Cooling of substrate using interposer channels

• US 7,434,308 B2
• Filed: 09/02/2004
• Issued: 10/14/2008
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Mok, Lawrence S., Lu, Minhua
• Primary Examiner(s): Reichard; Dean A.
• Assistant Examiner(s): Getachew; Abiy
• Application Number:
  US10/933,051
• Publication Number:
  US 20060042825A1
• Time in Patent Office: 1,503 Days
• Field of Search: 298/52, 298/32, 298/30, 174/252, 257/678
• US Class Current: 29/830
• CPC Class Codes: F28D 15/0266 with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers F28D15/043 takes precedence
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445
• CPC Class Codes: H01L 23/433 Auxiliary members in containers characterised by their shape, e.g. pistons
• 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 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base
• CPC Class Codes: Y10T 29/49204 Contact or terminal manufacturing

Abstract

A structure, and method of forming and cooling the structure. The structure may include a substrate (e.g., a semiconductor chip) having N continuous substrate channels and an interposer having N continuous interposer channels (N≧2). The N interposer channels are coupled to the N substrate channels to form M continuous loops (1≦M≦N). The M loops may transfer heat from a heat source within the substrate to the interposer and then to a heat sink thermally coupled to the interposer. The structure may include an interposer having a thermally conductive enclosure surrounding a cavity. The cavity contains a thermally conductive foam material (e.g., graphite foam). The foam material contains a serpentine channel having contiguously connected channel segments. The serpentine channel may transfer heat from a heat source within a substrate (e.g., a semiconductor chip) to the interposer and then to a heat sink thermally coupled to the interposer.

Claims

1. A method of cooling a substrate, comprising:

providing a substrate comprising N continuous substrate channels on a first side of the substrate, said substrate having a heat source therein, said N being at least 2;

providing an interposer comprising N continuous interposer channels, said N interposer channels being coupled to the N substrate channels so as to form M continuous loops such that 1≦

M≦

N, each loop of the M loops independently consisting of K substrate channels of the N substrate channels and K interposer channels of the N interposer channels in an alternating sequence of substrate channels and interposer channels, for each loop of the M loops said K is at least 1 and is subject to an upper limit consistent with a constraint of having the M loops collectively consist of the N interposer channels and the N substrate channels, each loop of the M loops independently being open ended or closed, said first side of the substrate being connected to the interposer, said interposer being thermally coupled to a heat sink such that the interposer is interposed between the substrate and the heat sink;

generating heat by the heat source; and

circulating fluid in the N interposer channels and the N substrate channels, wherein a portion of the heat generated by the heat source is transferred to the fluid in the N substrate channels, and wherein a percentage of the portion of the heat is transferred from the fluid in the N interposer channels to the heat sink.

2. The method of claim 1, wherein said M=N.

3. The method of claim 1, wherein said M=1 such that the M continuous loops consist of one continuous loop.

4. The method of claim 3, wherein the one continuous loop is open ended.

5. The method of claim 1, wherein 1<

M<

N.

6. The method of claim 5, wherein K>

1 in each loop of the M loops.

7. The method of claim 5, wherein K=1 in at least one loop of the M loops.

8. The method of claim 1, wherein a first loop of the M loops comprises a first interposer channel of the N interposer channels, wherein the first interposer channel comprises a first channel segment and a second channel segment, and wherein the first channel segment is about perpendicular to the second channel segment.

9. The method of claim 1, wherein each substrate channel of the N substrate channels has a larger flow area than each interposer channel of the N interposer channels.

10. The method of claim 1, wherein the interposer is thermally coupled to the heat sink by a thermally conductive cover that is sandwiched between the heat sink and the interposer.

11. The method of claim 1, wherein a coefficient of thermal expansion (CTE) of the interposer is substantially equal to a CTE of the substrate.

12. The method of claim 1, wherein the N substrate channels and the N interposer channels are hermetically sealed with a vacuum therein.

13. The method of claim 12, wherein a fluid partially but not totally fills each substrate channel of the N substrate channels and each interposer channel of the N interposer channels, and wherein the fluid is adapted to transfer heat from the heat source to the interposer.

14. The method of claim 1, wherein the substrate comprises a semiconductor chip, wherein the semiconductor chip comprises active electronic devices on a second side of the substrate that is opposite the first side of the substrate, and wherein the heat source comprises the active electronic devices.

15. The method of claim 1, wherein the portion of the heat transferred from the heat source to the fluid is by a heat transfer mechanism that includes a phase change from a liquid phase of the fluid to a vapor phase of the fluid, and wherein the percentage of the portion of the heat transferred from the fluid to the heat sink is by a heat transfer mechanism that includes a phase change from the vapor phase of the fluid to the liquid phase of the fluid.

16. A method of cooling a structure, comprising:

providing a heat source, a heat sink, and an interposer, said the interposer being interposed between the heat sink and the heat source, said interposer comprising an enclosure that encloses a cavity, said enclosure being made of a thermally conductive material, said cavity comprising a thermally conductive foam material therein, said foam material comprising pores and comprising at least one serpentine channel, each serpentine channel having a plurality of contiguously connected channel segments, each serpentine channel independently forming a closed loop or an open ended loop, said foam being soaked by a liquid filling said pores;

generating heat by the heat source; and

providing a fluid in each serpentine channel, wherein a portion of the heat generated by the heat source is transferred to the fluid, and wherein a percentage of the portion of the heat is transferred from the fluid to the heat sink.

17. The structure of claim 16, wherein the substrate comprises a semiconductor chip, wherein a first side of the semiconductor chip is in mechanical and thermal contact with the interposer, wherein the semiconductor chip comprises active electronic devices on a second side of the semiconductor chip that is opposite the first side of the semiconductor chip, and wherein the heat source comprises the active electronic devices.