RFID integrated circuits with large contact pads

• US 9,436,902 B1
• Filed: 08/04/2014
• Issued: 09/06/2016
• Est. Priority Date: 03/11/2008
• Status: Active Grant

• Current Assignee: Impinj International Ltd. (Impinj, Inc.)
• Original Assignee: Impinj International Ltd. (Impinj, Inc.)
• Inventors: Koepp, Ronald Lee, Wu, Tan Mau, Oliver, Ronald A., Heinrich, Harley, Mavoori, Jaideep, Diorio, Christopher J.
• Primary Examiner(s): Le, Hoanganh
• Application Number:
  US14/451,416
• Time in Patent Office: 764 Days
• Field of Search: 343/700.MS, 343/793, 343/795, 296/00
• US Class Current: 1/1
• 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 19/07752 using an interposer
• CPC Class Codes: G06K 19/07754 the connection being galvanic
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01Q 1/2283 mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them

Abstract

An RFID IC assembly having a repassivation layer and a conductive redistribution layer may be assembled onto a tag substrate with an additional layer. The additional layer includes one or more etchants for creating an opening in a nonconductive barrier layer between the assembly and the substrate, and may also include an adhesive for attaching the assembly to the substrate.

Claims

1. A Radio Frequency Identification (RFID) tag precursor comprising:

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 first portion of the redistribution layer is electrically connected to the IC through a first opening in the repassivation layer,

a substrate including a first antenna terminal;

a second opening, formed by an etchant, in a nonconductive barrier present on at least one of the first antenna terminal and the first portion of the redistribution layer, and

an adhesive attaching the assembly to the substrate;

wherein

a first electrical connection is formed between the first antenna terminal and the first portion of the redistribution layer through the second opening; and

the first opening and the second opening are nonoverlapping.

2. The RFID tag precursor of claim 1, in which the redistribution layer is patterned which allows portions that have a local parasitic capacitance to the IC that exceeds a predefined threshold are excised.

3. The RFID tag precursor of claim 1, in which the nonconductive barrier is at least one of an oxide and a masking layer.

4. The RFID tag precursor of claim 1, in which the first electrical connection includes the adhesive.

5. The RFID tag precursor of claim 1, in which the etchant includes a textured surface on the redistribution layer that forms the second opening by breaking the nonconductive barrier.

6. The RFID tag precursor of claim 1, in which the etchant includes conductive particles that form the second opening by breaking the nonconductive barrier.

7. The RFID tag precursor of claim 1, in which the etchant forms the second opening by reacting with the nonconductive barrier.

8. The RFID tag precursor of claim 1, wherein:

the substrate further includes a second antenna terminal;

the redistribution layer further includes a second portion electrically isolated from the first portion and electrically connected to the IC;

the nonconductive barrier is further present on at least one of the second antenna terminal and the second portion of the redistribution layer,

the tag precursor further includes a third opening, formed by the etchant, in the nonconductive barrier; and

a second electrical connection is formed between the second antenna terminal and the second portion of the redistribution layer through the third opening.

9. A Radio Frequency Identification (RFID) tag precursor comprising:

an assembly including an RFID integrated circuit (IC) with an IC contact, 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;

a substrate including a first antenna terminal;

an adhesive attaching the assembly to the substrate;

a first electrical connection between a first portion of the redistribution layer and the IC contact;

an opening, formed by an etchant, in a nonconductive barrier present on at least one of the first antenna terminal and the first portion of the redistribution layer; and

a second electrical connection formed between the first antenna terminal and the first portion of the redistribution layer through the opening.

10. The RFID tag precursor of claim 9, wherein the IC contact and the opening are nonoverlapping.

11. The RFID tag precursor of claim 9, further comprising a plurality of openings formed by the etchant in the nonconductive barrier, and wherein the IC contact and at least one of the plurality of openings are nonoverlapping.

12. The RFID tag precursor of claim 9, wherein at least one of:

the etchant includes a textured surface on the redistribution layer that forms the opening by breaking the nonconductive barrier;

the etchant includes conductive particles that form the opening by breaking the nonconductive barrier;

the etchant forms the opening by reacting with the nonconductive barrier; and

the etchant is included in the adhesive.

13. The RFID tag precursor of claim 9, wherein the nonconductive barrier is at least one of an oxide and a masking layer.

14. The RFID tag precursor of claim 9, wherein:

the substrate further includes a second antenna terminal;

the redistribution layer further includes a second portion electrically isolated from the first portion and electrically connected to the IC;

the nonconductive barrier is further present on at least one of the second antenna terminal and the second portion of the redistribution layer; and

the tag precursor further includes a third electrical connection between the second antenna terminal and the second portion of the redistribution layer through another etchant-formed opening in the nonconductive barrier.