Method of producing a radio frequency transponder with a molded environmentally sealed package

• US 5,420,757 A
• Filed: 06/11/1993
• Issued: 05/30/1995
• Est. Priority Date: 02/11/1993
• Status: Expired due to Term

• Current Assignee: Assa Abloy AB
• Original Assignee: Indala Corporation (Assa Abloy AB)
• Inventors: Delbecq, Jean-Marc, Eberhardt, Noel H.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Thomas, L.
• Application Number:
  US08/158,922
• Time in Patent Office: 718 Days
• Field of Search: 174/52.2, 174/52.4, 361/728, 361/767, 361/813, 29/827, 29/841, 29/855, 29/856
• US Class Current: 361/813
• CPC Class Codes: G01R 15/14 Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
• CPC Class Codes: G06K 19/047 the record carrier being shaped as a coin or a gambling token
• CPC Class Codes: G06K 19/07724 the record carrier being at least partially made by a molding process molding in general B29C45/14
• 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 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 23/49562 for devices being provided for in H01L29/00
• CPC Class Codes: H01L 23/642 Capacitive arrangements H01L23/49589, H01L23/645, H01L23/647, H01L23/66 take precedence; capacitive effects between wiring layers on the semiconductor body H01L23/5222
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: Y10T 29/49121 : Beam lead frame or beam lead device

Abstract

A method of forming an environmentally sealed transponder type circuit wherein the circuit components are mounted on a lead type substrate frame, the components are encapsulated in a plastic housing in a plastic molding process so that the housing is supported in the frame only by a plurality of the leads, and then severing the leads at the periphery of the housing to provide a leadless package. The frame may be formed of a conductive material, an insulating material or as a printed circuit board. A novel printed circuit type lead frame whereby a coil of the circuit may be mechanically attached and directly secured to the frame is additionally disclosed.

Claims

1. A method of forming a hermetically sealed radio frequency identification device comprising:

providing a flat carrier having an opening and a plurality of inwardly directed supporting arms extending into the opening for supporting a radio frequency identification circuit including at least one coil for transmitting or receiving radio frequency energy, and an integrated circuit chip connected to the coil;

mounting the circuit on the supporting arms such that the circuit including the coil is completely within the opening;

forming a hermetically sealed plastic housing completely around the circuit and coil by transfer molding so that the housing is disposed within the opening and supported in the carrier only by the supporting arms; and

severing the supporting arms at the periphery of the housing.

2. A method as defined in claim 1 wherein the carrier is formed of metal.

3. A method as defined in claim 2 wherein said step of mounting includes electrically connecting at least the coil and the circuit chip of the radio frequency circuit together via at least some of the supporting arms.

4. A method as defined in claim 1 wherein said carrier is formed of an insulating material.

5. A method as defined in claim 1 wherein said carrier includes a plurality of said openings arranged in a row and a respective plurality of the inwardly directed supporting arms extending into each opening.

6. A method as defined in claim 1 wherein the coil is a flat coil and said step of mounting includes positioning the coil and a circuit chip such that the coil rests on said supporting arms and the chip is disposed within the coil.

7. A method of forming an environmentally sealed radio frequency identification device comprising:

providing a printed circuit board having a flat carrier of an insulating material and a plurality of respective conductor patterns arranged in a row on respective spaced device mounting regions of the carrier, with the carrier having openings such that each of the respective mounting regions includes a respective central portion which contains the respective conductor pattern and which is connected to the remainder of the carrier only by a respective plurality of supporting arms distributed about the periphery of the central portion;

mounting a respective circuit chip for a radio frequency identification circuit and at least one coil for transmitting or receiving radio frequency energy on a respective said mounting region and connecting same via the respective conductor pattern to form a radio frequency identification circuit;

forming a respective hermetically sealed plastic housing completely around the central portion of the respective mounting region and the associated radio frequency identification circuit by plastic molding so that the sealed housing is connected to the carrier only via the respective plurality of said supporting arms; and

severing the supporting arms to remove the housed radio frequency identification circuit device from the carrier.

8. A method as defined in claim 7 wherein said step of providing a printed circuit board comprises:

providing a printed circuit board including a carrier of insulating material clad on one surface side with a conductive layer;

selectively etching the conductive layer to form said plurality of respective conductive patterns; and

removing portions of the printed circuit board carrier to provide a plurality of said openings to form said plurality of mounting regions with the respectively associated plurality of supporting arms.

9. A method as defined in claim 8 wherein:

the coil is a flat coil; and

said step of removing includes forming the respective central portions of the mounting regions to be of a size less than an inner diameter of the coil; and

said step of mounting includes positioning the coil so that it surrounds the associated central portion and so that the coil is engaged and supported on its one side facing the printed circuit board by the supporting arms.

10. A method as defined in claim 9 wherein:

said step of removing additionally includes forming at least one outwardly directed projection on the periphery of the central portion of said mounting region between at least some of two adjacent supporting arms; and

said step of mounting further includes bending at least some of the respective projections so that they extend through the associated coil and engage same on its side opposite said one side to physically secure the coil to the mounting region.

11. A method as defined in claim 8 wherein:

the coil is a flat coil; and

said step of removing includes forming the respective mounting regions to be of a size greater than an outer diameter of the associated coil; and

said step of mounting includes placing the coil on the central portion so that it surrounds the respective conductor pattern and in turn is surrounded by said central portion.

12. A method as defined in claim 7 wherein each of said central portions of the mounting regions is provided with a pair of said supporting arms which are oppositely disposed.

13. A method as defined in claim 7 wherein each of said central portions of said mounting regions is provided with two orthogonal pairs of oppositely disposed supporting arms.

14. A method as defined in claim 7 wherein said supporting arms are symmetrically disposed about the periphery of the central portion of the mounting region.

15. A method as defined in claim 7 wherein said central portions of the mounting regions and said plastic housings are circular.

16. A non-metal lead frame for mounting of a circuit including at least a flat coil and an integrated circuit connected thereto;

said lead frame comprising;

a printed circuit board having a flat carrier of an insulating material and a plurality of respective conductor patterns disposed on one surface of said carrier and arranged in a row on respective spaced circuit component mounting regions of the carrier;

a plurality of openings formed in said carrier such that each respective of said mounting regions includes a central portion which completely contains the respective said conductive pattern and which is connected to the remainder of the carrier only by a respective plurality of supporting lead-like portions of said carrier distributed about the periphery of said central portion.

17. A non-metal lead frame according to claim 16 wherein each of said central portions of the mounting regions is provided with a pair of oppositely disposed of the said lead-like portions.

18. A non-metal lead frame according to claim 16 wherein each of said central mounting regions is provided with two orthogonal pairs of oppositely disposed supporting lead-like portions.

19. A non-metal lead frame according to claim 16 wherein said supporting lead-like portions are symmetrically disposed about the periphery of the central portion of the mounting region.

20. A non-metal lead frame according to claim 19 wherein:

each of said central portions is of a size smaller than an inner diameter of the coil to be mounted thereon; and

said mounting region further includes at least one outwardly directed finger projecting from the periphery of the respective central portion between each two adjacent of said supporting lead-like portions, with said fingers being of a length such that they can extend through a coil placed on a surface of said carrier to mechanically secure the coil on the mounting region.

21. A non-metal lead frame according to claim 20 wherein said fingers are symmetrically disposed about the periphery of said central portion.