Self-identifying integrated circuits and method for fabrication thereof

• US 20040124437A1
• Filed: 12/30/2002
• Published: 07/01/2004
• Est. Priority Date: 12/30/2002
• Status: Active Grant

• Current Assignee: Potomac Photonics Incorporated
• Original Assignee: Potomac Photonics Incorporated
• Inventors: Doudoumopolous, Nicholas
• Granted Patent: US 7,015,795 B2
• Time in Patent Office: Days
• US Class Current: 257/200
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers
• CPC Class Codes: G11C 16/20 Initialising; Data preset; Chip identification
• CPC Class Codes: G11C 17/14 in which contents are determined by selectively establishing, breaking or modifying connecting links by permanently altering the state of coupling elements, e.g. PROM
• CPC Class Codes: G11C 2029/4402 Internal storage of test result, quality data, chip identification, repair information
• CPC Class Codes: H01L 2223/54433 containing identification or tracking information
• CPC Class Codes: H01L 2223/5444 for electrical read out
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/49838 Geometry or layout
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• 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 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

A self-identifying integrated circuit contains a primary function circuit and an immutable, unique identification code, which is presented at an output port thereof upon demand by, an external circuit. The unique identification code may be an N bit digital number or may be a response signal to an interrogating excitation signal. The circuitry to store the unique identification code is fabricated on a microscopic scale such as by a direct-write laser forward transfer of material process or by a laser ablation of select material process. The identification storage means may be disposed on a package substrate or on an integrated circuit die and is permanently encased within the integrated circuit package so as to be protected from alteration by external means.

Claims

1. A self-identifying integrated circuit for performing a predetermined electrical function in an external electric circuit via a plurality of electrodes electrically coupled thereto, the self-identifying integrated circuit further providing a unique identification code to the external electric circuit, the predetermined electrical function being exclusive of providing the unique identification code to the external electric circuit, the self-identifying integrated circuit comprising:

identification storage means for immutably storing the unique identification code;

a primary function circuit for performing the predetermined electrical function in the external electric circuit, said primary function circuit being fabricated on a circuit die electrically coupled to the plurality of electrodes;

an output port including at least one electrode, said output port electrically coupled to said identification storage means for conveying the unique identification code to the external circuit; and

encasement means for permanently enclosing said primary function circuit and said identification storage means therein, the plurality of electrodes coupled to said primary function circuit, said at least one electrode of said output port extending through said encasement means.

2. The self-identifying integrated circuit as recited in claim 1, wherein said encasement means includes a package substrate and an encapsulant.

3. The self-identifying integrated circuit as recited in claim 2, wherein said identification storage means is disposed on said package substrate.

4. The self-identifying integrated circuit as recited in claim 3, wherein said identification storage means includes a voltage tap network, the unique identification code being stored as a set of discrete voltage levels in said voltage tap network.

5. The self-identifying integrated circuit as recited in claim 4, wherein the plurality of electrodes coupled to said primary function circuit includes said at least one electrode of said output port.

6. The self-identifying integrated circuit as recited in claim 5, further comprising an identification transferal means for selectively coupling said voltage tap network and the primary function circuit to the output port.

7. The self-identifying integrated circuit as recited in claim 6, wherein said voltage tap network is fabricated by direct-write laser forward transfer of material.

8. The self-identifying integrated circuit as recited in claim 6, wherein said voltage tap network is fabricated by laser ablation of select material.

9. The self-identifying integrated circuit as recited in claim 3, wherein said identification storage means includes an identification circuit for providing the unique identification code upon excitation by an interrogation signal, the unique identification code being a predetermined response signal to said interrogation signal.

10. The self-identifying integrated circuit as recited in claim 9, wherein said identification circuit is a resonant electric circuit providing a response signal of one of a maximum value and a minimum value at a predetermined interrogation frequency.

11. The self-identifying integrated circuit as recited in claim 9, wherein said identification circuit is a time-constant circuit providing a decaying signal of predetermined duration in response to a pulsed interrogation signal.

12. The self-identifying integrated circuit as recited in claim 9, wherein said identification circuit is a resistive circuit of a predetermined resistance value.

13. The self-identifying integrated circuit as recited in claim 9, wherein said identification circuit is fabricated by direct-write laser forward transfer of material.

14. The self-identifying integrated circuit as recited in claim 9, wherein said identification circuit is fabricated by laser ablation of select material.

15. The self-identifying integrated circuit as recited- in claim 1, wherein said identification storage means is disposed on a circuit die containing the primary function circuit.

16. The self-identifying integrated circuit as recited in claim 15, wherein said identification storage means is fabricated by direct-write laser forward transfer of material.

17. The self-identifying integrated circuit as recited in claim 15, wherein said identification storage means is fabricated by direct-write forward transfer of material.

18. A method of fabricating self-identifying integrated circuits, the method comprising the steps of:

(a) selecting a unique identification code for one of the self-identifying circuits;

(b) fabricating a unique conductor network on a first substrate section for immutably storing said unique identification code;

(c) coupling an electric circuit disposed on a second substrate section to said conductor patterns;

(d) coupling a plurality of electrodes to said electric circuit;

(e) coupling at least one electrode to said conductor network; and

(f) encapsulating said conductor network and said electrical circuit in encasement means such that said plurality of electrodes coupled to said electric circuit and said at least one electrode coupled to said conductor network protrude through at least one surface thereof.

19. The method of manufacturing self-identifying integrated circuits as recited in claim 18, wherein said first substrate section and said second substrate section are integrated as a single integrated circuit die.

20. The method of manufacturing self-identifying integrated circuits as recited in claim 18, wherein said encasement means includes a package substrate and an encapsulant, said encapsulating step including the step of applying said encapsulant to surround said conductor network and said electric circuit.

21. The method of manufacturing self-identifying integrated circuits as recited in claim 20, wherein said first substrate section is said package substrate and said second substrate section is an integrated circuit die.

22. The method of manufacturing self-identifying integrated circuits as recited in claim 21, wherein said conductor network fabrication step includes the process of direct-write laser forward transfer of material, said material being either electrically conductive or treatable to become electrically conductive.

23. The method of manufacturing self-identifying integrated circuits as recited in claim 18, wherein said unique conductor network fabrication step further includes the steps of:

(1) constructing a generic conductor pattern on said substrate;

(2) forming at least one gap in said generic conductor pattern to provide said unique conductor network.

24. The method of manufacturing self-identifying integrated circuits as recited in claim 23, whereby said at least one gap is formed by laser ablation of select material.

25. The method of manufacturing self-identifying integrated circuits as recited in claim 23, wherein said conductor network fabrication step includes the step of:

(3) filling at least one of said at least one gap with a conductive material or with a material subsequently made conductive.

26. The method of manufacturing self-identifying integrated circuits as recited in claim 25, wherein said conductive material and said material made conductive have a different conductivity than said conductor web.

27. The method of manufacturing self-identifying integrated circuits as recited in claim 18, further including the step of incrementing said unique identification code and repeating the method at step (b).