Abstract: A novel aromatic carboxylic acid useful as a material for macromolecular compounds and, in particular, for polycondensed macromolecular compounds exhibiting excellent heat resistance, an acid halide derivative thereof and a process for producing these compounds are disclosed. The aromatic carboxylic acid and the acid halide derivative thereof have structures represented general formulae (1) and (2), respectively, and can be efficiently produced from a dialkyl ester derivative of isophthalic acid and an acetylene derivative in accordance with the disclosed process comprising specific steps. In the above formulae, A represents: —C?C—R1??(a) or (R1 represents hydrogen atom, an alkyl group or an aromatic group, R2 represents an alkyl group or an aromatic group) and X represents a halogen atom.

Abstract: A novel aromatic carboxylic acid useful as a material for macromolecular compounds and, in particular, for polycondensed macromolecular compounds exhibiting excellent heat resistance, an acid halide derivative thereof and a process for producing these compounds are disclosed. The aromatic carboxylic acid and the acid halide derivative thereof have structures represented general formulae (1) and (2), respectively, and can be efficiently produced from a dialkyl ester derivative of isophthalic acid and an acetylene derivative in accordance with the disclosed process comprising specific steps.

Abstract: A precursor of a polybenzoxazole resin which comprises a crosslinking group in a molecule and has a specific structure, a polybenzoxazole resin obtained from the precursor by the condensation reaction and the crosslinking reaction, an insulating film comprising the polybenzoxazole resin and a semiconductor device comprising an insulating interlayer film in multi-layer wiring or a film for protecting surfaces which comprises the above insulating film. The precursor exhibits excellent processability due to excellent solubility in solvents and, after the ring closure, excellent heat stability in applications. The resin exhibits excellent electric, physical and mechanical properties and is advantageously used for insulating interlayer films of semiconductor devices and the like applications.

Abstract: A precursor of a polybenzoxazole resin which comprises a crosslinking group in a molecule and has a specific structure, a polybenzoxazole resin obtained from the precursor by the condensation reaction and the crosslinking reaction, an insulating film comprising the polybenzoxazole resin and a semiconductor device comprising an insulating interlayer film in multi-layer wiring or a film for protecting surfaces which comprises the above insulating film.