Q-mass spectroscopic measurement confirmed a HF dissociation reaction and a C-Au-S molecule synthesis during cooperation process of plasma CVD and sputtering. Then the C-Au-S molecule was expected to compose conductive grains in C-Au-S films. The semi-conductive C-Au-S film at 1 nm thickness worked successfully in a PVDF ferroelectric electron emitter by a polarization inversion method. The chemical reactions in the cooperation plasma process were discussed.

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Permeation of insulin through grafted PTFE films was controlled by pH decline which was caused by the enzymatic reaction of glucose oxidase (GOD) with glucose. The PTFE-g-P(AAc-co-AAm) films were prepared by the combined use of oxygen plasma pretreatment and photografting. The immobilization of GOD was performed by condensation with grafted polymer chains. The maximum amount (5 mmol/g) of GOD immobilized to P(AAc-co-AAm) was obtained at around 4 hours of the reaction time. The permeation of insulin through the GOD immobilized ePTFE-g-P(AAc-co-AAm) films can be enhanced through the addition of glucose, and then further Catalase. The enzymatic activity of immobilized GOD decreased to 25% of native GOD. However, the enzymatic activity holds for prolonged preservation, e.g., more than 30 days significantly.

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Uniaxial polymer blend sheets were produced by melt-extruding from a mixture of poly(L-lactic acid) (PLLA) with poly(butylene succinate) (PBS). These sheets were treated by use of O₂- or Ar-plasma, and the surface effects were examined by the plasma susceptibility. Mass loss by plasma etching depended on the polymer blend ratio; the etching was greater in the blend sheets with higher ratio of PBS. Microstructures were formed on the surface as a result, and the sheets treated with Ar-plasma had a finer morphology than these treated with O₂-plasma. A new IR absorption peak appeared at 1616 cm^-1 in the PLLA portions in the polymer blends after the O₂-plasma treatments. Plasma treatments increased the surface wetting of these polymer blends. PBS sheet was biologically degraded, but the degradation decreased substantially by the blending of PLLA even after the plasma treatments.

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A Photosensitive polyimide (PSPI) precursor for light-induced self-written (LISW) waveguide based on a poly(amic acid) (PAA) and 1,4-dihydropyridine derivatives (DHP)s has been developed. The PAA was prepared by ring-opening polyaddition of aromatic fluorinated tetracarboxylic dianhydrides and diamines. Upon exposing the PSPI precursor to laser light, a self-focusing effect induced by the difference in refractive index between the exposed and unexposed portions was observed. Thermal treatment of the laser exposed PSPI precursor gave a polyimide LISW wave guide with no other processing steps. The coupling loss between two multimode fibers with a 0.5 mm gap, was decreased from 5.2 dB in air to 0.7 dB by insertion of the PSPI LISW waveguide. This simple new fabrication method of LISW waveguide structures allows convenient and easy alignment of optical waveguide components.

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The integration of new low k dielectric materials into active devices has proven challenging due to the fragile nature of these emerging dielectrics. This has created a number of semiconductor process challenges, which to a large degree have been overcome, and the latest set of challenges is now related to die fragility in a packaged device, which manifests itself primarily in poor thermal cycling reliability. To address this limitation, a number of packaging architectures now involve the use of compliant packages or low modulus materials. Today, polynorbornene-based stress buffer coatings are well suited to respond to the challenges presented by low k integration. The polymer has attractive processing properties, such as a low cure temperature, excellent dielectric properties, and desirable mechanical properties, most notably, low residual stress after cure. The suitability of the polymer as a stress buffer layer was further validated via a Finite Element Method simulation in an assembled flip chip package. A discussion of the polymer properties, processing conditions, and the results of the finite element model (FEM) simulation will be presented.

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A novel positive-type photosensitive polyimide with low modulus based on soluble block copoly(imide-siloxane) with hydroxyl group and diazonaphthoquinone as a photoreactive compound has been developed. The base block copoly(imide-siloxane) was prepared by a direct one-pot polycondensation of biphenyltetracarboxylic dianhydride(BPDA) 2,2-Bis(3-amino-4-methyl)phenylhexafluoropropane(Bis-AP-AF) and diamino(poly)siloxane in the presence of a γ-valerolactone and pyridine catalyst system using dipolar aprotic solvent such as N-methyl-2-pyrrolidone(NMP). The base block copoly(imide-siloxane) consists of aromatic polyimide unit as a hard segment, and polysiloxane unit as a soft segment.The polysiloxane unit contributed to the resulting poly(imide-siloxane) film with not only colorlessness and transparency which are the important factors for a photosensitive polyimide but also low modulus. Due to the low modulus, it can reduce the residual wafer stress caused by the CTE (coefficient of thermal expand) mismatch between silicon wafer (3ppm/K) and polyimide (30∼60ppm/K), and prevent semiconductor devices from physical and electric damage. Photosensitive block copoly(imide-siloxane) containing 20wt% Ester of 2,3,4,4'-trihydrobenzophenone with 1,2-naphthoquinone-(2)-diazide-5-sulfonic acid (4NT-300) showed a sensitivity of 350mj/cm² and a contrast of 1.95 when it was exposed to UV light, followed by development with 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution containing 10wt% isopropyl alcohol (IPA) at room temperature.

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We developed novel positive-tone photosensitive polyimide coatings for insulation layers in organic light emitting diode (OLED) displays. We evaluated the features of the novel coatings in comparison to other candidate polymers including novolak resin, acrylic resin, and polybenzoxazole. After curing, the novel coatings exhibited excellent and stable electrical and thermal properties, and good adhesion to various substrates with quite a low thickness loss during cleaning process, e.g., UV-O₃, O₂-plasma, etc. In addition we confirmed that the novel coatings could solve the "pixel shrinkage" problem in OLED displays.

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Poly(aryl ether ketone) (1) containing alkyl groups was prepared by nucleophilic substitution of 4,4'-difluorobenzophenone (DFBP) with 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane (TMBPA). And co-poly(aryl ether ketone) (2) containing heterocyclic moiety was prepared from DFBP, TMBPA, and 2,6-dichrolopyridine (DCP). The polymers were soluble in common organic solvents, such as N-methyl-2-pyrroridone, tetrahydrofurane, chloroform, and cyclopentanone at room temperature. Thermogravimetry of the polymers showed good thermal stability, indicating that a 5% weight loss of the polymer (1) and (2) were observed at 421°C and 395°C in air respectively. Glass transition temperature of the polymers ranged from 206 to 212°C. Transparency of the polymers at 365nm was almost 40-50% . The polymers showed low water absorption of 0.1-0.2%. The polymers acted as a negative-working photoreactive polymer by UV radiation. Adhesion to copper substrate of the polymer (2) was improved compared with the polymer (1). Then the polymer (2) was capable to resolve a 20μmφ hole pattern on copper plating surface when a 10μm-thick film was used. The dielectric constant and dissipation factor of the polymer (2) were 2.71 and 0.0043 at 12GHz respectively.

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This article reviews the optical properties of fluorinated polyimides (FPIs) that exhibit outstanding optical transparency as well as excellent thermal, mechanical, and electric properties for the applications to optical components, in particular for telecommunication applications. The optical transparency of polyimides in the near-infrared (NIR) region are explained based on the harmonic oscillations of infrared absorptions. The variations and the methods of controlling refractive indices, birefringence and thermo-optic coefficients of polyimides are described, and a variety of recent applications of FPIs to optical components, such as single-mode and multi-mode waveguide circuits, substrates for WDM filters, waveplates and polarizers are reviewed. Partially fluorinated and perfluorinated polyimides are promising optical materials for future telecommunication systems.

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We found unusual exhaust pressure dependency on photo-sensitivity of positive photo-definable polyimide (posi-PDPI) when soft baking PDPI. Higher exhaust pressure of soft baking makes higher photo-sensitivity. This tendency is reverse thing what we expected, because higher exhaust pressure seems to give lower solvent in the soft baking film. We measured the dissolution change of base polymer, and posi-PDPI by using dissolution rate monitoring method.

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A fluorinated aromatic polyimide derived from 1,4-bis (4-aminophenoxy)-2-[(3', 5'-ditrifluoromethyl)phenyl]benzene was prepared through a typical two-step polymerization method. The polyimide had a high thermal stability, and the temperature at the 5% weight loss was 509°C in nitrogen. It showed good solubility in NMP, DMAc, DMF, Chloroform and THF at room temperature. The dielectric constant estimated from the average refractive index was 2.71.

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The electroluminescence (EL) properties of the organic electroluminescent devices (OELDs) using three kinds of fluorescent polyimides, ODPA/DCHM (HFPI-1), 10FEDA/DCHM (HFPI2), and P2FDA/DCHM (HFPI-3), for light emitting layers were investigated. The HOMO energy levels of HFPI-1 and HFPI-2 were determined as 6.7 and 6.9 eV, respectively, using cyclic voltammetry. Single-layer EL devices having the ITO/HFPI/Al structure were fabricated using HFPI-1 and HFPI-2, but these devices did not exhibit any current and EL properties. This is due to the quite large energy gaps between ITO (work function: 4.7 eV) and the HOMO levels of polyimides (>2.0 eV). Further, multilayer devices were fabricated using carrier transport materials. For these devices, the carrier injection properties from both electrodes were expected to be improved. However, no current and EL properties were observed for all devices. These experimental facts indicate that fluorescent polyimides have little carrier transportability. The EL properties of the devices using TPD-dispersed fluorescent poly-imides as hole transport layers were also investigated. In case of using HFPI-3 whose excitation spectrum is overlapped with the emission of Alq3, the device emits a distinct EL at 520 nm under the operation at 15 V. Further, the emission was displaced to 560 nm under the operation at 30 V, which can be explained by the energy transfer to HFPI-3 or the displacement of the recombination zone of electrons and holes from Alq3 to HFPI-3+TPD layer. This device mechanism might be promising as a novel wavelength-tunable OELD.

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A novel thermal-stable positive-tone photodefinable material has been proposed which applies chemical amplification system to a poly(benzoxazole). To fabricate thick film and also to obtain high dissolution contrast, we paid attention to a three-component system consisting of a poly(benzoxazole) precursor, photoacid generator, and dissolution reverser. In this paper, we describe the design concept of dissolution reversers affording a significant difference in dissolution rate between the exposed and the unexposed area. Moreover, we discuss the photolithographic and film properties of the proposed material. On the basis of the dissolution behavior study, we have designed some promising dicarboxylic acid derivatives for dissolution reversers. We found that the chemically amplified poly(benzoxazole) using the dissolution reversers will afford excellent photolithographic properties such as high sensitivity, fine resolution, and good critical dimension control, along with excellent film properties comparable to those of the conventional non-photodefinable polyimide.

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Polybenzoxazoles (PBO) are also expected as low-K & low-CTE dielectric materials as well as polyimides. High molecular weight PBO precursors, polyhydroxyamides (PHAs), were prepared from silylated bis(3-hydroxy-4-amino)biphenyl(p-HAB) and dichlorides of terephthalic acid (TPA) or trans-1,4-cyclohexanedicarboxylic acid in DMAc/HMPA in the presence of pyridine and LiCl. After precipitation of the PHA solution into water to remove the salts, it was difficult to re-dissolve into salt-free aprotic solvents. Therefore, the salt-containing PHA solution was cast on a glass plate and washed with water to remove salt, then the dried films fixed in a frame were heated at 400°C/1h to ensure complete transformation to PBO. The obtained PBO films showed a much lower K, a lower CTE and a higher Tg than the corresponding PIs. The use of a fluorine-containing bis(o-aminophenol) as a comonomer for the homo p-HAB/TPA system improved significantly the solubility into salt-free solvents. Another PHA derived from an isomer of p-HAB, bis(4-hydroxy-3-amino)biphenyl (m-HAB) and TPA also showed a high solubility. These new PBO systems made possible the convenient film formation process (cast-drying-thermal treatment like PI systems) for microelectronic applications. Simultaneously, these PBO films maintained comparatively low K values, considerable low CTEs, and high Tg's as in the homo p-HAB/TPA systems.

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New positive-working photosensitive polyimides (PSPIs) based on polyimides bearing sulfo groups (PISs) and 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl} -4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) as a photosensitive compound have been developed. PISs were prepared by ring-opening polyaddition of 2,2'-oxybis(5-aminobenzenesulfonic acid) (OBAS) or, 2,2'-thiobis(5-aminobenzenesulfonic acid) (TBAS) and 4,4'-oxydianiline (ODA), with 4,4'-hexafluoropropylidenebis(phthalic anhydride) (6FDA), followed by thermal cyclization in m-cresol. PIS containing 30wt% of S-DNQ showed a sensitivity of 100 mJ cm-2 and a contrast of 2.6, when it was exposed to 365-nm light followed by developing with 2.38 wt % aqueous tetramethylammonium hydroxide (TMAH) solution at room temperature. A fine positive image featuring 20μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm^-2 of UV-light at 365 nm by the contact mode. The positive image was successfully converted to the polyimide pattern by thermal treatment.

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Soluble polyimides having pendant carboxyl groups were prepared by one-pot polycondensation of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 3,5-diaminobenzoic acid (DABz) and bis[4-(3-aminophenoxy)phenyl]-sulfone (m-BAPS) in the presence of γ-valerolactone/pyridine catalyst system using N-methyl-2-pyrrolidone (NMP)/toluene mixture as a solvent, and used for the electrodeposition coating. Positive-type photosensitive polyimide compositions for electrodeposition coating consisted of the pendant carboxyl-containing polyimide, NMP and cyclohexanone as solvents, N-methylmorpholine as a neutralizing agent, deionized water and diazonaphthoquinone(DNQ) compound(PC-5^®) as a photosensitive material. The electrodeposition coating under a fixed voltage provided photosensitive polyimide films with high levels of appearance and smoothness on a copper foil. These photosensitive polyimide films formed by electrodeposition coating gave positive-tone behavior by UV irradiation and following development in an aqueous tetramethylammonium hydroxide(TMAH) or ethanolamine-containing solution. The scanning electron microscopic photographs of the resulting images showed fine and sharp line/space patterns.

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Transient refractive index change of poly(N-isopropylacrylamide) gels (PNIPA gels) by the photo-thermal conversion were measured in water-ethanol mixture solvent. The magnitude of the refractive index change was as large as 10, and the response time was as small as 10 msec. The transient refractive index change is induced by the thermal expansion of the gels, while the magnitude of the refractive index change is not only affected by the thermal expansion of solvent, but also by the mobility of the solvent, which is restricted by the existence of polymer chain.

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Controlling refractive index of materials is important for optical processing system. Especially, photochromic reactions are one of the potential techniques which induce irreversible refractive index change in materials. The photochromic reactions are usually performed in the solid state because of the applications to devices. However, the kinetic and the reactivity of the photochromism are basically different from those in solution. We measured the dynamics of refractive index change of photochromic dyes by a Michelson interferometer.

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Aluminum(III) bis(2-methyl-8-quinolinate)4-phenylphenolate (BAlq) is well-known to be a hole blocking material against phosphorescent light-emitting diodes. The authors investigated the EL mechanism of BAlq. The PL intensity of BAlq was stronger than that of Alq3, but the EL performance of BAlq LED was poorer than that of Alq3 LED because of lower electron injection. The introduction of Alq3 electron injection layer improved EL performance, but EL decreased with decreasing BAlq thickness beyond the optimal Alq3 thickeness. The authors clarified by doping method that the recombination zone of BAlq/Alq3 LED is located near the interface between BAlq and Alq3 and Alq3 may act as quencher to BAlq.

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Blue phosphorescence and white phosphorescence from organic light-emitting devices (OLEDs) based on phosphorescent iridium complexes are discussed. To improve emission efficiency, 4,4'-Bis(9-carbazolyl)-2,2'-Dimethyl-biphenyl (CDBP), which has a high triplet energy, was used as the carrier-transporting host for the emissive layer. The blue phosphorescent OLED exhibited a maximum external quantum efficiency of 10.4%, which corresponds to a current efficiency of 20.4 cd/A. This result can be explained as due to the efficient confinement of triplet energy on blue phosphorescent molecules, which is consistent with the results of transient photoluminescence experiments. The white phosphorescent OLED with greenish-blue and red emissive layers exhibited a maximum external quantum efficiency of 12% and a luminous efficiency of 18 cd/A. This is primarily attributed to improved greenish-blue emission efficiency as well as the emission efficiency of the blue phosphorescent OLED.

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Multi-layered polymer light-emitting diodes (ML-PLEDs) with the structure of [transparent anode / buffer-layer / emitting-layer / hole-blocking layer / cathode] have been fabricated by organic-all-wet coating process, and the device characteristics have been studied. The multi-layered device, [ITO / PEDOT:PSS / poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) / poly[(9,9-dioctylfluorene)-alt-{1,4-distyryl-2-methoxy-5-(2-ethylhexyloxy)benzene}] (PF8-DSB) / Ca / Al], has shown enhanced electroluminescent (EL) efficiency of 3.6 cd/A while the conventional device [ITO / PEDOT:PSS / MEH-PPV / Ca / Al] has shown only 1.0 cd/A in the EL efficiency. It is considered that this improvement is achieved by the adequate confinement of the recombination site of holes and electrons in the emitting layer and also by the effects of the interlayer between two polymers.

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We investigated the device characteristics of field-effect transistors (FETs) based on a regioregular polythiophene for their dependence on device fabrication conditions. The device performance varied depending on solvents, chemical species of insulator-surface modifier and polymer solution concentration, with the result that the field-effect mobility for hole ranged from 10^-4 to ∼10^-2 cm²/V·sec. We concluded from the variation in the device characteristics of a series of FETs made with toluene solutions that, in addition to the higher regioregularity of the polymer, chemical and/or physical properties of the contact between the polymer solution and insulator surface substantially influenced the device performance.

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The morphology of polymer-walls in liquid crystal/monomer mixtures, produced by irradiating selective areas of a cell with non-uniform ultraviolet (UV) light irradiation through a photomask to induce phase separation by photopolymerization, have been investigated using both optical and scanning electron microscopy. It was found that it is possible regulate the morphology of the polymer-walls by controlling the photopolymerization process which occurs during curing in two-phase region. The mechanisms of polymer-wall formation are complex, including local photopolymerization and diffusion processes.

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