A polyimide-polybenzoxazole precursor solution, a polyimide-polybenzoxazole film, and a method of manufacturing the film are disclosed. A polyimide-polybenzoxazole film manufactured using the polyimide-polybenzoxazole precursor solution is formed by copolymerizing a unit structure of diamine and dianhydride and a unit structure of diaminophenol and dicarbonyl chloride in an organic solvent. The film is colorless and transparent, like conventional polyimide films, and can exhibit improved heat resistance and low birefringence.

A manufacturing method of a continuous transparent polyimide film for a display includes the following steps providing a roll-to-roll polyimide film; providing a polyimide precursor, which is coated on the polyimide film; and baking the polyimide precursor at a baking temperature that is at least 20° C. higher than a glass transition temperature of the transparent polyimide film, such that the transparent polyimide film has an optical transmittance of greater than 85%, a chromaticity (b*) of less than 2, and a standard deviation of three axial refractive indices of the transparent polyimide film is less than 0.0012. Thus, the transparent polyimide film with reduced light leakage can be obtained.

A polyimide resin has an acid dianhydride-derived structure and a diamine-derived structure, the acid dianhydride contains an acid dianhydride represented by the general formula (1) and a fluorine-containing aromatic acid dianhydride, and the diamine contains a fluoroalkyl-substituted benzidine. In the general formula (1), n is an integer of 1 or more, and R.sup.1 to R.sup.4 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a perfluoroalkyl group having 1 to 20 carbon atoms. The content of the acid dianhydride represented by the general formula (1) may be 10 to 65 mol %, and the content of the fluorine-containing aromatic acid dianhydride may be 30 to 80 mol %, based on 100 mol % of the total of the acid dianhydride.

##STR00001##

The present disclosure discloses a liquid crystal alignment film, a method for producing the same, a substrate, and a display device. The liquid crystal alignment film includes a polyimide having a fluorine-containing group, wherein the polyimide is polymerized from dicarboxylic anhydride containing one or more fluorine atoms, a C.sub.12-20 monoamine and a diamine. The introduction of the long flexible chain and the fluorine-containing group allow the pretilt angle of the polyimide synthesized by the present disclosure to reach 3 to 5, and the introduction of fluorine element remarkably improves the transmittance of the synthesized polyimide and decreases water absorption. The modified fluorine-containing long flexible chain polyimide material prepared may be used in a liquid crystal alignment film of TFT-LCD, and enhance light transmittance, thermal stability, chemical stability, adhesion, etc. of the liquid crystal alignment film, thereby avoiding related defects caused by polyimide materials.

A resin composition for display substrates includes the following: the resin (a): a resin containing, as a main component, a repeating unit represented by the chemical formula (1), wherein the resin contains the total of 95 mass % or more of a tetracarboxylic acid residue A, having 2 or more carbon atoms and an SP value of 15 or more and 17 or less and a diamine residue having an SP value of 11 or more and 13 or less with respect to the total of 100 mass % of A and B contained in the resin; the solvent (b): a solvent having an SP value of 7.5 or more and less than 9.5; and the solvent (c): a solvent having an SP value of 9.5 or more and 14.0 or less;

##STR00001##

wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, hydrocarbon group having 1 to 10 carbon atoms, alkylsilyl group having 1 to 10 carbon atoms, alkali metal ion, ammonium ion, imidazolium ion, or pyridinium ion.

A polyamic acid according to an embodiment is formed by a polymerization reaction of a dianhydride compound, a first diamine compound represented by the following Formula 1, and a second diamine compound, which is different from the first diamine compound. A polyimide film derived from the polyamic acid may exhibit excellent heat resistance and improved optical properties:

##STR00001##

A simplified method for removing foreign matters formed on a substrate in a semiconductor device manufacturing process; and a composition for forming a coating film for foreign matter removal use, which can be used in the method. A coating film is formed on a semiconductor substrate using a composition preferably containing a polyamic acid produced from (a) a tetracarboxylic dianhydride compound and (b) a diamine compound having at least one carboxyl group or a polyamic acid produced from (a) a tetracarboxylic dianhydride compound, (b) a diamine compound having at least one carboxyl group and (c) a diamine compound, and then foreign matters occurring on the coating film are removed together with the coating film by the treatment with a developing solution.

A solution comprising a polyamic acid in a high-boiling, aprotic solvent wherein the polyamic acid comprises three or more tetracarboxylic acid components and one or more diamine components such that a polyimide film can be made from the solution, and the film exhibits properties appropriate for use in electronics applications. Methods for preparing the film are disclosed.

A polyamide acid composition and a polyimide composition are obtained from a tetracarboxylic acid compound containing an aromatic tetracarboxylic acid compound having a naphthalene skeleton and a diamine compound containing an aromatic diamine compound having a biphenyl skeleton.

The invention provides a selenium-containing polyimide polymer, preparation method and use thereof. The method comprises: (1) polymerizing a selenide diamine monomer with a dianhydride monomer to give a selenium-containing polyamic acid; and (2) performing thermal imidization on the selenium-containing polyamic acid obtained in the step (1) to give a selenium-containing polyimide polymer. In the invention, selenium is introduced into polyimides for increasing refractive index to 1.7-1.82, this greatly improves the defects of low refractive index of the existing polyimide materials, thereby expanding its applications in the optics field.