VLSI hot-spot minimization using nanotubes

• US 7,842,554 B2
• Filed: 07/08/2008
• Issued: 11/30/2010
• Est. Priority Date: 03/29/2006
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Dimitrakopoulos, Christos Dimitrios, Georgiou, Christos John
• Primary Examiner(s): EVERHART, CARIDAD
• Application Number:
  US12/169,458
• Publication Number:
  US 20080316711A1
• Time in Patent Office: 875 Days
• Field of Search: 438/677, 438/122, 257/E21.153, 257/E21.499
• US Class Current: 438/122
• 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 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.

2. The process of claim 1 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.

3. The process 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

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

4. The process of claim 3 comprising forming said nanotube means from a material comprising carbon and said matrix from a material comprising a metal.

5. The process of claim 3 wherein said semiconducting device comprises a VLSI device.

6. 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.

7. The process of claim 6 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.

8. The process of claim 7 wherein said semiconducting device comprises a VLSI device.