Radio frequency identification tag on a single layer substrate

• US 20020067268A1
• Filed: 08/10/2001
• Published: 06/06/2002
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Lee, Youbok, Furey, Lee, Amand, Roger St.
• Granted Patent: US 6,496,113 B2
• Time in Patent Office: Days
• 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 on the surface of said substrate, said inductor coil having an outer end and an inner end;

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

a jumper conductor disposed over said inductor coil, wherein said jumper conductor connects the outer end of said inductor coil to said RFID tag device.

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 7, wherein the spiral coil has a plurality of coil turns.

9. The RFID tag of claim 1, wherein said jumper conductor is a bond wire.

10. The RFID tag of claim 9, further comprising a connection pad connected to said RFID tag device and adapted for connect to the bond wire.

11. The RFID tag of claim 7, further comprising a plurality of connection pads located between the plurality of coil turns and adapted for connection to a plurality of bond wires and a one of the plurality of connection pads also being connected to said RFID tag device.

12. The RFID tag of claim 1, wherein said jumper conductor is an electrical conductor insulated from said inductor coil where crossing thereover.

13. The RFID tag of claim 10, wherein said RFID tag device is a flipchip connected to said inductor coil and the connection pad.

14. The RFID tag of claim 1, further comprising protective encapsulation over said RFID tag device and jumper.

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

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

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

19. The method of claim 18, further comprising the step of encapsulating said RFID tag device and said jumper conductor with a protective material.

20. The method of claim 19, wherein the protective material is epoxy.

21. The method of claim 18, further comprising applying an insulating coating to said inductor coil on the surface of said substrate.

22. The method of claim 18, further comprising providing test connection pads on said substrate and connecting said test connection pads to said RFID tag device.

23. The method of claim 18, further comprising providing programming connection pads on said substrate and connecting said programming connection pads to said RFID tag device.

24. 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).

25. 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.

27. The RFID tag of claim 26, further comprising a conductive trace through said RFID tag device, wherein said conductive trace is adapted for connecting a capacitor to said inductor coil.

28. The RFID tag of claim 27, further comprising a capacitor located on the surface of said substrate and connected to said inductor coil

29. The RFID tag of claim 28, wherein the capacitor is connected in parallel with said inductor coil.

30. The RFID tag of claim 28, wherein the capacitor is connected in series with said inductor coil.

31. The RFID tag of claim 26, wherein said inductor coil forms a resonant circuit antenna with an internal capacitor of said RFID tag device.

32. The RFID tag of claim 31, wherein said inductor coil and the internal capacitor form a parallel resonant circuit antenna.

33. The RFID tag of claim 26, wherein said RFID tag device is a flipchip having solder bump connections which are adapted to connect to the inner and outer ends of said inductor coil.

34. The RFID tag of claim 26, wherein said RFID tag device connects to the inner and outer ends of said inductor coil with bond wires

35. The RFID tag of claim 26, wherein said inductor coil turns have a substantially constant width.

36. The RFID tag of claim 35, wherein said inductor coil turns have a low resistance and a high quality factor (Q).

37. The RFID tag of claim 26, further comprising an electrically insulating layer between said RFID tag device and the portion of said inductor coil.

38. The RFID tag of claim 37, wherein the electrically insulating layer is selected from the group consisting of mylar, mica, plastic, teflon, kapton and polyimide

39. The RFID tag of claim 37, wherein the electrically insulating layer is attached to the portion of said inductor coil and said RFID tag device.

18. 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;

forming an inductor coil on the surface of said substrate, said inductor coil having an outer end and an inner end;

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

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

disposing a jumper conductor over said inductor coil; and

connecting the outer end of said inductor coil to said RFID tag device with said jumper conductor.

26. 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 on the surface of said substrate, said inductor coil having an outer end and an inner end;

a RFID tag device positioned over a portion of said inductor coil on the surface of said substrate, wherein said RFID tag device connects to the inner and outer ends of said inductor coil.

40. 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;

forming an inductor coil on the surface of said substrate, said inductor coil having an outer end and an inner end;

disposing a RFID tag device over a portion of said inductor coil on the surface of said substrate; and

connecting said RFID tag device to the inner and outer ends of said inductor coil.

41. The method of claim 40, further comprising the step of providing a conductive trace through said RFID tag device, wherein said conductive trace is adapted for connecting a capacitor to said inductor coil.

42. The method of claim 41, further comprising the steps of locating a capacitor on the surface of said substrate and connecting said capacitor to said inductor coil

43. The method of claim 42, wherein the capacitor is connected in parallel with said inductor coil.

44. The method of claim 42, wherein the capacitor is connected in series with said inductor coil.

45. The method of claim 40, further comprising the steps of providing an internal capacitor of said RFID tag device and connecting said internal capacitor to said inductor coil to form a resonant circuit antenna.

46. The method of claim 45, wherein said inductor coil and the internal capacitor form a parallel resonant circuit antenna.

47. The method of claim 40, wherein said RFID tag device is a flipchip having solder bump connections which are adapted for connecting to the inner and outer ends of said inductor coil.

48. The method of claim 40, further comprising the steps of connecting said RFID tag device to the inner and outer ends of said inductor coil with bond wires

49. The method of claim 40, wherein said inductor coil turns have a substantially constant width.

50. The method of claim 49, wherein said inductor coil turns have a low resistance and a high quality factor (Q).