Tetramethylammonium Hydroxide Aqueous Solution Research Articles

Synthesis and micropatterning properties of a novel base‐soluble, positive‐working, photosensitive polyimide having an o‐nitrobenzyl ether group

AbstractA novel positive‐working, photosensitive polyimide, poly[1,4‐phenyleneoxy‐1,4‐phenylene‐2,2′‐di(2‐nitrobenzyloxy)benzophenone‐3,3′,4,4′‐tetracarboxdiimide] (OPI‐Nb), developable with an aqueous base was prepared by the o‐nitrobenzylation of a polyimide, poly(1,4‐phenyleneoxy‐1,4‐phenylene‐2,2′‐dihydroxybenzophenone‐3,3′,4,4′‐tetracarboxdiimide) (OPI), derived from 2,2′‐dihydroxy‐3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (DHBA) and 4,4′‐oxydianiline, and it micropatterning properties were investigated. The o‐nitrobenzylation of OPI to OPI‐Nb was conducted with o‐nitrobenzyl bromide in N‐methyl‐2‐pyrrolidinone containing Et3N. The DHBA monomer was synthesized by exhaustive KMnO4 oxidation of bis(2‐dimethoxy‐3,4‐dimethylphenyl)methane obtained by etherification of bis(2‐hydroxy‐3,4‐dimethylphenyl)methane with iodomethane, followed by deprotection of the methoxy groups and cyclodehydration of the obtained 2,2′‐dihydroxy‐3,3′4,4′‐benzophenonetetracarboxylic acid. The intermediate bis(2‐hydroxy‐3,4‐dimethylphenyl)methane was prepared by the condensation of 2,3‐dimethylphenol with paraformaldehyde. The degree of o‐nitrobenzylation was determined to be over 94 mol % from 1H NMR absorption of benzylic CH2 protons. The aromatic OPI was perfectly soluble in a dilute aqueous NaOH solution and tetramethylammonium hydroxide (TMAH), whereas OPI‐Nb was not even swellable in them. In the micropatterning process, OPI‐Nb showed a line‐width resolution of 0.4‐μm and a sensitivity of 5.4 J/cm2 when its thin films were irradiated with 365‐nm light and developed with a 2.38% aqueous TMAH solution at room temperature for 90 s. The thickness loss of OPI‐Nb films measured after postbaking at 350 °C was in the 8–9% range. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 776–788, 2007

Micro/Nanofabrication by Spin Dewetting on a Poly(Dimethylsiloxane) Mold

ABSTRACTThe process of spin dewetting was used to fabricate polymer micro and nanostructures from poly(methyl methacrylate) (PMMA), poly (propyl methacrylate) (PPMA), and polystyrene (PS). Polymer structures were formed on poly(dimethylsiloxane) (PDMS) molds by dewetting of a polymer solution during spin coating. Features were removed from the mold using heat and pressure to transfer the polymer to silicon or glass substrates. By varying the coating conditions, a variety of different polymer feature morphologies were obtained for a given PDMS mold geometry. In this study, the ability to fabrication polymer micro and nanostructures using spin dewetting was demonstrated on a variety of PDMS mold geometries. The effects of polymer solution concentration and mold feature size on the resulting polymer structures were examined. In addition, microfabricated PMMA structures were used as etch masks for anisotropic etching of silicon in an aqueous solution of tetramethylammonium hydroxide (TMAH).

Synthesis and Activation of PtRu Alloyed Nanoparticles with Controlled Size and Composition

FCC PtRu nanoparticles with narrow size distribution were prepared by polyalcohol reduction of platinum acetylacetonate and ruthenium acetylacetonate in diphenyl ether, using oleylamine as the capping agent. The particle size ranged from 3.5 to 6.5 nm and was controlled by varying the amount of capping agent added in the synthesis. Adjusting the stoichiometric ratio of introduced Pt and Ru precursors yielded particles with different compositions. A simple fractionation was employed to narrow the size distribution of particles and nearly monodispersed particles were obtained. To activate the catalytic activity of the particles, oleylamine bound to the particle surface was removed through repeated washing of the as-prepared particles with ethanol and tetramethylammonium hydroxide (TMAOH) aqueous solution. The washed particles could be well redispersed and electrostatically stabilized in TMAOH aqueous solution and uniformly loaded on a Vulcan XC-72 carbon support. A cyclic voltammetry (CV) study revealed that the carbon-supported, cleaned PtRu nanoparticles exhibit considerably higher electrocatalytic activity for methanol oxidation compared with the as-prepared particles that have oleylamine ligands.

Synthesis and Structure of Large Optically Clear Crystals of Gallogermanate Sodalite

Large transparent crystals (up to 800 μm) of a hydroxy-sodium gallogermanate sodalite have been prepared at between 100 and 150 °C in aqueous sodium tetramethylammonium hydroxide solutions. Single-crystal structure analysis gave the expected space group (P43n) but an unexpectedly small unit cell (8.951 A) in which the longer (Ga,Ge)−O bond lengths are compensated by T−O−T bond angles of ∼110°. The crystals provide a readily made framework for structure studies of encapsulated chemical species.

A chemically amplified positive-working photosensitive polyimide based on a blend of poly(amic acid ethoxymethyl ester) and poly(amic acid)

We prepared a novel chemically amplified photosensitive polyimide based on a blend of poly(amic acid ethoxymethyl ester) (PAAE) and poly(amic acid); this blend produces polyimide (PI) films with improved mechanical properties after imidization with photoacid generator (PAG). PAAE and poly(amic acid) were end-capped with 5-norbornene-2,3-dicarboxylic dianhydride and 2,3-dimethyl maleic anhydride, respectively, to lower their molecular weights without compromising the properties of the resulting PI films. As a result of the blending of these PI precursors, the mechanical properties of the PI films were found to be less affected by the strong acid generated from the PAG than PI films fabricated by imidization of PAAE alone. The relatively high solubility of the blended PI precursor film in basic aqueous solutions was found to be effectively controlled by the use of a high-temperature post-exposure bake process to partially imidize the end-capped PAA. It was found that a 10-μm-thick film of the PSPI precursor system containing 13 wt% PAGs exhibits a sensitivity ( D 0) of 700 mJ/cm 2 when developed with 2.38 wt% aqueous tetramethyl ammonium hydroxide solution at room temperature. A fine positive pattern was fabricated in a 12 μm thick film with 1000 mJ/cm 2 of i-line exposure. The resultant PI film was also found to exhibit excellent mechanical and thermal properties, which are critical to its practical use as a stress buffer layer in semiconductor packaging.

Positive-type Alkaline Developable Photosensitive Branched Polyamides with Low Degree of Branching and Diazonaphthoquinone as a Photosensitive Compound

A positive-type photosensitive polyamide based on the branched polyamides with low degree of branching and 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl}-4-{1-[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) as a photosensitive compound has been developed. The branched polyamides with low degree of branching having amino end groups (2a and 2b) were prepared from a ABB′ type monomer, 4-(2,4-diaminophenoxy) benzoic acid 1 in the presence of diphenyl(2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (DBOP) and triphenylphosphite/pyridine (TPP/Py) as a condensing agent, of which the degrees of branching (DB) were 0.10 and 0.36, respectively. Followed by end-capping with 4-hydroxy benzoic acid, end-modified polymers with phenolic hydroxy groups (4a and 4b) were successfully prepared. The polymer properties were characterized by 1H and 13C NMR, GPC, TG/DTA and DSC, respectively. The photosensitive polymer based on polymer 4a and 30 wt % S-DNQ showed a sensitivity of 140 mJ cm−2 and a contrast of 2.1 when it was pre-baked at 80 °C for 5 min, subsequently exposed to a 436 nm light (g-line) and developed with a developer of 5 wt % aqueous tetramethylammonium hydroxide (TMAH) solution: 2-propanol (4:1 by weight ratio) at 25 °C. A fine positive image of 6 μm line-and-space pattern was obtained when the film was exposed to 300 mJ cm−2 by contact-printing mode.

A novel positive‐type photosensitive polyimide based on soluble block copolyimide showing low dielectric constant with a low‐temperature curing process

AbstractA soluble block copolyimide (Bco‐PI) was prepared by direct one‐pot polycondensation of 2,2‐bis‐(3‐amino‐4‐hydroxyphenyl)hexafluoropropane, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, and cyclohexane‐tetracarboxylic dianhydride in the presence of γ‐valerolactone and a pyridine catalyst system using γ‐butyrolactone as the solvent. The thermal transmission temperature (Tg) of Bco‐PI was 282°C. By having the curing process occur at 250°C, which was below the Tg, colorless and transparent films could be obtained. The film showed excellent optical characteristics. Such properties could not be attained by the conventional high‐temperature thermal imidization process of poly(amic acid). The hydroxy groups in the polyimide backbone gave the Bco‐PI the potential to become alkaline. To the Bco‐PI was added 15 wt % ester of 2,3,4‐trihydroxybenzophenone with 1,2‐naphthoquinone‐(2) diazide‐5‐sulfonic acid (NT200) as the photoreactive compound. The system worked as a positive‐type photosensitive polyimide (PSPI). The sensitivity and contrast of the PSPI system were 220 mJ/cm2 and 1.27, respectively, when exposed to UV light, followed by development with a 5% tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature. After curing at 250°C for 1 h, the average refractive index of Bco‐PI with and without NT200 was 1.5543 and 1.5563, and the optically estimated dielectric constant of the polyimides was 2.66 and 2.67, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4240–4246, 2006

Preparation of a chemically amplified photosensitive polyimide based on norbornene‐end‐capped poly(amic acid ethoxymethylester)

AbstractA positive‐working chemically amplified photosensitive polyimide (PSPI) developable with basic aqueous solutions was obtained from poly(amic acid ethoxymethylester) (PAAE) as a polyimide precursor and diphenyliodonium 5‐hydroxynaphthalene‐1‐sulfonate (DINS) as a photoacid generator. The norbornene‐end‐capped PAAE based on 4,4′‐oxydiphthalic anhydride and 4,4′‐oxydianiline exhibited high transparency at 365 nm. The protection ratio of the ethoxymethyl groups was optimized to maximize the difference between the dissolution rates of the exposed and unexposed areas. The acid generated from DINS in the UV‐exposed region effectively deprotected the ethoxymethyl groups of PAAE by a chemical amplification mechanism. A 10‐μm‐thick film of the PSPI precursor system containing 16 wt % DINS exhibited a sensitivity (Do) of 1100 mJ cm−2 when developed with a 2.38 wt % aqueous tetramethyl ammonium hydroxide solution at room temperature. A fine, positive, 5‐μm line‐and‐space pattern was fabricated in a 15‐μm‐thick film with 1500 mJ cm−2 of UV exposure. This resolution is excellent in comparison with those previously reported for chemically amplified PSPIs, and such a film can thus be used as a buffer coating in semiconductor packaging. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5520–5528, 2005

Novel positive‐type photosensitive polyimide with low dielectric constant

AbstractA novel positive‐type photosensitive polyimide (PSPI) with a low dielectric constant was developed. The PSPI system was composed of soluble block PI (Bco‐PI) with a hydroxy group and diazonaphthoquinone as a photoreactive compound. The base Bco‐PI was prepared by a direct one‐pot polycondensation of 2,2‐bis(3‐amino‐4‐hydroxy‐phenylhexafluoropropane), 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, and cyclohexanetetracarboxylic dianhydride in the presence of a γ‐valerolactone and pyridine catalyst system using N‐methyl‐2‐pyrrolidone as the solvent. The film of Bco‐PI was colorless and transparent, both important factors for a PSPI. Photosensitive soluble block PI (Bco‐PI), containing 20 wt % ester of 2,3,4‐trihydroxybenzophenone with 1,2‐naphthoquinone‐(2)‐diazide‐5‐sulfonic acid (NT200), showed a sensitivity of 350 mJ/cm2 and a contrast of 1.20 when it was exposed to UV light, followed by development with 5% tetramethylammonium hydroxide aqueous solution at room temperature. The estimated optical dielectric constants of the PIs with and without NT200 were 2.68 and 2.75, respectively. These values were significantly lower than those of conventional aromatic PIs, such as Kapton film (50EN). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 15–21, 2005

Tetramethylammonium hydroxide (TMAH) thermochemolysis of lignin: Improvement of the distribution profile of products derived from β-aryl ether subunits

Tetramethylammonium hydroxide (TMAH) thermochemolysis of softwood lignin provides Z/ E-1-(3,4-dimethoxyphenyl)-2-methoxyethene ( 5) and erythro/ threo-1-(3,4-dimethoxyphenyl)-1,2,3-trimethoxypropane ( 9), as products derived from β-aryl ether subunits. To increase the contribution of 9, Japanese cedar ( Cryptomeria japonica) wood meals were derivatized by: (1) diazomethane-methylation, (2) acetylation and (3) a combination of the methylation and acetylation. The non-derivatized (control) and derivatized wood meals were moistened with a 25% TMAH aqueous solution, dried at 80 °C for 15 min and followed by TMAH thermochemolysis at 315 °C for 4 s. Although all samples produced 5 and 9, their yields and the 9/ 5 ratios differed. The diazomethane-methylated cedar provided the largest values for the 5 + 9 yield, the 9 yield and the 9/ 5 ratio. The 5 + 9 yield from the diazomethane-methylated cedar was 1.17 that from the control and the 9 yield of the methylated cedar was 1.82 that of the control. The 9/ 5 ratios were 1.80 and 0.71 for the diazomethane-methylated cedar and the control, respectively. Acetylated cedars provided a lower 5 + 9 yield and a lower 9/ 5 ratio than the control.

New Negative-type Photosensitive Alkaline-developable Semi-aromatic Polyimides with Low Dielectric Constants Based on Poly(amic acid) from Aromatic Diamine Containing Adamantyl Units and Alicyclic Dianhydrides, A Cross-linker, and A Photoacid Generator

A new negative-working and alkaline-developable photosensitive polyimide precursor based on semi-aromatic poly(amic acid)s (4), 4,4′-methylenebis[2,6-bis(hydroxymethyl)]phenol (MBHP) as a cross-linker, and a photoacid generator (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-2-(methylphenyl)acetonitrile (PTMA) has been developed. Novel polymers 4 were prepared by ring-opening polyadditions of alicyclic dianhydrides (1), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (1a), bicyclo[2.2.2]oct-7-ene-2,3;5,6-tetracarboxylic dianhydride (1b), and bicyclo[2.2.1]heptane-2-methanecarboxylic-3,5,6-tricarboxylic-2,3:5,6-dianhydride (1c) with 1,3-bis(4-aminophenoxy)adamantane (3). Polymers 4 were converted to corresponding poly(imide)s (5) by thermal treatment. The dielectric constants (ε) of 5 estimated from the refractive indices were 2.72–2.74. The photosensitive polyimide precursor containing 4 (60 wt %), MBHP (30 wt %), and PTMA (10 wt %) cast from 2-methoxyethanol solution showed a clear negative image featuring 15 μm line and space patterns when it was exposed to 436 nm light, post-exposure baked at 110 °C for 3 min, followed by developing with 2.38 wt % aqueous tetramethylammonium hydroxide (TMAH) solution at 25 °C for 40 s.

A novel positive‐type photosensitive polyimide having excellent transparency based on soluble block copolyimide with hydroxyl group and diazonaphthoquintone

AbstractA novel positive‐type photosensitive polyimide having excellent transparency based on soluble block copolyimide (Bco‐PI) with hydroxyl group and diazonaphthoquinone (DNQ) as a photoreactive compound was developed. The base Bco‐PI A was prepared by a direct one‐pot polycondensation of cyclohexanetetracarboxylic dianhydride (H‐PMDA), 2,2‐bis(3‐amino‐4‐hydroxyphenylhexafluoropropane) (Bis‐AP‐AF), and bis(4‐(3‐aminophenoxy)phenyl)sulfone (m‐BAPS) in the presence of a γ‐valerolactone and pyridine catalyst system by using dipolar aprotic solvent such as N‐methyl‐2‐pyrrolidone (NMP).The wholly aromatic polyimides have strong absorptions in the visible regions, because of their change–transfer complex formation. On the other hand, alicyclic dianhydride, H‐PMDA, contributed to the resulting Bco‐PI film with colorlessness and transparency, which are the important factors for a photosensitive polyimide. Photosensitive Bco‐PI, containing 20 wt % 1,2‐naphthoqiunonediazide‐5‐sulfonic acid p‐cresol ester (PC5), showed a sensitivity of 250 mJ/cm2 and a contrast of 2.56 when it was exposed to UV light, followed by development with 5% tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1619–1624, 2005

Influence of parameters on pyrolysis-GC/MS of lignin in the presence of tetramethylammonium hydroxide

Thermally assisted hydrolysis and methylation (THM) with tetramethylammonium hydroxide (TMAH) was performed on spruce milled wood lignin (MWL) in order to investigate THM parameters. The objective was the maximization of information on lignin structure. The main emphasis was laid on the formation of lignin monomer derivatives with intact propane side chain, as these fragments are thought to be indicators of favourable THM conditions. In the tested temperature range (310–710 °C) the lowest temperature of 310 °C was found to produce the highest yield of these monomers. The elution of unmethylated lignin monomers, such as phenols and methoxyphenols, was also minimized at 310 °C. In addition, a number of different TMAH to sample ratios were applied. The yield of the most lignin monomer derivatives was increased by using the highest tested TMAH concentration, whereas some unmethylated products, such as phenol, were unaffected. Methanol as solvent for TMAH was compared to an aqueous solution of TMAH of same concentration in respect of the influence on degradation product yields. The elution of 3,4-dimethoxybenzoic acid methyl ester increased and the yield of 3,4-dimethoxybenzaldehyde decreased when methanol was used. At last a prolonged incubation time of the TMAH–sample mixture was shown to be useful to enhance especially the yield of lignin monomer derivatives with intact propane side chain in case of application of a low TMAH to sample ratio.

Negative‐working photoresist based on a first‐generation dendrimer consisting of 4,4‐diphenylpentyloxy units

AbstractA first‐generation dendrimer (2), containing phenol groups in the exterior for solubilization in aqueous alkaline solutions, was evaluated as a new negative‐working, alkaline‐developable photoresist material. A negative‐working photoresist based on 2, 4,4′‐methylenebis[2,6‐bis(hydroxymethyl)phenol] as a crosslinker, and diphenyliodonium 9,10‐dimethoxyanthracene‐2‐sulfonate as a photoacid generator was demonstrated. This resist gave a clear negative pattern through postbaking at 90 °C after exposure to UV light, which was followed by development with a 2.38% aqueous tetramethyl ammonium hydroxide solution at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1210–1215, 2005

Negative-type Chemically Amplified Photosensitive Semi-alicyclic Polybenzoxazole via Acid-catalyzed Electrophilic Substitution

A negative-type photosensitive semi-alicyclic polybenzoxazole (Nega-PSPABO) based on poly(o-hydroxy amide) containing an adamantyl unit (PAHA) and oxybis(3,4-dihydroxymethyl)benzene (OBHB) as a cross-linker, and a photoacid generator, (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA) has been developed. PAHA with a weight average molecular weight of 24,100 was prepared from 1,3-adamantanedicarbonyl chloride (ADC) and 4,4′-(hexafluoroisopropylidene)bis(o-aminophenol) (6FAP) in the presence of lithium chloride in N-methyl pyrrolidinone (NMP) at 0 °C for 12 h. The photosensitive polymer based on 85 wt % PAHA, 10 wt % OBHB, and 5 wt % PTMA showed a sensitivity of D0.5=14.4 mJ/cm2 and a contrast of 2.4 when it was exposed to a 365 nm light (i-line) and developed with a 2.38 wt % aqueous tetramethylammonium hydroxide solution (TMAHaq) at 25 °C. A fine negative image of 7 μm line-and-space pattern was also printed in the film which was exposed to 80 mJ/cm2 of i-line by contact-printing mode. The negative image in PAHA was converted to the corresponding PABO pattern image by thermal treatment without pattern deformation. The average refractive index of Nega-PSPABO was 1.542 from which the dielectric constant estimated was 2.62 at 1 MHz.

Application of sol–gel method in the synthesis of gallium(III)-oxide

Precipitations by hydrolysis of gallium(III)-isopropoxide and from aqueous GaCl 3 solution by addition of aqueous tetramethylammonium hydroxide (TMAH) solution were utilized to obtain gallium(III)-oxide precursors. The precursors thus formed and the samples obtained upon heating these precursors at high temperatures were analysed by XRD, FT-IR and TEM. Amorphous phase (dominant) and nanosized α-GaOOH particles (several nanometers in size) were obtained by addition of hot water and TMAH solution to the solution of gallium(III)-isopropoxide dissolved in 2-propanol. A completely amorphous precipitate was obtained by hydrolysis of gallium(III)-isopropoxide with pure water at room temperature, and upon heating this precipitate at 500 °C the nanosized β-Ga 2O 3 particles (size ∼10 to 20 nm) were obtained. On the other hand, α-GaOOH particles, as a single phase, were obtained by precipitation from aqueous GaCl 3 solution with addition of aqueous TMAH solution. These α-GaOOH particles transformed at 500 °C to α-Ga 2O 3 as a single phase. Upon heating at 900 °C, in all cases only β-Ga 2O 3 was detected. The size and morphology of the particles in the samples investigated depended on the starting chemicals and the conditions of the experiment. Differences in the mechanism of the precipitation by hydrolysis of gallium(III)-isopropoxide or the precipitation from aqueous solution of GaCl 3 by addition of strong organic alkali (TMAH) were suggested.

A Novel Positive Type Photosensitive Polyimide Based on Soluble Block Copolyimide with Alicyclic Dianhydride

A novel positive type photosensitive polyimide based on soluble block copolyimide (Bco-PI) with alicyclic dianhydride has been developed. The base Bco-PI was prepared by a direct one-pot polycondensation of cyclohexanetetracarboxylic dianhydride (H-PMDA), 2, 2-Bis (3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF) and bis(4-(3-aminophenoxy)phenyl)sulfone (m-BAPS) in the presence of a γ-valerolactone and pyridine catalyst system and N-methyl-2-pyrrolidone(NMP) was used as solvent. The resulting film was transparent and colorless. It exhibited the cutoff at 290nm, and the refractive index was 1.55. The Tg and CTE were 278°C and 39 ppm/°C. As alicyclic dianhydride, H-PMDA, contributed to the resulting Bco-PI film with good thermal properties and excellent optical properties.By the addition of 20wt% 1,2-Naphthoqiunonediazide-5-sulfonic acid p-cresol ester (PC5) to the Bco-PI, It was found to be a positive type photosensitive polyimide. It showed a sensitivity of 350mJ/cm2 and a contrast of 2.42 when it was exposed to UV light, followed by development with 5% tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature.

Pyrolysis and THM reactions of melamine and its resins

Melamine resins and a melamine polyester copolymer have been investigated with pyrolysis-GC/MS and thermally assisted hydrolysis and methylation (THM). Conventional pyrolysis yields characteristic volatile products only at temperatures above 500 °C and hexamethylenetetramine is the main product. A series of methylated melamines and secondary pyrolysis products were also found. THM yields high amounts of methylated melamines and therefore provides a sensitive method for the detection of melamine in resins and copolymers. Deduced from this results a preparative approach for the synthesis of methylated melamines with aqueous tetramethylammonium hydroxide solution was successfully developed.

A positive type alkaline developable thermally stable and photosensitive polymer based on partially O-methylated poly(2,6-dihydroxy-1,5-naphthylene), an acidolytic de-cross-linker, and a photoacid generator

A positive working and chemically amplified photosensitive polymer based on partially (30%) O-methylated poly(2,6-dihydroxy-1,5-naphthylene) [PMPDHN (30)], 1,3,5-tris[(2-vinyloxy)ethoxy]benzene (TVEB) as an acidolytic de-cross-linker, and a photoacid generator (5-propylsulfonyloxyimino-5 H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA) has been developed. Poly(2,6-dihydroxy-1,5-naphthylene) (PDHN) with a number-average molecular weight of 33,000 was prepared by oxidative coupling polymerization of 2,6-dihydroxynaphthalene (2,6-DHN) using di-μ-hydroxo-bis-[( N, N, N′, N′-tetramethylethylenediamine)copper(II)] chloride [CuCl(OH)TMEDA] as the catalyst in 2-methoxyethanol at room temperature. PDHN was converted to PMPDHN by treating with iodomethane. The resist showed a sensitivity of 19.4 mJ cm −2 and a contrast of 7.5 when it was exposed to 436 nm light, followed by post-baking at 120 °C for 5 min and developing with 2.38 wt% aqueous tetramethylammonium hydroxide (TMAH) solution at 25 °C. A fine positive image featuring 6 μm line and space patterns was obtained on the film exposed to 20 mJ cm −2 of UV-light at 436 nm by the contact-printed mode. The optically estimated dielectric constants (at 1 MHz) of PMPDHN (30) with and without TVEB and PTMA are 3.03 and 3.01, respectively. The moisture absorption (1.7 wt%) of the resist system based on PMPDHN (30) and TVEB is very low compared to that (4.3%) of the resist system consisting of PDHN and 4,4′-methylenebis[2,6-bis(hydroxymethyl)]phenol (MBHP).

Formation and properties of Cd(OH) 2 and CdO particles

The formation and properties of Cd(OH) 2 and CdO particles were monitored by X-ray powder diffraction (XRD), DTA, FT-IR spectroscopy and Field Emission SEM. Trigonal Cd(OH) 2 was precipitated as a single phase at room temperature (RT) by adding aqueous solution of tetramethylammonium hydroxide (TMAH) into ethanolic solution of cadmium acetate. The DTA curve of Cd(OH) 2, recorded in air, showed a strong endothermic peak centered at 245 °C due to recrystallization of CdO. After autoclaving the Cd(OH) 2 suspension at 220 °C, CdO was found in the precipitates as the dominant phase. These precipitates also contained Cd(OH) 2 with trigonal symmetry, Cd(OH) 2 having monoclinic symmetry (possible identification) and one unidentified phase. Platelike particles of Cd(OH) 2 changed at 300 °C to almost spherical monodisperse CdO particles. The particles obtained by autoclaving the Cd(OH) 2 suspension showed very different size and shapes. These particles were in the form of nanowires, school rulers or bundles of long rods (cable-like). Some of these long rods were broken.