Radio frequency identification tag on a single layer substrate

• US 6,496,113 B2
• Filed: 08/10/2001
• Issued: 12/17/2002
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Lee, Youbok, Furey, Lee, St. Amand, Roger
• Primary Examiner(s): Tweel, John
• Application Number:
  US09/927,840
• Publication Number:
  US 20020067268A1
• Time in Patent Office: 494 Days
• Field of Search: 340/572.7, 340/572.8, 340/572.5, 340/551, 340/10.34, 343/872, 343/873
• US Class Current: 340/572.7
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/19041 being a capacitor

Abstract

A radio frequency identification (RFID) tag on a single layer substrate comprises a semiconductor integrated circuit RFID tag device and antenna circuit. A connection jumper may be used to bridge over the antenna circuit coil turns. The RFID tag device is located on the same side as an inductor coil and capacitor which forms a parallel resonant antenna circuit. The inductor coil has an inner end and an outer end. The inner or outer end may be connected directly to the RFID tag device and the outer or inner end be may connected to the RFID tag device with a jumper over the inductor coil turns, or the RFID tag device may bridge the inductor coil turns when being connected to both the inner and outer ends. An encapsulation (glop top) may be used to seal the RFID tag device and jumper, and an insulated coating may be used to cover the entire surface of the substrate to create an inexpensive “chip-on-tag.” The encapsulation may be epoxy, plastic or any protective material known to one of ordinary skill in the art of electronic circuit encapsulation. The insulated coating may be of any type suitable for the application of use of the RFID tag.

Claims

1. A radio frequency identification (RFID) tag, comprising:

a substrate that is electrically insulated and transparent to radio frequency signals, said substrate having a surface;

an inductor coil having a plurality of turns, an outer end and an inner end, said inductor coil disposed on the surface of said substrate;

a RFID tag device on the surface of said substrate, said RFID tag device connected to the inner end of said inductor coil;

at least one connection pad disposed between the plurality of turns; and

a plurality of conductive jumpers, wherein respective ones of said plurality of conductive jumpers connect the outer end of said inductor coil, said at least one connection pad and said RFID tag device together, whereby said plurality of conductive jumpers are disposed over respective ones of the plurality of turns.

2. The RFID tag of claim 1, further comprising a capacitor on the surface of said substrate and connected to said inductor coil to form a resonant circuit antenna.

3. The RFID tag of claim 2, wherein said inductor coil and said capacitor form a parallel resonant circuit antenna.

4. The RFID tag of claim 2, wherein said inductor coil and said capacitor form a series resonant circuit antenna.

5. The RFID tag of claim 1, wherein said inductor coil forms a resonant circuit antenna with an internal capacitor of said RFID tag device.

6. The RFID tag of claim 5, wherein said inductor coil and the internal capacitor form a parallel resonant circuit antenna.

7. The RFID tag of claim 1, wherein said inductor coil is a spiral coil.

8. The RFID tag of claim 1 wherein said plurality of conductive jumpers are a plurality of bond wires.

9. The RFID tag of claim 8, further comprising a device connection pad connected to said RFID tag device and adapted for connection to a one of said plurality of conductive jumpers.

10. The RFID tag of claim 1, wherein said plurality of conductive jumpers are insulated from said inductor coil where crossing thereover.

11. The RFID tag of claim 9, wherein said RFID tag device is a flipchip connected to said inductor coil and the device connection pad.

12. The RFID tag of claim 1, further comprising protective encapsulation over said RFID tag device and said plurality of conductive jumpers.

13. The RFID tag of claim 1, further comprising an insulation coating over said inductor coil.

14. The RFID tag of claim 1, further comprising test connection pads on said substrate and connected to said RFID tag device.

15. The RFID tag of claim 1, further comprising programming connection pads on said substrate and connected to said RFID tag device.

22. The RFID tag of claim 1, wherein material for said substrate is selected from the group consisting of PET, mylar, paper, plastic, silicon, kapton, ceramic, polyimide and polyvinylchloride (PVC).

23. The RFID tag of claim 1, wherein material for said inductor coil is selected from the group consisting of copper, aluminum, gold, plated metal, and electrically conductive organic and inorganic materials.

16. A method of fabricating an inexpensive radio frequency identification (RFID) tag, said method comprising the steps of:

providing a substrate that is electrically insulated and transparent to radio frequency signals, wherein said substrate has a surface;

disposing an inductor coil on the surface of said substrate, said inductor coil having a plurality of turns, an outer end and an inner end;

disposing a RFID tag device on the surface of said substrate;

disposing at least one connection pad between the plurality of turns;

connecting said RFID tag device to the inner end of said inductor coil; and

connecting the outer end of said inductor coil to said at least one connection pad and said RFID tag device with conductive jumpers.

17. The method of claim 16, further comprising the step of encapsulating said RFID tag device and said conductive jumpers with a protective material.

18. The method of claim 17, wherein the protective material is epoxy.

19. The method of claim 16, further comprising applying an insulating coating to said inductor coil on the surface of said substrate.

20. The method of claim 16, further comprising providing test connection pads on said substrate and connecting said test connection pads to said RFID tag device.

21. The method of claim 16, further comprising providing programming connection pads on said substrate and connecting said programming connection pads to said RFID tag device.