Positive-type Photosensitive Polyimide Research Articles

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

AbstractA 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.

Exploration of photosensitive polyimide as the modification layer in thin film microcircuit

Positive type photosensitive polyimide is used as the modification layer in the thin film transistors production process. The photosensitive polyimide is not only used as the second insulating layer, it can also be used instead of a mask because of the photosensitivity. A suitable curing condition can help photosensitive polyimide form the high performance polyimide with orderly texture inside, and the performance of imidization depends on the precise control of temperature, time, and heat control during the curing process. Therefore, experiments of different stepped up heating tests are made, and the ability of protecting silicon dioxide is analyzed.

Alkaline-developable and Positive-type Photosensitive Polyimide based on Fluorinated Poly(amic acid) from Diamine with High Hydrophobicity and Fluorinated Diazonaphtoquinone

Alkaline-developable and Positive-type Photosensitive Polyimide based on Fluorinated Poly(amic acid) from Diamine with High Hydrophobicity and Fluorinated Diazonaphtoquinone

Facile formulation of alkaline-developable positive-type photosensitive polyimide based on fluorinated poly(amic acid), poly(amic acid), and fluorinated diazonaphthoquinone

An alkaline-developable, positive-type, and photosensitive polyimide (PSPI) based on fluorinated poly(amic acid) (FPAA), poly(amic acid) (PAA), and fluorinated diazonaphthoquinone (FDNQ-1) as a photoactive compound has been successfully developed. The solution of FPAA, PAA, and FDNQ-1 was spin-coated on a silicon wafer and prebaked. The two phase-separated layers, a thin top layer of FPAA containing FDNQ-1 and a thick bottom layer of PAA, were formed due to the high polarity difference between PAA and FPAA containing FDNQ-1. This phase separation was directly observed in an SEM image. The upper thin layer acted as a photosensitive layer, and a fine pattern was formed in the bottom layer. The PSPI containing PAA (85 wt%), FPAA (15 wt%), and FDNQ-1 (25 wt% to polymers) showed an excellent sensitivity of 60 mJ cm−2 and a high contrast of 3.3 when it was exposed to 365 nm wavelength light (i-line) and developed with a 0.238 wt% tetramethylammonium hydroxide aqueous solution (TMAHaq) at 25 °C. A fine positive pattern having a 6 μm resolution on the 1.0 μm film was obtained by exposure to 100 mJ cm−2i-line in the contact-printed mode. The resulting polymer film was converted to the corresponding PI cured at 300 °C. This novel positive patterning PI system can be one of the candidates for the next generation microchip fabrication process which provides a facile formulation of PSPI.

Alkaline-developable Positive-type Photosensitive Polyimide based on Fluorinated Poly(amic acid) and Fluorinated Diazonaphthoquinone

Alkaline-developable Positive-type Photosensitive Polyimide based on Fluorinated Poly(amic acid) and Fluorinated Diazonaphthoquinone

Direct patterning of poly(amic acid) and low‐temperature imidization using a crosslinker, a photoacid generator, and a thermobase generator

AbstractA positive‐type photosensitive polyimide (PSPI) based on poly(amic acid) (PAA), a crosslinker 1,1,1‐tris{4‐[2‐(vinyloxy)ethoxy]phenyl}ethane (TVPE), a photoacid generator (PAG) (5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐2‐(methylphenyl)acetonitrile (PTMA), and a thermobase generator (TBG) t‐butyl 2,6‐dimethylpiperidine‐1‐carboxylate (BDPC) has been developed as a promising material in microelectronics. The PAA was prepared from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 4,4′‐oxydianiline (ODA) in dimethyl sulfoxide (DMSO). The PSPI, consisting of PAA (69 wt %), TPVE (21 wt %), PTMA (3 wt %), and BDPC (7 wt %), showed high sensitivity of 21 mJ/cm2 and a high contrast of 6.8 when it was exposed to a 436‐nm line (g‐line), postbaked at 90 °C for 5 min, and developed with 1.69 wt % TMAHaq. A clear positive image of 8 μm line and space pattern was printed on film, which was exposed to 50 mJ/cm2 of g‐line by a contact printing mode and fully converted to the corresponding polyimide (PI) pattern on heating at 200 °C, confirmed by FTIR spectroscopy. Thus, this system will be a good candidate for next generation PSPIs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3362–3369, 2009

Colorless Polyimides Derived from Cycloaliphatic Tetracarboxylic Dianhydrides with Controlled Steric Structures (4). Applications to Positive-type Photosensitive Polyimide Systems with Controlled Extents of Imidization.

Novel colorless polyimides (PIs) derived from 1R, 2S, 4S, 5R-cyclohexane tetracarboxylic dianhydride (a new hydrogenated pyromellitic dianhydride (PMDA) with a controlled steric structure, H"-PMDA) with various aromatic diamines were applied to positive-type photosensitive PI systems. The H"-based PI precursors, poly(amic acid)s (PAAs), were partially imidized with controlled extents of imidization (χI) by adding established amounts of a cyclodehydration reagent (acetic anhydride/pyridine) into the PAA solutions and stirring at room temperature for 24 h while keeping the homogeneity of the reaction mixture except when 4,4'-oxydianiline (4,4'-ODA) was used as a diamine component. A good linear relationship was obtained between the amount of cyclodehydration reagent added and the extent of imidization (%) in the partially imidized PAAs (pi-PAAs) obtained. The pi-PAA cast films (10 μm thick) displayed a considerably high light transmittance at 365 nm (> 85%) in addition to its adequately controlled alkali-solubility. The photosensitive films consisting of the pi-PAAs and diazonaphthoquinone (DNQ) as a photosensitizer provided good positive-tone patterns through uv-irradiation and subsequent development using a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution. The fully imidized films showed very high glass transition temperatures exceeding 300oC in some cases, sufficient film-forming ability (flexibility), and excellent transparency. The use of a thermally crosslinkable mono-functional end-capper, nadic anhydride (NA), was very effective to inhibit gelation during the chemical imidization process even in the H"-PMDA/4,4'-ODA system owing to its adequately controlled molecular weight. In addition, thermal curing of the NA-terminated system significantly improved the film toughness.

Positive-type Photosensitive Polyimide Based on Poly(amide acid), Vinyl Ether Crosslinker, and a Photoacid Generator

A positive-type photosensitive polyimide (PSPI) based on poly(amic acid) (PAA), 1,3,5-tris[(2-vinyloxy)ethoxy]benzene (TVEB) as a crosslinking dissolution inhibitor and a photoacid generator (PAG) has been developed. PAA was prepared from pyromellitic dianhydride (PMDA), 2,5(6)-bis(aminomethyl)bicyclo[2.2.1]heptane (NBDA) and 4,4'-oxydianiline (ODA) in N,N-dimethylacetamide (DMAc), which has moderate transparency above 365 nm and solubility for 1 % sodium carbonate aqueous solution (aq.). Without isolation of PAA, the photosensitive resist solution was formulated with the polymerization solution (23 wt% in DMAc), TVEB (15 wt% for polymer) and PAG (3 wt% for polymer). No anomaly was recognized after the flexural endurance test by use of the 16 6mu;m PSPI film, which was cured at 2506DC, on a Kapton(r) film. Furthermore a positive image featuring 30 μm line and space patterns was observed by the contact mode when a 9 μm thick film of the PSPI system was exposed to broadband UV light followed by development in a 1 % sodium carbonate aq. at room temperature.

Positive-type photosensitive polyimide based on a photobase generator containing oxime-urethane groups as a photosensitive compound

The chemical structure of a semi-aromatic polyimide-I, which was prepared by the chemical imidization of cyclopentanetetracarboxylic dianhydride and 2,2-bis(4-aminophenyl)hexafluoropropane, was characterized by13C-NMR spectroscopy. The chemically imidized polyimide-I was used for the preparation of a photosensitive polyimide (PSPI)|through the addition of benzophenone and benzophenone oxime hexamethylene diurethane (BOHD), a photobase generator containing oxime-urethane groups. The polyimide-I film containing benzophenone and BOHD was not soluble in 2.38 wt% tetrabutylammonium hydroxide solution in H2O. However, it became soluble following irradiation with 310 nm UV light. A positive tone image with a resolution of 5 μm was obtained with this PSPI, having sensitivity (Dc)|of 1.2 J/cm2 and contrast (γp)|of 1.08. Thus, a polyimide, which is not intrinsically photosensitive, can become photosensitive through the addition of a photobase generator containing oxime-urethane groups as a photosensitive compound.

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

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

Positive-type Photosensitive Polyimide with Low Modulus based on Soluble Block Copoly(imide-siloxane)

A novel positive-type photosensitive polyimide with low modulus based on soluble block copoly(imide-siloxane) with hydroxyl group and diazonaphthoquinone as a photoreactive compound has been developed. The base block copoly(imide-siloxane) was prepared by a direct one-pot polycondensation of biphenyltetracarboxylic dianhydride(BPDA) 2,2-Bis(3-amino-4-methyl)phenylhexafluoropropane(Bis-AP-AF) and diamino(poly)siloxane in the presence of a γ-valerolactone and pyridine catalyst system using dipolar aprotic solvent such as N-methyl-2-pyrrolidone(NMP). The base block copoly(imide-siloxane) consists of aromatic polyimide unit as a hard segment, and polysiloxane unit as a soft segment.The polysiloxane unit contributed to the resulting poly(imide-siloxane) film with not only colorlessness and transparency which are the important factors for a photosensitive polyimide but also low modulus. Due to the low modulus, it can reduce the residual wafer stress caused by the CTE (coefficient of thermal expand) mismatch between silicon wafer (3ppm/K) and polyimide (30∼60ppm/K), and prevent semiconductor devices from physical and electric damage. Photosensitive block copoly(imide-siloxane) containing 20wt% Ester of 2,3,4,4'-trihydrobenzophenone with 1,2-naphthoquinone-(2)-diazide-5-sulfonic acid (4NT-300) showed a sensitivity of 350mj/cm2 and a contrast of 1.95 when it was exposed to UV light, followed by development with 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution containing 10wt% isopropyl alcohol (IPA) at room temperature.

Characterization of Positive-type Photosensitive Polyimide Films Formed by Electrodeposition Coating

Soluble polyimides having pendant carboxyl groups were prepared by one-pot polycondensation of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 3,5-diaminobenzoic acid (DABz) and bis[4-(3-aminophenoxy)phenyl]-sulfone (m-BAPS) in the presence of γ-valerolactone/pyridine catalyst system using N-methyl-2-pyrrolidone (NMP)/toluene mixture as a solvent, and used for the electrodeposition coating. Positive-type photosensitive polyimide compositions for electrodeposition coating consisted of the pendant carboxyl-containing polyimide, NMP and cyclohexanone as solvents, N-methylmorpholine as a neutralizing agent, deionized water and diazonaphthoquinone(DNQ) compound(PC-5®) as a photosensitive material. The electrodeposition coating under a fixed voltage provided photosensitive polyimide films with high levels of appearance and smoothness on a copper foil. These photosensitive polyimide films formed by electrodeposition coating gave positive-tone behavior by UV irradiation and following development in an aqueous tetramethylammonium hydroxide(TMAH) or ethanolamine-containing solution. The scanning electron microscopic photographs of the resulting images showed fine and sharp line/space patterns.

New positive-type photosensitive polyimide having sulfo groups

A new positive-working photosensitive polyimide (PSPI) has been developed, which is based on polyimide bearing sulfo groups (PIS) 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. PIS was prepared by ring-opening polyaddition of 1,3-phenylenediamine-4-sulfonicacid (PDAS), 4,4′-oxydianiline (ODA), and 4,4′-hexafluoropropylidenebis(phthalic anhydride) (6FDA), followed by thermal cyclization in m-cresol. PIS containing 30 wt% of S-DNQ showed a sensitivity of 100 mJ cm −2 and a contrast of 1.7, when it was exposed to 365 nm light followed by developing with 2.38 wt% aqueous tetramethylammonium hydroxide (TMAH) solution at room temperature. A fine positive image featuring 10 μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm −2 of UV-light at 365 nm by the contact mode. The positive image was successfully converted to the polyimide pattern by thermal treatment.

Characterization of Positive-type Photosensitive Polyimide Films Formed by Electrodeposition Coating

Characterization of Positive-type Photosensitive Polyimide Films Formed by Electrodeposition Coating

Synthesis and Photodegradation of a Polyimide Having N-Carbonyloxyimide Moieties in the Main Chain

A new positive-type photosensitive polyimide containing simultaneously N-carbonyloxyimide groups and cyclobutane rings in the main chain was prepared, and its photodegradation behavior was investigated by FT-IR, 1H NMR, and GC-MS spectroscopy. The polyimide underwent a photo-induced decomposition through the cleavage of N-O bond as well as cyclobutane ring, affording maleimide as a photoproduct. The polyimide exhibited enhanced photosensitivity compared to conventional cyclobutane-containing polyimides.

New Positive Type Photosensitive Polyimide: Hyperbranched Poly (Ether imide) with Diazonaphthoquinone

A positive working photosensitive polyimide based on hyperbranched poly (ether imide) (H-PEI) and 2, 3, 4-tris[1-oxo-2-diazonaphthoquinone-5-sulfonyloxy] benzophenone (D5SB) as a photoreactive compound has been developed. H-PEI was prepared by polycondensation of 3, 5-di-tert-butyldimethylsilyloxyphenyl-4-fluorophthalimide, followed by deprotection of tert-butyldimethylsilyl group with KF-HBr. The H-PEI has an excellent transparency to UV light. The photosensitive polyimide containing 30wt% of D5SB showed a sensitivity of 120MJ•cm-2 and a contrast of 2.8 when it was exposed to 365nm light followed by developing with a 2.38% aqueous tetramethylammonium hydroxide (TMAH) solution at room temperature.

New positive-type photosensitive polyimide: poly(hydroxyimide) with diazonaphthoquinone

A positive working photosensitive polyimide based on polyhydroxyimide (PHI) and 2,3,4-tris[1-oxo-2-diazonaphthoquinone-4-sulfonyloxy] benzophenone (D4SB) as a photoreactive compound has been developed. The PHI was prepared by the ring-opening polyaddition of 4,4′-hexafluoroisopropylidenebis(phthalic anhydride) (6FDA), 4,4′-diamino-4″-hydroxytriphenylmethane (DHTM), and 4,4′-oxydianiline (ODA), followed by thermal cyclization in refluxing xylene. The PHI film showed excellent transparency to UV light. The photosensitive polyimide containing 30 wt% of D4SB showed a sensitivity of 250 mJ/cm 2 and a contrast of 5.2 when it was exposed to 436 nm light followed by developing with a 1% aqueous tetramethylammonium hydroxide (TMAH) solution at 35°C.