Novel Negative-Type Soluble Photosensitive Polyimides:  Synthesis and Characterization

Abstract

In the present paper, we describe the synthesis and characterization of a novel negative-type soluble photosensitive polyimide (PSPI). A group of new photosensitive polyimides has been prepared by condensation of dianhydrides bearing photoreactive ester groups and aromatic diamines in N-methylpyrrolidone (NMP), followed by chemical imidization using acetic anhydride without acid acceptors such as pyridine or triethylamine. Thus, the starting monomer used in the synthesis of a commercial aromatic polyimide has been chemically modified with four different photosensitive groups (chlorine-free synthesis). All the intermediates as well as the resulting polymers have been characterized. The PSPI esters were found to be soluble in N-alkyl-substituted amides. Their irradiation with UV light induces cross-linking of the photoreactive ester groups. These systems change from being weakly to being heavily cross-linked during irradiation and do not swell during development. The remaining PSPI esters do not require thermal imidization because they are already imidized, and shrinkage is about 20% due to volatilization of photoreactive groups.

Synthesis and characterization of negative‐type photosensitive hyperbranched polyimides with excellent organosolubility from an A2 + B3 monomer system

“…The peak around 6.55 ppm was from the absorption of the inner phenyl hydrogen H 1 of the TAPOB residues; the broad bands at 7.25 and 7.48 ppm corresponded to the resonance absorption of the outer phenyl hydrogens of TAPOB residues; and the broad peaks in the range of 7.6–82 ppm could be attributed to the other phenyl hydrogens in the polyimide 39. The band around 6.95 ppm was assigned to the vinyl proton H 2 42. By a comparison of the integration of the absorption peaks of hydrogens H 1 and H 2 , the molar ratio of the TAPOB residues to the photosensitive groups was estimated to be about 0.91.…”

“…39 The band around 6.95 ppm was assigned to the vinyl proton H 2 . 42 By a comparison of the integration of the absorption peaks of hydrogens H 1 and H 2 , the molar ratio of the TAPOB residues to the photosensitive groups was estimated to be about 0.91. As for HB-PSPIa and HB-PSPIm, the molar ratios were 0.91 and 0.93, respectively.…”

“…These might be attributed mostly to the heat decomposition loss of the peripheral acrylate derivative groups. 42 The differences in the weight-loss values among the photosensitive HB-PIs were probably due to the differences in the steric bulkiness for their terminal acrylate derivative groups. The sharp weight loss above 500°C was due to the heat decomposition of the polyimide backbone.…”

Synthesis and Characterization of New Soluble Polyimides from 3,3‘,4,4‘-Benzhydrol Tetracarboxylic Dianhydride and Various Diamines

“…In addition, the hydroxy group in the polymer chain would allow further modification of the polyimide, such as cross-linking reaction or incorporation of photosensitive functional groups. [25][26][27][28] Our previous studies have synthesized a series of new diamine-containing flexible unit such as sulfone, ether, isopropylidene, and oxyethylene, as well as bulky tertbutyl substituents and noncoplanar 2,2′-dimethyl-4,4′-biphenylene units. [29][30][31][32][33][34] Most polyimides prepared from these diamines and various common dianhydrides were soluble and thermally stable.…”

Synthesis of soluble and autophotosensitive hyperbranched polyimides with good optical properties and thermal properties

“…Linear PSPIs with acrylate groups at the side chains and Michler's ketone and triethanolamine as the photosensitizer were reported to have sensitivities in the ranges of 600-1400 mJ cm À2 . 40 The autophotosensitive HBPIs, especially for 6FDA-based and BPADAbased films, showed little change in the sensitivity but without the introduction of small-molecule initiators and small molecules during thermal cyclization, which could reduce the great shrinkage in the patterned films. HBPI-2 has the lowest sensitivity (D g ) of 2880 mJ cm À2 , indicating that C¼ O group that increased the electron acceptability of dianhydride caused the CTC effect of both intra-and intermolecular forces, although the content of the benzophenone units were even higher.…”