Micro-scale interconnect device with internal heat spreader and method for fabricating same

• US 20030116851A1
• Filed: 11/08/2002
• Published: 06/26/2003
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: AAC Technologies Pte Limited (AAC Technologies Holdings Inc.)
• Original Assignee: Coventor, Inc. (Lam Research Corporation)
• Inventors: Sett, Subham, Cunningham, Shawn Jay
• Granted Patent: US 6,847,114 B2
• Time in Patent Office: Days
• US Class Current: 257/758
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2201/018 Switches not provided for in B81B2201/014 - B81B2201/016
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 3/0024 Transducers for transforming thermal into mechanical energy or vice versa, e.g. thermal or bimorph actuators electric motors using thermal effects H02N10/00
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 2201/0107 Sacrificial metal
• CPC Class Codes: B81C 2201/0108 Sacrificial polymer, ashing of organics
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: H01H 1/04 Co-operating contacts of different material
• CPC Class Codes: H01H 1/504 by thermal means
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet
• CPC Class Codes: H01H 2001/0063 having electrostatic latches, i.e. the activated position is kept by electrostatic forces other than the activation force
• CPC Class Codes: H01H 2001/0089 Providing protection of elements to be released by etching of sacrificial element; Avoiding stiction problems, e.g. of movable element to substrate
• CPC Class Codes: H01H 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 61/04 wherein the thermally-sensitive member is only heated directly
• CPC Class Codes: H01L 23/3735 : Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/522 : including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
• CPC Class Codes: H01L 27/1203 : the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• 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 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H02N 1/006 : of the gap-closing type H02N1/004 takes precedence
• CPC Class Codes: H02N 10/00 : Electric motors using thermal effects motors using expansion or contraction of bodies due to heating or cooling F03G7/06
• CPC Class Codes: Y10T 29/49222 : forming array of contacts or terminals

Abstract

A micro-scale interconnect device with internal heat spreader and method for fabricating same. The device includes first and second arrays of generally coplanar electrical communication lines. The first array is disposed generally along a first plane, and the second array is disposed generally along a second plane spaced from the first plane. The arrays are electrically isolated from each other. Embedded within the interconnect device is a heat spreader element. The heat spreader element comprises a dielectric material disposed in thermal contact with at least one of the arrays, and a layer of thermally conductive material embedded in the dielectric material. The device is fabricated by forming layers of electrically conductive, dielectric, and thermally conductive materials on a substrate. The layers are arranged to enable heat energy given off by current-carrying communication lines to be transferred away from the communication lines.

Claims

1. A micro-scale interconnect device for transmitting electrical current or discrete signals, comprising:

(a) a first array of generally coplanar electrical communication lines disposed generally along a first plane;

(b) a second array of generally coplanar electrical communication lines disposed generally along a second plane spaced from the first plane and electrically isolated from the first array; and

(c) a heat spreader element comprising a dielectric material disposed in thermal contact with at least one of the arrays, and a layer of thermally conductive material embedded in the dielectric material, wherein the thermally conductive material is electrically isolated from the first and second arrays.

2. The device according to claim 1 wherein the first array is separated from the second array by a distance ranging from approximately 3 to approximately 8 microns.

3. The device according to claim 1 wherein adjacent coplanar communication lines of each array are separated from each other by a distance ranging from approximately 25 to approximately 250 microns.

4. The device according to claim 1 wherein each communication line has a width ranging from approximately 10 to approximately 100 microns.

5. The device according to claim 1 wherein each communication line has a thickness ranging from approximately 1 to approximately 5 microns.

6. The device according to claim 1 wherein the first array, the second array, and the heat spreader element are formed on an electrically isolated substrate.

7. The device according to claim 6 wherein the substrate is a semiconductor material and a dielectric layer is formed on the substrate.

8. The device according to claim 6 wherein the substrate is a bulk dielectric substrate.

9. The device according to claim 1 wherein the heat spreader element is interposed between the first and second arrays of communication lines.

10. The device according to claim 9 wherein the dielectric material comprises first and second dielectric layers, and the thermally conductive layer is interposed between the first and second dielectric layers.

11. The device according to claim 10 wherein the first dielectric layer is formed on the first array, the thermally conductive layer is formed on the first dielectric layer, the second dielectric layer is formed on the thermally conductive layer, and the second array is formed on the second dielectric layer.

12. The device according to claim 11 wherein the first array is formed on an electrically isolated substrate.

13. The device according to claim 12 wherein the substrate is a semiconductor material and a dielectric layer is formed on the substrate.

14. The device according to claim 12 wherein the substrate is a bulk dielectric substrate.

15. The device according to claim 11 comprising a top dielectric layer formed on the second array.

16. The device according to claim 1 wherein the thermally conductive material has an out-of-plane thickness ranging from approximately 0.1 to approximately 1 microns.

17. The device according to claim 1 wherein the thermally conductive material comprises a material selected from the group consisting of gold, copper, aluminum, and diamond.

18. A micro-scale interconnect device for transmitting electrical current or discrete signals, comprising:

(a) a first dielectric layer;

(b) a first layer of communication lines formed on the first dielectric layer;

(c) a second dielectric layer formed on the first layer of communication lines and on the first dielectric layer;

(d) a thermally conductive layer formed on the second dielectric layer;

(e) a third dielectric layer formed on the thermally conductive layer; and

(f) a second layer of communication lines formed on the third dielectric layer.

19. The device according to claim 18 wherein the first dielectric layer is formed on a substrate.

20. The device according to claim 18 wherein the first dielectric layer is a bulk substrate.

21. The device according to claim 18 wherein the first dielectric layer has a thickness ranging from approximately 0.5 to approximately 1 micron.

22. The device according to claim 18 wherein adjacent coplanar communication lines of each array are separated from each other by a distance ranging from approximately 25 to approximately 250 microns.

23. The device according to claim 18 wherein the thermally conductive material has an out-of-plane thickness ranging from approximately 0.1 to approximately 1 microns.

24. The device according to claim 18 wherein the thermally conductive material comprises a material selected from the group consisting of gold, copper, aluminum, and diamond.

25. The device according to claim 18 wherein at least one of the dielectric layers has a thickness ranging from approximately 1 to approximately 5 microns.

26. A micro-scale system comprising:

(a) a first array of generally coplanar electrical communication lines disposed generally along a first plane;

(b) a second array of generally coplanar electrical communication lines disposed generally along a second plane spaced from the first plane and electrically isolated from the first array;

(c) a heat spreader element comprising a dielectric material disposed in thermal contact with at least one of the arrays, and a layer of thermally conductive material embedded in the dielectric material, wherein the thermally conductive material is electrically isolated from the first and second arrays; and

(d) a micro-scale device electrically communicating with a communication line of at least one of the first and second arrays.

27. The system according to claim 26 wherein adjacent coplanar communication lines of each array are separated from each other by a distance ranging from approximately 25 to approximately 250 microns.

28. The system according to claim 26 wherein the thermally conductive material has an out-of-plane thickness ranging from approximately 0.1 to approximately 1 microns.

29. The system according to claim 26 wherein the thermally conductive material comprises a material selected from the group consisting of gold, copper, aluminum and diamond.

30. A method for fabricating a micro-scale device having internal heat spreading capability to reduce operating temperature, comprising the steps of forming a plurality of generally coplanar arrays of electrical transmission lines in a heterostructure, and embedding a thermally conductive element in one or more dielectric layers at a location of the heterostructure where a heat transfer path can be established in response to a thermal gradient generally directed from at least one of the arrays to the thermally conductive layer.

31. The method according to claim 30 wherein adjacent coplanar transmission lines of each array are separated from each other by a distance ranging from approximately 25 to approximately 250 microns.

32. The method according to claim 30 comprising forming the arrays, the thermally conductive element, and the dielectric layers on an electrically isolated substrate.

33. The method according to claim 30 wherein the plurality of arrays comprises a first array and a second array, and the embedded thermally conductive element is interposed between the first and second arrays.

34. The method according to claim 33 wherein the thermally conductive element reduces capacitive coupling between the first and second arrays.

35. The method according to claim 30 wherein the thermally conductive element has an out-of-plane thickness ranging from approximately 0.1 to approximately 1 microns.

36. The method according to claim 30 wherein the thermally conductive element comprises a material selected from the group consisting of gold, copper, aluminum and diamond.

37. A micro-scale device fabricated according to the method of claim 30.

38. A method for fabricating a micro-scale device having internal heat spreading capability to reduce operating temperature, comprising the steps of:

(a) forming a first array of conductive elements on a substrate;

(b) depositing a first dielectric layer on the first array;

(c) depositing a layer of thermally conductive material on the first dielectric layer;

(d) depositing a second dielectric layer on the layer of thermally conductive material; and

(e) forming a second array of conductive elements on the second dielectric layer.

39. A micro-scale device fabricated according to the method of claim 38.

40. A method for conducting current in a micro-scale interconnect device at a reduced device operating temperature, comprising the steps of:

(a) conducting current in a micro-scale interconnect device comprising a first array of generally coplanar electrical communication lines disposed generally along a first plane, and a second array of generally coplanar electrical communication lines disposed generally along a second plane spaced from the first plane and electrically isolated from the first array, wherein the current is conducted through at least one of the communication lines of the arrays; and

(b) causing heat energy given off by the at least one current-conducting communication line to be transferred away from the arrays by providing a heat spreader element integrated with the interconnect device, the heat spreader element comprising a dielectric material disposed in thermal contact with at least one of the arrays, and a layer of thermally conductive material embedded in the dielectric material, whereby the heat energy is directed toward the heat spreader element in response to a thermal gradient created between the at least one current-conducting communication line and the heat spreader element.