Study on organosilicon positive resist. II. Organosilicon positive photoresist (OSPR–1334) and its application to bilayer resist system

A new alkali-developable organosilicon positive photoresist (OSPR–1334) and a bilayer resist process with OSPR–1334 has been developed. OSPR–1334 is composed of poly(p-hydroxybenzylsilsesquioxane) and naphthoquinone diazide. The sensitivity and the resolution are almost the same as those of conventional novolac-based resists when aqueous tetrakis (2-hydroxyethyl) ammonium hydroxide is used as a developer. Also, OSPR–1334 has excellent resistance to O₂RIE. The etching rate is 3.6 nm/min, while that of polyimide resins or hard-baked novolac-based resists is 100 nm/min. OSPR–1334 is suitable for use as the top layer of the bilayer resist system. OSPR–1334, after O₂RIE, can be eliminated by dissolving an unchanged layer followed by spinning out or filtrating a changed surface layer. Submicron patterns with a high aspect ratio can easily be obtained with this bilayer resist process.     

Organosilicon deep UV positive resist consisting of poly(p-disilanylenephenylene)

A new class of positive deep ultravoilet (UV) resists consisting of poly(p-disilanylenephenylene)s was developed, in which a disilanylene unit and a phenylene unit are connected alternatively in the polymer main chain. These resists had very high etching resistance against oxygen plasma. The lithographic applications of a double-layer resist system in which the poly(p-disilanylenephenylene) film was used as the top imaging layer were examined. As a result, very high resolution and high contrast were attained. The double-layer resist technique using organosilicon deep UV positive resist appears very promising for lithographic applications.     

Novel positive deep UV resist for KrF excimer laser lithography

A novel positive deep UV resist for KrF excimer laser lithography has been developed. The resist is composed of 1,7-bis(4-chlorosulfonyl phenyl)-4-diazo-3,5-heptanedione as the alkaline dissolution inhibitor and an alkali-soluble sytrene polymer as the main-polymer. 1,7-bis(4-chlorosulfonyl phenyl)-4-diazo-3,5-heptanedione has great capability of alkaline dissolution inhibition. High thermal stability and excellent photobleachability at 248 nm of the compound are also characterized. The alkali-soluble styrene polymer has a high transmittance of 70% in 1.0 μm thickness at 248 nm. The novel positive resist had an excellent property for dissolution kinetics and photobleaching. We achieved high aspect ratio half-micron pattern fabrication in 1.0 μm thickness using the new resist.     

A negative resist for KrF excimer laser lithography

The design and preparation of a series of negative resists for KrF excimer laser lithography are described. Each resist is composed of poly(hydroxystyrene) and an aromatic azide. The base resin shows high transmittance of 62%/μm at 248 nm, when p-ethylphenyl p-azidophenylsulfonate. 4-azido-4α-methoxy-chalcone, 1-(4 azidobenzylidene)-3-(α-hydroxy-4-azidobenzyl)-indene, 4,4α-diazido-3,3α-dimethoxybiphenyl, or 1-(4-azidostyryl)-5, 5-dimethyl-2-cyclohexen-1-one is employed as a sensitizer. These azides are obtained by red-shifting the absorption maxima to lower energy regions than the exposing wavelength of 248 nm. Transmittance of resists can be controlled from 10 to 30%. The resist is exposed with a KrF excimer laser stepper and developed in an alkaline solution. Sensitivities of about 15 mJ/cm² are observed. A good, subhalf-micron resist profile is achieved. The photochemical reaction mechanisms of poly(hydroxystyrene) and 4,4α-diazido-3,3α-dimethoxybiphenyl were studied at 248 nm and 313 nm exposure. Quantum yield for photodecomposition at 248 nm is seven times larger than that at 313 nm, but dissolution-inhibition effects are larger at 313 nm exposure. Consequently, the resist shows higher sensitivity at 313 nm than at 248 nm.     

Dry-developed organosilicon resists for 193-nm excimer laser lithography

Irradiation of certain organosilicon polymers with a 193-nm excimer laser forms a latent image that contains increased amounts of oxygen. Patterning is achieved by dry development in an HBr plasma, where the oxidized polymer etches more slowly than the unexposed areas. With these polymers as the top layer in a bilayer resist scheme, 0.2 μm resolution has been demonsrated and resist sensitivities less than 50 mJ/cm² have been achieved. Three classes of organosilicon layers have been investigated: polysilynes; polysilanes, in particular poly(phenylmethyl) silane; and a plasma-deposited polymer derived from tetramethylsilane (PPTMS). The PPTMS, when used with plasma-deposited planarizing layers, opens the possibility of an all-dry, cluster-tool-compatible lithographic cycle.     

Study on organosilicon positive resist. I. Syntheses and characterization of silsesquioxane,siloxane, and silmethylene polymers with phenolic hydroxy groups

Silsesquioxane, siloxane, and silmethylene polymers with phenolic hydroxy groups were prepared in order to obtain alkali-soluble organosilicon polymers. These polymers have structures in which the phenol moieties are separated by one carbon from the silicon. The hydroxy groups were protected as methoxy groups in polymerization processes, then were changed into hydroxy groups by a reaction with trimethylsilyl iodide followed by alcoholysis. In the course of discussion on the characteristics of these polymers, silsesquioxane with phenolic hydroxy groups is found to possess excellent properties for matrix resins of alkalidevelopable organosilicon resists, such as O₂RIE resistance and heat resistance.     

Thermally-reacted poly(methacrylamide) as a positive electron beam resist

Thermally-reacted poly(methacrylamide) degrades under high-energy irradiation. It has a sensitivity of 2-3 × 10^?7 C/cm² when exposed to 10 KV electrons. The resist is thermally stable to 330°C and has a high glass transition temperature, 180 200°C. It may be used for the lift-off process and ion-milling.     

Parameters,affecting the sensitivity of poly(methyl methacrylate) as a positive lithographic resist

The contribution of parameters such as molecular weight, molecular weight distribution and stereochemistry to electron beam sensitivity of poly(methyl methacrylate), PMMA, has been investigated. The sensitivity is interpreted here as the minimum radiation dose required to obtain a predetermined solubility rate ratio, S/S_o = S_R, of the exposed, S, and unexposed, S_o, material. The G-value was foam be independent of molecular weight, molecular weight distribution, and stereochemistry. Data indicate that the weight average molecular weight ratio correlates better with S_R than the number average molecular weight ratio. The tacticity of the resist and the developer solvent molecular weight or size have a large effect on solubility rate. Although the solubility rate pf isotactic PMMA is much greater than the syndiotactic and heterotactic stereoforms, the sensitivity appears to be independent of tacticity. In a homologous series of n-alkyl acetate developer solvents, the molecular size of the solvent has a greater effect on the solubility rate than the molecular weight of the resist. A developer solvent has been selected from the n-alkyl acetates which enhanced the sensitivity of PMMA.     

Poly(methyl α-trifluoromethylacrylate) as a positive electron beam resist

A mechanistic hypothesis is presented which explains the radiation chemistry of poly(methyl α-haloacrylate)s. In order to test the hypothesis poly(methyl α-trifluoromethylacrylate) PMTFMA was synthesized together with copolymers of methyl methacrylate (MMA), and the α-trifluoromethyl analog. The mechanistic hypothesis predicts that PMTFMA should have a higher G scission than PMMA and that it should have no crosslinking propensity. This prediction was verified by experiment. Imaging of PMTFMA as a positive e-beam resist is also presented. The new material is a more sensitive resist than PMMA.     

Ablation of poly(2-hydroxyethyl methacrylate) by 193-nm excimer laser radiation

Data on the ablation of poly(2-hydroxyethyl methacrylate) (PHEMA) by 193-nm radiation pulses, produced by an ArF excimer laser, are presented for the first time and are compared with the data for poly(methyl methacrylate) (PMMA). The ablation rate of PHEMA is lower than that of PMMA and some possible explanations are advanced. The other features of the etch curves are similar and confirm a predicted ablative behavior of the addition polymers susceptible to depolymerization. Geometric aspects of the ablated polymer's surface, and the influence of inhomogeneities in the material, are also presented and discussed.     

A study of CO2 and excimer laser treatments of poly(etheretherketone)

CO₂ and excimer laser (193, 248, 350 nm) treatments were performed on poly(etheretherketone) (PEEK). High fluence excimer laser irradiation induced efficient etching, mainly due to thermal effects. The irradiation with CO₂ lasers and high fluence excimer lasers introduced limited changes in surface chemistry and morphology. Low fluence excimer laser irradiation, particularly at 193 nm and 248 nm, favored the occurence of photochemical phenomena. Surface chemical modifications leading to oxygen depletion and preferential elimination of the ketonic bridge were assessed. At the same time surface morphological alterations were found, diffraction effects led to cone-like structures while the redeposition of heavy oligomers caused the formation of debris on the surface.     

有机硅改性SBS树脂的研究

本文以SBS树脂和含双键的硅烷偶联剂为原料,采用化学接枝的方法合成了粘接性能良好的改性SBS树脂。考察了反应温度、时间、引发剂用量及原料配比对产物粘接强度的影响,优选的最佳条件为:SBS树脂与有机硅摩尔比为1∶0.8,引发剂BPO用量为总单体量的1.5wt%,65℃下反应2～3h,可制得性能优异的有机硅改性SBS树脂。红外分析表明,有机硅被成功地接枝到了SBS树脂上。     

Study of unsaturated polyester and vinylester morphologies using excimer laser surface treatment

A technique based on the use of an ArF excimer laser (193 nm) to analyze the morphology of the unsaturated polyester and vinylester networks has been developed. This method is based on the use of the differences between the thresholds at which ablation of the various constituent phases of the materials occurs. After having determined the ablation threshold of a polystyrene, various surface treatments using excimer lasers fluence around this threshold were applied to unsaturated polyesters and vinylester. In the latter case, a two-phase structure consisting of microgels in a polystyrene phase was shown by scanning electron microscopy observations, allowing us to conclude that the mechanisms by which vinylester and unsaturated polyester networks are formed are similar. We also observed that the two-phase structure of the vinylester matrixes, unlike that of the unsaturated polyesters, is organized rather than random-structured, which could represent a major parameter contributing to the very good hydrolysis stability of these materials. In the event of degradation by osmotic mechanisms, the organized structure network would enable limiting of the development of the osmotic pressures by distributing the forces within the material, thus avoiding crazing. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1703–1714, 1997     

Preparation of periodic surface structures on doped poly(methyl metacrylate) films by irradiation with KrF excimer laser

In this work, we describe laser modification of poly(methyl methacrylate) films doped with Fast Red ITR, followed by dopant exclusion from the bulk polymer. By this procedure, the polymer can be modified under extremely mild conditions. Creation of surface ordered structure was observed already after application of 15 pulses and 12 mJ cm⁻² fluence. Formation of grating begins in the hottest places and tends to form concentric semi-circles around them. The mechanism of surface ordered structure formation is attributed to polymer ablation, which is more pronounced in the place of higher light intensity. The smoothness of the underlying substrate plays a key role in the quality of surface ordered structure. Most regular grating structures were obtained on polymer films deposited on atomically ‘flat’ Si substrates. After laser patterning, the dopant was removed from the polymer by soaking the film in methanol.     

改性有机硅织物柔软剂的研究

采用乳液滴加法合成了酯基改性有机硅织物柔软剂,并对影响聚合的各种因素进行了讨论。结果表明,利用水溶性催化剂,含氢硅油与丙烯酸酯在８０°Ｃ条件下进行乳液聚合,可得到性能稳定的有机硅复合乳液,其对织物具有很好的柔软整理效果。     

有机硅改性丙烯酸酯接枝共聚乳液的研制

由乙烯基硅油采用接枝共聚法对丙烯酸酯乳液进行改性,合成了性能优良的硅丙乳液。讨论了引发剂、乳化剂、聚合反应温度及有机硅单体对乳液性能的影响。     

Poly(N-phenolicmaleimide) for high-temperature stable near-UV resist

Poly[N-(4-hydroxyphenyl)maleimide] (PHPMI) was prepared by the radical polymerization of N-(4-acetoxyphenyl) maleimide, followed by transesterification of the acetoxy group. The cyclic maleimide group was responsible for high-temperature stabilities. Thus, a high glass transition temperature of 227°C and a thermal decomposition temperature of 417°C were found. PHPMI sensitized by a diazonaphthoquinone or an aromatic bisazide was prepared and evaluated as a positive or a negative near-UV resist. Microlithographic positive/negative images were obtained that were stable to temperatures higher than 200°C. The developed images showed no pattern deformation induced by swelling during development. © 1993 John Wiley & Sons, Inc.     

Azide-phenolic resin UV resist (MRL) for microlithography

Poly(4-vinylphenol) sensitized by an aromatic monoazide compound (4-azidochalcone), called MRL (Micro Resist for Longer wavelengths), has been prepared and evaluated as a negative UV resist. The resist is sensitive to radiation in the 300 to 400 nm region. The sensitivity of MRL is comparable to that of a positive quinonediazide photoresist under exposure to unfiltered light from a high pressure Hg lamp. An aqueous base developer removes the unexposed areas of MRL with no evidence of swelling of the exposed areas, indicating its high resolution capability. The main products in the exposure of MRL films are found to be primary and secondary amines. It is concluded that the formation of secondary amines attached to the polymer chain is responsible for the insolubilization of the exposed MRL in the base developer.     

Study of physico-chemical surface treatments on dyeing properties of polyamides. Part 2: Effect of UV excimer laser irradiation

Polyamide (nylon 6) fabrics were irradiated with a 193 nm argon fluoride excimer laser and the effects on the dyeing properties of the fabrics were studied. Chemical analysis indicated that carbonisation occurred in the laser-irradiated samples. The laser treatment breaks the long chain molecules of nylon, increasing the number of amine end-groups which change the dyeing properties of acid and disperse dyes. The results suggest that laser treatment could be used to improve the dyeing properties of nylon fabric with a disperse dye.     

有机硅封闭剂及其性能的研究

研究了由甲基三乙氧基硅烷等有机硅氧烷单体,通过缩聚反应,制得甲基硅树脂;并以此为原料加入固化促进剂和偶联剂配制成一种应用于金属电镀后表面封闭处理的封闭剂溶液。另外还研究了固化条件对封闭剂涂层性能的影响。