The steps of the LIGA process (deep-etch synchrotron X-ray radiation lithography, electroforming and plasic molding) for mass fabrication of microstructures having high aspect ratio and great structural height are described. Based on the LIGA method, a large number of microstructures for various fields of application may be produced. However, it has been demonstrated until now on a laboratory scale only. Therefore, it has to be emphasized that further intensive work is necessary for successful commercial utilization of this new microfabrication method. For miniaturization of machines it is necessary to integrate the diversity of techniques. In this context, research and development in the LIGA process is urgently necessary.

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Several overcoat materials are applied to a chemically amplified positive X-ray resist (CANI). Although water-soluble materials are preferable in terms of safety and cost, they reduce the resist sensitivity. One reason for this is that moisture originating in the overcoats lessens activity of the catalytic acids needed for chemical amplification. Among the materials investigated, poly(α-methylstyrene) treated with xylene as a solvent most efficiently reduces post-exposure delay effect and withdraws the lithographic performance of CANI.

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Azide-phenol resin resist is applied to a trilayer resist system for KrF excimer lithography. It was found that smaller size patterning below 0.2-μm-level limit the film thickness to 0.5μm of bottom layer due to pattern collapse and micro-loading during the dry etching processes. Under such condition, the analysis of multi-interference effect for trilayer resist system leads to a photoabsorptive resist as a top layer. The photoabsorptive resist with extinction coefficient of 0.045 for trilayer resist system gives linewidth variation less than 0.005μm, resolution limit of 0.15-μm L/S and depth of focus of ±0.8μm for 0.16-μm L/S pattern.

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A new positive-tone ArF single layer resist based on chemical amplification is described. High transparency at 193nm and dry-etch resistance required for ArF single layer resist can be achieved by introducing compounds containing alicyclic groups, such as adamantyl derivatives, in the resins. The dry-etch resistance of the resist is comparable to that of novolac resists, and high transparency ensures pattern imaging at 193nm. This resist is capable of resolving 0.2μm features with an ArF exposure system, and is suitable for ArF single layer resist.

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A new contrast enhancement method using the salting out effect has been developed. We have applied this method to the development of a positive type electro-deposition (ED) resist (Sonne EDUV P-100). By designing the resist structure to be suited to the ion strength of its developer, the contrast has been dramatically improved. The dissolution of the unexposed region of this resist is completely inhibited by the salting out effect, while the dissolution of the exposed region and the sensitivity for the UV exposure are being kept high. This resist thus can prevent surface degradation during the development and obtain high durability for the overdevelopment. Otherwise the resist can be removed by dissolution to aqueous alkaline of low ion strength. In the printed circuit board production, very wide process latitude can be obtained for the pattern transfer with this resist.

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A new water-soluble photoresist consisting of a polymeric azide sensitizer and Poly(acrylamide-diacetone acrylamide) (PAD) was developed for this potential application to a black matrix process in a color picture tube fabrication. The polymeric azide sensitizer was prepared by the condensation reaction of Poly(4-vinylacetophenone-maleic acid) with 4-azidobenzaldehyde-2-sodium salt. This newly developed resist shows higher sensitivity than that of our current resist that is composed of 4, 4′-diazidostilbene-2, 2′-disulfonate and PAD. The resist exhibits the reciprocity-law failing characteristic that is desirable for high contrast patterning. One of the mechanisms of increase in sensitivity is presumed to be due to the tangle of polymers between a polymeric azide sensitizer and PAD.

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In order to establish a kinetics of the reaction between reactive groups attached to polymer side chains, we have measured the reaction rate of photodimerization of anthryl groups attached in part to polymethylmethacrylate (PMMA) side chains in dilute solutions. A dynamic light scattering (DLS) measurement and a gel permeation chromatography (GPC) have been used to estimate the volume of an individual polymer coil. At the initial stage of the reaction, the volume does not change so greatly and the reaction obeys a second order kinetics in the same manner as a monomer-like model compound. When the reaction proceeds up to some extent, the volume decreases rapidly and the reaction is restricted to deviate from the second order kinetics

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A novel doped EL device was fabricated utilizing thermal ring closure reaction of 3, 3′-dibenzanthronyl (1) in the vacuum deposition process. By controlling deposition temperature of (1), part of (1) reacted to violanthrone (2) to give a thin film of compound (1) doped with (2). Red emission of (2) was observed from the EL cell consisted of ITO/TPD/(1) doped with (2)/Al.

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The photochemistry of triphenylmethane dye was investigated in organic solutions at room temperature. Malachite green oxalate showed photobleaching upon visible light irradiation and recovery in the dark in less polar 1, 2-dimethoxyethane. Such inverse photochromism was due to the formation of leuco ester from photoassisted binding of cation and anion, and to thermal ionic dissociation. In polar solvents such as acetonitrile these reactions were not observed.

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Promotion of polymer decomposition by light irradiation was studied to establish efficient methods of treatment of plastic garbage. Plastic waste is now a pollution source in our environments. It was found from this work that carbon tetrachloride and chloroform were effective solvents for promotion of a chain scission of polymers by UV irradiation. Irradiation was carried out to the solutions of polystyrene and polyethylene oxide.

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Refractive indices of films containing NBDA and QCA, and photoinduced refractive index changes of films containing norbornadiene moiety were measured, and the applicability of these materials to optical waveguide lithography was examined. Refractive indices of PMMA films containing QCA were smaller than those of PMMA films containing NBDA due to the difference of molar refractions between NBDA and QCA. Photoinduced refractive index change was measured for a P(NBDA/mXDA) film. The refractive index decreased as photochemistry proceeded keeping wide transparent wavelength region.

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The Förster energy transfer was applied to study layer structures of mixed LB films of 11-(9-carbazolyl)undecanoic acid and palmitic acid deposited from surface supermonomolecular layers. The structure of Y-type LB films composed of a monolayer unit, which was proposed previously for such systems, was confirmed by the present method. It was further shown that the energy transfer was able to specify the supermonomolecular LB films.

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Non-conjugated cyclic dienes and maleic anhydride co-polymers were synthesized via co-polymerization which involves an addition cyclization process, and they were investigated an application to a photo resist base resin. Every these polymers, which have an alicyclic hydrocarbon main-chain, showed excellent transparency in the wavelength regions of deep UV rays, and some of these polymers have high reactive ion etch resistance as similar as phenolic base resin; i.e. polyvinyl-phenol. One of these polymers (EBH-MAH) was modified to a photo resist, which has diazo photo sensitive functional groups. This polymer appeared high sensitivity for exposure of the deep UV ray. Solubility rate of the polymer in an aqueous alkaline solution, which could be dissolved difficulty for the solution, increased excellently after deep UV exposure. Namely this polymer showed a function as a deep UV positive resist that could be developed in alkaline.

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Esterification of a sulfonate group of zinc(II) tetrasulfonatophthalocyanine with a nitrophenyl or a cyanophenyl group suppressed significantly the color fading due to one-electron reduction of the phthalocyanine moiety induced by ultraviolet light irradiation in color filters as well as in solutions.

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The present paper reports the formation of negative images for negative diazotype process based on the using of the MEM (methoxethoxymethyl) ether of α-naphthol and naphthol AS-OL as blocked couplers; BlueBB-PF₆(4-benzoylamino-2, 5-diethoxybenzene diazonium hexafluorophosphate) as diazo component. UV-vis absorption spectra of the imaging films have been measured and the characteristic curves have been discussed. The structure of an unblocked coupler has been determined by GC/MS analysis to describe blocked-coupler imaging chemistry.

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Vacuum ultraviolet(VUV) irradiation (wavelength 147 nm) of siloxane polymers in the presence of air was studied using ATR FTIR and XPS spectroscopy. The ATR FTIR study revealed the formation of CO and OH groups in the surface layer depending on irradiation time and air pressure. The concentrations of CO and OH groups level off with the increase of irradiation time and pass through the maximum value with the increase of pressure in the range of 0.1-100torr. The XPS study of irradiated polysiloxane films demonstrated that intermolecular crosslinking via oxygen atoms also takes place on the polymer surface. The concentrations of the most important oxygen species O and O3, produced by VUV photolysis of air and coming to the polymer surface were calculated for the air pressure range 0.1-100torr. The photooxidation mechanism for siloxane polymers under VUV irradiation in air has been proposed.

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Aqueous alkali developable UV-cure solder mask, which is an opaque liquid photo-imagable ink for printed circuit board, has been investigated in our laboratory. The fine patterns and excellent performances of the film made from photo-imagable solder mask can be obtained by optimization of concentration of developer, developing temperature and time. The proper heat postcuring makes the film highly resistent to solder heat, alkali and humidity.

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The visible sensitive photoinitiating system composed of 2, 5-bis(4′-diethylaminobenzylidene) cyclopentanone(DEAP) and 2-chloroheuaarylbiimidazole (o-Cl-HABI) can initiate the polymerization of methyl methaczylate (MMA). The kinetic study an photopolymerization of MMA was carried out in toluene solution at 30°C by dilatometry. The polymerization rate was determined to be proportional to the concentration with exponent of 0.85, -0.28, 0.30, 1.0 for DEAF, o-Cl-HABI, 3-mercapto-4-methyl-4H-1, 2, 4-triazole (MTA), MMA, respectively. The photopolymer materials can record stable hologram with sensitivity of 30-300mJ/cm² and resolution of 4000l/mm.

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Photoreduction of double- bridged viologen 1b in polymermatrix film under UV-irradiation goes through two stages. In the first, 1b was reduced to its single cation radical 1b′ and its polymer films become green (λ_max=628nm) not blue the color for benzyl viologen (λ_max=600nm), because of the strong intramolecular interaction between the reduced bipyridinium cation radical unit and the unreduced bipyridinium cation unit in 1b′. Then, 1b′ is further reduced to the double cation radical 1b" and the polymerfilm turns to violet (λ_max=532nm) because of intramolecular pimerization of the two cation radical in 1b".

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Methylene blue borate(MB.Ph₃RB) is a stable salt in the dark and readily proceeds electron transfer (ET) to produce a neutral radical pair upon irradiation by visible light. The unstable boranyl radical undergoes the carbon-boron cleavege to generate active alkyl radical immediatly, along with MB dye bleaching. The association state of salt plays an important role in controlling the photophysical and photochemical properties. The photoinduced ET rate of MB borate in the tight ion pair state (k_et 9×10^-11 s^-1) which predominatly exists in non-polar solution, is far greater than that observed in the free solvated ion state in polar solvents. Photopolymerization of MMA in CH₃CN solution not occurs with MB borate(MB Ph₃RB) alon, but undergoes with MB Ph₃RB/Et₄NPh₃RB combination system. Addition of weak H-donor, such as methanol, results in a great rate-acceleration. The photoinitiation mechanism and different influences were also discussed.
Photoinduced electron-transfer reactions play a central role in many proc of technological importance, such as silver halide sensitization, electrophotography and photoinduced polymerization[1]. However, the quantum yields of such reactions, in general, are very low, which means that the most part of incident photon energy is wasted[2.3]. This is mainly due to rapid exothermic back electron transfer to reform the starting materials, which occurs within the formed radical ion pair in competition with chemical reaction [2.3]. Recently the electron transfer reaction followed by rapidly bond cleavage, in which one or both two of ion radical in the pair is unstable with respect to fragmentation into an ion and a free radical, has attracted a great interesting to design new high efficient photosensitized initiation system for visible photopolymerization[4.5]. In the previous papers[6, 7], we have proposed a type of electron transfer sensitization system composed different xanthene dyes as electron donor and aryliodonium salts as electron acceptor in the form of ion pair. The latter rapidly undergoes G-I bond cleavege through electron transfer from excited dye to iodonium salt to afford a radical species capable of initiation. In this paper we report other type of electron transfer photosensitization system for polymerization, in which triphenylalkyl borate employed as electron donating activator in combination with cationic dyes as excited electron acceptor, ouch ae thiazene. Their spectral propertiee, photochemical behaviors and application for polymerization were studied kinetically.

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S-phenyl thiobenzoates are a new kind of photoinitiator possessing high efficiency of photoinitiation for the polymerization of vinyl monomer. The sensitized photofragmentation reaction was studied in this paper in order to extend the range of spectral response. The results show that s-phenyl thiobenzoates are able to undergo photoinduced electron transfer reaction with different senaitizers such as pyrene, perylene etc., leading to cleavage of molecule of s-phenyl thiobenzoates as well as production of various fragmental products. Results from GC-MS indicate that the main products obtained from photolysis are benzaldehyde and Biphenyl disulfide. On the basis of these, the mechanism of sensitized photolysis of the title compounds has been proposed; moreover, the fact that this system is capable to initiate the polymerization of methyl methacrylate confirm that s-phenyl thiobenzoates are able to combine with proper electron donating compounds to form the photo -sensitization system which enables to extend the available wavelength beyond 400nm.

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Hydrophilic tertiary amine accelerators derived from benzoin have been synthesized. Their accelerative effect on thioxanthone compounds approaches or even equals to that of DMBI. Their thermal stabilities are also excellent. They are expected to be used as accelerators in a wide range of waterborne and nonwaterborne photocompositions.

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Hydrogen bonding between several novolak oligomers as donors and phenylsulfoxide as acceptor was investigated as a model for the interaction of inhibitors with o-o-connected phenolic blocks in practical novolak resins. It was found that the attraction of the novolak dimer for the acceptor was more than twice as strong as that of the corresponding monomeric phenol.

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We have synthesised the serries of xanthene dye iodouium (XT On, including FL, FC, FI, EO, ER and RB) and studied their spectral properities and photochemical behavior. Under irradiation of visible light, the electron transfer reaction which occured between xanthenic moiety and oaium caused the photolysis of onium to generate active radical, simultaneousty, xanthene dye occured photobleaching reaction. The results of spectral kinetic studies indicate that their photobleaching rate is in the order of FL>FC>FI>EO>ER>RB. At the same time, we have also studied the role of energy transfer sensitization among different xanthene dyes, and depended on this method to speed up the photobleaching reaction. In photochemical reaction system of multi-xanthene iodonium, the rate of electron transfer process is higher than the one of energy transfer process, so their photochemical reaction is equivalent to the one of each single component . On the basis of the result, different systems of multi-xanthene onium can be used in the certain ranges of wave length, for their spectral response covers most region of visible light from 440nm to 600nm. Application of the multi-dye photosensitization system can effectively improved the effecience of photopolymeization initiated radical.

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