Fingerprint sensor, fabrication method thereof and fingerprint sensing system

• US 20050018884A1
• Filed: 07/22/2004
• Published: 01/27/2005
• Est. Priority Date: 07/22/2003
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Heon Min, Lee, Don Hee
• Application Number:
  US10/898,487
• Publication Number:
  US 20050018884A1
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger

Abstract

A fingerprint sensor of the present invention includes a substrate; a plurality of electrode patterns formed on the substrate for detecting an impedance signal in response to the contact of a fingerprint; and an insulating layer formed on the substrate including the electrode patterns.

Claims

1. A fingerprint sensor comprising:

a substrate;

a plurality of electrode patterns formed on the substrate, for detecting an impedance signal in response to the contact of a fingerprint; and

an insulating layer formed on the substrate including the electrode patterns.

2. The fingerprint sensor according to claim 1, wherein the electrode patterns are made of one selected from the group consisting of Poly-Si, Al, Cr, Ta, Ti, Pt, Ir, Au and Mo.

3. The fingerprint sensor according to claim 1, wherein the insulating layer is planarized such that the electrode patterns are exposed to the outside when the electrode patterns are made of a material resistive against foreign materials.

4. The fingerprint sensor according to claim 3, wherein the material resistive against foreign materials is one selected from the group consisting of Pt, Mo and Ir.

5. The fingerprint sensor according to claim 3, further comprising passivation conductor patterns formed on the exposed electrode patterns.

6. The fingerprint sensor according to claim 5, wherein the passivation conductor patterns are made of one selected from the group consisting of ITO (Indium Tin Oxide), RuO₂ and IrO₂.

7. The fingerprint sensor according to claim 1, wherein the insulating layer is made of one selected from the group consisting of oxide, SiO₂ and SiNx.

8. A fingerprint sensor system comprising:

a sensor array including a plurality of unit sensors arranged into a matrix configuration, each of the unit sensors having electrode patterns for detecting fingerprints; and

a drive unit for outputting an output signal in response to an impedance signal detected by a corresponding one of the electrode patterns.

9. The fingerprint sensor system according to claim 8, wherein each of the unit sensors has a size of about 50×

50 μ

m².

10. The fingerprint sensor system according to claim 8, wherein the electrode patterns are one selected from the group consisting of open comb, closed comb and specifically patterned electrodes.

11. The fingerprint sensor system according to claim 8, wherein the drive unit determines the electrode signal based upon voltage division.

12. A method for fabricating a fingerprint sensor, the method comprising the steps of:

depositing electrode material on a substrate;

forming a plurality of electrode patterns using the electrode material; and

depositing an insulating layer on the substrate including the electrode patterns.

13. The method according to claim 12, further comprising the step of planarizing the insulating layer such that the electrode patterns is exposed to the outside if the electrode patterns are made of a material resistive against foreign materials.

14. The method according to claim 13, wherein the material resistive against foreign materials is one selected from the group consisting of Pt, Mo and Ir.

15. The method according to claim 12, wherein the electrode patterns are made of one selected from the group consisting of poly-Si, Al, Cr, Ta, Ti, Pt, Ir, Au and Mo.

16. The method according to claim 12, wherein the insulating layer is made of one selected from the group consisting of oxide, SiO₂ and SiNx.

17. A method for fabricating a fingerprint sensor, the method comprising the steps of:

sequentially depositing first and second materials on a substrate;

forming a plurality of electrode patterns and passivation conductor patterns using the first and second materials;

forming an insulating layer on the substrate including the electrode patterns and the passivation conductor patterns; and

planarizing the insulating layer such that the passivation conductor patterns are exposed.

18. The method according to claim 17, wherein the first material is one selected from the group consisting of poly-Si, Al, Cr, Ta, Ti, Pt, Ir, Au and Mo.

19. The method according to claim 17, wherein the insulating layer is made of one selected from the group consisting of oxide, SiO₂ and SiNx.

20. The method according to claim 17, wherein the second material is one selected from the group consisting of Indium Tin Oxide (ITO), RuO₂ and IrO₂.