High-speed RFID tag assembly using impulse heating

• US 9,846,833 B1
• Filed: 07/09/2014
• Issued: 12/19/2017
• Est. Priority Date: 02/25/2013
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Koepp, Ronald Lee, Heinrich, Harley, Diorio, Christopher J.
• Primary Examiner(s): Vo, Peter DungBa
• Assistant Examiner(s): Carley, Jeffrey T
• Application Number:
  US14/327,207
• Time in Patent Office: 1,259 Days
• CPC Class Codes: G06K 19/07722 the record carrier being multilayered, e.g. laminated sheets flat articles in general, see B32B37/00
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: G06K 19/07752 using an interposer
• CPC Class Codes: G06K 19/07754 the connection being galvanic
• CPC Class Codes: H01L 2224/13124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/13144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/13147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13164 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/81143 Passive alignment, i.e. self alignment, e.g. using surface energy, chemical reactions, thermal equilibrium
• CPC Class Codes: H01L 2224/81424 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/81447 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/81464 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/81493 with a principal constituent of the material being a solid not provided for in groups H01L2224/814 - H01L2224/81491, e.g. allotropes of carbon, fullerene, graphite, carbon-nanotubes, diamond
• CPC Class Codes: H01L 24/16 of an individual bump connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• 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 2924/14 Integrated circuits
• CPC Class Codes: H01P 5/028 : between strip lines
• CPC Class Codes: H01Q 1/2225 : used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H05K 2201/10098 : Components for radio transmission, e.g. radio frequency identification [RFID] tag, printed or non-printed antennas
• CPC Class Codes: H05K 3/321 : by conductive adhesives
• CPC Class Codes: H05K 3/3431 : Leadless components
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/49016 : Antenna or wave energy "plumbing" making

Abstract

RFID inlays or straps may be assembled using impulse heating of metal precursors. Metal precursors are applied to and/or included in contacts on an RFID IC and/or terminals on a substrate. During assembly of the tag, the IC is disposed onto the substrate such that the IC contacts physically contact either the substrate terminals or metal precursors that in turn physically contact the substrate terminals. Impulse heating is then used to rapidly apply heat to the metal precursors, processing them into metallic structures that electrically couple the IC contacts to the substrate terminals.

Claims

1. A method for assembling a Radio Frequency Identification (RFID) tag precursor, the method comprising:

providing an assembly including an RFID integrated circuit (IC), a nonconductive repassivation layer on a surface of the IC and confined within a perimeter of the surface, and a conductive redistribution layer on the repassivation layer and confined within the perimeter of the surface, in which at least a portion of the redistribution layer is electrically connected to the IC through an opening in the repassivation layer;

providing a substrate including an antenna terminal; and

impulse heating a first metal precursor that includes a reducing substance, to process the first metal precursor into a metallic conductor, the metallic conductor providing an electrical connection between the portion of the redistribution layer and the antenna terminal, wherein;

impulse heating the first metal precursor comprises heating the reducing substance to accelerate the reduction of an oxide on at least one of the redistribution layer and the antenna terminal, and

the electrical connection and the opening are at least partially nonoverlapping.

2. The method of claim 1, wherein the first metal precursor includes at least one of solder powder, solder paste, unsintered metal, and a thin metal layer, and includes at least one of tin, palladium, copper, silver, and bismuth.

3. The method of claim 1, further comprising applying the first metal precursor on the portion of the redistribution layer as an oxidation barrier during the IC fabrication process.

4. The method of claim 1, wherein impulse heating the first metal precursor comprises impulse beating using at least one of a laser, an infrared, light source, and a thermode.

5. The method of claim 1, wherein providing the substrate further comprises forming the antenna terminal by impulse heating a second precursor to process the second precursor into the antenna terminal.

6. The method of claim 5, wherein the first metal precursor and the second precursor are the same precursor.

7. The method of claim 1, wherein the electrical connection and the opening are entirely nonoverlapping.