Photocrosslinking of polymethoxymethylstyrene and copolymers containing (2,2-disubstituted-1,3-dioxolan-4-yl)methoxymethylstyrene

Methoxymethylstyrene (MSt), (2,2-dimethyl-1,3-dioxolan-4-yl)methoxymethylstyrene (MMSt), and (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methoxymethylstyrene (EMSt) were synthesized and homopolymerized and copolymerized. The photochemical behavior of resultant homopolymers and copolymers with methyl methacrylate (MMA) and styrene (St) were investigated. The infrared (IR) and ultraviolet (UV) spectra of poly(MSt) showed that new bands ascribed to methyl benzoate residue increase rapidly with irrdiation time in air, but no detectable changes are observed in vacuum. The solubility measurements of poly(MSt) indicate that the main factor in crosslinking is the direct coupling of the benzyl radical generated by UV irradiation, which was confirmed by photopolymerization of MMA by means of benzyl methyl ether. It was also found that copolymers of MMSt or EMSt with MMA or St are easily crosslinked by UV irradiation. From the results of solubility measurements of these copolymers irradiated both in air and in vaccum, it was concluded that not only the 1,3-dioxolane structure but also the benzyl methyl ether structure takes part in photocrosslinking, as we expected.     

(4-羟基苯基)甲基苄基硫鎓六氟锑酸盐的合成及表征

以4-羟基苯硫酚和氯苄为原料、三乙胺为缚酸剂,制备了4-苄硫基苯酚;4-苄硫基苯酚在甲苯溶液中,经硫酸二甲酯甲基化制备了（4-羟基苯基）甲基苄基硫鎓硫酸盐;室温甲醇溶剂中,与六氟锑酸钠离子进行交换合成了目的产物（4-羟基苯基）甲基苄基硫鎓六氟锑酸盐。通过紫外光谱和核磁共振测定,对产物进行了结构鉴定。总收率大于75%。     

Donor–acceptor complexes in copolymerization. XLIII. Cyclization of alternating and random styrene–(meth)acrylic ester copolymers

Equimolar alternating copolymers of styrene and methyl methacrylate (prepared with Et_1.5AlCl_1.5, SnCl₄, and ZnCl₂) as well as equimolar random copolymer were treated with polyphosphoric acid at 135°C. The extent of cyclization of the alternating copolymers was about 40%, independent of the cotacticity of the copolymer, and there was little or no crosslinking. The random copolymer underwent only 10% cyclization and considerable crosslinking. The extent of cyclization of the alternating copolymer of styrene and methyl acrylate (prepared with Et_1.5AlCl_1.5) was the same as that of the random copolymer and was lower than that of the corresponding methyl methacrylate copolymer. Both alternating and random copolymers underwent extensive crosslinking.     

Methacrylic silicon-containing tercopolymers for chemically amplified resists

Tercopolymers of methyl methacrylate with methacrylic acid and dimethylphenyl (methyldiphenyl)silyl methacrylates are synthesized and investigated as components of chemically amplified resistive formulations with sulfonium and iodonium salts as photoacid generators for UV lithography in the 254-nm range. The surface behavior and the kinetics of dissolution of resistive films in an aqueous solution of tetraethylammonium hydroxide in relation to the concentration of onium salts and the temperatures of postapply and postexposure bakes are studied. The introduction of sulfonium salt into the resistive formulation brings about an increase in the solubility of unexposed films, thereby erasing the difference in dissolution rates of exposed and unexposed areas of a resist and preventing image formation. The iodonium salt plays the role of an inhibitor for dissolution of unexposed films of both copolymers, which makes it possible to obtain a high-contrast positive image in resists.     

Synthesis and radiation degradation of vinyl polymers with fluorine: Search for improved lithographic resists

Homopolymers of methyl α-fluoroacrylate (MFA), trifluoroethyl methacrylate (TFEM), and hexafluoroisopropyl methacrylate (HFIM) were prepared, as were their methyl methacrylate (MMA) copolymers. Copolymers of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE) with MMA were also prepared. The radiation susceptibilities of these polymers were measured by the ⁶⁰Co γ-irradiation method, in which molecular weights were measured by membrane osmometry and gel permeation chromatography (GPC). All the copolymers degraded by predominant chain scission except poly(methyl α-fluoroacrylate), (PMFA), which crosslinks even at low doses (ca. 1 Mrad). The G_s - G_x and G_s values of the chain scissioning polymers and copolymers are higher than those of poly(methyl methacrylate) PMMA reference. The high susceptibility of PMFA homopolymer to crosslinking is in contrast to that of poly(methyl α-chloroacrylate), as we reported earlier. This effect is interpreted as resulting from extensive hydrogen fluoride and polyenlyl radical formation, which leads to facile crosslinking. However, incorporation of the MFA monomer unit causes the (22/78) MFA/MMA copolymer to degrade with a larger value of G_s that PMMA. Apparently a second-order process leads to crosslinking in PMFA and this is retarded in the copolymer. In the hehomopolymers of HFIM and TFEM and in the HFIM-MMA and TFEM-MMA copolymers the HFIM and TFEM components facilitate degradation with negligible crosslinking. The increased degradation susceptibility of VDF and CTFE copolymers with MMA over that of PMMA is attributed to processes at the VDF or CTFE components present in smaller concentrations (3-5 mole %) than the threshold levels (25-50% necessary for significant crosslinking).     

环氧／环氧丙烯酸酯的光交联和动态力学性能

用硬度法研究了环氧／环氧丙烯酸酯混杂体系中以硫翁盐引发光交联时，组成对光交联的影响；安息香二甲醚能促进混杂体系的光交联；动态力学性能的测定表明该体系是一相容性互网络体系；组成对体系的相容性，交联密度、互穿程度均有影响。     

Chain scission efficiency and reactive-ion etch resistance of alternating copolymers of styrene and olefins trisubstituted or tetrasubstituted with electron-withdrawing groups

Alternating copolymers of styrene (St) with electron-deficient olefins trisubstituted or tetrasubstituted with cyano and carboalkoxy groups have been subjected to ⁶⁰Co γ-radiolysis together with a series of copolymers of methyl methacrylate (MMA) and St. The chain scission susceptibility G_s—G_x determined by membrane osmometry drastically decreases as St is incorporated in poly(methyl methacrylate) (PMMA). Whereas the alternating St-MMA copolymer is slightly crosslinked upon irradiation, an alternating copolymer of St with diethyl 2-cyano-1,1-ethylenedicarboxylate maintains a fairly high degradation sensitivity (G_s—G_x = 1.2). The reactive-ion etch rates were determined for the series of polymers in CF₄/O₂ (92/8). The etch resistance is significantly increased by introduction of St units in PMMA, and the highly substituted alternating copolymer etches as slowly as the MMA(50)—St(50) copolymers. Thus the alternating copolymer of NCCH=C(CO₂Et)₂ with St behaves like PMMA when exposed to high-energy radiation but is comparable to PSt in plasma environments.     

Photocrosslinking of copolymers of vinyloxyethyl methacrylate–styrene initiated by sulfonium salts. I. Transient species formed on photolysis of sulfonium salt

Benzyl cation was detected by transient absorption spectroscopy with a spectroscopic multichannel analyzer on pulse excitation (fourth harmonic of Nd:YAG laser, 266 nm; 10 ns fwhm) of benzyl(4-hydroxyphenyl) methylsulfonium hexafluoroantimonate(BSS) in 1,2-dichloroethane (EDC). The benzyl cation was long-lived (lifetime, 59 ms) at room temperature and quenched by a vinyl ether compound. The formation of the benzyl cation as active species on photolysis of BSS is in contrast to the formation of Brønsted acids in other sulfonium salts so far reported. © 1992 John Wiley & Sons, Inc.     

Radiolysis of resist polymers. VI. Copolymers of trihalophenylmethacrylate and methyl methacrylate

Copolymers of several compositions of methyl methacrylate (MMA), trichlorophenyl methacrylate (TCPMA), and tribromophenyl methacrylate (TBPMA) have been synthesized and characterized. Gamma radiolysis yields are very sensitive to the presence of the halogenated monomers. With less than 10% of the halogenated monomer in the copolymers. G_s values were found to be much greater than that of PMMA. However, the halogenated monomer introduces a tendency toward crosslinking. The results are consistent with the enhancement of chain scission by dissociative electron capture and the tendency of phenyl radical intermediates to cause crosslinking. These structure-property relationships were found to be valid for all the homopolymers and copolymers investigated in this series.     

Polymerization of coordinated monomers. XIV. Systematic deviations from alternating regulation in copolymerization of methyl methacrylate with styrene in the presence of metal halides

Methyl methacrylate (MMA) and styrene (St) copolymerize in the presence of zinc chloride at 3°C under photoirradiation. The contents of methyl methacrylate in the copolymers obtained at a [ZnCl₂]/[MMA] molar ratio of 0.4 are systematically larger than 53 mole %, which is the limiting value at a small feed ratio of methyl methacrylate. The resulting copolymers are confirmed as the sole products and not the mixtures by thin layer chromatography. The effect of dilution of the monomer feed mixture with toluene on copolymer composition suggests that it depends chiefly on the feed concentration of styrene and hardly at all on monomer feed ratios. Copolymerizations are also conducted in the presence of stannic chloride at ?17°C under photoirradiation and in the presence of ethylaluminium sesquichloride at 0°C with spontaneous initiation. The contents of methyl methacrylate in both copolymers obtained at feed ratios lower than 60 mole % almost correspond to the 1:1 alternating copolymer and increase systematically with higher feed ratios. The systematic deviations of copolymer composition obtained in the presence of metal halides are reasonably interpreted by the participation of the binary molecular complex composed of metal halide and methyl methacrylate in the polymerization of the ternary molecular complex composed of metal halide, methyl methacrylate, and styrene.     

Vinyl polymerization. 410. Polymerizations of vinyl monomers initiated by poly(styrene-co-sodium acrylate) or poly(methyl methacrylate-co-sodium methacrylate). A verification of the concept of hard and soft hydrophobic areas and monomers

It was found that the copolymers of sodium acrylate (AA-Na) with styrene (St) and of sodium methacrylate (MAA-Na) with methyl methacrylate (MMA) could polymerize vinyl monomers in an aqueous phase without the usual initiator. Interestingly, there was a definite composition of the copolymer for the polymerization of a given monomer; for example, when poly(St-co-AA-Na) was used, St, MMA, vinyl acetate, ethyl acrylate, methyl acrylate, and acrylonitrile were polymerized by the copolymer having mole ratios of AA-Na:St of 0.61:0.29, 0.47:0.53, 0.38:0.62, 0.30:0.70, 0.24:0.76, and 1.00:0, respectively. The copolymers of various compositions can form hydrophobic areas (HAs) in the water phase. As has been repeatedly reported, the polymerization proceeds in the HAs, and the following new hypothesis was recently proposed that the hard (the less hydrophilic) HA prefers to incorporate the hard monomer and the soft (the less hydrophobic or the more hydrophilic) HA prefers to incorporate the soft monomer. The results mentioned above support this hypothesis.     

甲基丙烯酸甲酯和二乙烯苯对苯乙烯共聚合的影响

以甲基丙烯酸甲酯(MMA)、苯乙烯(St)和二乙烯苯(DVB)三元共聚体系为研究对象,采用气相色谱法研究了体系中MMA和DVB浓度对聚苯乙烯型树脂交联的影响。结果表明:MMA加速St和DVB的聚合速率,其中对St的加速作用又明显大于对DVB的。随MMA含量的增加,聚苯乙烯型树脂交联不均匀的情况得以明显改善,而增加体系中DVB的含量,DVB与St、MMA反应速率的差异变大,树脂交联不均匀的情况变严重。     

Copolymerization and copolymers of brominated phenylmaleimides with some vinyl monomers

The kinetics of the free radical copolymerization in solution of N-(4-bromophenyl)maleimide (MBPMI), N-(2, 4-dibromophenyl)maleimide (DBPMI) and N-(2, 4, 6-tribromophenyl)maleimide (TBPMI) with styrene (St), methyl acrylate (MA), methyl methacrylate (MMA) and acrylonitrile (AN) at low and high conversions were described. Some characteristic properties of the copolymers obtained, particularly their thermal behaviour were also presented.     

Transformation of “living” carbocationic and other polymerizations to controlled/“living” radical polymerization

Transformation of “living” carbocationic polymerization of styrene and isobutene to controlled atom transfer radical polymerization (ATRP) is described and formation of the corresponding AB and ABA block copolymers with styrene (St), methyl methacrylate (MMA, methyl acrylate (MA) and isobornyl acrylate (IBA) was demonstrated. A similar approach was applied to the cationic ring opening polymerization of tetrahydrofuran leading to the AB and ABA block copolymers with St, MMA and MA using ATRP. Site transformation approach was also used for the ring opening metathesis polymerization of norbornene and polycondensation systems using polysulfone as an example. In both cases, AB and ABA block copolymers were efficiently formed with styrene and acrylates.     

Radiation‐induced fabrication of polymer nanoporous materials from microphase‐separated structure of diblock copolymers as a template

Polymer nanoporous materials with periodic cylindrical holes were fabricated from microphase‐separated structure of diblock copolymers consisting of a radiation‐crosslinking polymer and a radiation‐degrading polymer through simultaneous crosslinking and degradation by γ‐irradiation. A polybutadiene‐block‐poly(methyl methacrylate) (PB‐b‐PMMA) diblock copolymer film that self‐assembles into hexagonally packed poly(methyl methacrylate) cylinders in polybutadiene matrix was irradiated with γ‐rays. Solubility test, IR spectroscopy, and TEM and SEM observations for this copolymer film in comparison with a polystyrene‐block‐poly(methyl methacrylate) diblock copolymer film revealed that poly(methyl methacrylate) domains were removed by γ‐irradiation and succeeding solvent washing to form cylindrical holes within polybutadiene matrix, which was rigidified by radiation crosslinking. Thus, it was demonstrated that nanoporous materials can be prepared by γ‐irradiation, maintaining the original structure of PB‐b‐PMMA diblock copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5916–5922, 2007     

Photocrosslinking of silicones. VI. Photocrosslinking kinetics of silicone acrylates and methacrylates

The photoinduced radical crosslinking of silicones containing pendant acrylate and methacrylate groups has been investigated with calorimetric and ESR measurements. Oxygen very strongly influences this process, which leads to a prolonged induction period and a pseudo first-order termination reaction between polymer radicals and oxygen. Kinetically, such reaction steps are responsible for light intensity and monomer exponents, both of unity. In the absence of oxygen, second-order processes take place between polymer and primary radicals. The results of conversion-time and reaction-rate time measurements using stationary irradiations and postpolymerization experiments agree with the corresponding kinetic expressions. Long-lived polymer radicals and their decay have also been determined with ESR techniques. Long-chain spacer groups, which link the unsaturated ester moiety at the silicone backbone, increase the crosslinking rate. The final conversions of the double bonds exceed high values in each case. © 1992 John Wiley & Sons, Inc.     

高玻璃化温度化学增幅光致抗蚀剂的制备

本文合成了一种具有高玻璃化温度的苯乙烯和N-(4-羟基苯基)马来酰亚胺的共聚体,并将其应用于紫外负性水型化学增幅抗蚀剂中,并初步确定了该光致抗蚀剂的光刻工艺操作条件,得到了分辨率为1.39µm的光刻图形。     

The use of the DPE radical polymerization method for the synthesis of chromophore-labelled polymers and block copolymers

Two analogues of diphenylethene carrying phenanthrene (1-(9-phenanthryl)-1-phenylethene (PPE)) and anthracene (1-(2-anthryl)-1-phenylethene (APE)) units were used in radical polymerization of styrene (St) and methyl methacrylate (MMA) at 80 °C using AIBN as initiator. Because of the nature of the polymerization, the resulting polymers possess the corresponding chromophoric groups. Using the methodology of a DPE system, these labelled polymers were further used for the synthesis of block copolymers. In this way poly(methyl methacrylate)-b-poly(styrene) and poly(methyl methacrylate)-b-poly(acrylonitrile) with molar masses of 60,000-90,000 g/mol were synthesized. Incorporation of the chromophoric groups into both homo- and block copolymers was confirmed by spectral measurements.     

活性正离子聚合与原子转移自由基聚合转换合成聚β-蒎烯接枝共聚物

通过活性正离子聚合与原子转移自由基聚合(ATRP)转换合成了β-蒎烯与甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、苯乙烯(St)的新型接枝共聚物.首先以α-氯代乙苯/TiCl4/Ti(OiPr)4/nBu4NCl体系引发β-蒎烯活性正离子聚合,合成预定分子量大小和窄分子量分布的聚β-蒎烯,然后经N-溴代琥珀酰亚胺(NBS)定量溴化,得到溴化聚β-蒎烯大分子引发剂(Br/β-蒎烯链节摩尔比为0.5).然后将该大分子引发剂与溴化亚铜(CuBr)/2,2′-联吡啶(bpy)复合,引发MMA、BA、St进行ATRP接枝聚合.接枝反应显示一级动力学特征,且产物的分子量及分子量分布可控,表明上述ATRP接枝聚合反应具有可控聚合特征.接枝产物的结构经1H-NMR分析得到进一步证实.     

Grafting on polybutadiene with polytetrahydrofuran macroperoxyinitiators. Postpolymerization studies

Grafting reactions of polybutadiene with macro peroxy initiators and postpolymerization were studied. The cationic polymerization of tetrahydrofuran (THF) initiated by the cationic species derived from bis-(4-bromomethylbenzoyl) peroxide (BBP) or bis-(3,5-dibromomethylbenzoyl) peroxide (BDBP) gave the PTHF macroperoxy initiator (MPI). PTHF-b-PMMA macroperoxy initiator (MPIb) was also obtained by the redox polymerization of methyl methacrylate initiated with the hydroxyl ends of PTHF and Ce(IV) salts without decomposing the peroxide groups in the middle. Macroperoxy initiators thermally grafted on cis-polybutadiene (PBD) with thermal curing to yield graft copolymers containing crosslinked and soluble parts, which were separated by the sol-gel analysis. FTIR spectra of the crosslinked samples indicated the characteristic signals of the PTHF, PBD and PMMA blocks. The crosslinked copolymers decomposed at around 470 °C. Postpolymerization of the crosslinked products indicated the increase in crosslinking density which has been followed by measuring the gradual increase of swelling values. Postpolymerization crosslinking was estimated as a first order reaction rate.