化学亚胺化程度对正性光敏聚酰亚胺影响

选用2,2′-双三氟甲基-4,4′-联苯二胺(TFDB)与二苯醚四甲酸二酐(ODPA)作为聚合物的基本骨架进行缩聚反应生成聚酰胺酸,再经过化学亚胺化得到可溶性聚酰亚胺(PI)。通过调节2-甲基吡啶在亚胺化试剂中的含量以达到控制酰亚胺化程度的目的,探讨不同亚胺化程度的PI胶的显影性能。结果表明,当n(2-甲基吡啶)∶n(乙酸酐)=1∶5时,所合成的光敏聚酰亚胺的显影性能最优。     

Synthesis and mechanical properties of novel photosensitive polyimides

This paper surveys novel photoimageable polyimides (PHIMPI), with emphasis on synthesis. Details of the chemistry and synthesis techniques on PHIMPI are discussed. A number of associated issues such as swelling, storage stability, shrinkage, photospeed, solvent developability, moisture absorption, thermal expansion and mechanical properties are presented. Most of the photoimageable polyimides that are commercially suitable to date are negative-acting, although recent developments in positive-acting PHIMPI are included.     

The improved photosensitivity of photosensitive polyimides containing o-nitrobenzyl ether groups induced by the addition of photoacid generator

In this article, photosensitive polyimides (PSPIs) with photosensitive groups, o-nitrobenzyl ether groups (Nb), were successfully synthesized based on 2,2′-dihydroxy benzophenone-3,3′,4,4′-tetracarboxylic dianhydride and on diamine containing ethylene glycol chains (ODA). Also, a series of polyimide (PI), ODA-1-PI, ODA-3-PI, and ODA-5-PI with a number of ethylene glycol chains of 1, 3, and 5 were prepared to investigate the relationship between structure and solubility. Interestingly, ODA-5-PI, which possesses a large number of ethylene glycols, exhibited the most excellent solubility. Therefore, due to the good solubility of ODA-5-PI in organic solvents and alkaline solutions, a PSPI, poly(1,4-phenyleneoxy-3,6,9,12,15-pentaoxaoctane-1,4-phenylene-2,2′-di[2-nitrobenzyloxy]benzophenone-3,3′,4,4′-tetracarboxdiimide), named ODA-5-PSPI, was synthesized by linking Nb, which is a photosensitive group. Aiming at producing positive tone patterns, the synthesized ODA-5-PSPI was exposed to UV irradiation and then to a post-exposure bake. Afterward, it was developed using a 2.38 wt% tetramethylammonium hydroxide solution. Furthermore, a photoacid generator (PAG) was additionally incorporated for a micropatterning process. Notably, in the presence of the PAG, the photocleavage of ODA-5-PSPI occurred not only by the intramolecular rearrangement of Nb but also by its hydrolysis reaction. As a result, due to the synergistic effect of photocleavage, the micropatterning of ODA-5-PSPI with PAG could be clearly obtained with less energy (2.0 J/cm²) compared with that without PAG (3.6 J/cm²). Therefore, through the addition of PAG, the photosensitivity was improved by 45%.     

Structure and properties of a photosensitive polyimide: Effect of photosensitive group

The photosensitive poly(p-phenylene biphenylteracarboximide) (BPDA-PDA) precursor was synthesized by attaching photocross-linkable 2-(dimethylamino)ethyl methacrylate (DMAEM) monomer to its poly(amic acid) through acid/base complexation. The polyimide thin films were prepared by a conventional cast/softbake/thermal imidization process from the photosensitive precursors with various concentrations of DMAEM. The structure and properties of the polyimide films were investigated by small-angle and wide-angle x-ray scattering, refractive indices and birefringence analysis, residual stress and relaxation analysis, stress-strain analysis, and dynamic mechanical thermal analysis. In comparison with the polyimide film from the poly(amic acid), the films, which were imidized from the photosensitive precursors, exhibited a better molecular order and microstructure; however, they exhibited less molecular orientation in the film plane. Despite the enhancement in both the molecular order and microstructure, the film properties (i.e., mechanical properties, thermal expansion, residual stress, optical properties, dielectric constant, and water sorption) degraded overall due to both the decrease in molecular in-plane orientation and the formation of microvoids caused by the bulky photosensitive group during thermal imidization. That is, on one hand, the PSPI precursor formation provides an advantageous, direct patternability to the BPDA-PDA precursor, and on the other hand, it results in degraded properties to the resulting polyimide film. © 1995 John Wiley & Sons, Inc.     

Soluble and degradable polyimides with phenyl-2-pyridyl ether structure: Synthesis and characterization

A diamine monomer o-phenylenedioxybis(5-amino-2-pyridine) was synthesized via reduction of a dinitro compound o-phenylenedioxybis(5-nitro-2-pyridine), producing a series of new polyimides from this diamine and various commercially available aromatic dianhydrides via conventional two-stage processes. The resulting polyimides are able to form tough and transparent films, with decomposition temperatures in the range of 529–551 °C, and can be dissolved in organic polar solvents. Meanwhile, these polyimides can be degraded in a hydrazine hydrate medium, a degradation mechanism proposed by analyzing the degradation products suggests that the degradable properties could be attributed to the phenyl-2-pyridyl ether structure in the polymer. In addition, the transformation of the compound structure from dinitro compound to damine monomer in the synthetic process is discussed in respect to X-ray structure.     

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.     

Synthesis and properties of novel photosensitive polyimides containing chalcone moiety in the main chain

Two chalcone-derivative isomers, 4,4′-diaminochalcone ( 4DAC ) and 3,3′-diaminochalcone ( 3DAC ), were synthesized and used as monomers together with tetracarboxylic dianhydrides to prepare novel photosensitive polyimides that contain a chalcone moiety in the main chain. The polyimides were characterized and their photochemical behavior was investigated as thin films and in solutions with the aid of ultraviolet and infrared spectroscopy. Compared with 4DAC -based polyimides, the 3DAC -based polyimides exhibited lower glass transition temperatures and higher photocrosslinking rates of the carbon–carbon double bond as well as higher photosensitivities obtained from the exposure characteristic curves, suggesting that an increase in the photoreactivity of the 3DAC -based polyimides might arise from the improved flexibility of their backbones. The polyimide from 3DAC and 6FDA (2,2-bis[3,4-dicarboxypheny]hexa-fluoropropane dianhydride) showed a photosensitivity of 33 mJ/cm² with a contrast of 1.5 upon light irradiation using a Xenon lamp. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 685–693, 1998     

Preparation and alignment properties of photosensitive polyimide containing benzophenone in main chain

ABSTRACT

In order to study the effect of benzophenone (BP) group in the main chain on the photo-alignment behaviour of cinnamoyl groups, a novel photosensitive polyimide (BTDA-PI-CA) is synthesised by 3,3?,4,4?-benzophenonetetracarboxylic dianhydride (BTDA), 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (AHHFP) and cinnamoyl chloride. The BTDA-PI-CA films exhibit good alignment performance after the non-polarised ultraviolet ageing lamp exposure, which is due to the polyimide with BP group can be used to improve the photosensitivity. Moreover, the thermal stability of the LC cells is pretty good and the pretilt angle of the LC cells is 0.5, which can be used in parallel mode LCD.     

基于3,5-二氨基苯甲酸(4-烷氧基)苯酯可溶性聚酰亚胺的合成与表征

本文合成了含长烷基侧链的二胺单体3,5-二氨基苯甲酸(4-烷氧基)苯酯,然后使它与2,2-双[4.(3,4-二羧酸基苯氧基)苯基]丙烷二酐在N甲基-2-吡咯烷酮溶液中聚合,再通过化学酰亚胺化得到一系列含有长烷基侧链的聚酰亚胺。聚酰亚胺的结构经红外光谱和核磁共振氢谱确认,并对它的溶解性能、特征粘数、光学性能和热性能等进行了表征。结果表明,所合成的聚酰亚胺具有好的溶解性能、较高的分子量、优异的透光率和较好的热稳定性。     

A mechanism for the electron beam lithography of solvent-soluble photosensitive polyimides

Solvent-soluble and intrinsically photosensitive polyimides were prepared, and their electron beam reaction was investigated. Negative tone patterns were formed by the electron beam irradiation of PI(BTDA/DEDPM) and PI(BEDA/DEDPM). The mechanism for the pattern formation of PI(BTDA/DEDPM) was determined from transient absorption measurements, changes in the molecular weights, and IR spectrum measurements to be crosslinking via hydrogen abstraction by the triplet excited state benzophenone moiety. For the case of PI(BEDA/DEDPM), the pattern was formed by insolubilization due to chemical change in the polymer. These reactions are found to be so inhomogeneous that insolubilization of the polymer occurs at an early stage of gelation.     

Solubility and transport of water vapor in some 6FDA-based polyimides

Permeability, diffusion, and solubility coefficients for H₂O vapor in four different 6FDA-based polyimides were determined at temperatures between 25 and 45°C and over a wide range of relative humidities. The solubility of H₂O vapor in some of the polyimides studied can be described by the “dual-mode sorption” model whereas in other polyimides it is represented by the Flory-Huggins equation, which suggests that the latter polymers are plasticized by H₂O. The solubility of H₂O vapor in the polyimides decreases as the temperature is raised and increases with increasing polarity of the polymer. The diffusion coefficients for H₂O in the polyimides studied either increase or pass through a weak maximum with increasing H₂O activity, or concentration in the polymers. The latter behavior is probably due to a clustering of H₂O molecules in the polyimides at higher H₂O activities or concentrations. The diffusion coefficients for H₂O decrease as the chain-packing density of the polyimides increases. The permeability coefficients for H₂O vapor in 6FDA-based polyimide membranes either increase slightly or are constant as the H₂O activity is increased. The experimental values of the permeability coefficients are consistent with the values determined from diffusion and solubility coefficients. The permeability of the polyimides to H₂O vapor appears to be controlled by the solubility of H₂O in the polymers. The polyimides studied exhibit a very high selectivity for H₂O vapor relative to CH_4, and therefore are potentially useful membrane materials for the dehydration of natural gas. ©1995 John Wiley & Sons, Inc.     

Negative-type photosensitive polyimide precursors developable with aqueous alkaline solutions

New photosensitive polyimide precursors developable with aqueous alkaline solutions were synthesized. Among diamine monomers having a photofunctional group, 2′-(methacryloyloxy)ethyl 3,5-diaminobenzoate yields high molecular weight polyamic acid. A photosensitive polymer composition consisting of Michler's ketone and a thermally stable peroxide, 3,3′,4,4′-tetrakis(t-butyldioxycarbonyl)benzophenone, results in a high photosensitivity of 200 J/m². The photosensitive coating of the composition is soluble in aqueous alkaline solutions as well as in organic aprotic polar solvents, and both solvents can be used as developers. However, the resolution of patterns is quite different, especially in thick films. Solvent developers results in poor resolution, whereas aqueous alkaline developers give patterns of high aspect ratio even in thick films. This is probably due to the difference in the diffusion efficiency and swelling properties of the polymer compared to the developers.     

Low‐CTE photosensitive polyimide based on semialicyclic poly(amic acid) and photobase generator

A negative‐type photosensitive polyimide (PSPI) based on semialicyclic poly(amic acid) (PAA), poly(trans‐1,4‐cyclohexylenediphenylene amic acid), and {[(4,5‐dimethoxy‐2‐nitrobenzyl)oxy]carbonyl} 2,6‐dimethylpiperidine (DNCDP) as a photobase generator has been developed as a next‐generation buffer coat material. The semialicyclic PAA was synthesized from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and trans‐1,4‐cyclohexyldiamine in the presence of acetic acid, and the PAA polymerization solution was directly used for PSPI formulation. This PSPI, consisting of PAA (80 wt %) and DNCDP (20 wt %), showed high sensitivity of 70 mJ/cm² and high contrast of 10.3, when it was exposed to a 365‐nm line (i‐line), postexposure baked at 190 °C for 5 min, and developed with 2.38 wt % tetramethylammonium hydroxide aqueous solution containing 20 wt % isopropanol at 25 °C. A clear negative image of 6‐μm line and space pattern was printed on a film, which was exposed to 500 mJ/cm² of i‐line by a contact printing mode and fully converted to poly(trans‐1,4‐cyclohexylenebiphenylene imide) pattern upon heating at 250 °C for 1 h. The PSPI film had a low coefficient of thermal expansion of 16 ppm/K compared to typical PIs, such as prepared from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and 4,4′‐oxydianiline. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1317–1323, 2010     

New base‐soluble positive‐working photosensitive polyimides having o‐nitrobenzyl ester group

A new positive‐working polyimide having photosensitive o‐nitrobenzyl ester group as side substituent, poly{1,4‐phenyleneoxy‐1,4‐phenylene‐3,6‐di[4‐(o‐nitrobenzyloxy)carbonylphenyl]pyromellitimide} (ODA‐PI‐Nb), was prepared and its aqueous alkali‐developability and photosensitivity were investigated. ODA‐PI‐Nb was synthesized by the esterification reaction of poly[1,4‐phenyleneoxy‐1.4‐phenylene‐3,6‐di(4‐carboxylphenyl)pyromellit imide] (ODA‐PI) with o‐nitrobenzyl bromide in the presence of triethylamine (Et₃N). ODA‐PI‐Nb obtained was characterized by FT‐IR and ¹H‐NMR spectroscopy. The degree of esterification reaction was found from ¹H‐NMR absorption of CH₂ proton to be over 95 mol%. Upon photo‐irradiation ODA‐PI‐Nb transformed to the freely aqueous alkali‐soluble ODA‐PI under formation of o‐nitrosobenzaldehyde. The thickness loss of thin ODA‐PI‐Nb films upon post‐baking at 400°C was in the 10–15% range. ODA‐PI‐Nb showed positive‐tone behavior in characteristic sensitivity curve and positive patterns were obtained using a typical lithographic process using aqueous tetramethylammonium hydroxide developer. The patterns with excellent resolution were observed and evaluated by optical microscopy and scanning electron microscopy. Copyright © 2005 John Wiley & Sons, Ltd.     

Physicochemical and thermal effects of pendant groups,spatial linkages and bridging groups on the formation and processing of polyimides

Aromatic polyimides are known for their remarkable thermal and chemical properties which are greatly influenced by their precursors. In this study, we report synthesis and characterization of four different aromatic polyimides. The four different dianhydrides (ODPA, BTDA, BPDA, and PMDA) were reacted with a diamine (BisAPAF) via azeotropic imidization under same conditions. FTIR analysis confirmed the formation of aromatic polyimides and all but one polyimide (HPI-BPDA) were found to be completely soluble in common solvents. The obtained molecular weights were between 16,000 and 32,000?g/mol, glass transition temperatures were between 250?°C and 275?°C, degradation temperatures were above 550?°C, and the d-spacing values were around 5?Å. These properties are promising and can be beneficial for various applications such as thin films and membranes.     

A positive-working photosensitive alkaline-developable polyimide with a highly dimensional stability and low dielectric constant based on poly(amic acid) as a polyimide precursor and diazonaphthoquinone as a photosensitive compound

A positive-working photosensitive polyimide precursor based on fluorinated poly(amic acid) (FPAA) and 2,3,4-tris(1-oxo-2-diazonaphthoquinon-4-ylsulfonyloxy)benzophenone (D4SB) as a photosensitive compound has been developed. FPAA was prepared by ring-opening polyaddition of dianhydrides, pyromellitic dianhydride and biphenyltetracarboxylic dianhydride, with diamine, 2,2′-bis(trifluoromethyl)benzidine, in methanol. The FPAA film showed excellent transparency to UV light and good solubility in a wide range of organic solvents. The dissolution behavior of FPAA containing 30 wt % D4SB after exposure was studied, and it was found that the difference of dissolution rate between exposed and unexposed parts was enough to get high contrast due to the photochemical reaction of D4SB in the polymer film. The photosensitive fluorinated polyimide (FPI) precursor containing 30 wt % D4SB showed a sensitivity of 80 mJ cm⁻² and a contrast of 7.8 with 365 nm light when it was developed with 0.3% aqueous tetramethyl ammonium hydroxide solution at room temperature. The FPI film cured up to 360°C had a low coefficient of thermal expansion of 10.3 ppm °C⁻¹ and a low dielectric constant of 3.04. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2261–2267, 1998     

Near‐surface structure formation in chemically imidized polyimide films

Free‐standing polyimide films are manufactured by the chemical imidization of linear, soluble polymeric precursors. The reactive solution is coated onto a heated substrate, peeled off after partial imidization, and then dried and cured as a free‐standing film. Adhesive bonds to the cast side of the final film more strongly than to the air side. Near‐surface elastic moduli of film samples were measured with a nanoindentation setup. Samples were annealed at different final temperatures. The air side of the samples annealed at 400 °C had a higher modulus of 1.4 GPa than the 0.8 GPa of the casting side. This difference diminished as the annealing temperature was raised to 460 °C. Polyamic acid and polyimide exhibit phase transitions from disordered, isotropic solutions to ordered, liquid‐crystalline states. A theoretical model of drying and curing demonstrates formation of a gradient in conversion and ordering: the air side vitrifies at a lower solvent content, lower conversion, and higher ordering; the casting side, at a greater solvent content, higher conversion, and less ordering. Subsequent high‐temperature drying and curing of the free‐standing films removes solvent, completes reaction, and nematically orders both sides. However, longer times and higher temperature annealing are needed to bring the two sides to their common equilibrium state of nematic order. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1824–1838, 2001     

Alkaline-developable positive-type photosensitive polyimide with high mechanical strength and high resolution based on chain extendable poly(amic acid), thermally degradable cross-linker and photoacid generator

A positive-type photosensitive polyimide ( PSPI ) based on a chain extendable poly(amic acid) ( PAA ), a thermally degradable cross-linker 1,3,5-tris[(2-vinyloxy)ethoxy]benzene ( TVEB ), and a photoacid generator (PAG) (5-propylsulfonyloxyimino-5H-thiophene-2-ylidene)-(2-methylphenyl)acetonitrile ( PTMA ) has been developed. The chain extendable PAA was prepared from 3,3′,4,4′-biphenyltetracarboxylic dianhydride ( BPDA ) and 4,4′-oxydianiline ( ODA ) and end-capped with di-tert-butyl dicarbonate ( DIBOC ) in N-methyl-2-pyrrolidone (NMP), which has a controlled molecular weight for developing in a 2.38 wt% tetramethyl ammonium hydroxide aqueous solution ( TMAH _aq ) and undergoes a chain extending reaction during curing stage. The photosensitive resist solution was formulated with the polymerization solution (30 wt% in NMP), TVEB (15 wt% for the polymer), and PAG (4.5 wt% for the polymer). The PSPI showed a sensitivity of 47 mJ cm⁻² and a contrast of 5.8 when exposed to 365-nm light, followed by postexposure baking at 90 °C for 10 min and development with the 2.38 wt% TMAH _aq at room temperature. A fine-positive image with 3-μm line-and-space patterns was obtained on a 3-μm thick film exposed to UV light at 365 nm in the contact-printed mode. After thermal curing at 350 °C for 1 hr, the resulting PSPI features excellent mechanical strength and elongation.     

Relationships between the chemical structures and the solubility,diffusivity, and permselectivity of propylene and propane in 6FDA‐based polyimides

The solubility, diffusivity, and permselectivity of propylene and propane in 40 different polyimides synthesized from 2,2‐bis(3,4‐decarboxyphenyl)hexafluoropropane dianhydride (6FDA) were determined at 298 K. The influence of the chemical structures on the physical and gas permeation properties of the 6FDA‐based polyimides was studied. The solubility of propylene in an unrelaxed volume of a polymer matrix mainly contributes to the total solubility of propylene for various 6FDA‐based polyimides. The diffusivity, the permeability of propylene, and the permselectivity in the propylene/propane mixed‐gas system depend on the solubility of propylene. This is thought to be associated with the penetrant‐induced plasticization effect. 6FDA‐based polyimides, which have a high glass‐transition temperature and a large fractional free volume, exhibit a high permeability with a relatively low permselectivity. Changing the number of  CH3 substituents in the phenylene linkage and changing the connectivity in the main chain are good ways of controlling the solubility of propylene and the corresponding permselectivity in the propylene/propane mixed‐gas system. Some 6FDA‐based polyimides restrict the solubility of propylene through the introduction of a  CONH linkage between the phenylene linkage; the  Cl substituent in the phenylene linkage at the diamine moiety exhibits a high separation performance in the mixed‐gas system. The polyimides are potentially useful membrane materials for the separation of propylene and propane in the petrochemical industry. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2525–2536, 2000     

Synthesis of alkaline‐developable,photosensitive hyperbranched polyimides through the reaction of carboxylic acid dianhydrides and trisamines

Hyperbranched polyimides (HBPI)s with high glass‐transition temperatures and excellent thermal stability were synthesized through the reaction of commercially available carboxylic acid dianhydrides with tris[4‐(4‐aminophenoxy)phenyl]ethane (TAPE). In particular, hyperbranched polyimide HBPI(TAPE‐DSDA), prepared through the reaction of TAPE with 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride (DSDA), showed higher thermal stability and good solubility. Furthermore, alkaline‐developable, photosensitive HBPI(TAPE‐DSDA)‐MA‐CA was prepared through the reaction of HBPI(TAPE‐DSDA) with glycidyl methacrylate with tetrabutylammonium bromide as a catalyst in N‐methyl‐2‐pyrrolidinone (NMP) followed by the addition reaction of cis‐1,2,3,6‐tetrahydrophthalic anhydride with triphenylphosphine as a catalyst in NMP. The glass‐transition temperatures of HBPI(TAPE‐DSDA)‐MA‐CA were greater than 300 °C. A resist composed of 74 wt % HBPI(TAPE‐DSDA)‐MA‐CA, 22.2 wt % trimethylpropane triacrylate, and 3.8 wt % Irgacure 907 as a photoinitiator achieved a resolution of a 55‐μm line pattern and a 275‐μm space pattern by UV irradiation (1000 mJ/cm²). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3697–3707, 2004