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.     

Resist performances and structure of phenolic resins using multi-substituted phenols

Positive photoresist systems comprising phenolic resin and quinonediazide are studied in detail. The structure of several novolak resins, which were synthesized from multi-substituted phenols, are analyzed with ¹³C-NMR. It is proved that these phenols are useful for the structural control of novolak resins. Phenols with two methyl substituents at meta-positions especially show a remarkable structural effect to control methylene bond types of novolak resins. The alkaline dissolution rate is also investigated on novolak resins synthesized from multi-substituted phenols to understand both the dissolution inhibition effect and the dissolution promotion effect. Key-structure of novolak resins for realizing high resolution is elucidated. In addition, the molecular design concept of novolak resin is clarified from several standpoints. Unsubstituted aromatic carbon of resin, hydrophobic effect of methyl substitutent and suitable structure of low M_w parts of novolak resin are also explored. Furthermore, it is proposed that a resist using a resin, which is based on the molecular design concept, has enough potential to produce critical dimensions of 0.2 μm or less taking advantage of phase-shifting technology.     

酚醛-重氮萘醌正性抗蚀剂溶解抑制机理

本文综述了酚醛 重氮萘醌正性抗蚀剂的溶解抑制机理,主要包括(1)分子间氢键作用机理;(2)偶联反应机理;(3)两步即静态、动态溶解抑制机理;(4)表面沉积溶解抑制机理;(5)酚醛树脂的分子溶解及相关的抑制机理.     

A new type of eco‐friendly resist based on nonchemically amplified system

Novel water‐processable photopolymers were designed to be useful as environment‐friendly photolithographic materials. By copolymerization of 2‐(2‐diazo‐3‐oxo‐butyryloxy)ethyl methacrylate (DOBEMA), hydroxyethyl methacrylate (HEMA), methacryllic acid (MAA), and sodium 4‐vinylbenzenesulfonate (SVBS), two kinds of polymers, poly(DOBEMA‐co‐HEMA‐co‐SVBS) for negative‐tone resist and poly(DOBEMA‐co‐MAA) for positive‐tone resist, were synthesized and their photolithographic properties were investigated. The single component negative‐tone resist produced 0.8 μm line and space patterns using a mercury‐xenon lamp in a contact printing mode using pure water as casting and developing solvent at a exposure dose of 25 mJ cm^?2. On the other hand, the single component positive‐tone resist produced 0.8 μm line and space patterns at a much higher dose of 150 mJ cm^?2. Thus, the negative resist showed much improved sensitivity when compared with the positive resist and the reported nonchemically amplified resists. This sensitivity is comparable with those of typical chemically amplified resists. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7534–7542, 2008     

一种高感度深紫外正性化学增幅型抗蚀剂的制备

聚对羟基苯乙烯和环己基乙烯基醚反应得到缩醛保护的聚合物.该聚合物易溶于常见的有机溶剂,具有较好的热稳定性,在248 nm处透明性良好.该聚合物可与聚对羟基苯乙烯-甲基丙烯酸金刚烷基酯及二砜光产酸剂等组成一种三组分正性化学增幅型深紫外光致抗蚀剂,初步研究了该抗蚀剂的感光成像性能.采用KrF激光（248 nm）曝光,在较低的后烘温度下,显影得到分辨率为180 nm的线条图形.显影后的留膜率在99%以上.在光致抗蚀剂体系中引入对羟基苯乙烯-金刚烷基甲基丙烯酸酯共聚物,可提高光刻胶材料的玻璃化转变温度,有利于其实际应用.     

Thermal degradation of metal novolak precursors for high temperature superconductors: thermogravimetric and mass spectroscopy studies

High temperature superconductor (HTS) materials were prepared from novolak metal precursors in a special annealing process. In the present paper the thermal behaviour of pure cresol novolaks and novolak metal salt (nitrate) precursors was investigated by means of simultaneous thermogravimetric analysis and mass spectroscopy in air. The results show significant differences in thermal stability between the pure novolaks and the novolak metal precursors, with respect to the process as well as the products of decomposition. The main volatile products for the precursors are CO₂, H₂O and NO, thus indicating that the thermal degradation results in the formation of metal oxides at a temperature of about 300 °C.     

含碘鎓盐光产酸剂和增感染料的化学增幅型i-线正性光致抗蚀剂

4,4’-二甲苯基三氟甲磺酸碘鎓盐可以被染料增感,在365 nm光照时分解产酸.尽管产生的酸与染料的胺基发生作用,依然能在后烘过程中催化缩醛聚合物酸敏基团的分解,但需要稍高的后烘温度和稍长的后烘时间.基于此,本文将酚醛树脂、缩醛聚合物、碘鎓盐产酸剂和染料组成了一种新型的化学增幅型i-线正性光致抗蚀剂材料,在曝光量为10...     

Synthesis, characterization, thermal properties and flame retardancy of a novel nonflammable phosphazene-based epoxy resin

Hexakis(4-hydroxyphenoxy)-cyclotriphosphazene (PN-OH) was synthesized through nucleophilic substitution of the chloride atoms of hexachlorocyclotriphosphazene and reduction of the aldehyde groups, and its chemical structure was characterized by elemental analysis, ¹H and ³¹P NMR, and Fourier transform infrared (FTIR) spectroscopy. A new phosphazene-based epoxy resin (PN-EP) was successfully synthesized through the reaction between diglycidyl ether of bisphenol-A (DGEBA) and PN-OH, and its chemical structure was confirmed by FTIR and gel permeation chromatography. Four PN-EP thermosets were obtained by curing with 4,4′-diaminodiphenylmethane (DDM), dicyandiamide (DICY), novolak and pyromellitic dianhydride (PMDA). The reactivity of PN-EP with the four curing agents presents an increase in the order of DDM, PMDA, novolak and DICY. An investigation on their thermal properties shows that the PN-EP thermosets achieve higher glass-transition and decomposition temperatures in comparison with the corresponding DGEBA ones while their char yields increase significantly. The PN-EP thermosets also exhibit excellent flame retardancy. The thermosets with novolak, DICY and PMDA achieve the LOI values above 30 and flammability rating of UL94 V-0, whereas the one with DDM reaches the V-1 rating. The nonflammable halogen-free epoxy resin synthesized in this study has potential applications in electric and electronic fields in consideration of the environment and human health.     

The resistance to over-oxidation for polyaniline initiated by the resulting quinone-like molecules

Polyaniline (PANI) suffers electrochemical over-oxidation at high anodic potentials, which leads to severe degradation, forming quinone-like molecules (hydroquinone/benzoquinone, HQ/BQ). A research area usually neglected is the influence of the newly-produced HQ/BQ on the over-oxidation of PANI. In this study, it has been examined by cyclic voltammetry (CV) and FT-IR spectroscopy. When HQ was intentionally added into sulfuric acid solutions, the cyclic voltammograms demonstrate that the rate of degradation turned to be lower as the concentration of introduced HQ increased. First-order rate constants obtained from kinetic study were shown to vary between 0.1399 and 0.1027 s⁻¹ within the concentration range of HQ from 0 to 0.05 M. An important finding is that the quinone-like molecules may have a great electronic exchange with the nitrogen atoms of the intact PANI chain when adsorbed on it, which leads to the changes in PANI structure at the molecule level. Less pernigraniline (PEB) was finally obtained and thus slower degradation was observed. This conclusion is supported by the phenomenon that the peak potentials for emeraldine/pernigraniline (EM/PEB) transitions shifted to more positive values when HQ was added. Moreover, from FT-IR analyses, it seemed that the relative content of the reduced form of PANI ascended with the degradation. So, the existence of HQ/BQ enhances the stability of PANI structure, endows PANI with resistance to over-oxidation and protects it from further degradation to a certain extent.     

Electroluminescence of Organoaluminum Complexes in the Presence of Silica Gel

It was demonstrated that light-emitting materials can be produced by the photochemical dissolution of aluminum in composites based on a cresol–formaldehyde novolak resin and CBr₄in the presence of triphenylmethane dyes such as aluminon, pyrocatechol violet, and malachite green. The electroluminescence (EL) is due to the formation of organoaluminum complexes. The SnO₂(anode)/novolak resin + pyrocatechol violet/Al (cathode) diodes exhibited the highest EL intensity. Compositions based on aluminon are characterized by weak EL, which increased by a factor of 30 upon the additional introduction of silica gel into the composition. As a result of supporting a PVA film on the diode surface (on the cathode side), the EL increased by a factor of 1.5 and became as high as 10 cd/m². This value is comparable to the EL of pyrocatechol violet–containing diodes. The possible mechanism of the influence of silica gel and the importance of a PVA film for increasing the EL intensity are discussed. In the aluminon-based compositions, the dependence of EL on the diode storage time both with and without an applied voltage was measured.     

Poly(aryline imide)s as E-beam resist: Sensitivity and resolution

Polyamic acids synthesized from di-trifluoromethyl methane bis(phthalic anhydride) and 4,4′-diaminophenyl sulfone and 4,4′-diaminophenyl ether were found to have excellent negative E-beam resist properties. The best materials contain about 90% imidized structural units having sensitivities of 1.5–2.5 μC cm^?2 and contrast of 1.0–1.3. Polyamic acid of pyromellitic dianhydride and 4,4′-diaminophenyl sulfone imidized to 97% exhibits useful positive E-beam resist properties. Radiation induces imidization or chain scission to alter the solubility of the resist polymers resulting in the formation of latent images.     

I-Line光刻胶材料的研究进展

酚醛树脂-重氮萘醌正型光刻胶由于其优异的光刻性能,在g-line(436 nm)、i-line(365 nm)光刻中被广泛使用.g-line光刻胶胶、i-line光刻胶,两者虽然都是用线型酚醛树脂做成膜树脂,重氮萘醌型酯化物作感光剂,但当曝光波长从g-line发展到i-line时,为适应对应的曝光波长以及对高分辨率的追求,酚醛树脂及感光剂的微观结构均有变化.在i-line光刻胶中,酚醛树脂的邻-邻'相连程度高,感光剂酯化度高,重氮萘醌基团间的间距远.溶解促进剂是i-line光刻胶的一个重要组分,本文对其也进行了介绍.     

Crowned polyacetylene. I. Synthesis and characterization of poly(4′-ethynylbenzo-15-crown-5)

4′-Ethynylbenzo-15-crown-5 ( EB15C5 ) polymerized with high yields in the presence of (bicyclo[2.2.1] hepta-2,5-diene) rhodium(I) chloride dimer and triethylamine as a cocatalyst in chloroform at 30°C. Common catalysts for the polymerization of substituted acetylenes, WCl₆ and MoCl₅, did not produce any polymer from EB15C5 . The structure of the main chain for poly(4′-ethynylbenzo-15-crown-5) ( PEB15C5 ) was determined to be predomi-nantly cis form, based upon the relatively sharp signals attributed to the main chain atoms that was observed in the ¹H and ¹³C NMR spectra. The cation-binding properties of PEB15C5 are very similar to that of poly(4′-vinylbenzo-15-crown-5), and the selectivity is in the order of K⁺> Rb⁺ ? Cs⁺ ? Na⁺, Li⁺. The electrical conductivity of PEB15C5 increased from 1.3 × 10^?10 to 1.3 × 10^?6 S. cm^?1, when the polymer was doped with iodine. © 1995 John Wiley & Sons, Inc.     

Crowned polyacetylene. 2. cis form determination of poly(4′-ethynylbenzo-15-crown-5) by solid-state NMR method

The chain structure of cis-poly(4′-ethynylbenzo-15-crown-5) (PEB15C5), prepared using the rhodium complex catalyst, was studied at ?175°C using the solid-state NMR technique. The second moment of PEB15C5 was 7.0 G² for the main chain and 19.0 G² for the side chain. These values agreed well with the respective theoretical ones for the cis form in the rigid state rather than the trans one. This agreement between experiment and theory suggested that the plane of the side chain (i.e., the benzo-15-crown-5 group) is orthogonal to the main chain plane of the cis-transoidal form. It was verified that the strong dipoledipole interaction between the side chains plays an important role as a clue to theoretically determine the cis-transoidal form. NMR results in solid state confirmed theoretically that multipeaks in the ¹H and ¹³C NMR spectra in CDCl₃ solution are attributed to cis-transoidal form in the chain. © 1995 John Wiley & Sons, Inc.     

Resist system based on the cationic photocrosslinking of poly(4-hydroxystyrene) and polyfunctional electrophiles

New resist systems based on acid-catalyzed, electrophilic aromatic substitution are described. These new resists show high sensitivity to deep UV and E-beam radiation with values approaching 2 mJ/cm² and 2 μC/cm², respectively. The resists are based on a three component system consisting of poly(4-hydroxystyrene), a polyfunctional, low molecular weight, latent electrophile, and a photoactive onium salt used as an acid generator. Irradiation of the resist film produces a latent image of acid dispersed in the matrix. During the postbaking step the photo-generated acid reacts with the latent polyfunctional electrophile and releases a reactive carbocationic intermediate with concomitant liberation of acetic acid. The carbocationic intermediate then reacts with neighboring phenolic moieties in a crosslinking reaction. The substitution reaction liberates a proton, making the process catalytic in nature, thus incorporating the concept of chemical amplification. These highly sensitive materials can be used as nonswelling negative multipurpose resists that function in deep-UV, x-ray or E-beam modes. © 1993 John Wiley & Sons, Inc.     

A novel photo‐acid generator bound molecular glass resist with a single protecting group

A novel photo‐acid generator (PAG) bound molecular glass photoresist with a single protecting group has been developed as a promising resist material for use in microelectronics. This single component molecular resist was prepared in four steps starting from 9,9‐bis(4‐hydroxyphenyl)fluorene. The single component molecular resist exhibited good thermal properties, such as a 10% weight loss temperature of 200 °C and a glass transition temperature of 91 °C. This resist showed a good sensitivity of 60 μC/cm² with e‐beam exposure (50 keV). On the other hand, the fine pattern with a half‐pitch of 50 nm in the presence of 4 wt % quencher, trioctylamine, was obtained using electron‐beam (100 keV) lithography. The LER value was 8.2 nm (3σ, 60 nm half‐pitch patterns). © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Alkaline-developable and negative-type photosensitive polyimide with high sensitivity and excellent mechanical properties using photo-base generator

An alkaline developable and negative-type PSPI with a high sensitivity and excellent mechanical properties based on a poly(amic acid) (PAA) and a photo-base generator has been developed. The PAA was prepared by the polycondensation of p-phenylenediamine (PDA) with an equimolar of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) and converted thermally to the corresponding polyimide, PI(PDA-BPDA/6-FDA). PI(PDA-BPDA/6-FDA) showed the high thermal and mechanical properties and the dimensional stability such as the thermal decomposition temperature of 530°C, glass transition temperature of 369°C, linear coefficient of thermal expansion of 28 ppm/K, ultimate tensile strength of 148 MPa, elongation at break of 25% and dielectric constant of 2.8. The PSPI was formulated directly from PAA(PDA-BPDA/6-FDA) with a photo-base generator (PBG), (E)-3-(2-hydroxy-4-methoxyphenyl)-1-(piperidin-1-yl)prop-2-en-1-one (HMPP) (10 wt% to PAA) and the optimized parameters for photolithographic process were investigated including the PBG content, post-exposure bake (PEB) temperature, and PEB time. The PSPI based on PAA(PDA-BPDA/6-FDA) and HMPP (10 wt% to PAA) showed a sensitivity of 114 mJ/cm² and contrast of 1.29 when exposed to 365-nm light (i-line), post-exposure baked at 160°C for 5 min, and developed with an aqueous solution of 2.38 wt% tetramethylammonium hydroxide and iso-propanol. A clear negative 8-μm features pattern was obtained by contact-printing and converted into the PI pattern upon heating at 250°C, confirming by scanning electron microscopy and infrared spectroscopy.     

Novel One-component Positive-tone Chemically Amplified I-Line Molecular Glass Photoresist Based on Tannic Acid

Molecular glass resist has been considered as one of the best choices for a new generation of lithography. In this work, a new type of photoactive compound was obtained by the esterification of tannic acid with 2-diazo-1- naphthoquinone-4-sulfonyl chloride(2,1,4-DNQ-Cl) and ditertbutyl dicarbonate. The new obtained compound possessed both a photosensitive group of diazonaphthoquinone sulfonate(2,1,4-DNQ) and a group of acidolytic protection. Upon the irradiation of the compound under 365 nm light, the former group was photolyzed and converted into indene carboxylic acid along with a small amount of sulfonic acid, which could lead to the deprotection of the latter group. As a result, a novel i-line molecular glass photoresist was formed with the chemical modification of tannic acid. The experimental results show that the modificated compound had a fair solubility in many organic solvents. The lithographic performance of the resist was evaluated on an i-line exposure system with high photosensitivity and resolution as well.     

Microstructure and morphology of self‐assembling multiblock poly(ethylene‐1‐butene)‐n copolymers in solution studied by wide‐Q small‐angle neutron scattering and microscopy

Multiblock ethylene‐1‐butene copolymers (PEB‐n) with graded ethylene content (where n is the number of ethyl branches per 100 backbone carbons) represent efficient cold filter plugging point (CFPP) depressants for crude oils and middle distillates. The aggregation behavior and the interaction with wax molecules of a tetrablock PEB‐2.6/PEB‐6.0/PEB‐10.9/PEB‐13.2 and triblock PEB‐6.5/PEB‐8.9/PEB‐10.1 copolymers in decane solutions were investigated over a wide temperature range by combining different small‐angle neutron scattering techniques and optical microscopy. The experimental results revealed in the decrease of temperature formation and evolution of multisized structural levels showing a hierarchical organization on the length scale from 1 nm up to 10 μm. One‐dimensional polymer aggregates arising as initial structures associate and branch that lead to the occurrence of complex macroaggregates with diffusive interfaces and sizes of several microns. The one‐dimensional copolymer structure shows longitudinal density modulation and micellar‐like substructures in neat polymer solutions. When wax is added, this structure becomes more homogeneous in decrease of temperature as a consequence of the cocrystallization of wax and copolymer. The wax crystallization in board‐like objects of much smaller size than required by the CFPP criterion of oil and refinery industry (filter mesh size of 45 μm) is templated and controlled by the assembling features of the crystalline–amorphous PEB‐n multiblock copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Synthesis and characterization of photo‐crosslinkable poly(amic acid ester)s with 2‐hydroxy‐4‐oxo‐hept‐5‐enyl side chain

Photosensitive poly(amic acid ester)s (PAEs) with 2‐hydroxy‐4‐oxo‐hept‐5‐enyl side group were simply synthesized from a non‐photosensitive polyamic acid (PAA), which was prepared from cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride (CBDA) and 4,4′‐diaminodiphenyl ether (DDE) in N‐methyl‐2‐pyrrolidinone (NMP). 1‐oxiranyl‐pent‐3‐en‐2‐one was added to the poly(amic acid) solution to give the photosensitive PAEs by a ring opening esterification of the poly(amic acid). The esterification reaction was conducted with changing a reaction time and amounts of 1‐oxiranyl‐pent‐3‐en‐2‐one. The degree of esterification (DOE) increased with increasing esterification reaction time and amounts of 1‐oxiranyl‐pent‐3‐en‐2‐one. A photo‐lithography evaluation for the PAE‐D4 with the highest DOE was conducted in the presence of 1‐[4‐(phenylthio)phenyl]‐2‐(O‐benzoyloxime)‐1,2‐octanedione (PPBO) as a photoinitiator at a wavelength of 365 nm using a high‐pressure mercury lamp. The normalized film thicknesses for PAE‐D3 were measured with various post‐exposure baking (PEB) temperatures, which showed that the optimum PEB temperature was 120°C. The resolution of the resulting polyimide film cured at 250°C for 60 min was 25 µm. The initial decomposition temperature of the polyimide film was around 354°C and there was no weight loss at the temperature of 250–350°C. Copyright © 2009 John Wiley & Sons, Ltd.