VLSI HOT-SPOT MINIMIZATION USING NANOTUBES

• US 20080316711A1
• Filed: 07/08/2008
• Published: 12/25/2008
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Georgiou, Christos John, Dimitrakopoulos, Christos Dimitrios
• Granted Patent: US 7,842,554 B2
• Time in Patent Office: Days
• US Class Current: 361/718
• CPC Class Codes: F28D 2015/0225 Microheat pipes
• CPC Class Codes: F28D 2021/0029 Heat sinks
• CPC Class Codes: F28F 21/02 of carbon, e.g. graphite
• CPC Class Codes: F28F 2255/00 Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
• CPC Class Codes: F28F 2260/02 having microchannels
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• 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

Abstract

The invention relates to a semiconductive device comprising a die with at least one defined hot-spot area lying in a plane on the die and a cooling structure comprising nanotubes such as carbon nanotubes extending in a plane different than the plane of the hot-spot area and outwardly from the plane of the hot-spot area. The nanotubes are operatively associated with the hot-spot area to decrease any temperature gradient between the hot-spot area and at least one other area on the die defined by a temperature lower than the hot-spot area. A matrix material comprising a second heat conducting material substantially surrounds the nanotubes and is operatively associated with and in heat conducting relation with the other area on the die defined by a temperature lower than the hot-spot area. The heat conductivity of the nanotubes is greater than the heat conductivity of the matrix material, with the distal ends of the nanotubes exposed to present a distal surface comprising the first heat conducting means for direct contact with a medium comprising a cooling fluid. The inventors also disclose processes for manufacturing and using the device and products produced by the processes.

Claims

1. A semiconductive device comprising a die, said device having:

(a) at least one defined hot-spot area lying in a plane on said die;

(b) cooling means comprising a plurality of nanotube means composed of a first heat conducting material and extending in a plane different than the plane of said hot-spot area and outwardly from the plane of said hot-spot area, said nanotube means operatively associated with said hot-spot area to decrease any temperature gradient between said hot-spot area and at least one other area on said die defined by a temperature lower than said hot-spot area;

(c) said nanotube means being substantially surrounded by a matrix material comprised of a second heat conducting material operatively associated with and in heat conducting relation with said other area on said die defined by a temperature lower than said hot-spot area;

(d) the heat conductivity of said first heat conducting material being greater than the heat conductivity of said second heat conducting material;

(e) the distal ends of said nanotube means comprising said first heat conducting material, and positioned for direct contact with a medium comprising a heat exchange medium.

2. The device of claim 1 wherein said nanotube means substantially:

(a) are parallel to one another;

(b) are linear or helical;

(c) are perpendicular to the plane of said hot spot; and

(d) comprise carbon;

(e) said heat exchange medium comprises a heat exchange fluid; and

(f) said nanotubes comprise single wall or multi-wall nanotubes.

3. The device of claim 2 wherein said first heat conducting material comprises carbon and said second heat conducting material comprises a metal.

4. The semiconducting device of claim 2 comprising a VLSI device.

5. A process for providing cooling means on the surface of a semiconductive device having a die comprising:

(a) defining at least one hot-spot area lying in a plane on said die;

(b) defining another area on said die having a temperature lower than said hot-spot area;

(c) forming cooling means comprising a plurality of nanotube means on said die and composed of a first heat conducting material;

said nanotube means extending in a plane different than the plane of said hot-spot area and outwardly from the plane of said hot-spot area, said nanotube means formed so as to be operatively associated with said hot-spot area to decrease any temperature gradient between said hot-spot area and said area on said die having a temperature lower than said hot-spot area;

(d) substantially surrounding said nanotube means with a matrix material so that said matrix material substantially extends over and is operatively associated with the surface of said die and in heat conducting relation with at least one of said areas on said die defined by a temperature lower than said hot-spot area, said matrix material composed of a second heat conducting material, said first heat conducting material having a heat conductivity higher than said second heat conducting material;

(e) providing the distal ends of said nanotube means with a surface comprising said first heat conducting material to make said distal ends available for direct contact with a medium comprising a heat exchange medium.

6. The process of claim 5 wherein said nanotube means substantially:

(a) are parallel to one another;

(b) are linear or helical;

(c) are perpendicular to the plane of said hot spot; and

(d) comprise carbon;

(e) said heat exchange medium comprises a heat exchange fluid; and

(f) said nanotubes comprise single wall or multi-wall nanotubes.

7. The process of claim 6 comprising forming said first heat conducting material from a material comprising carbon and said second heat conducting material from a material comprising a metal.

8. The process of claim 6 wherein said semiconducting device comprises a VLSI device.

14. A product produced by the process of claim 5.

9. A process for providing cooling means on the surface of a semiconducting device having a die comprising:

(a) defining by thermal analysis, at least one hot-spot area lying in a plane on said die;

(b) defining by thermal analysis, at least one other area on said die having a temperature lower than said hot-spot area;

(c) fabricating a mask corresponding to said hot-spot area;

(d) selectively applying to the surface of said die by means of said mask, a catalyst to define a catalyst area corresponding to said hot-spot area and thereby produce a semiconductive device having a die with a selectively catalyzed surface;

said catalyst selected to promote the growth of a plurality of heat conducting nanotube means;

(e) growing said nanotube means from a first heat conducting material and on said selectively catalyzed area to extend in a different plane than the plane of said hot-spot area and outwardly form the plane of said hot-spot area, said nanotube means being operatively associated with said hot-spot area to decrease any temperature gradient between said hot-spot area and said area on said device having a temperature lower than said hot-spot area;

(f) depositing a second heat conducting material on the surface of said die to form a matrix to surround said nanotube means, said second heat conducting material extending to and operatively associated with said other area on said die having a temperature lower than said hot-spot area to conduct heat away from said other area, said nanotube means made from said first heat conducting material having a higher heat conductivity than said matrix made from second heat conducting material;

(g) sufficiently removing any of said second heat conducting material that extends above the distal ends of said nanotube means to make said distal ends available for direct contact with a medium comprising a heat exchange medium.

10. The process of claim 9 wherein prior to selectively applying said catalyst layer to the surface of said die, the step of applying a metal adhesion layer to the surface of said die.

11. The process of claim 9 wherein said nanotube means substantially:

(a) are parallel to one another;

(b) are linear or helical;

(c) are perpendicular to the plane of said hot spot; and

(d) comprise carbon;

(e) said heat exchange medium comprises a heat exchange fluid; and

(e) said nanotube comprises single wall or multi-wall nanotube.

12. The process of claim 11 comprising forming said nanotube means from a material comprising carbon and said matrix from a material comprising a metal.

13. The process of claim 11 wherein said semiconducting device comprises a VLSI device.

15. A product produced by the process of claim 9.

16. A process for cooling the surface of a semiconductive device having a die comprising:

(a) defining at least one hot-spot area lying in a plane on said die;

(b) defining another area on said die having a temperature lower than said hot-spot area;

(c) forming cooling means comprising a plurality of nanotube means on said die that extend in a plane different than the plane of said hot-spot area and outwardly from the plane of said hot-spot area, said nanotube means formed so as to be operatively associated with said hot-spot area to decrease any temperature gradient between said hot-spot area and said area on said die having a temperature lower than said hot-spot area, said nanotube means composed of a first heat conducting material;

(d) substantially surrounding said nanotube means with a matrix material so that said matrix material substantially extends over and is operatively associated with the surface of said die and in heat conducting relation with at least one of said areas on said die defined by a temperature lower than said hot-spot area, said matrix material composed of a second heat conducting material, said first heat conducting material having a heat conductivity higher than said second heat conducting material;

(e) providing the distal ends of said nanotube means with a surface comprising said first heat conducting material to make said distal ends available for direct contact with a medium comprising a heat exchange medium.

(f) contacting said distal ends with said medium comprising a heat exchange medium, said heat exchange medium being at a temperature lower than the temperature of said distal ends.

17. The process of claim 16 wherein said nanotube means substantially:

(a) are parallel to one another;

(b) are linear or helical;

(c) are perpendicular to the plane of said hot spot; and

(d) comprise carbon;

(e) said cooling medium comprises a cooling fluid; and

(f) said nanotube comprises single wall or multi-wall nanotube.

18. A process for cooling the surface of a semiconducting device having a die comprising:

(a) defining by thermal analysis, at least one hot-spot area lying in a plane on said die;

(b) defining by thermal analysis, at least one other area on said die having a temperature lower than said hot-spot area;

(c) fabricating a mask corresponding to said hot-spot area;

(d) selectively applying to the surface of said die by means of said mask, a catalyst to define a catalyst area corresponding to said hot-spot and thereby produce a semiconductive device having a die with a selectively catalyzed surface;

said catalyst selected to promote the growth of a plurality of heat conducting nanotube means;

(e) growing said nanotube means from a first heat conducting material and on said selectively catalyzed area to extend in a different plane than the plane of said hot-spot area and outwardly form the plane of said hot-spot area, said nanotube means being operatively associated with said hot-spot area to decrease any temperature gradient between said hot-spot area and said area on said device having a temperature lower than said hot-spot area;

(f) depositing a second heat conducting material on the surface of said die to form a matrix to substantially surround said nanotube means, said second heat conducting material extending to and operatively associated with said other area on said die having a temperature lower than said hot-spot area to conduct heat away from said other area, said nanotube means made of said first heat conducting material having a higher heat conductivity than said matrix formed from said second heat conducting material;

(g) sufficiently removing any of said second heat conducting material that extends above the distal ends of said nanotube means to make said distal ends available for direct contact with a medium comprising a heat exchange medium;

(h) contacting said distal ends with said medium comprising a heat exchange medium, said heat exchange medium being at a temperature lower than the temperature of said distal ends.

19. The process of claim 18 wherein said nanotube means substantially:

(a) are parallel to one another;

(b) are linear or helical;

(c) are perpendicular to the plane of said hot spot; and

(d) comprise carbon;

(e) said heat exchange medium comprises a heat exchange fluid; and

(f) said nanotubes comprise single wall or multi-wall nanotubes.

20. The process of claim 19 wherein said semiconducting device comprises a VLSI device.