Arrangement for authentication of a person

• US 20050031174A1
• Filed: 01/22/2004
• Published: 02/10/2005
• Est. Priority Date: 01/22/2003
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Hjelt, Kari, Ryhanen, Tapani
• Granted Patent: US 7,606,400 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement
• CPC Class Codes: H01L 2224/04105 Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
• CPC Class Codes: H01L 2224/24226 the HDI interconnect connecting to the same level of the item at which the semiconductor or solid-state body is mounted, e.g. the item being planar
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73267 Layer and HDI connectors
• CPC Class Codes: H01L 2224/8203 Reshaping, e.g. forming vias
• CPC Class Codes: H01L 2224/92144 the second connecting process involving a build-up interconnect
• CPC Class Codes: H01L 24/24 of an individual high density interconnect connector
• CPC Class Codes: H01L 24/82 by forming build-up interconnects at chip-level, e.g. for high density interconnects [HDI] interconnection structure between a plurality of semiconductor chips H01L23/5389
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: Y10T 29/49144 by metal fusion
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.

Abstract

A capacitive fingerprint sensor is fabricated on a plastic substrate (363) with an embedded integrated circuit chip (380). The invention describes a way to create two or three dimensional forms for electrode structures (321, 322, 325, 365, 366) that can be used to optimize the performance of the sensor. When the three dimensional structure is designed to follow the shape of a finger, a very small pressure is required when sliding the finger along the sensor surface. This way the use of the sensor is ergonomic and the measurement is made very reliable. The inventive fabrication method describes the way, how to connect and embed an integrated circuit containing measurement electronics with a batch processed larger scale electrode configuration that is used for capturing the capacitive image of the fingerprint.

Claims

1. A fingerprint sensor arrangement comprising at least one driver electrode and at least one sensor electrode for a capacitive measurement, and an integrated signal processing circuit for the measurement of signals from the electrodes, and interconnecting wiring between the electrodes and the integrated circuit, characterized in that the at least one driver electrode, the at least one sensor electrode, said signal integrated circuit and said interconnecting wiring are embedded within an integrated module.

2. An arrangement according to claim 1, characterized in that said electrode and said integrated circuit are coupled with a substrate, the substrate comprising said wiring between the electrodes and the integrated circuit.

3. An arrangement according to claim 2, characterized in that the substrate comprises the at least one driver electrode, said at least one sensor electrode, or both.

4. An arrangement according to claim 2, characterized in that said substrate is a flexible film.

5. An arrangement according to claim 1, characterized in that it comprises a substrate comprising wiring for an external connection to the integrated circuit.

6. An arrangement according to claim 5, characterized in that it comprises wire bonding between the integrated circuit and wiring of the substrate.

7. An arrangement according to claim 5, characterized in that it comprises metallization between the integrated circuit and wiring of the substrate.

8. An arrangement according to claim 5, characterized in that said substrate is flexible film.

9. An arrangement according to claim 1, characterized in that said interconnecting wires are metallizations between polymer layers.

10. An arrangement according to claim 1, characterized in that said at least one driver electrode and/or said at least one sensor electrode is metallization between polymer layers.

11. An arrangement according to claim 1, characterized in that it comprises guard rings in the vicinity of the at least one driver electrode, in the vicinity of at least one sensor electrode, or both.

12. An arrangement according to claim 11, characterized in that said guard ring is metallization and the arrangement comprises an insulating polymer layer between the guard ring metallization and the sensor electrode.

13. An arrangement according to claim 1, characterized in that said integrated module is encapsulated with injection molded polymer.

14. An arrangement according to claim 1, characterized in that the surface of said sensor has a curved form in at least two dimensions.

15. An arrangement according to claim 14, characterized in that said form approximates the form of a finger.

16. An arrangement according to claim 1, characterized in that the arrangement comprises a bump for elevating the electrodes.

17. An arrangement according to claim 16, characterized in that said bump is a layer of polymer.

18. An arrangement according to claim 1, characterized in that said sensor comprises one driver electrode and a row of sensing electrodes.

19. An arrangement according to claim 18, characterized in that said measurement circuit is adapted to measure successive signals while the finger moves in a perpendicular direction in relation to said row of sensing electrodes, for providing a two dimensional matrix of capacitive measurement results from the finger.

20. An arrangement according to claim 1, characterized in that the arrangement further comprises a infrared light source, a infrared light detector and second measurement means for measuring absorption of infrared light from the finger.

21. An arrangement according to claim 1, characterized in that said arrangement further comprises a temperature sensor for measuring the temperature from the finger.

22. An arrangement according to claim 1, characterized in that said arrangement further comprises a humidity sensor for sensing humidity of the finger.

23. A mobile terminal, characterized in that it includes a fingerprint sensor arrangement according to claim 1.

24. A method for producing a fingerprint sensor, characterized in that the method comprises the following steps:

providing a signal processing integrated circuit,

providing at least one driver electrode,

providing at least one sensor electrode,

encapsulating said integrated circuit, said at least one driver electrode and said at least one sensing electrode into an integrated module.

25. A method according to claim 24, characterized in that said step of encapsulating comprises a step of encapsulating into polymer.

26. A method according to claim 24, characterized in that said step of providing said at least one driver electrode comprises a step of metallization.

27. A method according to claim 24, characterized in that said step of providing said at least one sensing electrode comprises a step of metallization.

28. A method according to claim 24, characterized in that the method comprises the step of providing at least one guard ring in the vicinity of at said least one sensor electrode.

29. A method according to claim 28, characterized in that the step of providing at least one guard ring comprises a step of metallization.

30. A method according to claim 28, characterized in that it comprises a step of providing an insulating polymer layer between said at least one guard ring and said at least one sensing electrode.

31. A method according to claim 24, characterized in that it comprises a step of providing a substrate and connecting said integrated circuit on said substrate before said encapsulating.

32. A method according to claim 31, characterized in that the method comprises a step of providing an aperture in said substrate for providing an electrical connection through the substrate.

33. A method according to claim 24, characterized in that the method comprises a step of providing an elevating bump between said substrate and the electrodes.

34. A method according to claim 33, characterized in that said bump is made of a layer of polymer.

35. A method according to claim 31, characterized in that said substrate is flexible and includes wiring.

36. A method according to claim 35, characterized in that an end of said flexible substrate is used for an electrically connecting external circuits to the fingerprint sensor.

37. A method according to claim 35, characterized in that wiring of said flexible substrate is used for providing said at least one sensing electrode, for providing said at least one driving electrode, or both.

38. A method according to claim 24, characterized in that said at least one sensing electrode, or said at least one driving electrode, or both are provided with metallization on the surface of the integrated circuit.

39. A method according to claim 31, characterized in that an electrical connection is provided by wire bonding between the integrated circuit and wiring of the substrate.

40. A method according to claim 31, characterized in that an electrical connection is provided by metallization between the integrated circuit and wiring of the substrate.

41. A method according to claim 24, characterized in that conductive bumps are connected with a flip chip process to a metallization of a substrate or the integrated circuit for providing external electrical connections to the integrated circuit.

42. A method according to claim 24, characterized in that a polymer layer is provided by injection molding using micro replicated mold.

43. A method according to claim 24, characterized in that the process comprises the steps of providing polymer layers and at least one metallization layer one upon the other.

44. A method according to claim 24, characterized in that the fingerprint sensor is embedded into an equipment cover.