JP2005347616A - Heat spreader, manufacturing method thereof and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat spreader excellent in thermal conductivity and in size stability, and to provide the manufacturing method of the heat spreader. <P>SOLUTION: The heat spreader has a first surface 10A and an opposite second surface, and comprises a matrix material 11, and a carbon fiber cloth 12 containing a carbon fiber material including a component extending along the first surface 10A. A plurality of the carbon fiber materials are disposed such that hypothetical projection lines of the plurality of the carbon fiber materials to the first surface 10A extend radially around a reference axis A1 extending in the direction Z of the thickness. In the manufacturing method of the heat spreader, a plurality of the carbon fiber cloths are disposed so as to extend radially along the reference axis and around the reference axis. Then, the plurality of the carbon fiber cloths are impregnated with the matrix material to obtain a carbon fiber reinforced material consisted of such members. Then, pieces of the heat spreader are cut out from the carbon fiber reinforced material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat spreader that is interposed between a heat generating component and a heat radiating component and conducts heat conduction from the heat generating component to the heat radiating component, an electronic device including the heat spreader, and a heat spreader manufacturing method.

  When heat generated by a heat generating component in a computer is radiated using a heat radiating component such as a heat sink, a heat spreader is generally provided between the heat generating component and the heat radiating component. FIG. 23 shows a stacked structure including the semiconductor chip 101, the heat sink 102, and the heat spreader 60 as an example of such a cooling structure.

  The semiconductor chip 101 is a silicon chip as a heat generating component constituting a predetermined CPU, and is mounted on the substrate 103. The heat sink 102 is a heat radiating fin having a large surface area and is made of a metal material having high thermal conductivity. The heat spreader 60 is for transferring heat generated in the semiconductor chip 101 to the heat sink 102, and is located between the semiconductor chip 101 and the heat sink 102. The heat spreader 60 and the semiconductor chip 101 are at least thermally connected by interposing a heat conductive bonding material 104 such as solder by soldering or thermal grease. On the other hand, the heat spreader 60 and the heat sink 102 are thermally connected by the thermal grease 105 interposed therebetween. The technology related to the cooling structure is described in, for example, the following Patent Documents 1 to 4.

Japanese Patent Laid-Open No. 11-279406 JP 2000-124369 A JP 2000-273196 A US 2002/0038704

  In the conventional technique, a metal plate made of a metal material (copper, silver, aluminum, etc.) having high thermal conductivity may be employed as the heat spreader 60. Since these highly heat-conductive metal materials generally have a high coefficient of thermal expansion, in this case, the coefficient of thermal expansion of the heat spreader 60 is considerably higher than that of the semiconductor chip 101 that is a silicon chip (about 3.5 ppm / ° C.). Big. Therefore, as the bonding material 104 between the heat spreader 60 and the semiconductor chip 101, it is necessary to employ a paste-like material (for example, thermal grease) that can absorb the thermal expansion difference between the two in the in-plane direction. However, a paste-like bonding material such as thermal grease has a higher thermal resistance (that is, a lower thermal conductivity) than a metal bonding material such as soldered solder. Thermal conductivity from the chip 101 to the heat spreader 60 tends to be low. Therefore, when a metal plate is employed as the heat spreader 60, there may be a case where a sufficient heat dissipation function cannot be obtained as the entire cooling structure (heat dissipation system).

  On the other hand, in the conventional technique, a ceramic plate made of a ceramic material (aluminum nitride, alumina, silicon carbide, etc.) having a thermal expansion coefficient comparable to that of a silicon chip may be employed as the heat spreader 60. In this case, the thermal expansion coefficient of the heat spreader 60 is approximately the same as the thermal expansion coefficient of the semiconductor chip 101 that is a silicon chip. Therefore, as a connection mode between the heat spreader 60 and the semiconductor chip 101, the thermal resistance is small (that is, Soldering with high thermal conductivity can be employed (ie, a metal bonding material can be employed as the bonding material 104). However, a ceramic material showing a thermal expansion coefficient comparable to that of a silicon chip tends to have a lower thermal conductivity than a highly thermally conductive metal such as copper or silver. For this reason, when the above-described ceramic plate is employed as the heat spreader 60, it is difficult to obtain a high heat radiation function as the entire cooling structure (heat radiation system).

  As can be understood from the above, the characteristics required of the heat spreader for obtaining a high heat dissipation function as the entire cooling structure include thermal conductivity and dimensional stability in the in-plane direction. For example, the heat spreader 60 shown in FIG. 23 is required to have high thermal conductivity in order to efficiently transfer heat generated in the semiconductor chip 101 to the heat sink 102, and soldering with the semiconductor chip 101 is performed with low thermal resistance. Therefore, it is required to have a thermal expansion coefficient close to that of the semiconductor chip 101 (silicon chip). In recent years, the amount of heat generated by electronic components such as CPUs has increased with the increase in performance and functionality of computers and electronic devices, and these demands have become particularly strong.

  Carbon fiber reinforced metal (CFRM) is attracting attention as a heat spreader material for meeting the above-mentioned requirements. CFRM is a material composed of a matrix metal and carbon fibers in the matrix metal. The matrix metal is a high thermal conductivity metal such as copper or silver, and the carbon fiber exhibits high thermal conductivity in the fiber extending direction. Moreover, the thermal expansion coefficient in the fiber extending direction of the carbon fiber is small.

  FIG. 24 shows a conventional heat spreader 70 made of CFRM. FIG. 24A shows a cross section of the heat spreader 70 disposed between the semiconductor chip 101 and the heat sink 102. From the viewpoint of simplifying the figure, the bonding material between the semiconductor chip 101 and the heat sink 102 and the heat spreader 70 is omitted. FIG. 24B is a partially enlarged perspective view of the heat spreader 70.

  The heat spreader 70 includes a matrix metal 71 having a high thermal conductivity and a plurality of carbon fibers 72 extending through the matrix metal 71. The plurality of carbon fibers 72 extend in the same direction (X direction). When the heat spreader 70 is disposed between the semiconductor chip 101 and the heat sink 102, the carbon fibers 72 are oriented parallel to the semiconductor chip 101 and the heat sink 102.

  In such a heat spreader 70, depending on the kind of the matrix metal 71 and the density of the carbon fibers 72, a high thermal conductivity of about 600 to 800 W / mK, for example, and a sufficiently small thermal expansion coefficient can be obtained in the X direction. Is possible. However, in the direction (Y direction) substantially parallel to the semiconductor chip 101 or the heat sink 102 and orthogonal to the X direction, only a low thermal conductivity of about 30 W / mK can be obtained, and the thermal expansion coefficient is relatively low. large. Also, only a low thermal conductivity of about 30 W / mK can be obtained in the thickness direction (Z direction) of the heat spreader 70. With such a heat spreader 70, sufficient dimensional stability and thermal conductivity required in the cooling structure cannot be obtained.

  FIG. 25 shows another conventional heat spreader 80 made of CFRM. FIG. 25A shows a cross section of the heat spreader 80 disposed between the semiconductor chip 101 and the heat sink 102. From the viewpoint of simplifying the figure, the bonding material between the semiconductor chip 101 and the heat sink 102 and the heat spreader 80 is omitted. FIG. 25B is a partially enlarged perspective view of the heat spreader 80.

  The heat spreader 80 includes a matrix metal 81 having a high thermal conductivity and a plurality of carbon fiber cloths 82 disposed in the matrix metal 81. The plurality of carbon fiber cloths 82 are arranged in parallel to each other. Each carbon fiber cloth 82 is a plain weave cloth (weave structure is omitted), and a plurality of carbon fibers 82a extending in the same direction (X direction) and a plurality of carbon fibers extending in the same direction (Y direction) orthogonal to the X direction. 82b. When the heat spreader 80 is disposed between the semiconductor chip 101 and the heat sink 102, the carbon fiber cloth 82 (carbon fibers 82 a and 82 b) is oriented in parallel to the semiconductor chip 101 and the heat sink 102.

  Assuming that the total density of the carbon fibers 82a and 82b is the same as the density of the carbon fibers 72 of the heat spreader 70 and that the density of each of the carbon fibers 82a and 82b is equal, the heat spreader 70 is compared with the heat spreader 70. In the heat spreader 80, the thermal conductivity and dimensional stability in the X direction are greatly reduced. This is because the density of carbon fibers extending in the X direction is halved in the heat spreader 80 as compared with the heat spreader 70. In addition, compared with the heat spreader 70, the heat spreader 80 improves the thermal conductivity and dimensional stability in the Y direction, but the degree of improvement is half of the thermal conductivity and dimensional stability in the X direction of the heat spreader 70. It is only to the extent. The heat conductivity in the X direction and the Y direction in the heat spreader 80 is only about 300 to 340 W / mK, for example. In addition, in the Z direction in the heat spreader 80, as in the heat spreader 70, only a low thermal conductivity of about 30 W / mK can be obtained. In such a heat spreader 80, sufficient dimensional stability and thermal conductivity required in the cooling structure may not be obtained.

  FIG. 26 shows another conventional heat spreader 90 made of CFRM. FIG. 26A shows a cross section of the heat spreader 90 disposed between the semiconductor chip 101 and the heat sink 102. From the viewpoint of simplifying the figure, the bonding material between the semiconductor chip 101 and the heat sink 102 and the heat spreader 90 is omitted. FIG. 26B is a partially enlarged perspective view of the heat spreader 90.

  The heat spreader 90 includes a matrix metal 91 having high thermal conductivity, and a plurality of carbon fiber cloths 92 and a plurality of carbon fibers 93 arranged in the matrix metal 91. The plurality of carbon fiber cloths 92 are arranged in parallel to each other. Each carbon fiber cloth 92 is a plain woven cloth (weave structure is omitted), and a plurality of carbon fibers 92a extending in the same direction (X direction) and a plurality of carbon fibers extending in the same direction (Y direction) orthogonal to the X direction. 92b. The plurality of carbon fibers 93 extend in the same direction (Z direction, that is, the thickness direction) perpendicular to both the XY directions. When the heat spreader 90 is disposed between the semiconductor chip 101 and the heat sink 102, the carbon fiber cloth 92 (carbon fibers 92a and 92b) is oriented in parallel to the semiconductor chip 101 and the heat sink 102, and the carbon fiber 93 is a semiconductor. Oriented perpendicular to the chip 101 and heat sink 102.

  Assuming the case where the carbon fiber 92a, the carbon fiber 92b, and the carbon fiber 93 have the same content density, the heat spreader 90 tends to greatly decrease the thermal conductivity and dimensional stability in the X direction compared to the heat spreader 70. is there. This is because, compared with the heat spreader 70, in the heat spreader 90, the content density of the carbon fibers extending in the X direction has to be reduced to ¼. Compared with the heat spreader 70, the heat spreader 90 improves the thermal conductivity and dimensional stability in the Y direction, but the degree of improvement is 1/4 of the thermal conductivity and dimensional stability in the X direction of the heat spreader 70. It is only to the extent. In addition, as compared with the heat spreader 70, the heat spreader 90 improves the thermal conductivity in the Z direction, but is only about ¼ of the thermal conductivity in the X direction in the heat spreader 70. The thermal conductivity in each of the XYZ directions in the heat spreader 90 is only about 150 to 200 W / mK, for example. In such a heat spreader 90, sufficient dimensional stability and thermal conductivity required in the cooling structure may not be obtained.

  The present invention has been conceived under such circumstances, and provides a heat spreader having excellent thermal conductivity and excellent dimensional stability, and a method for manufacturing such a heat spreader. For the purpose.

  According to a first aspect of the present invention, a heat spreader is provided. The heat spreader has a first surface and a second surface opposite to the first surface, and includes a matrix material and a plurality of carbon fiber materials extending through the matrix material. In the plurality of carbon fiber materials, a plurality of virtual projection lines of the plurality of carbon fiber materials with respect to the first surface extend radially about an orientation reference axis extending in a thickness direction from the first surface to the second surface. Is arranged. The virtual projection line of the carbon fiber material with respect to the first surface is virtually projected onto the first surface when the carbon fiber material is virtually projected parallel to the first surface from the second surface side. Means a line. An orientation reference axis is a virtual axis that is set as a reference for the orientation relationship of a plurality of carbon fiber materials. When the cross section does not have a significant area, the cross section has a significant area. Including cases. Further, the plurality of virtual projection lines extending radially about the orientation reference axis means that the plurality of virtual projection lines are oriented so that each extension line of the plurality of virtual projection lines passes through the orientation reference axis. Means that If the orientation reference axis does not have a significant cross section, the extension lines of the plurality of virtual projection lines all intersect at the orientation reference axis. If the orientation reference axis has a significant cross section, the extension of any two virtual projection lines may or may not intersect within the orientation reference axis. When such a heat spreader is used, for example, a heat generating component (for example, a silicon chip constituting a CPU) is joined on the first surface so that the orientation reference axis passes through the heat generating component, (For example, a heat sink) is bonded to the second surface.

  In the heat spreader according to the first aspect of the present invention, the plurality of carbon fiber materials have a plurality of virtual projection lines extending radially from the first surface with the orientation reference axis extending in the thickness direction of the heat spreader as the center. Is arranged. Further, as described above, it is known that the carbon fiber material has a low coefficient of thermal expansion and a high thermal conductivity in the extending direction. Accordingly, the plurality of carbon fiber materials in the heat spreader are parallel to the first surface and radially extend around the orientation reference axis (in the heat propagation surface direction of the heat spreader) and the heat conduction function and thermal expansion suppression. Functions can be exhibited efficiently. Due to the efficient performance of the heat conduction function of multiple carbon fiber materials, the heat generated in the heat-generating component and flowing into the heat spreader should be diffused well in the heat propagation plane in the heat spreader. It becomes. In addition, due to the fact that a plurality of carbon fiber materials efficiently exhibit the thermal expansion suppressing function, the present heat spreader has a low thermal expansion coefficient comparable to that of a silicon chip in terms of the thermal expansion coefficient in the heat propagation in-plane direction. It is possible to realize. Therefore, it is possible to employ soldering with low thermal resistance, that is, high thermal conductivity, as a joining method between the heat spreader and the heat generating component. Thus, the heat spreader according to the first aspect of the present invention is excellent in thermal conductivity and dimensional stability. Such a heat spreader is suitable for obtaining a high heat radiation function as the entire cooling structure (heat radiation system).

  In a preferred embodiment of the first aspect of the present invention, each of the plurality of carbon fiber materials extends along the first surface. Such a configuration is suitable in order for the plurality of carbon fiber materials in the heat spreader to efficiently exhibit the heat conduction function and the thermal expansion suppressing function in the heat propagation in-plane direction of the heat spreader.

  In another preferred embodiment of the first aspect of the present invention, the plurality of carbon fiber materials extend radially around the intersection of the first surface and the orientation reference axis. According to such a configuration, the plurality of carbon fiber materials in the heat spreader can efficiently exhibit a heat conduction function also in the thickness direction of the heat spreader.

  The heat spreader according to the first aspect of the present invention preferably further includes a plurality of carbon fiber materials each extending in the thickness direction. Such a configuration is suitable for realizing high thermal conductivity in the thickness direction of the heat spreader.

  According to the second aspect of the present invention, another heat spreader is provided. This heat spreader has a first surface and a second surface opposite to the first surface, and includes a matrix material and a group of three or more carbon fibers. Each of the plurality of carbon fiber groups includes a plurality of carbon fiber materials extending in the matrix material, and has an alignment reference line extending along the first surface. Each of the plurality of carbon fiber materials of each carbon fiber group is arranged such that a virtual projection line of the carbon fiber material with respect to the first surface extends along an alignment reference line in the carbon fiber group. All the alignment reference lines in the plurality of carbon fiber groups extend radially about the alignment reference axis extending in the thickness direction from the first surface to the second surface. The orientation reference line of each carbon fiber group is a virtual line set as a reference for the orientation relationship of a plurality of carbon fiber materials contained in the carbon fiber group. The orientation reference axis is a virtual axis that is set as a reference for the orientation relationship of a plurality of orientation reference lines of three or more. When the cross section does not have a significant area, the cross section is significant. The case of having an area is included. In addition, all the alignment reference lines in the plurality of carbon fiber groups extend radially around the alignment reference axis. The plurality of alignment reference lines are aligned so that each of the alignment reference lines passes through the alignment reference axis. Means that If the alignment reference axis does not have a significant cross section, all of the three or more alignment reference lines intersect at the alignment reference axis. If the orientation reference axis has a significant cross section, any two orientation reference lines may or may not intersect within the orientation reference axis. The inner angle formed by two adjacent alignment reference lines is less than 180 degrees. When such a heat spreader is used, for example, a heat generating component (for example, a silicon chip constituting a CPU) is joined on the first surface so that the orientation reference axis passes through the heat generating component, (For example, a heat sink) is bonded to the second surface.

  In the heat spreader according to the second aspect of the present invention, a plurality of carbon fiber materials included in a single carbon fiber group extend in parallel to an alignment reference line set for each carbon fiber group. At the same time, all orientation reference lines of the three or more carbon fiber groups extend radially about the orientation reference axis extending in the thickness direction of the heat spreader. According to such a configuration, the plurality of carbon fiber groups (that is, the plurality of carbon fiber materials) in the heat spreader are parallel to the first surface and extend radially around the orientation reference axis (the heat propagation surface of the heat spreader). In the inner direction), the heat conduction function and the thermal expansion suppressing function can be efficiently exhibited. Due to the efficient performance of the heat conduction function of multiple carbon fiber materials, the heat generated in the heat-generating component and flowing into the heat spreader should be diffused well in the heat propagation plane in the heat spreader. It becomes. In addition, due to the fact that a plurality of carbon fiber materials efficiently exhibit the thermal expansion suppressing function, the present heat spreader has a low thermal expansion coefficient comparable to that of a silicon chip in terms of the thermal expansion coefficient in the heat propagation in-plane direction. It is possible to realize. Therefore, it is possible to employ soldering with low thermal resistance, that is, high thermal conductivity, as a joining method between the heat spreader and the heat generating component. Thus, the heat spreader according to the second aspect of the present invention is excellent in thermal conductivity and dimensional stability. Such a heat spreader is suitable for obtaining a high heat radiation function as the entire cooling structure (heat radiation system).

  The heat spreader according to the second aspect of the present invention preferably further includes a plurality of carbon fiber materials each extending in the thickness direction. Such a configuration is suitable for realizing high thermal conductivity in the thickness direction of the heat spreader.

  In the second aspect of the present invention, preferably, each of the plurality of carbon fiber materials in the plurality of carbon fiber groups extends along the first surface. Such a configuration is suitable for a plurality of carbon fiber materials contained in a plurality of carbon fiber groups in the heat spreader to efficiently exhibit a heat conduction function and a thermal expansion suppressing function in the heat propagation plane direction of the heat spreader. is there.

  According to a third aspect of the present invention, there is provided an electronic device comprising a heat spreader and a heat-generating electronic component having any of the configurations described above with respect to the first or second aspect. In this electronic device, the electronic component is thermally connected to a location where the alignment reference axis passes on the first surface of the heat spreader. This electronic device includes the above-described heat spreader of the first or second side surface, and is therefore suitable for realizing a good cooling structure for suppressing an excessive temperature rise of the heat-generating electronic component.

  According to a fourth aspect of the present invention, there is provided an electronic device comprising a heat spreader having any one of the configurations described above with respect to the first or second aspect, a heat-generating electronic component, and a radiator. In the present electronic device, the electronic component is thermally connected to the location where the orientation reference axis passes on the first surface of the heat spreader, and the heat radiator is thermally connected to the second surface of the heat spreader. Has been. The electronic device includes the above-described heat spreader of the first or second side surface and a heat radiating body for receiving and dissipating heat from the heat spreader. Therefore, for suppressing an excessive temperature rise of the heat-generating electronic component. Has a good cooling structure.

  According to a fifth aspect of the present invention, a heat spreader manufacturing method is provided. This manufacturing method includes an arrangement step, an impregnation step, and a cutting step. In the arranging step, the plurality of carbon fiber cloths are arranged so as to extend radially along the orientation reference axis and centering on the orientation reference axis. The carbon fiber cloth includes, for example, a plurality of carbon fiber materials each extending in the first direction and a plurality of carbon fiber materials each extending in a direction intersecting the first direction. The orientation reference axis is a virtual axis that is set as a reference for the orientation relationship of a plurality of carbon fiber cloths. When the cross section does not have a significant area, the cross section has a significant area. Including cases. The plurality of carbon fiber cloths extending radially around the alignment reference axis while being along the alignment reference axis means that the plurality of carbon fiber cloths pass through the alignment reference axis. Means that they are oriented. In the impregnation step, the carbon fiber reinforced material body including the matrix material and the plurality of carbon fiber materials is obtained by impregnating the plurality of carbon fiber cloths with the matrix material. In the cutting step, the carbon fiber reinforced material body is cut. The cutting in this step includes at least cutting in a direction intersecting the orientation reference axis. In such a cutting step, the heat spreader pieces are cut out from the carbon fiber reinforced material body. According to such a manufacturing method, the heat spreader according to the first aspect of the present invention can be appropriately manufactured.

  In the first to fifth aspects of the present invention, preferably, the matrix material includes a metal selected from the group consisting of silver, copper, aluminum, and magnesium. Since these metal materials exhibit high thermal conductivity, they are suitable as matrix materials.

  In the first to fifth aspects of the present invention, preferably, the matrix material includes amorphous carbon. Amorphous carbon is suitable as a matrix material because it exhibits high thermal conductivity.

  1 and 2 show a heat spreader 10 according to a first embodiment of the present invention. 1 is a partially cutaway perspective view of the heat spreader 10, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  The heat spreader 10 includes a matrix material 11 and a plurality of carbon fiber cloths 12, and has a first surface 10A and a second surface 10B opposite to the first surface 10A. The first surface 10A is a surface that is thermally connected to the heat-generating component, and the second surface 10B is a surface that is thermally connected to the heat-radiating component.

  The matrix material 11 is made of, for example, metal or amorphous carbon having high thermal conductivity, and a part of the matrix material 11 is cut out in FIG. As a metal for constituting the matrix material 11, for example, a single metal selected from the group consisting of silver, copper, aluminum, and magnesium or an alloy containing a metal selected from the group is adopted. Can do. These metals areotropically exhibit a thermal conductivity of about 150 to 420 W / mK and a coefficient of thermal expansion of about 16 to 26 ppm / ° C. Amorphous carbon isotropically exhibits a thermal conductivity of about 100 to 250 W / mK and a thermal expansion coefficient of about -1 to 10 ppm / ° C. When the matrix material 11 is made of amorphous carbon, or when the matrix material 11 is made of amorphous carbon and another substance impregnated therein (for example, the above-described metal), the heat spreader 10 is a so-called carbon carbon composite (C / C). It has a material structure corresponding to the composite).

  The plurality of carbon fiber cloths 12 are arranged so as to extend in the thickness direction Z of the heat spreader 10 and to extend radially about the orientation reference axis A1 extending in the thickness direction Z. That is, all the extended surfaces of the plurality of carbon fiber cloths 12 intersect at the orientation reference axis A1. The orientation reference axis A1 is an imaginary axis that is set as a reference for the orientation relationship of the plurality of carbon fiber cloths 12 or the carbon fiber materials constituting the carbon fiber cloths 12. Each carbon fiber cloth 12 is a plain weave cloth (weave structure is omitted in FIG. 1). As shown in FIG. 2, a plurality of carbon fiber materials 12a extending along the first surface 10A and a thickness direction Z And a plurality of carbon fiber materials 12b extending in the direction. The carbon fiber materials 12a and 12b are carbon fiber yarns obtained by bundling a plurality of carbon fibers, and exhibit high thermal conductivity of about 400 to 800 W / mK in the fiber extending direction, and about −5 to 3 ppm / ° C. It exhibits a low coefficient of thermal expansion. The same applies to later-described carbon fiber materials in the embodiments described later. Moreover, the content rate of carbon fiber material 12a, 12b in the heat spreader 10 is 10-70 vol%, for example, and the content ratio of the carbon fiber material 12a and the carbon fiber material 12b is 1: 3-5: 1.

  As shown in FIG. 3, virtual projection lines 13 for the first surface 10A of the plurality of carbon fiber materials 12a included in the plurality of carbon fiber cloths 12 extend radially about the orientation reference axis A1. That is, the plurality of carbon fiber materials 12a included in the plurality of carbon fiber cloths 12 are arranged such that their virtual projection lines 13 with respect to the first surface 10A extend radially around the orientation reference axis A1. . In the present embodiment, all extension lines of the plurality of virtual projection lines 13 intersect at the orientation reference axis A1. From the viewpoint of simplifying the figure, only some of the extension lines are shown by broken lines. The virtual projection line 13 of each carbon fiber material 12a with respect to the first surface 10A is the first when the carbon fiber material 12a is virtually parallel projected from the second surface 10B side perpendicular to the first surface 10A. It is a line virtually projected on the surface 10A, and is represented by a solid line in FIG. Further, the virtual projection lines 13 of the plurality of carbon fiber materials 12a included in the same carbon fiber cloth 12 substantially coincide on the first surface 10A.

  FIG. 4 shows an example of a method for manufacturing the heat spreader 10. In this method, first, as shown in FIG. 4A, a plurality of carbon fiber cloths 12 'are arranged radially along the orientation reference axis A1 and centered on the orientation reference axis A1 (arrangement step). ). In this step, in order to make the carbon fiber density in the finally obtained heat spreader 10 substantially uniform, the farther from the orientation reference axis A1, the more the number of carbon fiber cloths 12 arranged in the circumferential direction increases. It is preferable to arrange a carbon fiber cloth 12 '. Next, as shown in FIG. 4B, the matrix material 11 is impregnated into the plurality of carbon fiber cloths 12 'arranged in this manner (impregnation step). Examples of the impregnation technique include a method of impregnating the carbon fiber cloth 12 ′ with the matrix material 11 using a hot isostatic pressing (HIP) apparatus, or a carbon in the matrix material 11 in a molten state. A method of immersing the fiber cloth 12 'can be employed. By this step, a carbon fiber reinforced material body 10 ′ including the matrix material 11 and a plurality of carbon fiber materials 12 ′ is obtained. Next, a plurality of heat spreaders 10 are cut out as shown in FIG. 4C by cutting predetermined portions of the carbon fiber reinforced material body 10 '(cutting step). Cutting in this step includes cutting in a direction orthogonal to the orientation reference axis A1. As described above, the heat spreader 10 including the matrix material 11 and the plurality of carbon fiber cloths 12 can be manufactured.

  FIG. 5 shows an example of a cooling structure including the heat spreader 10. The cooling structure has a laminated structure including the semiconductor chip 101, the heat sink 102, and the heat spreader 10 of the present invention. The semiconductor chip 101 is a silicon chip as a heat generating component constituting a predetermined CPU, and is mounted on the substrate 103. The heat sink 102 is a heat radiating fin having a large surface area and is made of a metal material having high thermal conductivity. The heat spreader 10 is positioned between the semiconductor chip 101 and the heat sink 102 with the first surface 10 </ b> A oriented toward the semiconductor chip 101. The semiconductor chip 101 which is a heat-generating component is soldered to the heat spreader 10 or its first surface 10A by solder 104 ', and is mechanically and thermally bonded. The semiconductor chip 101 is bonded to the first surface 10 </ b> A at a position where the alignment reference axis A <b> 1 of the heat spreader 10 passes through the semiconductor chip 101. On the other hand, the heat spreader 10 or its second surface 10B and the heat sink 102 are thermally connected by the thermal grease 105 interposed therebetween.

  When heat is generated in the semiconductor chip 101, a part of this heat flows into the heat spreader 10 through the solder 104 '. The inflow heat propagates radially from the inflow location in the in-plane direction of the heat spreader 10. At the same time, the heat that has flowed in also propagates in the thickness direction Z. The heat that has propagated through the heat spreader 10 and reached the second surface 10 </ b> B flows into the heat sink 102 via the thermal grease 105 and is then dissipated outside the cooling structure by the heat sink 102. In the heat spreader 10, the plurality of carbon fiber materials 12a are arranged so that the plurality of virtual projection lines 13 with respect to the first surface 10A (heat generating component joining surface) extend radially about the orientation reference axis A1. Yes. Accordingly, the plurality of carbon fiber materials 12a can efficiently exhibit the heat conduction function and the thermal expansion suppressing function in the above-described heat propagation in-plane direction.

  The heat generated in the semiconductor chip 101 and flowing into the heat spreader 10 due to the plurality of carbon fiber materials 12a efficiently exhibiting the heat conduction function is parallel to the first surface 10A and from the orientation reference axis A1. The heat spreader 10 is diffused well in the radially extending direction. In addition, since the plurality of carbon fiber materials 12b extend in the thickness direction Z, the heat spreader 10 can appropriately exhibit a heat conduction function also in the thickness direction Z. In addition, due to the fact that the plurality of carbon fiber materials 12a efficiently exhibit the thermal expansion suppressing function, in the heat spreader 10, the thermal expansion coefficient in the heat propagation in-plane direction is comparable to that of the semiconductor chip 101 (silicon chip). It is possible to realize a low coefficient of thermal expansion. Therefore, it is possible to employ soldering as a joining method between the heat spreader 10 and the semiconductor chip 101 and to join the two with the solder 104 ′. The solder 104 ′ exhibits low thermal resistance, that is, high thermal conductivity, and can realize good heat transfer from the semiconductor chip 101 to the heat spreader 10. Thus, the heat spreader 10 is excellent in thermal conductivity and dimensional stability. Such a heat spreader 10 is suitable for obtaining a high heat radiation function as a whole cooling structure (heat radiation system).

  The heat spreader 10 can be used without being directly joined to the heat-generating electronic component. For example, a location where one end of a heat transfer path member (for example, made of metal) having a significant length is at least thermally connected to the heat-generating electronic component and the orientation reference axis A1 passes through the first surface 10A of the heat spreader 10 However, the heat receiving function from the heat-generating electronic component by the heat spreader 10 may be secured by at least thermally connecting the other end of the heat transfer path member. Further, the heat spreader 10 can be used without being directly joined to the heat radiator. For example, one end of a heat transfer path member having a significant length is at least thermally connected to the heat spreader 10 and the other end of the heat transfer path member is at least thermally connected to the heat dissipator to dissipate heat from the heat spreader 10. The function of releasing heat to the body may be ensured. The fact that such a usage mode is possible is the same for the heat spreader of the embodiment described later.

  In the heat spreader 10, the orientation reference axis A1 may be set as having a significant cross-sectional area as shown in FIG. 6, for example. In the present invention, when a predetermined heat generating component (semiconductor chip 101) is bonded to a predetermined position (for example, the center) on the first surface 10A, as long as the alignment reference axis A1 can pass through the heat generating component, the alignment reference. It can set suitably about the cross-sectional area of axis | shaft A1. In this case, the plurality of carbon fiber cloths 12 are arranged such that all of the extended surfaces thereof pass through the alignment reference axis A1, but any two extended surfaces need not necessarily intersect within the alignment reference axis A1. There is no. That is, when the orientation reference axis A1 having a significant cross-sectional area is set, a degree of freedom occurs with respect to the orientation of each carbon fiber cloth 12. The greater the cross-sectional area of the alignment reference axis A1, the higher the degree of freedom. When this configuration is adopted, the heat-generating component (semiconductor chip 101) is bonded to a region including a portion where the first surface 10A and the orientation reference axis A1 intersect on the first surface 10A. Therefore, also in this configuration, the plurality of carbon fiber materials 12a arranged so that the plurality of virtual projection lines 13 with respect to the first surface 10A (heat generating component joint surface) extend radially about the orientation reference axis A1 are In the propagation in-plane direction, the heat conduction function and the thermal expansion suppressing function can be efficiently exhibited.

  7 and 8 show a heat spreader 20 according to the second embodiment of the present invention. 7 is a partially cutaway perspective view of the heat spreader 20, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

  The heat spreader 20 includes a matrix material 21 and a plurality of carbon fiber materials 22, and has a first surface 20A and a second surface 20B opposite to the first surface 20A. The first surface 20A is a surface thermally connected to the heat generating component, and the second surface 20B is a surface thermally connected to the heat radiating component.

  The matrix material 21 is made of, for example, metal or amorphous carbon having a high thermal conductivity, and a part of the matrix material 21 is notched in FIG. The material for forming the matrix material 21 is the same as that described above with respect to the matrix material 11 in the first embodiment.

  The plurality of carbon fiber materials 22 are arranged so as to diverge around the location S where the first surface 20A and the orientation reference axis A2 intersect (to extend radially). The orientation reference axis A <b> 2 is a virtual axis that is set as a reference for the orientation relationship of the plurality of carbon fiber materials 22, and extends in the thickness direction Z of the heat spreader 20. As shown in FIG. 9, virtual projection lines 23 for the first surface 20A of the plurality of carbon fiber materials 22 extend radially about the orientation reference axis A2. That is, the plurality of carbon fiber materials 22 are arranged so that their virtual projection lines 23 with respect to the first surface 20A extend radially around the orientation reference axis A2. In the present embodiment, all extension lines of the plurality of virtual projection lines 23 intersect at the orientation reference axis A2. From the viewpoint of simplifying the figure, only some of the extension lines are shown by broken lines. The virtual projection line 23 of each carbon fiber material 22 with respect to the first surface 20A is first when the carbon fiber material 22 is virtually projected parallel to the first surface 20A from the second surface 20B side. This line is virtually projected on the surface 20A, and is represented by a solid line in FIG. In the present embodiment, it may occur when the virtual projection lines 23 derived from the plurality of carbon fiber materials 22 coincide or overlap on the first surface 20A. Moreover, the content rate of the carbon fiber material 22 in the heat spreader 20 is 10-70 vol%, for example.

  FIG. 10 shows an example of a cooling structure including the heat spreader 20. This cooling structure has a laminated structure including the semiconductor chip 101, the heat sink 102, and the heat spreader 20 of the present invention. The heat spreader 20 is positioned between the semiconductor chip 101 and the heat sink 102 with the first surface 20 </ b> A oriented toward the semiconductor chip 101. The semiconductor chip 101, which is a heat generating component, is soldered to the heat spreader 20 or its first surface 20A by solder 104 'and is mechanically and thermally bonded. The semiconductor chip 101 is bonded to the first surface 20 </ b> A at a position where the alignment reference axis A <b> 2 of the heat spreader 20 passes through the semiconductor chip 101. On the other hand, the heat spreader 20 or its second surface 20B and the heat sink 102 are thermally connected by the thermal grease 105 interposed therebetween.

  When heat is generated in the semiconductor chip 101, part of the heat flows into the heat spreader 20 through the solder 104 '. The inflow heat propagates radially from the inflow location in the in-plane direction of the heat spreader 20. At the same time, the heat that has flowed in also propagates in the thickness direction Z. The heat that has propagated through the heat spreader 20 and reached the second surface 20 </ b> B flows into the heat sink 102 via the thermal grease 105, and is then dissipated outside the cooling structure by the heat sink 102. In the heat spreader 20, the plurality of carbon fiber materials 22 are arranged so that the plurality of virtual projection lines 23 with respect to the first surface 20A (heat generating component joining surface) extend radially about the orientation reference axis A2. Yes. Accordingly, the plurality of carbon fiber materials 22 can efficiently exhibit the heat conduction function and the thermal expansion suppressing function in the above-described in-plane direction of heat propagation.

  The heat generated in the semiconductor chip 101 and flowing into the heat spreader 20 due to the plurality of carbon fiber materials 22 exhibiting the heat conduction function efficiently is parallel to the first surface 20A and from the orientation reference axis A2. The inside of the heat spreader 20 is favorably diffused in the radially extending direction. In addition, since each of the plurality of carbon fiber materials 22 has a component extending in the thickness direction Z, the heat spreader 20 can appropriately exhibit a heat conduction function in the thickness direction Z as well. In addition, due to the fact that the plurality of carbon fiber materials 22 efficiently exhibit the thermal expansion suppressing function, in the heat spreader 20, the thermal expansion coefficient in the heat propagation in-plane direction is comparable to that of the semiconductor chip 101 (silicon chip). It is possible to realize a low coefficient of thermal expansion. Therefore, it is possible to employ soldering as a joining method between the heat spreader 20 and the semiconductor chip 101 and to join them together with the solder 104 ′. Thus, the heat spreader 20 is excellent in thermal conductivity and dimensional stability. Such a heat spreader 20 is suitable for obtaining a high heat radiation function as a whole cooling structure (heat radiation system).

  As with the orientation reference axis A1 of the heat spreader 10, the orientation reference axis A2 of the heat spreader 20 may be set as having a significant cross-sectional area. In this case, the plurality of carbon fiber materials 22 are arranged so that all the extension lines of the virtual projection lines 23 pass through the alignment reference axis A2, but any two extension lines are not necessarily the alignment reference axis A2. There is no need to cross within. That is, when the orientation reference axis A2 having a significant cross-sectional area is set, a degree of freedom occurs with respect to the orientation of each carbon fiber material 22. The greater the cross-sectional area of the orientation reference axis A2, the higher the degree of freedom. When this configuration is employed, the heat generating component (semiconductor chip 101) is bonded to a region including the portion S where the first surface 20A and the orientation reference axis A2 intersect on the first surface 20A. Therefore, also in this configuration, the plurality of carbon fiber materials 22 arranged so that the plurality of virtual projection lines 23 with respect to the first surface 20A (heat generating component joint surface) extend radially about the orientation reference axis A2 are In the propagation in-plane direction, the heat conduction function and the thermal expansion suppressing function can be efficiently exhibited.

  11 to 13 show a heat spreader 30 according to a third embodiment of the present invention. FIG. 11 is a partially cutaway perspective view of the heat spreader 30, and FIGS. 12 and 13 are cross-sectional views taken along lines XII-XII and XIII-XIII of FIG. 11, respectively.

  The heat spreader 30 includes a matrix material 31 and a plurality of carbon fiber cloths 32, and a part of the heat spreader 30 is cut out in FIG. The first surface 30A has a second surface 30B opposite to the first surface 30A. The first surface 30A is a surface that is thermally connected to the heat-generating component, and the second surface 30B is a surface that is thermally connected to the heat-radiating component.

  The matrix material 31 is made of, for example, metal or amorphous carbon having high thermal conductivity. The material for forming the matrix material 31 is the same as that described above with respect to the matrix material 11 in the first embodiment.

  Each carbon fiber cloth 32 is a plain woven cloth (weave structure is omitted in FIG. 11), and as shown in FIGS. 12 and 13, a plurality of carbon fiber materials 32a extending along the first surface 30A, and the thickness direction And a plurality of carbon fiber materials 32b extending in Z. The plurality of carbon fiber cloths 32 constitute a plurality of cloth groups, and each carbon fiber cloth 32 included in the single cloth group extends along the orientation reference line L set for each cloth group, and the heat spreader 30. It is arrange | positioned so that it may also extend in the thickness direction Z. In the present embodiment, as shown in FIG. 14, four fabric groups are configured. Each orientation reference line L is an imaginary line set as a reference for the orientation relationship of each carbon fiber cloth 32 included in a single cloth group or further the carbon fiber material 32a included therein, and the first surface 30A. Extending along. A plurality (four in this embodiment) of alignment reference lines L of the plurality of fabric groups extend radially about the alignment reference axis A3 extending in the thickness direction Z, as shown well in FIG. That is, the plurality of alignment reference lines L intersect at the alignment reference axis A3. The orientation reference axis A3 is a virtual axis that is set as a reference for the orientation relationship between the plurality of orientation reference lines L or the plurality of fabric groups.

  A plurality of carbon fiber materials 32a included in a single cloth group constitute one carbon fiber group. Moreover, the virtual projection line 33 with respect to the 1st surface 30A of the some carbon fiber material 32a contained in the same cloth group substantially corresponds, and as shown in FIG. 14, it is the same along the orientation reference line L of the said cloth group. Extend in the direction. The virtual projection line 33 of each carbon fiber material 32a with respect to the first surface 30A is the first when the carbon fiber material 32a is virtually projected parallel to the first surface 30A from the second surface 30B side. The line is virtually projected on the surface 30A, and is represented by a solid line in FIG. Moreover, the content rate of carbon fiber material 32a, 32b in the heat spreader 30 is 10-70 vol%, for example, and the content ratio of the carbon fiber material 32a and the carbon fiber material 32b is 1: 3-5: 1, for example.

  FIG. 15 illustrates a first example of a method for manufacturing the heat spreader 30. In this method, first, as shown in FIG. 15 (a), the carbon fiber reinforced material body 30 'is cut to obtain individual pieces 30a. The carbon fiber reinforced material body 30 ′ includes a matrix material 31 and a plurality of carbon fiber cloths 32 ′. The plurality of carbon fiber cloths 32 ′ are parallel to each other and extend in a certain direction within the carbon fiber reinforced material body 30 ′. The piece 30a is composed of the matrix material 31 and the carbon fiber cloth 32 described above, and in this step, the carbon pieces so that the plurality of carbon fiber cloths 32 included in each piece 30a constitute the above-described single carbon fiber group. The fiber reinforced material body 30 ′ is cut. In this embodiment, the piece 30a has an isosceles triangle shape with an apex angle of 90 °, and each carbon fiber cloth 32 included in the piece 30a extends in a direction perpendicular to the oblique side of the shape. . After obtaining such an individual piece 30a, as shown in FIG. 15B, the four individual pieces 30a are joined. For example, brazing or soldering can be employed as the joining means. As described above, the heat spreader 30 including the matrix material 31 and the plurality of carbon fiber cloths 32 can be manufactured.

  FIG. 16 shows a second example of the method for manufacturing the heat spreader 30. In this method, first, a predetermined number of pieces 30b as shown in FIG. 16A are obtained by cutting the same carbon fiber reinforced material body 30 'as described above. The piece 30b has a square shape, and each carbon fiber cloth 32 'included in the piece 30b extends along the diagonal of the shape and also extends in the thickness direction. Next, as shown in FIGS. 16B and 16C, a plurality of pieces 30b are joined. Next, the part shown with a broken line in FIG.16 (c) in this joined body is cut | disconnected. Even in this way, the heat spreader 30 can be manufactured. This method is efficient in mass-producing the heat spreader 30.

  FIG. 17 shows an example of a cooling structure including the heat spreader 30. This cooling structure has a laminated structure including the semiconductor chip 101, the heat sink 102, and the heat spreader 30 of the present invention. The heat spreader 30 is located between the semiconductor chip 101 and the heat sink 102. The semiconductor chip 101 that is a heat generating component is soldered to the first surface 30A or the second surface 30B of the heat spreader 30 by solder 104 'and is mechanically and thermally bonded. The semiconductor chip 101 is bonded to the heat spreader 30 at a position where the alignment reference axis A3 of the heat spreader 30 passes through the semiconductor chip 101. On the other hand, the second surface 30B or the first surface 30A of the heat spreader 30 and the heat sink 102 are thermally connected by the thermal grease 105 interposed therebetween.

  When heat is generated in the semiconductor chip 101, a part of this heat flows into the heat spreader 30 through the solder 104 '. The inflowing heat propagates radially from the inflow location in the in-plane direction of the heat spreader 30. At the same time, the heat that has flowed in also propagates in the thickness direction Z. The heat that has propagated through the heat spreader 30 and reached the second surface 30 </ b> B (first surface 30 </ b> A) flows into the heat sink 102 via the thermal grease 105, and is then dissipated outside the cooling structure by the heat sink 102. In the heat spreader 30, each cloth group is configured by a plurality of carbon fiber cloths 32 (consisting of carbon fiber materials 32a and 32a) extending in the thickness direction Z and parallel to each other, and the four cloth groups are The four alignment reference lines L are arranged so as to extend radially around the alignment reference axis A3. Therefore, the carbon fiber material 32a included in the carbon fiber cloth 32 in the heat spreader 30 and extending along the first surface 30A efficiently exhibits the heat conduction function and the thermal expansion suppressing function in the above-described heat propagation in-plane direction. be able to.

  The heat generated in the semiconductor chip 101 and flowing into the heat spreader 30 due to the plurality of carbon fiber materials 32a efficiently exhibiting the heat conduction function is parallel to the first surface 30A and from the orientation reference axis A3. The inside of the heat spreader 30 is favorably diffused in the radially extending direction. In addition, since each of the plurality of carbon fiber materials 32b extends in the thickness direction Z, the heat spreader 30 can appropriately exhibit a heat conduction function also in the thickness direction Z. In addition, due to the fact that the plurality of carbon fiber materials 32a efficiently exhibit the function of suppressing thermal expansion, in the heat spreader 30, the thermal expansion coefficient in the heat propagation in-plane direction is comparable to that of the semiconductor chip 101 (silicon chip). It is possible to realize a low coefficient of thermal expansion. Therefore, it is possible to employ soldering as a joining method between the heat spreader 30 and the semiconductor chip 101 and to join them together with the solder 104 ′. Thus, the heat spreader 30 is excellent in thermal conductivity and dimensional stability. Such a heat spreader 30 is suitable for obtaining a high heat radiation function as a whole cooling structure (heat radiation system).

  In the heat spreader 30, the carbon fiber cloth 32 may be provided in such a manner that the carbon fiber material 32a extends in the thickness direction Z together with the carbon fiber material 32b and has a component as shown in FIG. In this case, both the carbon fiber materials 32a and 32b extend in both the in-plane direction and the thickness direction Z and have components. Therefore, in this configuration, the carbon fiber materials 32a and 32b included in the carbon fiber cloth 32 in the heat spreader 30 efficiently perform the heat conduction function and the thermal expansion suppression function in both the heat propagation in-plane direction and the thickness direction Z. Can demonstrate well.

  In the heat spreader 30, the number of fabric groups or carbon fiber groups may be set to 3 or 5 or more. FIG. 19 shows a case where the number of fabric groups or carbon fiber groups is set to eight. As the number of fabric groups or carbon fiber groups increases, the orientation of the carbon fiber material 32a included in the heat spreader 30 approximates the orientation of the carbon fiber material 12a in the heat spreader 10 of the first embodiment. Also with such a configuration, high heat conductivity and high dimensional stability can be obtained in the heat spreader 30.

[Example 1]
[Production of heat spreader]
As the heat spreader having the configuration of the first embodiment (heat spreader 10), the heat spreader of this example was manufactured. In the production of the heat spreader of the present example, first, as shown in FIG. 20A, a carbon fiber cloth 12 ′ was placed in a cylindrical container 41 (inner diameter 65 mm, height 100 mm, wall thickness 0.5 mm) ( Placement process). In this embodiment, the cylindrical container 41 is made of copper. Further, the carbon fiber cloth 12 ′ of this example is a plain weave cloth (thickness) made of carbon fiber (trade name: K13C2U, manufactured by Mitsubishi Chemical Corporation) having a thermal conductivity of 620 W / mK in the fiber extending direction. 0.25 mm), and the weight ratio of the weft and warp is 1: 1. In this arrangement step, each carbon fiber cloth 12 'is erected so that the warp yarns follow the orientation reference axis A1 set to extend in the height direction at the center of the cylindrical container 41 (therefore, the weft yarn is a carbon fiber material. 12a, and the warp yarn corresponds to the carbon fiber 12b), and a plurality of carbon fiber cloths 12 'were arranged radially along the orientation reference axis A1 and centered on the orientation reference axis A1. Further, in order to make the carbon fiber density in the finally obtained heat spreader substantially uniform, the carbon fiber is increased so that the number of the carbon fiber cloths 12 'arranged in the circumferential direction increases as the distance from the orientation reference axis A1 increases. The cloth 12 was arranged (the arrangement mode was simplified on the drawing).

  Next, the carbon fiber reinforced copper 10 ′ is impregnated by impregnating the carbon fiber cloth 12 ′ arranged as described above with the matrix material 11 using a hot isostatic pressing (HIP) apparatus. (Impregnation step) was obtained. Specifically, first, as shown in FIG. 20 (b), a cylindrical container 41 packed with a carbon fiber cloth 12 is made into a steel-made capsule 42 having a predetermined nozzle (inner diameter 115 mm, inner dimension height 100 mm, The bottom part thickness is 15 mm, the top part thickness is 15 mm, and the side wall 42 a is 2 mm thick), and the gap between the cylindrical container 41 and the capsule 42 is filled with copper powder 43 (average particle size 100 μm). The entire body and the lid 42b were welded. Next, the inside of the capsule 42 was evacuated substantially by degassing the inside of the capsule 42 through a nozzle using a vacuum pump device. Next, the tip of the nozzle was welded to seal the capsule 42. Next, this capsule 42 was placed in the chamber of the HIP apparatus and subjected to hot isostatic pressing. At this time, the pressure in the chamber was about 100 MPa, the temperature in the chamber was 1130 ° C. (50 ° C. higher than the melting point of copper), and the pressurization time was 5 minutes. In such hot isostatic pressing, the cylindrical container 41 (made of copper in this embodiment) and the copper powder 43 in the capsule 42 are melted and the side wall 42a of the capsule 42 as shown in FIG. 20 (c). As a result, copper is well impregnated between the carbon fibers.

  Next, the capsule 42 was removed by mechanical cutting to obtain a cylindrical carbon fiber reinforced copper 10 '(65 mm in diameter and 100 mm in height) as shown in FIG. Next, about 30 heat spreaders (45 mm × 45 mm, thickness 3 mm) were cut out from the carbon fiber reinforced copper 10 ′ by mechanical cutting. At this time, each heat spreader was cut out so that the above-mentioned alignment reference axis A1 passes through the center of the heat spreader perpendicularly to the heat spreader. As described above, the heat spreader of this example was manufactured. The carbon fiber content of the heat spreader of this example is 30 vol%.

(Physical property measurement)
About the heat spreader of a present Example, the thermal conductivity and thermal expansion coefficient of radial direction (in-plane direction) were measured from the center of the heat spreader, and the thermal conductivity of the thickness direction was measured. Both the thermal conductivity in the radial direction and the thermal conductivity in the thickness direction were 400 W / mK, and a sufficiently high value was obtained. Further, the thermal expansion coefficient in the radial direction was 7 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. These values are listed in the table of FIG.

[Examples 2 and 3]
[Production of heat spreader]
The same as in Example 1, except that the content ratio of weft and warp was changed to 1: 1 and 2: 1 (Example 2) or 5: 1 (Example 3) while keeping the same carbon fiber content. The heat spreaders of Examples 2 and 3 were produced.

(Physical property measurement)
Regarding the heat spreaders of Examples 2 and 3, the thermal conductivity and thermal expansion coefficient in the radial direction and the thermal conductivity in the thickness direction were measured from the center of the heat spreader. The heat conductivity in the radial direction of the heat spreader of Example 2 was 470 W / mK, and the heat conductivity in the thickness direction was 300 W / mK, both of which were sufficiently high values. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Example 2 was 4.5 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. The heat spreader in the radial direction of the heat spreader of Example 3 was 560 W / mK, and the heat conductivity in the thickness direction was 250 W / mK, both of which were sufficiently high values. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Example 3 was 3 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. These values are listed in the table of FIG.

[Examples 4 to 6]
[Production of heat spreader]
Heat spreaders of Examples 4 to 6 were produced in the same manner as in Examples 1 to 3, except that aluminum was used instead of copper as the matrix material. In the manufacture of the heat spreaders of Examples 4 to 6, the cylindrical container 41 is made of aluminum and is used as a metal material that fills the gap between the cylindrical container 41 and the capsule 42 during the hot isostatic pressing process. Used aluminum powder (average particle size 100 μm) instead of copper powder 43. In the heat spreaders of Examples 4 to 6, the carbon fiber content is 30 vol%, and the content ratio of the weft and warp of the carbon fiber cloth 12 is 1: 1 (Example 4) and 2: 1 (implementation). Examples 5) and 5: 1 (Example 6).

(Physical property measurement)
About the heat spreader of Examples 4-6, the thermal conductivity and thermal expansion coefficient of radial direction and the thermal conductivity of thickness direction were measured from the center of the heat spreader. Both the heat conductivity in the radial direction and the heat conductivity in the thickness direction of the heat spreader of Example 4 were 350 W / mK, and a sufficiently high value was obtained. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Example 4 was 6 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. The heat spreader in the radial direction of the heat spreader of Example 5 was 420 W / mK and the heat conductivity in the thickness direction was 270 W / mK, both of which were sufficiently high values. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Example 5 was 4 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. The heat spreader in the radial direction of the heat spreader of Example 6 was 500 W / mK and the heat conductivity in the thickness direction was 220 W / mK, both of which were sufficiently high values. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Example 6 was 3 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. These values are listed in the table of FIG.

[Comparative Examples 1-4]
[Configuration of heat spreader]
A heat spreader (45 mm) having, in a copper matrix, carbon fibers extending in the X direction in the plane, carbon fibers extending in the Y direction in the plane perpendicular to the X direction, and carbon fiber materials extending in the thickness direction (Z direction). × 45 mm, thickness 3 mm) was prepared as a heat spreader of Comparative Example 1. In the heat spreader of Comparative Example 1, the total carbon fiber content was 30 vol%, and the content ratio of the X direction carbon fiber, the Y direction carbon fiber, and the Z direction carbon fiber was 1: 1: 1.

  A heat spreader (45 mm × 45 mm, thickness 3 mm) having, in a copper matrix, carbon fibers extending in the in-plane X direction and carbon fibers orthogonal to the X direction and extending in the Y direction in the plane. Prepared as. In the heat spreader of Comparative Example 2, the total carbon fiber content was 30 vol%, and the content ratio of the X-direction carbon fiber and the Y-direction carbon fiber was 1: 1.

  A heat spreader (45 mm) having carbon fibers extending in the X direction in the plane, carbon fibers extending in the Y direction in the plane perpendicular to the X direction, and a carbon fiber material extending in the thickness direction (Z direction) in the aluminum matrix. × 45 mm, thickness 3 mm) was prepared as a heat spreader of Comparative Example 3. In the heat spreader of Comparative Example 3, the total carbon fiber content was 30 vol%, and the content ratio of the X direction carbon fiber, the Y direction carbon fiber, and the Z direction carbon fiber was 1: 1: 1.

  A heat spreader (45 mm × 45 mm, thickness 3 mm) having a carbon fiber extending in the in-plane X direction and a carbon fiber orthogonal to the X direction and extending in the in-plane Y direction in an aluminum matrix Prepared as. In the heat spreader of Comparative Example 4, the total carbon fiber content was 30 vol%, and the content ratio of the X-direction carbon fiber and the Y-direction carbon fiber was 1: 1.

(Physical property measurement)
About the heat spreader of Comparative Examples 1-4, the thermal conductivity and thermal expansion coefficient of radial direction from the center of the heat spreader, and the thermal conductivity of thickness direction were measured. The heat conductivity in the radial direction and the thickness direction of the heat spreader of Comparative Example 1 was 190 W / mK, and a high value was not obtained. Further, the thermal expansion coefficient in the radial direction of the heat spreader of Comparative Example 1 was 10 ppm / ° C. The heat spreader in the radial direction of the heat spreader of Comparative Example 2 was 350 W / mK, the heat conductivity in the thickness direction was 50 W / mK, and a high value was not obtained. Moreover, the thermal expansion coefficient in the radial direction of the heat spreader of Comparative Example 2 was 5 ppm / ° C. The heat conductivity in the radial direction and the thickness direction of the heat spreader of Comparative Example 3 was 170 W / mK, and a high value was not obtained. Moreover, the thermal expansion coefficient in the radial direction of the heat spreader of Comparative Example 3 was 8 ppm / ° C. The heat spreader in Comparative Example 4 had a heat conductivity in the radial direction of 310 W / mK and a heat conductivity in the thickness direction of 20 W / mK, and a high value was not obtained. Moreover, the thermal expansion coefficient in the radial direction of the heat spreader of Comparative Example 4 was 4 ppm / ° C. These values are listed in the table of FIG.

[Example 7]
[Production of heat spreader]
A heat spreader of this example was manufactured as a heat spreader having a C / C composite material configuration. In the production of the heat spreader of the present example, first, a C / C composite (CX-2002U, manufactured by Toyo Tanso Co., Ltd.), which is a carbon fiber reinforced material body, is cut to obtain a triangular shape as shown in FIG. An isosceles triangle having an apex angle of 90 ° (oblique side 45 mm, thickness 3 mm) was obtained. The C / C composite used in this example is composed of amorphous carbon as a matrix material and a plurality of carbon fiber materials parallel to each other. In the present cutting step, the plurality of carbon fiber materials included in each piece extend in the in-plane direction and the direction perpendicular to the hypotenuse to form the single carbon fiber group described above with respect to the third embodiment. / C Cut the composite. Next, four pieces were joined by brazing with a silver brazing material (71Ag-Cu-Ti) as shown in FIG. As described above, the heat spreader (45 mm × 45 mm, thickness 3 mm) of this example was manufactured.

(Physical property measurement)
For the heat spreader of this example, the thermal conductivity and the thermal expansion coefficient in the radial direction from the center of the heat spreader were measured, and the thermal conductivity in the thickness direction was measured. Both the thermal conductivity in the radial direction and the thermal conductivity in the thickness direction were 370 W / mK, and a sufficiently high value was obtained. Moreover, the thermal expansion coefficient in the radial direction was 2 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. These values are listed in the table of FIG. For example, when the heat spreader of the present embodiment is incorporated as a heat spreader in a cooling structure as shown in FIG. 17 and the heat dissipation amount in the semiconductor chip 101 is 50 W, the temperature of the semiconductor chip 101 did not rise above 70 ° C. .

[Example 8]
[Production of heat spreader]
As another heat spreader having a C / C composite material structure, a heat spreader of this example was manufactured. In the manufacture of the heat spreader of this example, first, as in Example 7, a C / C composite (CX-2002U, manufactured by Toyo Tanso Co., Ltd.), which is a carbon fiber reinforced material body, was cut to obtain FIG. A piece (an isosceles triangle having an apex angle of 90 °) as shown in (1) (oblique side 45 mm, thickness 3 mm) was obtained.

  Next, using the HIP device, the four pieces were joined while impregnating the four pieces with copper. Specifically, first, as shown in FIG. 21 (a), a steel capsule 51 having a predetermined nozzle (inner dimensions 45 mm × 45 mm × 3 mm, bottom thickness 5 mm, top thickness 5 mm, sidewall thickness 30 mm). ), Four pieces are put in the orientation as shown in FIG. 15B, and then copper powder 52 (average particle size of 100 μm) is placed in the gap between the pieces and the gap between the pieces and the capsule 51. It filled and welded between the main body of the capsule 51, and the cover body 51a. Next, the inside of the capsule 51 was evacuated substantially by degassing the inside of the capsule 51 through a nozzle using a vacuum pump device. Next, the tip of the nozzle was welded to seal the capsule 51. Next, the capsule 51 was placed in the chamber of the HIP apparatus and subjected to hot isostatic pressing. At this time, the pressure in the chamber was about 100 MPa, the temperature in the chamber was 1130 ° C. (50 ° C. higher than the melting point of copper), and the pressurization time was 5 minutes. In such a hot isostatic pressing process, the copper powder in the capsule 51 is melted, and the lid 51a of the capsule 51 is dented as shown in FIG. The impregnation is good and the pieces are joined by copper.

  Next, by removing the capsule 51 by mechanical cutting, as shown in FIG. 21C, the heat spreader of this example was obtained. As described above, the heat spreader of this example was manufactured. The copper content of the heat spreader of this example is 5 vol%.

(Physical property measurement)
For the heat spreader of this example, the thermal conductivity and the thermal expansion coefficient in the radial direction from the center of the heat spreader were measured, and the thermal conductivity in the thickness direction was measured. Both the thermal conductivity in the radial direction and the thermal conductivity in the thickness direction were 400 W / mK, and a sufficiently high value was obtained. Moreover, the thermal expansion coefficient in the radial direction was 2 ppm / ° C., and a value sufficiently close to the thermal expansion coefficient of the silicon chip was obtained. These values are listed in the table of FIG. For example, when the heat spreader of the present embodiment is incorporated as a heat spreader in a cooling structure as shown in FIG. 17 and the heat dissipation amount in the semiconductor chip 101 is 50 W, the temperature of the semiconductor chip 101 does not rise above 65 ° C. .

  As a summary of the above, the configurations of the present invention and variations thereof are listed below as supplementary notes.

(Appendix 1) A heat spreader having a first surface and a second surface opposite to the first surface,
Including a matrix material and a plurality of carbon fiber materials extending through the matrix material;
The plurality of carbon fiber materials are centered on an orientation reference axis in which a plurality of virtual projection lines of the plurality of carbon fiber materials with respect to the first surface extend in a thickness direction from the first surface to the second surface. A heat spreader that is arranged to extend radially.
(Supplementary note 2) The heat spreader according to supplementary note 1, wherein the plurality of carbon fiber materials extend radially around a crossing point between the first surface and the orientation reference axis.
(Supplementary Note 3) A heat spreader having a first surface and a second surface opposite to the first surface,
Matrix material,
A plurality of carbon fiber groups each including a plurality of carbon fiber materials extending in the matrix material and each having an alignment reference line extending along the first surface,
Each of the plurality of carbon fiber materials in each carbon fiber group is arranged such that a virtual projection line of the carbon fiber material with respect to the first surface extends along the orientation reference line in the carbon fiber group,
The heat spreader, wherein the plurality of alignment reference lines in the plurality of carbon fiber groups extend radially around an alignment reference axis extending in the thickness direction.
(Additional remark 4) Each of these carbon fiber materials is a heat spreader of Additional remark 1 or 3 extended along the said 1st surface.
(Supplementary note 5) The heat spreader according to any one of supplementary notes 1 to 4, further comprising a plurality of carbon fiber materials each extending in the thickness direction.
(Supplementary note 6) The heat spreader according to any one of supplementary notes 1 to 5, wherein the matrix material includes a metal selected from the group consisting of silver, copper, aluminum, and magnesium.
(Appendix 7) The heat spreader according to any one of appendices 1 to 6, wherein the matrix material includes amorphous carbon.
(Appendix 8) An electronic device comprising the heat spreader according to any one of appendices 1 to 7 and a heat-generating electronic component,
The electronic device is an electronic device that is thermally connected to a location through which the orientation reference axis passes on the first surface of the heat spreader.
(Supplementary note 9) An electronic device comprising the heat spreader according to any one of supplementary notes 1 to 7, a heat-generating electronic component, and a radiator.
The electronic component is thermally connected to a location where the orientation reference axis passes on the first surface of the heat spreader,
The heat radiator is an electronic device that is thermally connected to the second surface of the heat spreader.
(Supplementary Note 10) A step of arranging a plurality of carbon fiber cloths so as to extend radially along the alignment reference axis and centering on the alignment reference axis;
A step for obtaining a carbon fiber reinforced material body including a matrix material and a plurality of carbon fiber cloths by impregnating the matrix material into the plurality of carbon fiber cloths;
And a step for cutting the carbon fiber reinforced material body.

1 is a partially cutaway perspective view of a heat spreader according to a first embodiment of the present invention. It is sectional drawing along line II-II of FIG. The virtual projection line with respect to the 1st surface of the carbon fiber material in 1st Embodiment is represented. The manufacturing method of the heat spreader which concerns on 1st Embodiment is represented. The cooling structure containing the heat spreader which concerns on 1st Embodiment is represented. The orientation reference axis | shaft in the modification of the heat spreader which concerns on 1st Embodiment, and the virtual projection line with respect to the 1st surface of a carbon fiber material are represented. It is a partially cutaway perspective view of a heat spreader according to a second embodiment of the present invention. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. The virtual projection line with respect to the 1st surface of the carbon fiber material in 2nd Embodiment is represented. The cooling structure containing the heat spreader which concerns on 2nd Embodiment is represented. It is a partially notched perspective view of the heat spreader which concerns on the 3rd Embodiment of this invention. It is sectional drawing along line XII-XII of FIG. FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 11. The virtual projection line with respect to the 1st surface of the carbon fiber material in 3rd Embodiment, or the carbon fiber cloth exposed on the said 1st surface is represented. An example of the manufacturing method of the heat spreader which concerns on 3rd Embodiment is represented. The other example of the manufacturing method of the heat spreader which concerns on 3rd Embodiment is represented. The cooling structure containing the heat spreader which concerns on 3rd Embodiment is represented. It is sectional drawing of the modification of the heat spreader which concerns on 3rd Embodiment. The virtual projection line with respect to the 1st surface of a carbon fiber material in the other modification of the heat spreader which concerns on 3rd Embodiment is represented. The heat spreader manufacturing method in Examples 1-6 is represented. The heat spreader manufacturing method in Example 8 is represented. It is the table | surface which put together the result of the physical-property measurement of Examples 1-8 and Comparative Examples 1-5. 1 represents an example of a cooling structure for a semiconductor chip in which a heat sink and a heat spreader are utilized. Represents a conventional heat spreader. (A) is sectional drawing, (b) is a partial expansion perspective view. It represents another conventional heat spreader. (A) is sectional drawing, (b) is a partial expansion perspective view. It represents another conventional heat spreader. (A) is sectional drawing, (b) is a partial expansion perspective view.

Explanation of symbols

10, 20, 30 Heat spreader 10A, 20A, 30A First side 10B, 20B, 30B Second side 11, 21, 31 Matrix material 12, 12 ', 32, 32' Carbon fiber cloth 12a, 12b, 22, 32a, 32b Carbon fiber material A1, A2, A3 Orientation reference axis L Orientation reference line 101 Semiconductor chip 102 Heat sink 103 Substrate 104 'Solder 105 Thermal grease

Claims (8)

A heat spreader having a first side and a second side opposite thereto,
Including a matrix material and a plurality of carbon fiber materials extending through the matrix material;
The plurality of carbon fiber materials are centered on an orientation reference axis in which a plurality of virtual projection lines of the plurality of carbon fiber materials with respect to the first surface extend in a thickness direction from the first surface to the second surface. A heat spreader that is arranged to extend radially.   2. The heat spreader according to claim 1, wherein the plurality of carbon fiber materials extend radially around a crossing point between the first surface and the orientation reference axis. A heat spreader having a first side and a second side opposite thereto,
Matrix material,
A plurality of carbon fiber groups each including a plurality of carbon fiber materials extending in the matrix material and each having an alignment reference line extending along the first surface,
Each of the plurality of carbon fiber materials in each carbon fiber group is arranged such that a virtual projection line of the carbon fiber material with respect to the first surface extends along the orientation reference line in the carbon fiber group,
The plurality of alignment reference lines in the plurality of carbon fiber groups extend radially around an alignment reference axis extending in a thickness direction from the first surface to the second surface.   4. The heat spreader according to claim 1, wherein each of the plurality of carbon fiber materials extends along the first surface.   The heat spreader according to any one of claims 1 to 4, further comprising a plurality of carbon fiber materials each extending in the thickness direction. An electronic device comprising the heat spreader according to any one of claims 1 to 5 and an exothermic electronic component,
The electronic device is an electronic device that is thermally connected to a location through which the orientation reference axis passes on the first surface of the heat spreader. An electronic device comprising the heat spreader according to any one of claims 1 to 5, an exothermic electronic component, and a radiator.
The electronic component is thermally connected to a location where the orientation reference axis passes on the first surface of the heat spreader,
The heat radiator is an electronic device that is thermally connected to the second surface of the heat spreader. A step of arranging a plurality of carbon fiber cloths along the alignment reference axis and extending radially about the alignment reference axis;
A step for obtaining a carbon fiber reinforced material body including a matrix material and a plurality of carbon fiber cloths by impregnating the matrix material into the plurality of carbon fiber cloths;
And a step for cutting the carbon fiber reinforced material body.

Images