US20040165354A1 - Heat radiating structure for electronic device - Google Patents
Heat radiating structure for electronic device Download PDFInfo
- Publication number
- US20040165354A1 US20040165354A1 US10/787,309 US78730904A US2004165354A1 US 20040165354 A1 US20040165354 A1 US 20040165354A1 US 78730904 A US78730904 A US 78730904A US 2004165354 A1 US2004165354 A1 US 2004165354A1
- Authority
- US
- United States
- Prior art keywords
- heat spreader
- heat
- electronic device
- electronic part
- spreader
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
- H01L23/433—Auxiliary members in containers characterised by their shape, e.g. pistons
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
- H01L23/427—Cooling by change of state, e.g. use of heat pipes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
- H01L2224/732—Location after the connecting process
- H01L2224/73251—Location after the connecting process on different surfaces
- H01L2224/73253—Bump and layer connectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01025—Manganese [Mn]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/10—Details of semiconductor or other solid state devices to be connected
- H01L2924/102—Material of the semiconductor or solid state bodies
- H01L2924/1025—Semiconducting materials
- H01L2924/10251—Elemental semiconductors, i.e. Group IV
- H01L2924/10253—Silicon [Si]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/161—Cap
- H01L2924/1615—Shape
- H01L2924/16152—Cap comprising a cavity for hosting the device, e.g. U-shaped cap
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12528—Semiconductor component
Definitions
- the present invention relates to a heat radiating structure for cooling an electronic device such as a processor, e.g., an MPU or an image processor by releasing the heat from the electronic device.
- a processor e.g., an MPU or an image processor
- An electronic device such as a processor (MPU) or an image processor has an increasing degree of integration and operating frequency. Accordingly, an electronic device of this kind generates more heat.
- MPU processor
- image processor image processor
- FIG. 7 A heat spreader 1 , as shown, is made of an anodized metal of aluminum or copper. This heat spreader 1 is constructed to have a flat plate portion 2 to be closely contacted by the electronic device, and a protrusion 3 protruding from the flat plate portion 2 . The heat spreader 1 is fixed by fitting the protrusion 3 in a pedestal portion 4 such as a lead frame or substrate.
- the heat spreader 1 is fixed on the pedestal portion 4 together with a die 5 including an integrated circuit and is contacted by the surface of the die 5 through a grease or jelly 6 having a high thermal conductivity. Moreover, the heat spreader 1 is made of a material having excellent thermal conductivity such as copper so that it can substantially increase the heat transfer area of the die 5 without damaging the die 5 or its circuit. Thus, the characteristics of heat radiation of the electronic device can be improved by fixing a heat sink 7 in close contact with the heat spreader 1 .
- the grease or jelly 6 having high thermal conductivity of the prior art which fills the clearance between the die 5 and the heat spreader 1 is preferably replaced by a join which is made directly between the die 5 and the heat spreader 1 by means of soft solder.
- the electronic part such as the die 5 is made of a material (e.g., silicon) emphasizing electric characteristics
- the heat spreader 1 is made of a material (e.g., copper) emphasizing thermal characteristics, so they have very different coefficients of thermal expansion or linear expansion.
- a main object of the invention is to lower heat resistance between an electronic part and a heat spreader.
- Another object of the invention is to provide a heat radiating structure which can keep the join between the electronic part and the heat spreader stable during temperature change and thereby improve heat dissipation from the electronic part.
- Still another object of the invention is to provide a heat radiating structure for an electronic device, which uses a heat spreader having excellent thermal conductivity.
- Still another object of the invention is to provide a heat radiating structure which uses a heat spreader to be contacted directly by an electronic part to improve heat radiation from the electronic part.
- the heat radiating structure of the invention there is sandwiched between an electronic part and a heat spreader a grading layer which has different coefficients of thermal expansion between the electronic part side and the heat spreader side. Therefore, the difference in the coefficient of thermal expansion at the contacting portion between the electronic part and the grading layer and the difference in the coefficient of thermal expansion at the contacting portion between the heat spreader and the grading layer are both reduced. As a result, high temperature does not produce high thermal stress to disengage the electronic part and the grading layer or disengage the heat spreader and the grading layer. In other words, heat resistance between the electronic part and the heat spreader does not rise and heat radiation from the electronic part can be maintained in an excellent state.
- the heat spreader is made of a material having a small coefficient of thermal expansion such as aluminum nitride or invar. Therefore, the difference in the coefficient of thermal expansion between the electronic part and the heat spreader is reduced so that heat stress between the electronic part and the heat spreader can be suppressed to a small value, even if the electronic part undergoes a temperature rise. As a result, contact between the electronic part and the heat spreader can maintained to cool the electronic part sufficiently.
- the heat spreader is provided with a chamber therein to act as a heat pipe.
- the heat spreader can be held in direct contact with the electronic part by making the heat spreader of aluminum and burying a lubricant member in the face to make contact with the electronic part.
- no intermediate substance is present between the electronic part and the heat spreader and heat resistance therebetween can be lowered.
- the coefficient of thermal expansion of the face making contact with the electronic part is reduced, so that thermal stress can be kept small even when the electronic part undergoes a temperature rise. As a result, no separation occurs between the electronic part and the heat spreader and heat resistance therebetween can be prevented from increasing.
- FIG. 1 is a sectional view showing one embodiment of the invention schematically
- FIG. 2 is a schematic sectional view of the structure of a grading layer used in a heat radiating structure of FIG. 1;
- FIG. 3 is a sectional view showing another embodiment of the invention schematically
- FIG. 4 is a sectional view showing a further embodiment of the invention schematically
- FIG. 5 is a sectional view showing a further embodiment of the invention schematically
- FIG. 6 is a schematic view showing a portion VI of FIG. 5 in an enlarged scale.
- FIG. 7 is a sectional view showing an example of the prior art schematically.
- a die 10 or an electronic part having a fine circuit is fixed on a pedestal portion 11 such as a substrate or socket.
- This die 10 has a structure similar to that known in the prior art and is a rectangular member having a thickness of several millimeters and a circuit formed on a silicon chip.
- the heat spreader 12 is made of a material having a high thermal conductivity such as copper or aluminum for aiding in the transmission of heat from the die 10 to a heat sink 13 .
- the heat spreader 12 is provided with a rectangular flat plate portion 12 a confronting the upper face of the die 10 and leg portions 12 b formed on the two right and left end portions or at the four corners of the flat plate portion 12 a .
- the heat spreader 12 is fixed on the pedestal portion 11 by leg portions 12 b.
- Leg portions 12 b are of such a height to be substantially equal to the thickness of the die 10 so that the lower face or back face 12 c of the flat plate portion 12 a and the die 10 may closely contact each other. Between the flat plate portion 12 a and the die 10 , moreover, there is located a grading layer 14 .
- Grading layer 14 is constructed to have different coefficients of thermal expansion between the upper face side and the lower face side. As schematically shown in FIG. 2, for example: a first layer 14 a on the lower side to make contact with the die 10 has a coefficient of thermal expansion approximate to that of the die 10 ; an intermediate second layer 14 b has a coefficient of thermal expansion intermediate between that of the die 10 and that of the heat spreader 12 ; and a third layer 14 c on the upper face side has a coefficient of thermal expansion approximate to that of the heat spreader 12 .
- This multi-layered structure can be formed either by laminating sheets of different materials or by changing the compositions of a composite material of a plurality of materials in its thickness direction.
- Heat sink 13 having a suitable structure is closely mounted on the upper face, as shown in FIG. 1, of the heat spreader 12 , which is joined to the die 10 through the grading layer 14 .
- the flat plate portion 12 a of the heat spreader 12 has an area larger than that of the front face of the die
- the base portion 13 a of the heat sink 13 has an area larger than that of the flat plate portion 12 a .
- the die 10 , the grading layer 14 and the heat spreader 12 can be joined to each other with a soft solder or solder or with an adhesive of a synthetic resin or the like.
- the grading layer 14 and the heat spreader 12 can also be joined to each other by a diffused junction method, in which interatomic diffusion is caused in the boundary between the grading layer 14 and the heat spreader 12 by pressurizing them.
- the heat spreader 12 is heated together with the die 10 so that it expands thermally according to the temperature. Therefore, the thermal expansion of the die 10 is exceeded by that of the heat spreader 12 .
- the first layer 14 a of the grading layer 14 which is directly contacted by the die 10 has a coefficient of thermal expansion substantially equal to that of the die 10 so that no serious thermal stress occurs between them.
- the third layer 14 c of the grading layer 14 which is directly contacted by the heat spreader 12 having a higher coefficient of thermal expansion, has a coefficient of thermal expansion substantially equal to that of the heat spreader 12 so that no serious thermal stress occurs between them.
- the thermal stresses are small between the two members contacting each other. Therefore, those two members do not disengage to establish any clearance therebetween and to raise the heat resistance.
- the heat transfer path from the die 10 to the heat spreader 12 is prevented from having a clearance or an air layer to obstruct the heat transfer so that heat resistance can be kept at a small value.
- the heat spreader 12 arranged across the die 10 is made of a material having a coefficient of thermal expansion approximate to that of silicon constituting the die 10 .
- the heat spreader 12 is made of aluminum nitride.
- this material may be made of nickel steel, i.e., invar containing 0.4% of Mn, 0.2% of C, 36% of Ni, and the remainder being Fe.
- the heat spreader 12 and the die 10 are joined to each other by graphite 15 located therebetween.
- the die 10 and the heat spreader 12 are integrally joined to each other by locating graphite 15 between the upper face of the die 10 and the lower face of the flat plate portion 12 a of the heat spreader 12 and by applying a predetermined heat to it while pressurizing it.
- a diffused junction method can adopted for joining the heat spreader 12 and graphite 15 .
- heat generated by the action of the die 10 is transferred through the heat spreader 12 to the heat sink 13 . Heat is then dissipated to the atmosphere so that the die 10 is efficiently cooled. Specifically, the die 10 and the heat spreader 12 are joined to each other such that heat resistance therebetween can be reduced to improve heat radiation efficiency.
- the thermal conductivity of the heat spreader 12 is raised to make the entire heat resistance lower.
- the heat spreader 12 shown in FIG. 4 has a hollow structure in its flat plate portion 12 a .
- the hollow portion 12 d can be constructed by attaching a cover member to a body portion having a recess.
- this hollow portion 12 d is prepared by evacuating an incondensable gas such as air from inside and by encapsulating a condensable fluid such as water as a working fluid 12 e therein.
- the heat spreader 12 is formed into a heat pipe having a so-called “vapor chamber”.
- join between the heat spreader 12 and the die 10 may be made either by the aforementioned structures or by a structure known in the prior art.
- heat generated by the die 10 is transferred to the heat spreader 12 in contact with the die 10 .
- the working fluid 12 e in the vapor chamber is evaporated by that heat, and the resultant vapor flows to the portion of lower temperature and pressure, i.e., the upper face side making contact with the heat sink 13 .
- the vapor of the working fluid 12 e releases its heat and condenses.
- the heat thus released from working fluid 12 e is transferred from the upper face side of the heat spreader 12 to the heat sink 13 and dissipated further from the heat sink 13 to the ambient air.
- the heat of the die 10 is dissipated to the air and the die 10 is cooled.
- the working fluid 12 e encapsulated in the vapor chamber transports the heat as its latent heat.
- the calories dissipated are far more than that due to the heat conduction so that the heat resistance of the heat spreader 12 is substantially lowered.
- the heat resistance from the die 10 to the heat sink 13 can be reduced to cool the die 10 efficiently.
- the metal suitable for the heat spreader 12 has a larger coefficient of thermal expansion than that of the silicon making the die 10 , as described above, because metal such as copper or aluminum has a high heat conductivity. If the die 10 and the heat spreader 12 are smoothed in their relative movements while being in close contact with each other for heat transfer, it is possible to suppress or prevent the occurrence of thermal stress between the die 10 and the heat spreader 12 , as exemplified in FIGS. 5 and 6.
- the heat spreader 12 as shown, is made of aluminum, and the back face 12 c (or the lower face of FIGS. 5 and 6) of the flat plate portion 12 a is anodized to form cracks 16 . These cracks 16 are filled with a soft lubricating material such as molybdenum sulfide 17 , which is partially exposed to the outside. Treated metal of this kind is known as “Fujimite” (Registered Trade Mark).
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
A heat radiating structure for an electronic device, for cooling an electronic part by transferring the heat generated in the electronic part to a heat spreader has a grading layer, which is located between the electronic part and the heat spreader and having a coefficient of thermal expansion varied such that it is substantially equal or approximate at its portion on the electronic part side to the coefficient of thermal expansion of the electronic part and such that it is substantially equal or approximate at its portion on the heat spreader side to the coefficient of thermal expansion of the heat spreader.
Description
- This application claims priority from Provisional Application Serial No. 60/330,618, filed Oct. 26, 2001, pending, incorporated herein by reference.
- 1. Field of the Invention
- The present invention relates to a heat radiating structure for cooling an electronic device such as a processor, e.g., an MPU or an image processor by releasing the heat from the electronic device.
- 2. Background of the Invention
- An electronic device such as a processor (MPU) or an image processor has an increasing degree of integration and operating frequency. Accordingly, an electronic device of this kind generates more heat.
- As the electronic device is heated to a higher temperature, it may malfunction or break. It is, therefore, necessary to dissipate heat more efficiently from the electronic device. In the prior art, for example, a heat sink is used as a means for cooling the electronic device.
- When heat is to be dissipated through a heat sink, it is necessary to transfer heat from the electronic device to the heat sink. For the most efficient heat transfer the electronic device and the heat sink may closely contact each other. However, an electronic device such as an MPU is constructed to have a circuit in a die of silicon and to emphasize electric characteristics. It is, therefore, difficult for a heat sink for heat radiation to make direct contact with the electronic device.
- In the prior art there has been developed a heat sink structure, in which a heat spreader is arranged in close contact with the surface of the electronic device to be contacted by the heat sink. One example of this heat sink structure is schematically shown in FIG. 7. A
heat spreader 1, as shown, is made of an anodized metal of aluminum or copper. Thisheat spreader 1 is constructed to have aflat plate portion 2 to be closely contacted by the electronic device, and a protrusion 3 protruding from theflat plate portion 2. Theheat spreader 1 is fixed by fitting the protrusion 3 in apedestal portion 4 such as a lead frame or substrate. - The
heat spreader 1 is fixed on thepedestal portion 4 together with adie 5 including an integrated circuit and is contacted by the surface of thedie 5 through a grease orjelly 6 having a high thermal conductivity. Moreover, theheat spreader 1 is made of a material having excellent thermal conductivity such as copper so that it can substantially increase the heat transfer area of thedie 5 without damaging thedie 5 or its circuit. Thus, the characteristics of heat radiation of the electronic device can be improved by fixing aheat sink 7 in close contact with theheat spreader 1. - In order to improve heat dissipation by using the
heat spreader 1, it is preferred to make heat resistance between thedie 5 and theheat spreader 1 as low as possible. Therefore, the grease orjelly 6 having high thermal conductivity of the prior art which fills the clearance between thedie 5 and theheat spreader 1 is preferably replaced by a join which is made directly between thedie 5 and theheat spreader 1 by means of soft solder. - However, the electronic part such as the die5 is made of a material (e.g., silicon) emphasizing electric characteristics, whereas the
heat spreader 1 is made of a material (e.g., copper) emphasizing thermal characteristics, so they have very different coefficients of thermal expansion or linear expansion. - When the temperature of the electronic device rises, therefore, thermal stress may occur between the electronic part such as the
die 5 and the heat spreader 1 to cause a separation. In other words, their adhesion may be broken by the thermal stress. As a result, heat resistance between thedie 5 and theheat spreader 1 may rise high enough to make it impossible to cool sufficiently the electronic part such as the die 5. - A main object of the invention is to lower heat resistance between an electronic part and a heat spreader.
- Another object of the invention is to provide a heat radiating structure which can keep the join between the electronic part and the heat spreader stable during temperature change and thereby improve heat dissipation from the electronic part.
- Still another object of the invention is to provide a heat radiating structure for an electronic device, which uses a heat spreader having excellent thermal conductivity.
- Still another object of the invention is to provide a heat radiating structure which uses a heat spreader to be contacted directly by an electronic part to improve heat radiation from the electronic part.
- In the heat radiating structure of the invention there is sandwiched between an electronic part and a heat spreader a grading layer which has different coefficients of thermal expansion between the electronic part side and the heat spreader side. Therefore, the difference in the coefficient of thermal expansion at the contacting portion between the electronic part and the grading layer and the difference in the coefficient of thermal expansion at the contacting portion between the heat spreader and the grading layer are both reduced. As a result, high temperature does not produce high thermal stress to disengage the electronic part and the grading layer or disengage the heat spreader and the grading layer. In other words, heat resistance between the electronic part and the heat spreader does not rise and heat radiation from the electronic part can be maintained in an excellent state.
- In the heat radiating structure of the invention the heat spreader is made of a material having a small coefficient of thermal expansion such as aluminum nitride or invar. Therefore, the difference in the coefficient of thermal expansion between the electronic part and the heat spreader is reduced so that heat stress between the electronic part and the heat spreader can be suppressed to a small value, even if the electronic part undergoes a temperature rise. As a result, contact between the electronic part and the heat spreader can maintained to cool the electronic part sufficiently.
- In the heat radiating structure of the invention the heat spreader is provided with a chamber therein to act as a heat pipe. With this structure dissipation of heat in the heat spreader is caused not only by heat conduction, but also by heat transport in the form of the latent heat of a working fluid, so that heat resistance in the heat spreader is reduced. Therefore, heat radiation from the electronic part can be improved to cool the electronic part efficiently.
- In the heat radiating structure of the invention the heat spreader can be held in direct contact with the electronic part by making the heat spreader of aluminum and burying a lubricant member in the face to make contact with the electronic part. With this construction, no intermediate substance is present between the electronic part and the heat spreader and heat resistance therebetween can be lowered. Moreover, the coefficient of thermal expansion of the face making contact with the electronic part is reduced, so that thermal stress can be kept small even when the electronic part undergoes a temperature rise. As a result, no separation occurs between the electronic part and the heat spreader and heat resistance therebetween can be prevented from increasing.
- The objects and features of the invention will more fully discussed in the following detailed description with reference to the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits to the invention.
- FIG. 1 is a sectional view showing one embodiment of the invention schematically;
- FIG. 2 is a schematic sectional view of the structure of a grading layer used in a heat radiating structure of FIG. 1;
- FIG. 3 is a sectional view showing another embodiment of the invention schematically;
- FIG. 4 is a sectional view showing a further embodiment of the invention schematically;
- FIG. 5 is a sectional view showing a further embodiment of the invention schematically;
- FIG. 6 is a schematic view showing a portion VI of FIG. 5 in an enlarged scale; and
- FIG. 7 is a sectional view showing an example of the prior art schematically.
- As shown in FIG. 1, a
die 10 or an electronic part having a fine circuit is fixed on apedestal portion 11 such as a substrate or socket. This die 10 has a structure similar to that known in the prior art and is a rectangular member having a thickness of several millimeters and a circuit formed on a silicon chip. - Across the die10 there is arranged a
heat spreader 12. Theheat spreader 12 is made of a material having a high thermal conductivity such as copper or aluminum for aiding in the transmission of heat from thedie 10 to aheat sink 13. As shown in FIG. 1, theheat spreader 12 is provided with a rectangularflat plate portion 12 a confronting the upper face of thedie 10 andleg portions 12 b formed on the two right and left end portions or at the four corners of theflat plate portion 12 a. Theheat spreader 12 is fixed on thepedestal portion 11 byleg portions 12 b. -
Leg portions 12 b are of such a height to be substantially equal to the thickness of the die 10 so that the lower face or back face 12 c of theflat plate portion 12 a and the die 10 may closely contact each other. Between theflat plate portion 12 a and thedie 10, moreover, there is located agrading layer 14. -
Grading layer 14 is constructed to have different coefficients of thermal expansion between the upper face side and the lower face side. As schematically shown in FIG. 2, for example: a first layer 14 a on the lower side to make contact with thedie 10 has a coefficient of thermal expansion approximate to that of the die 10; an intermediatesecond layer 14 b has a coefficient of thermal expansion intermediate between that of thedie 10 and that of theheat spreader 12; and a third layer 14 c on the upper face side has a coefficient of thermal expansion approximate to that of theheat spreader 12. This multi-layered structure can be formed either by laminating sheets of different materials or by changing the compositions of a composite material of a plurality of materials in its thickness direction. -
Heat sink 13 having a suitable structure is closely mounted on the upper face, as shown in FIG. 1, of theheat spreader 12, which is joined to the die 10 through thegrading layer 14. As shown in FIG. 1, theflat plate portion 12 a of theheat spreader 12 has an area larger than that of the front face of the die, and the base portion 13 a of theheat sink 13 has an area larger than that of theflat plate portion 12 a. Thus, thedie 10, thegrading layer 14 and theheat spreader 12 can be joined to each other with a soft solder or solder or with an adhesive of a synthetic resin or the like. Alternatively, thegrading layer 14 and theheat spreader 12 can also be joined to each other by a diffused junction method, in which interatomic diffusion is caused in the boundary between thegrading layer 14 and theheat spreader 12 by pressurizing them. - In the heat radiation or sink structure thus far described, heat generated when the die10 acts, is transferred through the
grading layer 14 to theheat spreader 12. As a result, the temperature of theheat spreader 12 rises, and heat is further transferred to theheat sink 13 and is dissipated from theheat sink 13 to the ambient air. Thus, the heat of the die 10 is dissipated to the atmosphere so that the temperature rise of the die 10 is suppressed. In other words, thedie 10 is cooled. - In this case, the
heat spreader 12 is heated together with the die 10 so that it expands thermally according to the temperature. Therefore, the thermal expansion of the die 10 is exceeded by that of theheat spreader 12. However, the first layer 14 a of thegrading layer 14 which is directly contacted by thedie 10 has a coefficient of thermal expansion substantially equal to that of the die 10 so that no serious thermal stress occurs between them. On the other hand, the third layer 14 c of thegrading layer 14, which is directly contacted by theheat spreader 12 having a higher coefficient of thermal expansion, has a coefficient of thermal expansion substantially equal to that of theheat spreader 12 so that no serious thermal stress occurs between them. Thus, the thermal stresses are small between the two members contacting each other. Therefore, those two members do not disengage to establish any clearance therebetween and to raise the heat resistance. - In the construction as shown in FIG. 1, the heat transfer path from the die10 to the
heat spreader 12 is prevented from having a clearance or an air layer to obstruct the heat transfer so that heat resistance can be kept at a small value. As a result, it is possible to provide a heat sink structure in which heat dissipation from thedie 10 is excellent. - Another embodiment of the invention will be described here. In FIG. 3, the
heat spreader 12 arranged across thedie 10 is made of a material having a coefficient of thermal expansion approximate to that of silicon constituting thedie 10. Specifically, theheat spreader 12 is made of aluminum nitride. Alternatively, this material may be made of nickel steel, i.e., invar containing 0.4% of Mn, 0.2% of C, 36% of Ni, and the remainder being Fe. - Moreover, the
heat spreader 12 and the die 10 are joined to each other bygraphite 15 located therebetween. For example, thedie 10 and theheat spreader 12 are integrally joined to each other by locatinggraphite 15 between the upper face of thedie 10 and the lower face of theflat plate portion 12 a of theheat spreader 12 and by applying a predetermined heat to it while pressurizing it. A diffused junction method can adopted for joining theheat spreader 12 andgraphite 15. - In the construction shown in FIG. 3, as in the foregoing embodiment, heat generated by the action of the die10, is transferred through the
heat spreader 12 to theheat sink 13. Heat is then dissipated to the atmosphere so that thedie 10 is efficiently cooled. Specifically, thedie 10 and theheat spreader 12 are joined to each other such that heat resistance therebetween can be reduced to improve heat radiation efficiency. - When heat generated by the die10 raises the temperature, no large difference occurs between the coefficients of thermal expansion of the
die 10 and theheat spreader 12 because the coefficients are approximate to each other. Specifically, no significant thermal stress is caused between the die 10 and theheat spreader 12 so that their join is satisfactory to keep heat resistance at a low value. - In an embodiment shown in FIG. 4, the thermal conductivity of the
heat spreader 12 is raised to make the entire heat resistance lower. Specifically, theheat spreader 12 shown in FIG. 4 has a hollow structure in itsflat plate portion 12 a. Thehollow portion 12 d can be constructed by attaching a cover member to a body portion having a recess. Moreover, thishollow portion 12 d is prepared by evacuating an incondensable gas such as air from inside and by encapsulating a condensable fluid such as water as a workingfluid 12 e therein. In other words, theheat spreader 12 is formed into a heat pipe having a so-called “vapor chamber”. - Here, the join between the
heat spreader 12 and the die 10 may be made either by the aforementioned structures or by a structure known in the prior art. - In the structure shown in FIG. 4, heat generated by the
die 10 is transferred to theheat spreader 12 in contact with thedie 10. The workingfluid 12 e in the vapor chamber is evaporated by that heat, and the resultant vapor flows to the portion of lower temperature and pressure, i.e., the upper face side making contact with theheat sink 13. At this point, the vapor of the workingfluid 12 e releases its heat and condenses. Then, the heat thus released from workingfluid 12 e is transferred from the upper face side of theheat spreader 12 to theheat sink 13 and dissipated further from theheat sink 13 to the ambient air. Thus, the heat of the die 10 is dissipated to the air and thedie 10 is cooled. - In the
heat spreader 12, as described above, the workingfluid 12 e encapsulated in the vapor chamber transports the heat as its latent heat. The calories dissipated are far more than that due to the heat conduction so that the heat resistance of theheat spreader 12 is substantially lowered. As a result, the heat resistance from the die 10 to theheat sink 13 can be reduced to cool the die 10 efficiently. - The metal suitable for the
heat spreader 12 has a larger coefficient of thermal expansion than that of the silicon making the die 10, as described above, because metal such as copper or aluminum has a high heat conductivity. If thedie 10 and theheat spreader 12 are smoothed in their relative movements while being in close contact with each other for heat transfer, it is possible to suppress or prevent the occurrence of thermal stress between the die 10 and theheat spreader 12, as exemplified in FIGS. 5 and 6. Theheat spreader 12, as shown, is made of aluminum, and theback face 12 c (or the lower face of FIGS. 5 and 6) of theflat plate portion 12 a is anodized to form cracks 16. Thesecracks 16 are filled with a soft lubricating material such asmolybdenum sulfide 17, which is partially exposed to the outside. Treated metal of this kind is known as “Fujimite” (Registered Trade Mark). - In the construction shown in FIGS. 5 and 6, therefore, adhesion between the die10 and the
heat spreader 12 is improved to lower heat resistance therebetween. Even if the difference between the coefficients of thermal expansion of thedie 10 and theheat spreader 12 is so large that the thermal expansions become different when thedie 10 generates heat to raise the temperature, thedie 10 and theheat spreader 12 will smoothly slide relative to each other and establish no thermal stress therebetween. With the construction shown in FIGS. 5 and 6 it is possible to improve heat radiation from thedie 10, i.e., improve the cooling performance of thedie 10.
Claims (21)
1. An electronic device comprising an electronic part, a heat radiating structure and a heat spreader,
wherein said heat radiating structure comprises a grading layer located between said electronic part and said heat spreader, said grading. layer comprising a coefficient of thermal expansion varied such that it is substantially equal or approximate at its portion on the electronic part side to the coefficient of thermal expansion of said electronic part and such that it is substantially equal or approximate at its portion on the heat spreader side to the coefficient of thermal expansion of said heat spreader.
2. The electronic device according to claim 1 ,
wherein said electronic part, said heat radiating structure and said heat spreader are joined with an adhesive or a solder.
3. The electronic device according to claim 1 ,
wherein said heat spreader and said grading layer are joined by a diffused junction method.
4. An electronic device comprising:
a heat spreader joined to an electronic part, said heat spreader comprising a material having a coefficient of thermal expansion approximate to that of said electronic part,
wherein said electric part is cooled by transferring heat generated in said electric part to said heat spreader.
5. The electronic device according to claim 4 ,
wherein said electronic part is comprised of silicon, and
wherein said heat spreader is comprised of nickel steel or aluminum nitride.
6. The electronic device according to claim 4 ,
wherein said heat spreader is comprised of invar.
7. The electronic device according to claim 4 ,
wherein said electronic device comprises graphite located between said electronic part and said heat spreader.
8. The electronic device according to claim 7 ,
wherein said electronic part, said heat spreader and said graphite are joined with an adhesive or a solder.
9. The electronic device according to claim 7 ,
wherein said heat spreader and said graphite are joined by a diffused junction method.
10. A heat radiating structure for cooling an electronic device comprising:
a heat spreader with a chamber formed in said heat spreader comprised of a sealed structure encapsulating a condensable fluid therein which can repeatedly evaporate and condense to transport heat.
11. A heat radiating structure for cooling an electronic device comprising: a heat spreader,
wherein said heat spreader comprises aluminum and further comprises a lubricating member buried in one face of said heat spreader.
12. The heat radiating structure according to claim 11 ,
wherein said face is anodized to form fine cracks therein, which cracks are filled with molybdenum sulfide comprised as said lubricating member.
13. A heat radiating structure for cooling an electronic device comprising:
a grading layer comprising a coefficient of thermal expansion varied such that it is substantially equal or approximate at one face to the coefficient of thermal expansion of an electronic part and such that it is substantially equal or approximate at the opposite face to the coefficient of thermal expansion of a heat spreader.
14. An electronic device comprising an electronic part, a heat radiating structure and a heat spreader, wherein
said spreader comprises a chamber formed in said heat spreader comprised of a sealed structure encapsulating a condensable fluid therein which can repeatedly evaporate and condensate to transport heat.
15. An electronic device comprising an electronic part, a heat radiating structure and a heat spreader,
wherein said heat spreader comprises of aluminum and further comprises a lubricating member buried in the face of said heat spreader on the side of said electronic part.
16. The electronic device according to claim 15 ,
wherein said face is anodized to form fine cracks therein, which cracks are filled with molybdenum sulfide comprised as said lubricating member.
17. The electronic device according to claim 6 , wherein said invar comprises 0.4% Mn, 0.2% C, 36% Ni, and the remainder Fe.
18. The electronic device according to claim 1 , wherein said grading layer comprises laminated sheets.
19. The heat radiating structure according to claim 13 , wherein said grading layer comprises laminated sheets.
20. The electronic device according to claim 1 , wherein said grading layer comprises a composite material of a plurality of materials having the composition of said plurality of materials changed in a thickness direction.
21. The heat radiating structure of claim 13 , wherein said grading layer comprises a composite material of a plurality of materials having the composition of said plurality of materials changed in a thickness direction.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/787,309 US20040165354A1 (en) | 2001-10-26 | 2004-02-27 | Heat radiating structure for electronic device |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US33061801P | 2001-10-26 | 2001-10-26 | |
US10/259,386 US7006354B2 (en) | 2001-10-26 | 2002-09-30 | Heat radiating structure for electronic device |
US10/787,309 US20040165354A1 (en) | 2001-10-26 | 2004-02-27 | Heat radiating structure for electronic device |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/259,386 Division US7006354B2 (en) | 2001-10-26 | 2002-09-30 | Heat radiating structure for electronic device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040165354A1 true US20040165354A1 (en) | 2004-08-26 |
Family
ID=26947270
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/259,386 Expired - Lifetime US7006354B2 (en) | 2001-10-26 | 2002-09-30 | Heat radiating structure for electronic device |
US10/787,309 Abandoned US20040165354A1 (en) | 2001-10-26 | 2004-02-27 | Heat radiating structure for electronic device |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/259,386 Expired - Lifetime US7006354B2 (en) | 2001-10-26 | 2002-09-30 | Heat radiating structure for electronic device |
Country Status (1)
Country | Link |
---|---|
US (2) | US7006354B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050157471A1 (en) * | 2002-10-08 | 2005-07-21 | Intel Corporation | Integrated heat spreader package for heat transfer and for bond line thickness control and process of making |
US20100326714A1 (en) * | 2009-06-24 | 2010-12-30 | Fujitsu Limited | Printed circuit board, printed circuit board fabrication method, and electronic device including printed circuit board |
US20130044433A1 (en) * | 2010-05-24 | 2013-02-21 | Icepipe Corporation | Heat-dissipating device for electronic apparatus |
Families Citing this family (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7014093B2 (en) * | 2003-06-26 | 2006-03-21 | Intel Corporation | Multi-layer polymer-solder hybrid thermal interface material for integrated heat spreader and method of making same |
US7082031B2 (en) * | 2003-09-30 | 2006-07-25 | Intel Corporation | Heatsink device and method |
DE102004022118A1 (en) * | 2004-05-05 | 2005-11-24 | Conti Temic Microelectronic Gmbh | Arrangement for cooling an electronic unit and production of such an arrangement |
US7439618B2 (en) * | 2005-03-25 | 2008-10-21 | Intel Corporation | Integrated circuit thermal management method and apparatus |
US7438832B2 (en) * | 2005-03-29 | 2008-10-21 | Eastman Kodak Company | Ionic liquid and electronically conductive polymer mixtures |
CN100543974C (en) * | 2005-09-02 | 2009-09-23 | 富准精密工业(深圳)有限公司 | Heat radiation module and manufacture method thereof |
JP2008160019A (en) * | 2006-12-26 | 2008-07-10 | Shinko Electric Ind Co Ltd | Electronic component |
US8018719B2 (en) * | 2009-05-26 | 2011-09-13 | International Business Machines Corporation | Vapor chamber heat sink with cross member and protruding boss |
US7957148B1 (en) | 2009-12-08 | 2011-06-07 | International Business Machines Corporation | Low profile computer processor retention device |
JP5530517B2 (en) * | 2010-06-18 | 2014-06-25 | シャープ株式会社 | Heat dissipation structure of electronic equipment |
US20120033384A1 (en) * | 2010-08-06 | 2012-02-09 | Pillai Unnikrishnan G | Graphite wrapped heat spreading pillow |
US8358506B2 (en) * | 2010-08-27 | 2013-01-22 | Direct Grid Technologies, LLC | Mechanical arrangement for use within galvanically-isolated, low-profile micro-inverters for solar power installations |
US20120155029A1 (en) * | 2010-12-20 | 2012-06-21 | Raytheon Company | Adaptive thermal gap pad |
US20130308274A1 (en) * | 2012-05-21 | 2013-11-21 | Triquint Semiconductor, Inc. | Thermal spreader having graduated thermal expansion parameters |
US9123686B2 (en) | 2013-04-12 | 2015-09-01 | Western Digital Technologies, Inc. | Thermal management for solid-state drive |
US9329646B2 (en) * | 2014-03-20 | 2016-05-03 | Qualcomm Incorporated | Multi-layer heat dissipating apparatus for an electronic device |
US9819144B2 (en) | 2015-05-14 | 2017-11-14 | Apple Inc. | High-efficiency vertical emitters with improved heat sinking |
US10034375B2 (en) * | 2015-05-21 | 2018-07-24 | Apple Inc. | Circuit substrate with embedded heat sink |
US9735539B2 (en) | 2015-07-20 | 2017-08-15 | Apple Inc. | VCSEL structure with embedded heat sink |
US10120423B1 (en) * | 2015-09-09 | 2018-11-06 | Amazon Technologies, Inc. | Unibody thermal enclosure |
CN106973543A (en) * | 2016-01-14 | 2017-07-21 | 中兴通讯股份有限公司 | One kind self-regulation high-low temperature protective device |
US10881028B1 (en) | 2019-07-03 | 2020-12-29 | Apple Inc. | Efficient heat removal from electronic modules |
US11710945B2 (en) | 2020-05-25 | 2023-07-25 | Apple Inc. | Projection of patterned and flood illumination |
US11699715B1 (en) | 2020-09-06 | 2023-07-11 | Apple Inc. | Flip-chip mounting of optoelectronic chips |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4029628A (en) * | 1974-05-22 | 1977-06-14 | The United States Of America As Represented By The Secretary Of The Navy | Bonding material for planar electronic device |
US4914551A (en) * | 1988-07-13 | 1990-04-03 | International Business Machines Corporation | Electronic package with heat spreader member |
US5151777A (en) * | 1989-03-03 | 1992-09-29 | Delco Electronics Corporation | Interface device for thermally coupling an integrated circuit to a heat sink |
US5296310A (en) * | 1992-02-14 | 1994-03-22 | Materials Science Corporation | High conductivity hydrid material for thermal management |
US5412535A (en) * | 1993-08-24 | 1995-05-02 | Convex Computer Corporation | Apparatus and method for cooling electronic devices |
US5582242A (en) * | 1992-05-15 | 1996-12-10 | Digital Equipment Corporation | Thermosiphon for cooling a high power die |
US5720338A (en) * | 1993-09-10 | 1998-02-24 | Aavid Laboratories, Inc. | Two-phase thermal bag component cooler |
US6256201B1 (en) * | 1998-10-21 | 2001-07-03 | Furukawa Electric Co., Ltd. | Plate type heat pipe method of manufacturing same and cooling apparatus using plate type heat pipe |
US6317322B1 (en) * | 2000-08-15 | 2001-11-13 | The Furukawa Electric Co., Ltd. | Plate type heat pipe and a cooling system using same |
US6490160B2 (en) * | 1999-07-15 | 2002-12-03 | Incep Technologies, Inc. | Vapor chamber with integrated pin array |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE68926211T2 (en) * | 1988-10-28 | 1996-11-07 | Sumitomo Electric Industries | Carrier for a semiconductor device |
US5981085A (en) * | 1996-03-21 | 1999-11-09 | The Furukawa Electric Co., Inc. | Composite substrate for heat-generating semiconductor device and semiconductor apparatus using the same |
CA2232517C (en) * | 1997-03-21 | 2004-02-17 | Honda Giken Kogyo Kabushiki Kaisha .) | Functionally gradient material and method for producing the same |
US6432497B2 (en) * | 1997-07-28 | 2002-08-13 | Parker-Hannifin Corporation | Double-side thermally conductive adhesive tape for plastic-packaged electronic components |
-
2002
- 2002-09-30 US US10/259,386 patent/US7006354B2/en not_active Expired - Lifetime
-
2004
- 2004-02-27 US US10/787,309 patent/US20040165354A1/en not_active Abandoned
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4029628A (en) * | 1974-05-22 | 1977-06-14 | The United States Of America As Represented By The Secretary Of The Navy | Bonding material for planar electronic device |
US4914551A (en) * | 1988-07-13 | 1990-04-03 | International Business Machines Corporation | Electronic package with heat spreader member |
US5151777A (en) * | 1989-03-03 | 1992-09-29 | Delco Electronics Corporation | Interface device for thermally coupling an integrated circuit to a heat sink |
US5296310A (en) * | 1992-02-14 | 1994-03-22 | Materials Science Corporation | High conductivity hydrid material for thermal management |
US5582242A (en) * | 1992-05-15 | 1996-12-10 | Digital Equipment Corporation | Thermosiphon for cooling a high power die |
US5412535A (en) * | 1993-08-24 | 1995-05-02 | Convex Computer Corporation | Apparatus and method for cooling electronic devices |
US5720338A (en) * | 1993-09-10 | 1998-02-24 | Aavid Laboratories, Inc. | Two-phase thermal bag component cooler |
US6256201B1 (en) * | 1998-10-21 | 2001-07-03 | Furukawa Electric Co., Ltd. | Plate type heat pipe method of manufacturing same and cooling apparatus using plate type heat pipe |
US6490160B2 (en) * | 1999-07-15 | 2002-12-03 | Incep Technologies, Inc. | Vapor chamber with integrated pin array |
US6317322B1 (en) * | 2000-08-15 | 2001-11-13 | The Furukawa Electric Co., Ltd. | Plate type heat pipe and a cooling system using same |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050157471A1 (en) * | 2002-10-08 | 2005-07-21 | Intel Corporation | Integrated heat spreader package for heat transfer and for bond line thickness control and process of making |
US20100326714A1 (en) * | 2009-06-24 | 2010-12-30 | Fujitsu Limited | Printed circuit board, printed circuit board fabrication method, and electronic device including printed circuit board |
US8642896B2 (en) * | 2009-06-24 | 2014-02-04 | Fujitsu Limited | Printed circuit board, printed circuit board fabrication method, and electronic device including printed circuit board |
US20130044433A1 (en) * | 2010-05-24 | 2013-02-21 | Icepipe Corporation | Heat-dissipating device for electronic apparatus |
US8879261B2 (en) * | 2010-05-24 | 2014-11-04 | Icepipe Corporation | Heat-dissipating device for electronic apparatus |
Also Published As
Publication number | Publication date |
---|---|
US7006354B2 (en) | 2006-02-28 |
US20030081385A1 (en) | 2003-05-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7006354B2 (en) | Heat radiating structure for electronic device | |
KR100836305B1 (en) | Thermoelectric module | |
KR100299002B1 (en) | Stacked semiconductor device | |
US7100679B2 (en) | Integrated circuit heat pipe heat spreader with through mounting holes | |
US9282675B2 (en) | Thermal expansion-enhanced heat sink for an electronic assembly | |
US6651732B2 (en) | Thermally conductive elastomeric heat dissipation assembly with snap-in heat transfer conduit | |
US20050083655A1 (en) | Dielectric thermal stack for the cooling of high power electronics | |
CN1813348B (en) | Device comprising heat-conductive intermediate layer and heat conductive material as intermediate layer | |
US5024264A (en) | Method of cooling a semiconductor device with a cooling unit, using metal sherbet between the device and the cooling unit | |
US20050139995A1 (en) | CTE-matched heat pipe | |
US20050083652A1 (en) | Liquid cooled semiconductor device | |
US7759790B2 (en) | Lidless semiconductor cooling | |
JP2015522943A (en) | Thermoelectric heat exchanger components including protective heat spreading lid and optimal thermal interface resistance | |
US20050088823A1 (en) | Variable density graphite foam heat sink | |
JP2008028163A (en) | Power module device | |
US7898076B2 (en) | Structure and methods of processing for solder thermal interface materials for chip cooling | |
US20110070459A1 (en) | Thermal Management System | |
JP2019021864A (en) | Power module | |
US7355276B1 (en) | Thermally-enhanced circuit assembly | |
JP2005005391A (en) | Semiconductor device | |
JP2003124665A (en) | Heat sink structure for electronic device | |
US11355411B2 (en) | Heat sink and assembly method for heat sink | |
US20020050341A1 (en) | Heat pipe heat spreader with internal solid heat conductor | |
Conversion | Thermal Management of eGaN® FETs | |
JP2002093960A (en) | Cooling structure of multichip module and its manufacturing method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |