Capacitance detection type sensor and manufacturing method thereof

• US 7,009,410 B2
• Filed: 10/24/2002
• Issued: 03/07/2006
• Est. Priority Date: 03/20/2002
• Status: Expired due to Term

• Current Assignee: Fujitsu Semiconductor Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Limited
• Inventors: Iwamoto, Shigeru, Ito, Masaki, Onodera, Hideo
• Primary Examiner(s): Nguyen, Vincent Q.
• Assistant Examiner(s): Teresinski, John
• Application Number:
  US10/279,008
• Publication Number:
  US 20030179001A1
• Time in Patent Office: 1,230 Days
• Field of Search: 324/763, 324/765, 324/661, 324/519, 324/662, 324/687, 324/688, 324/658
• US Class Current: 324/690
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger

Abstract

Capacitance sensor electrodes are arranged in a form of matrix on a semiconductor substrate and coated with a cover film. These capacitance sensor electrodes are connected to a drive circuit. ESD electrodes are arranged in the vicinities of corner portions of the capacitance sensor electrodes. Each ESD electrode is composed of a film containing, for example, aluminum excellent in conductivity and a TiN film formed thereon. The ESD electrodes are grounded through the semiconductor substrate. On each ESD electrode, a plurality of fine ESD holes reaching the ESD electrode from a surface of the cover film are formed.

Claims

1. A capacitance detection type sensor provided with a plurality of capacitance sensor electrodes, comprising:

a substrate;

an insulating film formed on the substrate;

a first electrostatic discharge electrode film conductive and formed on the insulating film;

a second electrostatic discharge electrode film conductive and formed so as to be electrically connected to the first electrostatic discharge electrode film; and

a cover film covering surfaces of the plurality of capacitance sensor electrodes and having a plurality of openings provided therein, the openings reaching the second electrostatic discharge electrode film.

2. The capacitance detection type sensor according to claim 1, wherein any of the openings provided in the cover film has any one of a diameter and a width equal to/less than 5 μ

m.

3. The capacitance detection type sensor according to claim 1, wherein the plurality of openings are arranged evenly on the second electrostatic discharge electrode film.

4. The capacitance detection type sensor according to claim 1, wherein the first electrostatic discharge electrode film and the second electrostatic discharge electrode film are formed in positions closer to the substrate than a position of the capacitance sensor electrodes.

5. The capacitance detection type sensor according to claim 1, wherein a wire formed between the capacitance sensor electrodes and the substrate and electrically connected to the capacitance sensor electrodes is provided, and the second electrostatic discharge electrode film is formed in a same wiring layer as a layer of the wire.

6. The capacitance detection type sensor according to claim 1, wherein the openings are formed in a form of stripes in the cover film.

7. The capacitance detection type sensor according to claim 1, wherein the openings are formed in a form of concentric circles in the cover film.

8. The capacitance detection type sensor according to claim 1, wherein the first electrostatic discharge electrode film is made of metal containing aluminum as a main component, and the second electrostatic discharge electrode film is made of TiN.

9. The capacitance detection type sensor according to claim 1, wherein the first and second electrostatic discharge electrode films are grounded through the substrate.

10. A capacitance detection type sensor provided with a plurality of capacitance sensor electrodes, comprising:

a substrate;

a first insulating film formed on the substrate;

a first electrostatic discharge electrode film conductive and formed on the first insulating film;

a second insulating film formed on the first insulating film and the first electrostatic discharge electrode film;

a second electrostatic discharge electrode film formed so as to be electrically connected to the first electrostatic discharge electrode film through a contact hole formed in the second insulating film; and

a cover film covering surfaces of the plurality of capacitance sensor electrodes and having an opening provided therein, the opening reaching the second electrostatic discharge electrode film.

11. The capacitance detection type sensor according to claim 10, wherein the capacitance sensor electrodes are formed on the second insulating film.

12. The capacitance detection type sensor according to claim 10, wherein the first electrostatic discharge electrode film is made of metal containing aluminum as a main component, and the second electrostatic discharge electrode film is made of TiN.

13. The capacitance detection type sensor according to claim 10, wherein the opening of the cover film is formed above a connected portion of the first electrostatic discharge electrode film and the second electrostatic discharge electrode film.

14. The capacitance detection type sensor according to claim 10, wherein the opening of the cover film is formed in a position different from a position of the connected portion of the first electrostatic discharge electrode film and the second electrostatic discharge electrode film.

15. The capacitance detection type sensor according to claim 14, wherein the opening of the cover film is formed along sides of the capacitance sensor electrodes.

16. The capacitance detection type sensor according to claim 10, wherein the first and second electrostatic discharge electrode films are grounded through the substrate.

17. A capacitance detection type sensor provided with a plurality of capacitance sensor electrodes, comprising:

a substrate;

a first insulating film formed on the substrate;

a first electrostatic discharge electrode film conductive and formed on the first insulating film;

a second insulating film formed on the first insulating film and the first electrostatic discharge electrode film;

a conductor plug formed in an opening of the second insulating film and electrically connected to the first electrostatic discharge electrode film;

a second electrostatic discharge electrode film formed so as to be electrically connected to the conductor plug; and

a cover film covering surfaces of the plurality of capacitance sensor electrodes and having an opening provided therein, the opening reaching the second electrostatic discharge electrode film.

18. The capacitance detection type sensor according to claim 17, wherein the first electrostatic discharge electrode film is made of metal containing aluminum as a main component, the conductor plug is made of metal containing tungsten as a main component, and the second electrostatic discharge electrode film is made of TiN.

19. The capacitance detection type sensor according to claim 17, wherein the capacitance sensor electrodes are formed on the second insulating film.

20. The capacitance detection type sensor according to claim 17, wherein the conductor plug is formed of a material difficult to be corroded in comparison with a material of the first electrostatic discharge electrode film.

21. The capacitance detection type sensor according to claim 17, wherein the first and second electrostatic discharge electrode films are grounded through the substrate.