Method for producing a thin film passive circuit element

Claim 1

A METHOD OF PRODUCING A THIN FILM RESISTOR ELEMENT COMPRISING THE STEPS OF PREPARING A SUBSTRATE IN WHICH AT LEAST TWO CONDUCTIVE WIRING PATHS ARE EMBEDDED, SAID SUBSTRATE HAVING AN INSULATING SURFACE TO RESPECTIVELY EXPOSE A PORTION OF IN SAID INSULATING SURFACE TO RESPECTIVELY EXPOSE A PORTION OF THE SURFACE OF EACH OF SAID TWO CONDUCTIVE WIRING PATHS; DEPOSITING A METALLIC FILM HAVING A SUBSTANTIALLY UNIFORM THICKNESS OVER THE SURFACE OF SAID SUBSTRATE AND SAID EXPOSE PORTIONS, SAID METALLIC FILM BEING OF A METAL OF HIGH RESISTIVTY SELECTED FROM THE GROUP CONSISTING OF TANTALUM, TITANIUM, MOLYBDENUM, AND NIOBIUM, ANODICALLY OXIDIZING SAID METALLIC FILM TO CONVERT THE SURFACE OF SAID METALLIC FILM INTO THE OXIDE OF SAID METAL; AND THEREAFTER ANODICALLY OXIDIZING A PREDETERMINED PORTION OF SAID METALLIC FILM TO CONVERT THE REMAINING THICKNESS OF SAID METALLIC FILM INTO THE OXIDE OF SAID METAL EXCEPT FOR A PREDETERMINED RESISTOR PORTION IN CONTACT WITH THE PREVIOUSLY EXPOSED PORTIONS OF THE SURFACE OF SAID TWO CONDUCTIVE WIRING PATHS.

Claim 2

A METHOD OF PRODUCING A THIN FILM RESISTOR ELEMENT COMPRISING THE STEPS OF PREPARING A SUBSTRATE IN WHICH AT LEAST TWO CONDUCTIVE WIRING PATHS ARE EMBEDDED, SAID SUBSTRATE HAVING AN INSULATING SURFACE TO RESPECTIVELY EXPOSE A PORTION OF IN SAID INSULATING SURFACE TO RESPECTIVELY EXPOSE A PORTION OF THE SURFACE OF EACH OF SAID TWO CONDUCTIVE WIRING PATHS; DEPOSITING A METALLIC FILM HAVING A SUBSTANTIALLY UNIFORM THICKNESS OVER THE SURFACE OF SAID SUBSTRATE AND SAID EXPOSE PORTIONS, SAID METALLIC FILM BEING OF A METAL OF HIGH RESISTIVTY SELECTED FROM THE GROUP CONSISTING OF TANTALUM, TITANIUM, MOLYBDENUM, AND NIOBIUM, ANODICALLY OXIDIZING SAID METALLIC FILM TO CONVERT THE SURFACE OF SAID METALLIC FILM INTO THE OXIDE OF SAID METAL; AND THEREAFTER ANODICALLY OXIDIZING A PREDETERMINED PORTION OF SAID METALLIC FILM TO CONVERT THE REMAINING THICKNESS OF SAID METALLIC FILM INTO THE OXIDE OF SAID METAL EXCEPT FOR A PREDETERMINED RESISTOR PORTION IN CONTACT WITH THE PREVIOUSLY EXPOSED PORTIONS OF THE SURFACE OF SAID TWO CONDUCTIVE WIRING PATHS.

Claim 5

A method of producing a thin film resistor element comprising the steps of preparing a substrate having first and second embedded conductive wiring paths and an insulating surface; opening first and second apertures in said surface of said insulating surface to partially expose the surface of said first and second embedded conductive wiring paths, respectively; depositing a film of anodizable material of high resistivity having a substantially uniform thickness over the surface of said substrate, first and second portions of said film extending to and being in contact with said first and second embedded conductive wiring paths through said first and second apertures, respectively; and converting by anodic oxidation a predetermined portion of said film into the oxide of said anodizable material to provide a resistor portion electrically connected between said first and second portions of said film and enclosed by the oxide of said anodizable material.

Claim 6

A method of producing a thin film resistor element comprising the steps of preparing a substrate having first and second embedded conductive wiring paths and an insulating surface; opening first and second apertures in said surface of said insulating surface to partially expose the surface of said first and second embedded conductive wiring paths, respectively; depositing a film of anodizable material of high resistivity having a substantially uniform thickness over the surface of said substrate, first and second portions of said film extending to and being in contact with said first and second embedded conductive wiring paths through said first and second apertures, respectively; and converting by anodic oxidation a predetermined portion of said film into the oxide of said anodizable material to provide a resistor portion electrically connected between said first and second portions of said film and enclosed by the oxide of said anodizable material.

Claim 10

A method of producing a semiconductor device having a thin film resistor element comprising the steps of preparing a semiconductor substrate having circuit elements formed therein, the surface of said semiconductor substrate being coated with an insulating film having apertures to allow electrical connection to said circuit elements; depositing an aluminum film on the surface of said insulating film; anodically oxidizing a selected portion of said aluminum film to provide aluminum wiring paths; depositing a tantalum film on the selectively anodically oxidized aluminum film; and thereafter anodically oxidizing a selected portion of said tantalum film to provide a tantalum resistor element connected between selected ones of said circuit elements.

Claim 11

A method of producing a semiconductor device having a thin film resistor element comprising the steps of preparing a semiconductor substrate having circuit elements formed therein, the surface of said semiconductor substrate being coated with an insulating film having apertures to allow electrical connection to said circuit elements; depositing an aluminum film on the surface of said insulating film; anodically oxidizing a selected portion of said aluminum film to provide aluminum wiring paths; depositing a tantalum film on the selectively anodically oxidized aluminum film; and thereafter anodically oxidizing a selected portion of said tantalum film to provide a tantalum resistor element connected between selected ones of said circuit elements.