RFID tag assembly methods

• US 8,188,927 B1
• Filed: 03/06/2009
• Issued: 05/29/2012
• Est. Priority Date: 03/11/2008
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Koepp, Ronald Lee, Oliver, Ronald A., Colleran, William T., Ma, Yanjun, Moretti, Vincent C., Fassett, Jay M.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US12/399,913
• Time in Patent Office: 1,180 Days
• Field of Search: 343/700.MS, 343/702
• US Class Current: 343/700.MS
• CPC Class Codes: G06K 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• CPC Class Codes: G06K 19/07754 the connection being galvanic
• CPC Class Codes: G06K 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: H01P 11/00 Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

RFID tags are assembled through affixing an antenna to an integrated circuit (IC) by forming one or more capacitors coupling the antenna and the IC with the dielectric material of the capacitor(s) including a non-conductive covering layer of the IC, a non-conductive covering layer of the antenna such as an oxide layer, and/or an additionally formed dielectric layer. Top and bottom plates of the capacitor(s) are formed by the antenna traces and one or more patches on a top surface of the IC.

Claims

1. An RFID tag, comprising:

an integrated circuit (IC);

an antenna; and

at least one capacitor providing the only coupling between electrical circuitry of the IC and the antenna, the at least one capacitor containing a dielectric material, wherein the dielectric material includes at least one of a covering layer of the IC and a covering layer of the antenna.

2. The RFID tag of claim 1, wherein the covering layer of the antenna includes an oxide layer formed on a conductive trace layer of the antenna, the oxide layer comprising one from a set of:

a naturally occurring aluminum oxide, an enhanced growth of aluminum oxide, and a grown layer of aluminum nitride on the conductive trace layer formed substantially from aluminum.

3. The RFID tag of claim 1, further comprising an interposer layer coupling the at least one capacitor to the antenna.

4. The RFID tag of claim 3, wherein the interposer layer comprises adhesive material with controlled dielectric characteristics such that a capacitance between the antenna and the electrical circuitry of the IC is greater than a predetermined value.

5. The RFID tag of claim 1, wherein the at least one capacitor is formed between a conductive layer of the antenna and at least one conductive patch covering substantially an entire surface of the IC adjacent to the antenna.

6. The RFID tag of claim 1, wherein the antenna is affixed to the IC by forming a plurality of capacitors formed between a conductive layer of the antenna and a plurality of conductive patches, each distinct capacitor being coupled to distinct electrical circuits of the IC including at least one from a set of:

a rectifier circuit, a demodulator circuit, and a modulator circuit.

7. The RFID tag of claim 1, wherein the antenna is affixed to a first surface of the IC, and another antenna terminal is affixed to a second surface of the IC opposite the first surface by forming at least one other capacitor coupling the other antenna terminal and the electrical circuitry of the IC, the at least one other capacitor containing a dielectric material that includes at least one of a covering layer of the IC and a covering layer of the other antenna terminal.