Abstract: Copolyimides and their precursors are disclosed comprising units represented by the formula ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are hydrogen or C.sub.1 to C.sub.6 linear or branched alkyl, with the proviso that R.sub.1, R.sub.2, R.sub.3 and R.sub.4 cannot simultaneously be hydrogen and where Z is a chemical bond, ##STR2## Ar is the tetravalent residue of a tetracarboxylic acid or acid dianhydride or di- or tetraester thereof, where x and y are integers from about 100 to about 1,000, and the ratio of x to y is from about 1:99 to about 49:51, and z is 0-5.These copolymers have improved resistance to stress cracking. They may also be used in applications such as coatings, or adhesives.

Abstract: In humid atmospheres (e.g., 40% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyimides tend to be unstable in the sense that during spin coating operations undesirable precipitate formation occurs on the rotating surface of the wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are solutions of these polyimide polymers in a solvent containing one or more liquid aromatic hydrocarbons having a boiling point at least about 110.degree. C. and one or more dipolar aprotic solvents having a boiling point of at least about 150.degree. C., such that the solution (a) contains on a weight basis from about 5% to about 50% of the polyimide, and (b) does not undergo precipitate formation during spin coating in an atmosphere of up to about 55% relative humidity.

Abstract: In humid atmospheres (e.g., 55% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyamic acid polymers tend to be unstable in the sense that during spin coating operations undesirable precipitate formation may occur on the rotating surface of a semiconductor wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described is a method of spin coating solutions of these polyamic acid polymers in a solvent containing one or more cycloaliphatic ketones, such that the solution (a) contains on a weight basis from about 5% to about 40% of the polyamic acid and (b) does not undergo precipitate formation during spin coating in an atmosphere of up to at least about 55% relative humidity.

Abstract: In humid atmospheres (e.g., 55% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis [4-(aminophenoxy)phenyl]hexafluoropropane polyamic acid polymers tend to be unstable in the sense that during spin coating operations undesirable precipitate formation may occur on the rotating surface of a semiconductor wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are solutions of these polyamic acid polymers in a solvent containing at least 40% by weight of one or more liquid aromatic hydrocarbons having a boiling point of at least about 110.degree. C. and at least 5% by weight of one or more dipolar aprotic solvents having a boiling point of at least about 150.degree. C.

Abstract: In humid atmospheres (e.g., 40% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyimides tend to be unstable in the sense that during spin coating operations undesirable precipitate formation occurs on the rotating surface of the wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are solutions of these polyimide polymers in a solvent containing one or more liquid aromatic hydrocarbons having a boiling point of at least about 110.degree. C. and one or more dipolar aprotic solvents having a boiling point of at least about 150.degree. C., such that the solution (a) contains on a weight basis from about 5% to about 50% of the polyimide, and (b) does not undergo precipitate formation during spin coating in an atmosphere of at least up to about 55% relative humidity.

Abstract: In human atmospheres (e.g., 55% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyamic acid polymers tend to be unstable in the sense that during spin coating operations undesirable precipitate formation may occur on the rotating surface of a semiconductor wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are solutions of these polyamic acid polymers in a solvent containing one or more cycloaliphatic ketones, such that the solution (a) contains on a weight basis from about 5% to about 40% of the polyamic acid and (b) does not undergo precipitate formation during spin coating in an atmosphere of up to at least about 55% relative humidity.

Abstract: In humid atmospheres (e.g., 40% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyimides tend to be unstable in the sense that during spin coating operations undesirable precipitate formation occurs on the rotating surface of the water. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are compositions especially adapted for use in spin coating wafers of semiconductive materials, which comprise solutions of these polyimide polymers in a solvent containing at least 10% of a cycloaliphatic ketone (e.g., cyclohexanone) or mixture of cycloaliphatic ketones, such that the solution (a) contains on a weight basis from about 5% to about 50% of the polyimide, and (b) does not undergo precipitate formation during spin coating in an atmosphere of up to at least about 55% relative humidity.

Abstract: In humid atmospheres (e.g., 55% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyamic acid polymers tend to be unstable in the sense that during spin coating operations undesirable precipitate formation may occur on the rotating surface of a semiconductor wafer. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are solutions of these polyamic acid polymers in a solvent containing at least 40% by weight of one or more liquid aromatic hydrocarbons having a boiling point of at least about 110.degree. C. and at least 5% by weight of one or more dipolar aprotic solvents having a boiling point of at least about 150.degree. C.

Abstract: A water-soluble salt of monoallylamine is polymerized in an aqueous reaction medium at a temperature of about 30.degree.-80.degree. C. in the presence of a polymerization initiator comprising about 3-15% by weight of hydrogen peroxide and about 1-700 ppm of a multi-valent metal ion, based on the weight of the monomer charge. The hydrogen peroxide is preferably introduced continuously or periodically during a substantial portion of the polymerization reaction. Preferred sources of the metal ion are water-soluble iron salts, such as ferric or ferrous chloride.