Electronic thin-film circuit and method for producing it

Claim 1

A method for producing an electronic thin-film circuit, having an insulating substrate plate (1) and a first pattern (M 1 ) of connection tracks, a second pattern (M 2 ) of circuit elements both deposited on said substrate plate (1) and blank spaces between said first and second patterns, comprising the steps of: (A) applying a continuous resistance film (2) to the substrate plate; (B) applying atop said continuous resistance film (2) a continuous metal film (3) capable of being soldered and of being reinforced by electroplating; (C) applying atop said continuous metal film (3) a photo-sensitive resist film (4); (D) introducing into the photo-sensitive resist film (4), by means of a first photographic exposure and development process, openings (41) corresponding to the desired first pattern (M 1 ) in order to delineate said connection tracks and facilitate their reinforcement with gold; (E) electro-depositing into each of said openings (41), and thus onto exposed portions of said metal film (3), a gold film (6,61); (F) removing, by means of a second photographic exposure and developing process, portions of the photo-sensitive resist film (4) from all areas of the metal film (3) which corresponds to said intended blank spaces (G) etching away, using as masks remaining portions of the photo-sensitive resist film (4) and the gold films (6,61), those portions of the metal (3) exposed by step (F); (H) removing, by means of a third photographic exposure and development process, portions of the photo-sensitive resist film (4) from areas (32) of the metal film (3) which are a part of said second pattern (M 2 ); (I) selectively etching away the metal film (3) at locations corresponding to the desired second pattern (M 2 ); (J) screen-printing anti-solder film (7,71) onto all areas of the first pattern (M 1 ) covered with the gold films (6,61), with the exception of a narrow end area (64) of said gold films (6,61) which is adjoined by an area of the first pattern (M 1 ) intended to be covered with soft solder; (K) immersing said circuit in liquid soft solder, in order to apply a soft-solder film (8) to the areas of the first pattern (M 1 ) not covered with the anti-solder film (7,71); and (L) dissolving away said anti-solder film (7,71).

Claim 2

A method for producing an electronic thin-film circuit, having an insulating substrate plate (1) and a first pattern (M 1 ) of connection tracks, a second pattern (M 2 ) of circuit elements both deposited on said substrate plate (1) and blank spaces between said first and second patterns, comprising the steps of: (A) applying a continuous resistance film (2) to the substrate plate; (B) applying atop said continuous resistance film (2) a continuous metal film (3) capable of being soldered and of being reinforced by electroplating; (C) applying atop said continuous metal film (3) a photo-sensitive resist film (4); (D) introducing into the photo-sensitive resist film (4), by means of a first photographic exposure and development process, openings (41) corresponding to the desired first pattern (M 1 ) in order to delineate said connection tracks and facilitate their reinforcement with gold; (E) electro-depositing into each of said openings (41), and thus onto exposed portions of said metal film (3), a gold film (6,61); (F) removing, by means of a second photographic exposure and developing process, portions of the photo-sensitive resist film (4) from all areas of the metal film (3) which corresponds to said intended blank spaces (G) etching away, using as masks remaining portions of the photo-sensitive resist film (4) and the gold films (6,61), those portions of the metal (3) exposed by step (F); (H) removing, by means of a third photographic exposure and development process, portions of the photo-sensitive resist film (4) from areas (32) of the metal film (3) which are a part of said second pattern (M 2 ); (I) selectively etching away the metal film (3) at locations corresponding to the desired second pattern (M 2 ); (J) screen-printing anti-solder film (7,71) onto all areas of the first pattern (M 1 ) covered with the gold films (6,61), with the exception of a narrow end area (64) of said gold films (6,61) which is adjoined by an area of the first pattern (M 1 ) intended to be covered with soft solder; (K) immersing said circuit in liquid soft solder, in order to apply a soft-solder film (8) to the areas of the first pattern (M 1 ) not covered with the anti-solder film (7,71); and (L) dissolving away said anti-solder film (7,71).