Photoreactive fluorinated polyimide protected by tetrahydropyranyl (THP) group based on chemical amplification: Acid generation in polyimide film and lithographic properties

The photochemistry of photoacid generator (PAG), diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) and diphenyliodonium 8-anilinonaphthalene-1-sulfonate (DIANS) was investigated in both alkalinesoluble polyimide (6FDA-AHHFP) and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA-AHHFP and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA-AHHFP and novolak films were determined as 0.11, 0.21, 0.12 and 0.26, respectively. On the other hand, the quantum yields for acid generation from DIAS and DIANS in both of these films were 0.07, 0.18, 0.09 and 0.22, respectively, in the presence of an acid indicator. These results indicate that the values of the quantum yields of photodissociation and photoacid formation for DIAS and DIANS in 6FDA-AHHFP film are lower than those in novolak film. In order to elucidate the lowering of the quantum yields in 6FDA-AHHFP film, fluorescence quenchings of sodium 9,10-dimethoxy-anthracene-2-sulfonate and ammonium 8-anilinonaphthalene-1-sulfonate by a model compound of polyimide was carried out in acetonitrile. The fluorescences of these two salts were efficiently quenched by the model compound with the diffusion-controlled rate constant in acetonitrile, suggesting that a strong electron-accepting capability of the imide carbonyl group may hinder the electron transfer process within PAG molecules in 6FDA-AHHFP film. Although a polyimide (6F-THP) protected by tetrahydropyranyl group is insoluble in aqueous base, 6F-THP film containing PAG became soluble in a 2:1 mixture of 2.0 wt% tetramethylammonium hydroxide (TMAH) and methanol by exposure to 365 nm light and successive post-exposure baking (PEB) at 120°C for 10 min. The sensitivity and contrast of 6F-THP with DIANS after the PEB conditions mentioned above were 110 mJ/cm² and 3.7, respectively. A high-resolution pattern with a good profile was transferred into the 3 μm thickness of the 6F-THP film.     

Study of ion desorption induced by a resonant core-level excitation of condensed NH3 using Auger-electron photo-ion coincidence (AEPICO) spectroscopy combined with synchrotron radiation

Photostimulated ion desorption at the 4a₁ ← N 1s resonant transition of condensed NH₃ was studied using electron emission spectroscopy and Auger-electron photoion coincidence (AEPICO) spectroscopy. The total ion yield divided by the Auger-electron yield exhibited a threshold peak at hν = 399 eV which is ascribed to the resonant transition from the N 1s to the N---H antibonding 4a₁ orbital. The electron emission spectrum at the 4a₁ ← N 1s resonance is decomposed into three components: a valence photoelectron emission spectrum, and normal- and resonant-Auger-electron emission spectra. We ascribe the resonant-Auger-electron emission spectrum mainly to spectator-Auger transitions on the basis of the peak assignment. A series of AEPICO spectra at the 4a₁ ← N 1s resonance was also measured as a function of the Auger-electron kinetic energy. The electron kinetic energy dependence of the H⁺ AEPICO yield displays a shape approximately similar to that of the mixed spectrum of normal- and spectator-Auger-electron emission spectra. Based on this result the H⁺ desorption at the 4a₁ ← N 1s resonance is concluded to originate from the spectator-Auger transitions and from the normal-Auger transitions following the delocalization of the excited electron.     

Transmission characteristics of optical waveguide corners

Two-dimensional dielectric waveguide corners with air reflector or metal reflector have been investigated by means of the method of plane-wave expansion, which has the advantage of being compact for optical integrated circuit applications. The operating principle of these waveguide corners is based on the total internal reflection or large partial reflection. The corner losses and field profiles are presented for various waveguide parameters. It is found that the corner loss can be small if the waveguide corner is properly fabricated.     

Structure of neooxazolomycin,an antitumor antibiotic

Based on the spectroscopic analysis and correlation with the degradation products of oxazolomycin, the structure of neooxazolomycin has been elucidated.     

Evaluation of mitochondrial function by measuring the heat production in state 3 and state 4 respiration

Using a microcalorimetric method, we have measured the heat production in states 3 and 4 respiration of a mitochondrial preparation from rat heart ventricle. Adenosine triphosphate production in state 3 respiration was also determined for the same preparation after heat production was measured. In Tris-buffered solution with pyruvate and malate used as substrates, the total heat production in states 3 and 4 respiration for a 10-min reaction period were about 709 and 207 mJ/mg of mitochondrial protein, respectively. 2,4-Dinitrophenol, an uncoupler of mitochondrial oxidative phosphorylation, increased the heat production in both states 3 and 4 respiration. On the other hand, antimycin A1, an inhibitor of the electron transport system, decreased the heat production in both states. When ventricle mitochondrial dysfunction was induced by the in vivo administration of a high dose of isoproterenol, heat production was increased in state 4 respiration. These results indicate that the calorimetric method can be used to evaluate the mitochondrial function.     

Asymmetric synthesis of γ-alkayl-α-methylene-γ-butyrolactones via 1,6-remote induction using 2-[(tributylstannyl) methyl]propenamides

Reaction of chiral 2-[(tributylstannyl)methyl]propenamides with aldehydes proceeded with 1,6-asymmetric induction to give, after hydrolysis, α,-methylene-γ-butyrolactones in enantiomeric excesses as high as 80%.     

Constituents of a fern, Davallia mariesii Moore. II. Identification and 1H- and 13C-nuclear magnetic resonance spectra of procyanidin B-5, epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin, and epicatechin-(4 beta----6)-epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin.

Procyanidin B-5 (1), epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin (2), and epicatechin-(4 beta----6)-epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin (3), which showed an inhibitory effect toward protein kinase C, were isolated from the rhizomes of Davallia mariesii Moore. Detailed analyses of their 1H- and 13C-nuclear magnetic resonance spectra were carried out by the use of two-dimensional nuclear magnetic resonance techniques.     

Chemical modification of poly(substituted-acetylene): II. Pervaporation of ethanol / water mixture through poly(1-trimethylsilyl-1-propyne) / poly(dimethylsiloxane) graft copolymer membrane

Poly(1-trimethylsilyl-1-propyne)/poly(dimethylsiloxane) (PTMSP/PDMS) graft copolymer was prepared to evaluate the permeation characteristic at pervaporation of aqueous ethanol solution through the graft copolymer membrane. For the preparation of PTMSP/PDMS graft copolymer, an improved synthetic procedure was released in this paper, which comprised a one-pot reaction of PTMSP in lithium bis(trimethylsilyl)amide followed by treatment with hexamethylcyclotrisiloxane and trimethylchlorosilane. PDMS content of the graft copolymer was controlled in the range 5–74 mol%. Very tough and thin membranes could be prepared from these copolymers having various PDMS content by the solvent casting method. The permselectivity of the membranes was investigated by pervaporation of ethanol/water mixture at 30°C. Preferential permeation of ethanol was observed for the membranes. It was also found that the selectivity of every copolymer membrane was higher than that of the PTMSP membrane. Moreover, the selectivity depended on the PDMS content of the graft copolymer. The separation factor and permeation rate assumed the maximum values at 12 mol% PDMS content. At the maximum point, 7 wt% aqueous ethanol solution was concentrated to about 70 wt% ethanol solution, and the separation factor and permeation rate were 28.3 and 2.45 × 10^?3g · m/m² · h, respectively. Such a high permselectivity for ethanol might be due to a delicate alteration of membrane structure, which was induced by the introduction of a short PDMS side chain into a PTMSP backbone.     

Development of muon polarization preserved scintillators

We measured the residual μ⁺ polarizations in various liquid scintillators to search for an ideal material for an active muon stopper in which the muon spin polarization can be preserved and at the same time their energy loss and tracks can be measured by scintillation lights from the stopper material. We found the residual polarizations of mineral‐oil base liquid scintillators were \sim 4 times larger than that of a plastic scintillator. Further increase of the residual polarization was observed with a mixture of CCl₄. This revised version was published online in August 2006 with corrections to the Cover Date.     

(Et4N)4[V4O12]·2H2O

The title compound, tetrakis(tetraethylammonium) cyclo‐tetra‐μ‐oxo‐tetrakis[dioxovanadium(V)] dihydrate, (C₈H₂₀N)₄[V₄O₁₂]·2H₂O, was obtained by reacting V₂O₅ with (C₂H₅)₄NOH. It consists of a discrete centrosymmetric molecular anion, [V₄O₁₂]^4?, where four tetrahedral VO₄ units share two vertices with each other to form a ring. A water mol­ecule is attached on each side of the ring through hydrogen bonds.