Abstract: The invention relates to negative photoresists of the polyimide type essentially containing, in an organic solvent, in each case at least(a) one polyamide-acid or polyamide-acid derivative prepolymer which can be converted into a highly heat-resistant polyimide polymer,(b) a photoinitiator, and, if appropriate, further customary additives which contain, as the photoinitiator, a compound of the formula IR.sup.1 --SO.sub.2 --SO.sub.2 --R.sup.2 Iin which R.sup.1 and R.sup.2 are as defined.

Abstract: Stabilized solutions of radiation-crosslinkable polymer precursors of highly heat-resistant polymers, containing chelate complex-formers as stabilizers, do not tend to gel through premature crosslinking and can thus be stored and used over a long period.

Abstract: Photoresist formulations for forming relief structures from highly heat-resistant polyimide polymers, containing in an organic solvent in essence at least(a) one polyamide ester prepolymer carrying photopolymerizable radicals(b) a radiation-reactive copolymerizable unsaturated compound(c) a photosensitizer(d) a photoinitiator(e) a leuco dye, exhibit enhanced photosensitivity if they contain as the photoinitiator a compound of the type of the N-azidosulphonylarylmaleimides and as leuco dye a compound of the type of the triarylmethanes.

Abstract: Photoresists suitable for use for forming relief structures of highly heat-resistant polymers and which contain soluble polymeric precursors which carry radiation-reactive radicals bonded through carboxylic ester groups have an increased light-sensitivity when they also contain at least one radiation-reactive, polymerizable allyl compound which has a boiling point above 180.degree., the allyl group thereof being bonded via an oxygen, sulfur and/or nitrogen atom. The highly heat-resistant polymers which can be prepared by means of these photoresists have excellent chemical, electrical and mechanical properties.

Abstract: An improved development process for relief structures based on radiation-crosslinked polymeric precursors of polymers which are resistant to high temperature in which the development fluid used is an aliphatic or cycloaliphatic ketone having 3 to 7 carbon atoms, is distinguished by rapid and complete removal of soluble polymeric material from the substrate with, at the same time, a minimum amount of attack on the radiation-crosslinked polymeric structures.

Abstract: Novel indoline derivatives of the formula ##STR1## wherein R is H or CH.sub.3 O and the X each are Cl or Br or collectively are --N(CH.sub.2 C.sub.6 H.sub.5)-- or acid addition salts thereof are obtained by treating a 3-hydroxy-1,2,3,4-tetrahydroquinoline of the formula ##STR2## with an inorganic acid halide and, if appropriate, the reacting resulting dihalogen compound with benzylamine or converting a resulting acid addition salt by treatment with a base in the free base or converting a free base by treatment with an acid to an acid addition salt.