Method of fabricating a surface shape recognition sensor

• US 6,248,655 B1
• Filed: 02/29/2000
• Issued: 06/19/2001
• Est. Priority Date: 03/05/1998
• Status: Expired due to Term

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Shigematsu, Satoshi, Morimura, Hiroki, Hirata, Akihiko, Machida, Katsuyuki
• Primary Examiner(s): QUACH, TUAN N
• Application Number:
  US09/515,962
• Time in Patent Office: 476 Days
• Field of Search: 438/597, 438/618, 438/622, 438/623, 438/650, 438/652, 438/674, 438/675, 438/678, 438/686, 438/687
• US Class Current: 438/597
• CPC Class Codes: G01B 7/004 for measuring coordinates of points
• CPC Class Codes: G01B 7/34 for measuring roughness or irregularity of surfaces
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

A surface shape recognition sensor of this invention includes at least a plurality of capacitance detection elements having sensor electrodes arranged in the same plane on an interlevel dielectric film formed on a semiconductor substrate to be insulated/isolated from each other, capacitance detection means for detecting the capacitances of the capacitance detection elements, and a stationary electrode disposed on the interlevel dielectric film to be insulated/isolated from the sensor electrodes. When an object to be recognized touches the upper surface of the stationary electrode, the capacitances detected by the capacitance detection elements change in accordance with the recesses/projections on the upper surface.

Claims

1. A method of fabricating a surface shape recognition sensor, comprising the steps of:

forming a plurality of capacitance detection elements on a semiconductor substrate on which at least a semiconductor element is formed; and

forming protective films on said plurality of capacitance detection elements,

wherein each of said capacitance detection elements includes a sensor electrode disposed on said semiconductor substrate and a counter electrode disposed above said sensor electrode,

said counter electrode of each of said capacitance detection elements is made of one common electrode member, and

said counter electrode is supported by a stationary electrode disposed for each of said capacitance detection elements, said stationary electrode being made of a conductive member.

2. A method according to claim 1, further comprising the steps of:

forming first and second interconnections through an interlevel dielectric film on said semiconductor substrate;

forming connection electrodes on said first and second interconnections;

forming a first metal film on a surface on which said connection electrodes are formed and then covering said first metal film with a first resist;

forming a sensor electrode by forming an opening portion in said first resist on said first interconnection and continuously forming second and third metal films;

forming a stationary electrode having conductivity by forming a second resist after removing said first resist, forming an opening portion in said second resist on said second interconnection, and sequentially forming fourth and fifth metal films in only the opening portion;

etching said first metal film by using said third and fifth metal films as masks after removing said second resist;

covering a major surface side of said semiconductor substrate with a sacrificial film having a thickness not less than a thickness of said stationary electrode;

exposing only said fifth metal films by etching said sacrificial film;

forming a counter electrode on said sacrificial film to connect said fifth metal films to each other; and

covering said counter electrode with a protective film after removing said sacrificial film.

3. A method according to claim 2, wherein said first, second, and fourth metal films are made of copper.

4. A method according to claim 2, wherein said third and fifth metal films are made of gold.

5. A method according to claim 2, further comprising the step of forming a new metal film made of the same material as that for said first metal film after formation of said first metal film, and forming a third metal film on said new metal film.

6. A method according to claim 1, further comprising the steps of:

forming first and second interconnections through an interlevel dielectric film on said semiconductor substrate;

forming connection electrodes on said first and second interconnections;

forming a first metal film on a surface on which said connection electrodes are formed and then covering said first metal film with a first resist;

forming a sensor electrode (105) by forming an opening portion in said first resist on said first interconnection and continuously forming second and third metal films;

covering only a portion above said second interconnection with a second resist after removing said first resist;

etching said first metal film by using said third metal film and said second resist as masks;

removing said second resist, forming a sacrificial film, and forming an opening portion in a portion above said second interconnection;

forming a stationary electrode having conductivity by sequentially forming fourth and fifth metal films;

forming a counter electrode on said sacrificial film to connect said fifth films to each other; and

covering said counter electrode with a protective film after removing said sacrificial film.

7. A method according to claim 1, further comprising the steps of:

forming first and second interconnections through an interlevel dielectric film on said semiconductor substrate;

forming connection electrodes on said first and second interconnections;

forming a first metal film on a surface on which said connection electrodes are formed and then covering an entire surface of said first metal film with a first resist;

forming a sensor electrode by forming an opening portion in said first resist on said first interconnection and continuously forming second and third metal films;

forming a stationary electrode having conductivity by forming a second resist after removing said first resist, forming an opening portion in said second resist at a position above said second interconnection, and sequentially forming fourth and fifth metal films in only the opening portion;

removing said second resist and etching said first metal film by using said third and fifth metal films as masks; and

bonding a counter electrode, formed in advance under a protective film, on said stationary electrode through a conductive adhesive.

8. A method according to claim 1, wherein said sensor electrodes and said stationary electrode are formed in the same plane.

9. A method according to claim 8, wherein the same plane is located on an insulating film formed on said semiconductor substrate.

10. A method according to claim 1, wherein said stationary electrode is formed to surround said sensor electrode of each of said capacitance detection elements.

11. A method according to claim 1, wherein said protective film having projections each made highest at a position corresponding to a central portion of each of said capacitance detection element.

12. A method according to claim 11, wherein said protective film is made of a thermoplastic film.

13. A method according to claim 12, wherein said thermoplastic film is made of polytetrafluoroethylene.

14. A method according to claim 1, wherein said sensor electrode and said stationary electrode are connected to an input side of a sense unit.

15. A method according to claim 1, wherein said counter electrode is processed into a mesh pattern.

16. A method of fabricating a surface shape recognition sensor, comprising the steps of:

forming first and second interconnections on a semiconductor substrate;

forming an interlevel dielectric film on said semiconductor substrate to cover said first and second interconnections;

forming a first metal film electrically connected to said first and second interconnections through first and second through holes formed in said interlevel dielectric film;

forming a first mask pattern on said first metal film, said first mask pattern having an opening portion in a region above the first through hole;

selectively forming a second metal film on an upper surface of said first metal film which is exposed on a bottom portion of the opening portion of said first mask pattern;

forming a second mask pattern on said first and second metal films, said second mask pattern having a groove crossing over the second through hole and surrounding said second metal film;

selectively forming a third metal film on an upper surface of said first metal film which is exposed on a bottom portion of the groove of said second mask pattern, said third metal film being thicker than said second metal film;

forming a sensor electrode and a stationary electrode by removing said first metal film except for portions under said second and third metal films, said sensor electrode being made up of said first and second metal films and connected to said first interconnection through the first through hole, and said stationary electrode being made up of said first and third metal films and connected to said second interconnection through the second through hole;

forming a sacrificial film on said interlevel dielectric film to cover said sensor electrodes and expose upper portions of said stationary electrode;

forming a counter electrode on said sacrificial film and said stationary electrode; and

selectively removing only said sacrificial film after forming said counter electrode,

wherein said first and second interconnections are formed to be connected to capacitance detection means for detecting capacitances formed between said sensor electrodes and said counter electrode.

17. A method according to claim 16, wherein said first, second, and third metal films are made of copper.

18. A method according to claim 16, wherein said first, second, and third metal films are made of gold.

19. A method according to claim 16, further comprising the step of forming protective films having conductivity to cover side and upper surfaces of said sensor electrodes and said stationary electrode after formation of said sensor electrodes and said stationary electrode.

20. A method according to claim 19, wherein said protective films are made of ruthenium.

21. A method according to claim 19, wherein said protective films are made of gold.

22. A method according to claim 16, further comprising the step of forming an insulating film on said counter electrode, said insulating film having projections at positions above said respective sensor electrodes.

23. A method of fabricating a surface shape recognition sensor, comprising the steps of:

forming first and second interconnections on a semiconductor substrate;

forming an interlevel dielectric film on said semiconductor substrate to cover said first and second interconnections;

forming a plurality of sensor electrodes in the same plane on said interlevel dielectric film to be insulated/isolated from each other;

forming a stationary electrode in the same plane to be insulated/isolated from said sensor electrodes; and

forming a passivation film made of an insulating member to cover said sensor electrodes while an upper surface of said stationary electrode is partly exposed,

wherein said first and second interconnections are formed to be connected to capacitance detection means for detecting capacitances formed between said sensor electrodes and said stationary electrode.

24. A method of fabricating a surface shape recognition sensor, comprising at least the steps of:

forming first and second interconnections on a substrate through a lower insulating film;

forming an interlevel dielectric film on said lower insulating film to cover said first and second interconnections;

forming first and second through holes in said interlevel dielectric film to partly expose upper surfaces of said first and second interconnections;

forming a barrier film to cover the upper surfaces of the said first and second interconnections which are exposed on bottom portions of said first and second through holes, said barrier film preventing diffusion of a material used for said first and second interconnections and impregnation of other materials into said first and second interconnections;

forming a first metal film made of a first metal material on said interlevel dielectric film including said barrier film;

forming a first resist pattern having an opening portion in a region above the through hole on said first resist pattern;

forming a second metal film made of the first metal material on said first metal film exposed in the opening portion of said first resist pattern by plating;

forming a third metal film made of a second metal material, which is more resistant to oxidation than the first metal material, on said second metal film, following the step of forming said second metal film;

forming a second resist pattern covering said second and third metal films and having an opening portion around said second and third metal films and above the second through hole after removing said first resist pattern;

forming a fourth metal film made of the first metal material on said first metal film exposed in the opening portion of said second resist pattern by plating;

successively forming a fifth metal film made of the second metal material on said fourth metal film by plating;

removing said second resist pattern, selectively etching said first metal film by using said third and fifth metal films as masks, and forming a sensor electrode made up of said first and second metal films and a stationary electrode made up of said first and fourth metal films; and

forming a passivation film made of an insulating member to cover said sensor electrode and have a flat surface while an upper portion of said stationary electrode is partly exposed,

wherein said first and second interconnections are connected to capacitance detection means for detecting a capacitance formed between said sensor electrode and said stationary electrode.

25. A method of fabricating a surface shape recognition sensor, comprising the steps of:

forming first and second interconnections on a semiconductor substrate;

forming an interlevel dielectric film on said semiconductor substrate to cover said first and second interconnections;

forming a first metal film electrically connected to said first and second interconnections through first and second through holes formed in said interlevel dielectric film;

forming a first mask pattern on said first metal film, said first mask pattern having an opening portion above the first through hole;

selectively forming a second metal film on an upper surface of said first metal film which is exposed on a bottom portion of the opening portion of said first mask pattern;

forming a second mask pattern on said first and second metal films, said second mask pattern having a groove crossing over the second through hole and surrounding said second metal film;

selectively forming a third metal film on an upper surface of said first metal film which is exposed on a bottom portion of the groove of said second mask pattern, said third metal film being thicker than said second metal film;

forming a sensor electrode and a stationary electrode by removing said first metal film except for portions under said second and third metal films, said sensor electrode being made up of said first and second metal films and connected to said first interconnection via the first through hole, and said stationary electrode made up of said first and third metal films and connected to said second interconnection via the second through hole; and

forming a passivation film on said interlevel dielectric film to cover said sensor electrode and expose an upper portion of said stationary electrode,

wherein said first and second interconnections are connected to capacitance detection means for detecting a capacitance formed between said sensor electrode and said stationary electrode.

26. A method according to claim 25, wherein said first, second, and third metal films are made of copper.

27. A method according to claim 26, wherein said first, second, and third metal films are made of gold.

28. A method according to claim 27, further comprising the step of forming protective films having conductivity to cover side and upper surfaces of said sensor electrode and said stationary electrode after formation of said sensor electrode and said stationary electrode.

29. A method according to claim 28, wherein said protective films are made of ruthenium.

30. A method according to claim 29, wherein said passivation film is made of polyimide.

31. A method according to claim 30, wherein the polyimide is polybenzaoxazole.