As represented by the uses of a surface protecting paint of an element for semiconductor device, a binder for die bonding adhesive, a cloth impregnated material, an organic film for orientation of a liquid crystal or a shielding film for preventing soft error of large scale integrated circuits, where a polyimide film is provided on the interface of an article wherein the surface is Si or Si--O--Si, the article has a poor adhesion to the polyimide polymer. Therefore, a method of treating the interface between the polyimide film and Si or Si--O--Si or a method of introducing an alkoxy group or siloxane group into the polyimide polymer has heretofore been employed to improve the adhesion.
Further, as the process which can provide good results as compared with the conventional techniques, a process has been proposed, which comprises reacting a portion of an organic tetracarboxylic acid component with an aminosilane compound represented by the formula (3) ##STR1## wherein R.sub.2 is a divalent organic group containing a carbon atom which directly bonds to a silicon atom, X is a hydrolyzable group selected from alkoxy, acetoxy, phenoxy or halogen and Y is a group selected from alkyl, alkoxy, acetoxy, phenoxy, silyl, siloxy, disilanyl, organosilyl, organosiloxy, organohalosilyl or organohalosiloxy, through the amino group (NH.sub.2 --) and at least one hydrolyzable group (X) in the formula (3) to obtain a silane-modified polycarboxylic acid component represented by the formula (4) ##STR2## wherein T.sub.c1 is a monovalent residue of the organic tetracarboxylic acid component, T.sub.c2 is a divalent residue of the organic tetracarboxylic acid component, Z is an acid radical which may contain X which bonds to carbonyl carbon, R.sub.2, X and Y are the same as defined in the formula (3), and n is an integer of 2 or 3 when Y is alkoxy, acetoxy or phenoxy and is an integer of 2 when Y is other groups, and polymerizing the resulting carboxylic acid component and a diamine together with the residual organic tetracarboxylic acid component.
The polyimide polymer produced by this process, however, showed excellent initial adhesion and also excellent adhesion under Pressure Cooker Test at 121.degree. C. under 2 atoms (hereinafter referred to as "PCT"), but the problem occurred that the retention characteristic of the initial adhesive strength under high temperature and high humidity conditions gradually lowered. This lacked the reliability of devices in view of the recent severe requirement on the moisture resistance property.