Wirebond structure and method to connect to a microelectronic die

• US 20030075804A1
• Filed: 10/18/2001
• Published: 04/24/2003
• Est. Priority Date: 10/18/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Paluda, Patrick M., Gleixner, Robert J., Danielson, Donald, Naik, Rajan
• Granted Patent: US 6,683,383 B2
• Time in Patent Office: Days
• US Class Current: 257/762
• CPC Class Codes: H01L 2224/02126 Collar structures
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05009 Bonding area integrally formed with a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/05073 Single internal layer
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05556 in side view
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05664 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05666 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05669 Platinum [Pt] as principal constituent
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/48644 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48647 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48664 Palladium (Pd) as principal constituent
• CPC Class Codes: H01L 2224/48666 Titanium (Ti) as principal constituent
• CPC Class Codes: H01L 2224/48669 : Platinum (Pt) as principal constituent
• CPC Class Codes: H01L 2224/48744 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48747 : Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48764 : Palladium (Pd) as principal constituent
• CPC Class Codes: H01L 2224/48766 : Titanium (Ti) as principal constituent
• CPC Class Codes: H01L 2224/48769 : Platinum (Pt) as principal constituent
• CPC Class Codes: H01L 2224/78 : Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 2224/85 : using a wire connector
• CPC Class Codes: H01L 2224/85205 : Ultrasonic bonding
• CPC Class Codes: H01L 24/03 : Manufacturing methods
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• 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 2924/00014 : 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: Y10T 428/1291 : Next to Co-, Cu-, or Ni-base component
• CPC Class Codes: Y10T 428/24248 : One piece

Abstract

A wirebond structure includes a copper pad formed on or in a surface of a microelectronic die. A conductive layer is included in contact with the copper pad and a bond wire is bonded to the conductive layer. The conductive layer is formed of a material to provide a stable contact between the bond wire and the copper pad in at least one of an oxidizing environment and an environment with temperatures up to at least about 350° C.

Claims

1. A wirebond structure, comprising:

a substrate;

a copper pad formed on a surface of the substrate;

a conductive layer in contact with the copper pad; and

a bond wire bonded to the conductive layer, wherein the conductive layer includes a material to provide a stable contact between the bond wire and the copper pad in at least one of an oxidizing environment and an environment with temperatures up to at least about 350°

C.

2. The wirebond structure of claim 1, wherein the conductive layer comprises a single layer of titanium.

3. The wirebond structure of claim 1, wherein the conductive layer has a thickness between about several hundred nanometers and several microns.

4. The wirebond structure of claim 1, wherein the bond wire comprises aluminum.

5. The wirebond structure of claim 1, wherein the conductive layer comprises titanium and the bond wire comprises aluminum and wherein the titanium conductive layer and the aluminum bond wire are annealed at a selected temperature for a predetermined period of time.

6. The wirebond structure of claim 1, further comprising at least one layer of passivation material formed on the substrate and including an opening formed therein through which the conductive layer contacts the copper pad.

7. The wirebond structure of claim 1, further comprisng:

a first layer of silicon nitride formed on the surface of the substrate; and

a second layer of polyimide formed on the first layer, wherein an opening is formed in the first layer of silicon nitride and the second layer of polyimide through which the conductive layer contacts the copper pad.

8. The wirebond structure of claim 1, wherein the substrate is an inter-dielectric layer of a microelectronic die.

9. A wirebond structure, comprising:

a substrate;

a copper pad formed on a surface of the substrate;

at least one layer of passivation material formed on the substrate and covering the copper pad;

a single layer of conductive material formed on the at least one layer of passivation material and in contact with the copper pad through an opening formed in the at least one layer of passivation material; and

a bond wire bonded to the single conductive layer, wherein the bond wire is a different material than the copper pad and the single layer of conductive material provides adhesion between the bond wire and the copper pad.

10. The wirebond structure of claim 9, wherein the single layer of conductive material comprises titanium.

11. The wirebond structure of claim 9, wherein the bond wire comprises aluminum.

12. The wirebond structure of claim 9, wherein the single layer of conductive material comprises titanium and the bond wire comprises aluminum and wherein the single layer of conductive material and the bond wire are annealed at a selected temperature for a predetermined period of time.

13. The wirebond structure of claim 9, wherein the at least one layer of passivation material comprises:

a first layer of silicon nitride; and

a second layer of polyimide formed on the first layer.

14. A microelectronic die, comprising:

a substrate;

a plurality of copper bond pads formed on the substrate;

at least one layer of passivation material formed on the substrate and covering the plurality of copper bond pads;

a plurality of electrical contacts each formed from a single conductive layer, each of the plurality of electrical contacts being connected to a corresponding one of the plurality of copper bond pads through openings formed in the at least one layer of passivation material; and

a plurality of bond wires each bonded to a corresponding one of the plurality of electrical contacts.

15. The microelectronic die of claim 14, wherein each of the plurality of electrical contacts comprises titanium.

16. The microelectronic die of claim 14, wherein each of the plurality of bond wires comprises aluminum.

17. The microelectronic die of claim 14, wherein each of the electrical contacts comprises titanium and each of the plurality of the bond wires comprises aluminum and wherein the microelectronic die is annealed at a selected temperature for a predetermined period of time.

18. The microelectronic die of claim 14, wherein the substrate is an inter-layer dielectric of the microelectronic die.

19. A method of making an electrical connection to a microelectronic die, comprising:

forming a copper pad in a surface of the microelectronic die;

forming at least one layer of passivation material on the surface of the die and the copper pad;

forming an opening in the at least one layer of passivation material to expose at least a portion of the copper pad;

forming a layer of conductive material in contact with the copper pad through the opening; and

attaching a bond wire to the layer of conductive material to form a wirebond assembly, wherein the layer of conductive material includes a material to provide a stable contact between the bond wire and the copper pad in at least one of an oxidizing environment and an environment with temperatures up to at least about 350°

C.

20. The method of claim 19, wherein forming the opening in the at least one layer of passivation material comprises at least one of mechanical removal and chemical removal of material.

21. The method of claim 19, wherein forming the layer of conductive material comprises forming a single layer of titanium.

22. The method of claim 19, further comprising selectively removing portions of the layer of conductive material to form a predetermined pattern.

23. The method of claim 19, further comprising annealing the wirebond assembly at a selected temperature for a predetermined period of time.

24. The method of claim 19, wherein attaching the bond wire to the layer of conductive material comprises wedge bonding.

25. A method of making a microelectronic die package, comprising:

providing a microelectronic die; and

electrically coupling each of a plurality of bond wires to a corresponding one of a plurality of copper pads formed in a surface of the microelectronic die, wherein coupling each of the bond wires to the corresponding one of the plurality of copper pads includes;

forming a plurality of openings in at least one layer of passivation material to expose at least a portion of each of a plurality of copper pads,

forming a layer of conductive material in contact with each of the plurality of copper pads through the openings,

selectively removing portions of the layer of conductive material to form a plurality of separate electrical contacts of the layer of conductive material, each separate electrical contact being connected to a corresponding one of the plurality of copper pads, and

electrically connecting each of the plurality of bond wires to a corresponding one of the plurality of separate electrical contacts of the layer of conductive material to form the microelectronic die package, wherein the layer of conductive material includes a material to provide a stable contact between each of the plurality of bond wires and the corresponding one of the plurality of copper pads in at least one of an oxidizing environment and an environment with temperatures up to at least about 350°

C.

26. The method of claim 25, wherein forming the layer of conductive material comprises forming a single layer of titanium.

27. The method of claim 25, wherein electrically connecting each of the plurality of bond wires to a corresponding one of the plurality of separate electrical contacts comprises wedge bonding.

28. The method of claim 25, further comprising annealing the microelectronic die package at a selected temperature for a predetermined time period.