will analyze the several resist options available for 193 nm lithography and provide results for evolutionary single layer, bilayer and revolutionary “all-dry” plasma polymerized methyl silane (PPMS) resist schemes. For single layer schemes, we have synthesized several co- and terpolymers with cycloolefins, maleic anhydride and acrylates (acrylic, methacrylic acids and esters) and have used the protected polymers as matrix resins in three component systems with a photoacid generator (PAG) and dissolution inhibitor(s) (DI). Alternately, we have used the unprotected terpolymer with DI's and PAG in three component systems. The lithographic results for single layer and bilayer resist materials were obtained at 193 nm using a 0.55 NA Nikon or 0.56 NA ISI (Integrated Solutions Inc.) small field exposure systems. Single layer resist materials showed at least 0.16 μm l/s pair resolution and modulation down to 0.14 μm l/s pairs using a formulation and process optimized at 248 nm. We have also evaluated the performance of P(SI-CMS) (poly(trimethyl silyl methyl methacrylate-co-chloromethyl styrene), a negative e-beam resist, at 193 nm and have obtained 0.25 μm l/s pair resolution without much optimization. Structure-activity relationships between the polymer properties and lithographic performance for this system have been identified. The results obtained for PPMS, a plasma deposited all-dry resist technology, on the 193 nm Micrascan (0.50 NA) were also very encouraging. Again using a non-optimized process, we have obtained at least 0.15 μm l/s pair resolution in a bilayer scheme.

We describe a new two-dimensional NMR technique for structural studies of polycrystalline and noncrystalline solids. The technique is a variant of 2D exchange spectroscopy applicable to organic molecules, macromolecules, or molecular complexes that are doubly 13 C-labeled at a specific carboncarbon bond and singly 13 C labeled at a specific functional group. A Carr-Purcell sequence is used to obtain dipolar spectra in the t 1 dimension. Spectra in the t 2 dimension are determined primarily by the chemical-shift anisotropy. With spin diffusion among the labeled sites between the t 1 and t 2 periods, the resulting 2D spectra reveal correlations between the direction of the labeled bond and the orientation of the labeled functional group. Experimental spectra of two polycrystalline model compounds, dimethyl succinate and diammonium succinate, are presented and compared with simulations to illustrate the structural information contained in the 2D spectra.

Alkali metal fullerides (A x C 60 ) are a subject of considerable current interest because of the occurrence of superconductivity for A x C 60 at temperatures surpassed only by the high T c copper oxides. The preparation and characterization of A x C 60 (A = alkali metal, x = 2,3,4,6) by powder X-ray diffraction, NMR ( 13 C, 23 Na and 87 Rb), and d.c. magnetization are reported. The structures are described as intercalation compounds of the FCC structure of pristine c 60 or of hypothetical BCC or BCT structures. The structures and phase diagrams can be rationalized on the basis of ion size and electrostatic considerations. Only the A 3 C 60 compounds are metallic (and superconducting). The superconducting T c increases nearly linearly with unit cell size. EHT (Extended Huckel Theory) calculations and 13 C NMR relaxation measurements indicate higher densities of states for the higher T c compositions.

The recent synthesis of macroscopic quantities of spherical molecular carbon compounds, commonly called fullerenes, has stimulated a wide variety of studies of the chemical and physical properties of this novel class of compounds. We discovered that the smallest of the known fullerenes, C60, could be made conducting and superconducting by reaction with alkali metals. In this paper, an overview of the motivation for these discoveries and some recent results are presented.

We describe a method for measuring nuclear magnetic dipole—dipole couplings in NMR spectra of solids undergoing rapid magic angle spinning (MAS). We show in theory, simulations, and experiments that the couplings, which are averaged out by MAS alone, can be recovered by applying simple resonant radiofrequency pulse sequences in synchrony with the sample rotation. Experimental 13 C dipolar powder pattern spectra of polycrystalline ( 13 CH 3 ) 2 C(OH)SO 3 Na obtained in a two-dimensional experiment based on this method are presented. The method provides a means of determining internuclear distances in polycrystalline and noncrystalline solids while retaining the high resolution and sensitivity afforded by MAS.

Various Cu(I) salts have been tested as precursors for organocuprates in side-by-side comparisons under controlled conditions. CuCN and CuBr·SMe2 appear to be superior to CuI, CuBr, and CuCl. CuSCN and CuOTf are also good precursors in some circumstances.

We describe a technique for measuring chemical-shift-anisotropy (CSA) lineshapes in NMR spectra of polycrystalline or amorphous solids. By combining magic-angle spinning (MAS) with a radiofrequency pulse sequence synchronized with the sample rotation in one time period of a two-dimensional experiment, we obtain two-dimensional spectra in which the CSA lineshapes appear along one axis and the normal MAS spectrum appears along the other axis. The CSA lines are thereby resolved as long as the inequivalent nuclei have resolved isotropic chemical shifts in the MAS spectrum. Our technique differs from previous, related techniques in that we employ pulse sequences designed so that the CSA lineshapes in the two-dimensional spectrum are precisely the same as those obtained from one-dimensional spectra of nonspinning samples in the absence of spectral overlap; the analysis of the spectra is thus simplified substantially. We describe the theory and experimental implementation of the technique in detail, and present resolved 13C CSA lineshapes for methyl-α- d -glucopyranoside. We analyze the effects of pulse imperfections on the observed lineshapes and show how such effects can be minimized.

Organocopper(I) reagents, RCu, are both more stable and more reactive when prepared in dimethyl sulfide instead of ether or tetrahydrofuran. A wide range of Li reagents has been investigated with good results, as has a selection of Grignard reagents. Excellent yields of products are observed with typical substrates such as α,β-unsaturated ketones and acid chlorides.