Ceramic substrate and method for manufacturing ceramic substrate

Abstract

Provided are: a ceramic substrate provided with a path capable of sufficiently dissipating heat; and a method for manufacturing said ceramic substrate. A ceramic substrate (1) comprises: a laminate (10) that includes a plurality of layered ceramic layers and has a first main surface (11), a second main surface (12) facing the first main surface (11), and side surfaces (13) connecting the first main surface (11) and the second main surface (12); a housing part (30) that is formed inside the laminate (10); and a heat dissipation member (40) that is made of a carbon material and is disposed in the housing part (30). The heat dissipation member (40) has an inner portion (41) housed in the housing part (30) and an outer portion (42) protruding from at least one of the side surfaces (13).

Description

Ceramic substrate and method for manufacturing the same

[0001] The present invention relates to a ceramic substrate and a method for manufacturing the ceramic substrate.

[0002] Ceramic substrates generally have high heat resistance, high thermal conductivity, low thermal expansion, low dielectric loss, and high reliability, and are therefore widely used in applications such as module components for small electronic devices that require high-density packaging.

[0003] Patent Document 1 discloses a method for producing an oxide ceramic containing auxiliary components consisting of at least three or more metal oxides selected from copper oxide, titanium oxide, silver oxide, and manganese oxide, with the auxiliary components contained in an amount of 2 to 20 parts by weight, in which a mixed powder of all the auxiliary components is reacted in advance by heat treatment and then added to a main component. Patent Document 1 also discloses a ceramic substrate having an insulator layer made of the oxide ceramic produced by this method, and a conductor whose main component is at least silver or copper, formed in an inner layer of the insulator layer.

[0004] Japanese Patent Application Laid-Open No. 2005-145722

[0005] In recent years, with the miniaturization and high integration of electronic devices, the design of paths for dissipating heat from heat-generating components such as ICs has become important. The ceramic substrate described in Patent Document 1 has a problem in that it cannot sufficiently dissipate heat from heat-generating components such as ICs.

[0006] The present invention has been made to solve the above problems, and an object of the present invention is to provide a ceramic substrate having a path that can sufficiently dissipate heat, and a method for manufacturing the ceramic substrate.

[0007] The present inventors discovered that efficient heat dissipation can be achieved by arranging a heat dissipation member that is continuous from the interior to the exterior of a ceramic substrate, and completed the present invention. That is, the ceramic substrate of the present invention comprises a laminate including a plurality of stacked ceramic layers, the laminate having a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, a housing portion formed inside the laminate, and a heat dissipation member made of a carbon material and disposed in the housing portion, the heat dissipation member having an inner portion accommodated in the housing portion and an outer portion protruding from at least one of the side surfaces.

[0008] The method for manufacturing a ceramic substrate of the present invention includes a pre-fired laminate preparation step of preparing a pre-fired laminate, the pre-fired laminate including a plurality of stacked ceramic green sheets and a ceramic green sheet laminate having a hole therein, and a heat dissipation member made of a carbon material placed in the hole; and a firing step of firing the pre-fired laminate to produce a ceramic substrate in which the ceramic green sheets are made into ceramic layers, the hole is made into an accommodation portion, and the heat dissipation member is placed in the accommodation portion.The ceramic green sheet laminate prepared in the pre-fired laminate preparation step has a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, and the heat dissipation member has an inner portion that is accommodated in the hole and an outer portion that protrudes to the outside from the side surface.

[0009] According to the present invention, it is possible to provide a ceramic substrate having a path capable of sufficiently dissipating heat, and a method for manufacturing the ceramic substrate.

[0010] FIG. 1A is a perspective view schematically showing an example of a ceramic substrate according to a first embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line A-A in FIG. 1A. FIG. 1C is a cross-sectional view taken along line B-B in FIG. 1A. FIG. 2A is a perspective view schematically showing an example of a ceramic substrate according to a second embodiment of the present invention. FIG. 2B is a cross-sectional view taken along line C-C in FIG. 2A. FIG. 3 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through a heat dissipation member. FIG. 4A is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4B is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4C is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4D is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4E is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4F is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4G is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 4H is a plan view schematically showing another example of a heat dissipation member in a ceramic substrate according to a third embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through a heat dissipation member having a through hole. FIG. 6A is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through a heat dissipation member. FIG. 6B is a cross-sectional view taken along line D-D in FIG. 6A. FIG. 7 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the side surface protruding outward of the heat dissipation member and perpendicular to the first main surface of the laminate. FIG. 8A is a cross-sectional view schematically showing another example of the shape of a recess in a ceramic substrate according to a third embodiment of the present invention. FIG. 8B is a cross-sectional view schematically showing an example of another shape of the recess in the ceramic substrate according to the third embodiment of the present invention.FIG. 8C is a cross-sectional view schematically showing an example of another recess shape in the ceramic substrate according to the third embodiment of the present invention. FIG. 8D is a cross-sectional view schematically showing an example of another recess shape in the ceramic substrate according to the third embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing an example of a cross section of the ceramic substrate according to the third embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through the heat dissipation member. FIG. 10 is a cross-sectional view schematically showing an example of a cross section of the ceramic substrate according to the fourth embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through the heat dissipation member. FIG. 11A is a cross-sectional view schematically showing an example of a cross section of the ceramic substrate according to the fifth embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through the heat dissipation member. FIG. 11B is a cross-sectional view taken along line E-E of FIG. 11A. FIG. 12A is a cross-sectional view schematically showing an example of a ceramic substrate according to the fifth embodiment of the present invention, having a heat dissipation member with a different shape. FIG. 12B is a cross-sectional view schematically showing an example of a ceramic substrate according to the fifth embodiment of the present invention, having a heat dissipation member with a different shape. FIG. 12C is a cross-sectional view schematically showing an example of a ceramic substrate according to a fifth embodiment of the present invention having a heat dissipation member of a different shape. FIG. 13 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a fifth embodiment of the present invention, cut in a direction perpendicular to the side surface protruding outward from the heat dissipation member and in a direction perpendicular to the first main surface of the laminate. FIG. 14 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a fifth embodiment of the present invention, cut in a direction perpendicular to the side surface protruding outward from the heat dissipation member and in a direction perpendicular to the first main surface of the laminate. FIG. 15A is a process diagram sequentially illustrating an example of a pre-fired laminate preparation step in a method for manufacturing a ceramic substrate according to a sixth embodiment of the present invention. FIG. 15B is a process diagram sequentially illustrating an example of a pre-fired laminate preparation step in a method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. FIG. 15C is a process diagram sequentially illustrating an example of a pre-fired laminate preparation step in a method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. FIG. 15D is a process diagram sequentially illustrating an example of a pre-fired laminate preparation step in a method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention.FIG. 16 is a plan view schematically showing an example of a ceramic green sheet in which a heat dissipation member is disposed in a hole. FIG. 17 is a cross-sectional view schematically showing an example of a pre-fired laminate produced by the method for manufacturing a ceramic laminate according to the sixth embodiment of the present invention. FIG. 18A is a cross-sectional view schematically showing an example of a firing step in the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. FIG. 18B is a cross-sectional view schematically showing an example of a ceramic substrate on which a constraining layer is formed after the firing step in the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. FIG. 19 is a plan view schematically showing a heat dissipation member according to Example 1. FIG. 20 is a plan view schematically showing a heat dissipation member according to Example 2. FIG. 21 is a plan view schematically showing a heat dissipation member according to Comparative Example 2. FIG. 22 is a schematic diagram of a test method for evaluating heat dissipation performance.

[0011] The ceramic substrate of the present invention and the method for manufacturing the ceramic substrate of the present invention will be described below. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied within the scope that does not change the gist of the present invention. Note that a combination of two or more of the individual desirable configurations of the present invention described below also constitutes the present invention.

[0012] The ceramic substrate of the present invention comprises a laminate including a plurality of laminated ceramic layers, the laminate having a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, a housing portion formed inside the laminate, and a heat dissipation member made of a carbon material and disposed in the housing portion, the heat dissipation member having an inner portion housed in the housing portion and an outer portion protruding from at least one of the side surfaces. The ceramic substrate of the present invention may include any configuration as long as the above configuration is satisfied and the effects of the present invention are exhibited.

[0013] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment.

[0014] The drawings used in the following description are schematic drawings for the sake of convenience, and may differ in scale and detail from the actual product.

[0015] [First Embodiment] A ceramic substrate according to a first embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1A is a perspective view schematically showing an example of a ceramic substrate according to the first embodiment of the present invention. Fig. 1B is a cross-sectional view taken along line A-A in Fig. 1A. Fig. 1C is a cross-sectional view taken along line B-B in Fig. 1A.

[0016] As shown in FIGS. 1A and 1B , ceramic substrate 1 includes a laminate 10 that includes a plurality of stacked ceramic layers (individual ceramic layers are not shown in FIGS. 1A and 1B ) and has a first main surface 11, a second main surface 12 opposite to first main surface 11, and a side surface 13 connecting first main surface 11 and second main surface 12, a housing portion 30 formed inside laminate 10, and a heat dissipation member 40 made of a carbon material that is placed in housing portion 30.

[0017] As shown in Fig. 1A, the laminate 10 has a rectangular parallelepiped shape. As shown in Fig. 1C, the side surface 13 includes a first side surface 13a, a second side surface 13b, a third side surface 13c, and a fourth side surface 13d, which are successively arranged.

[0018] As shown in FIGS. 1B and 1C, in the ceramic substrate 1, the heat dissipation member 40 has an inner portion 41 accommodated in the accommodation portion 30 and an outer portion 42 protruding outward from the first side surface 13a.

[0019] 1A and 1B , ceramic substrate 1 may have heat-generating component 50 mounted on first main surface 11, and outer portion 42 of heat dissipation member 40 connected to external heat dissipation mechanism 60. When heat is generated from heat-generating component 50 in ceramic substrate 1, the heat moves from inner portion 41 to outer portion 42 of heat dissipation member 40, and then reaches external heat dissipation mechanism 60. This action allows ceramic substrate 1 to quickly dissipate heat.

[0020] Although not shown, in the ceramic substrate 1, surface electrodes and internal electrodes are arranged on the laminate 10, and the surface electrodes and internal electrodes may be electrically connected by internal conductors or wiring vias. The internal conductors may also be electrically connected to each other by internal conductors or wiring vias. The ceramic substrate 1 may also be arranged with a heat-transfer member with high heat conductivity that connects the heat-generating component 50 to the heat dissipation member 40.

[0021] In the ceramic substrate 1, the height (indicated by the symbol L in FIG. 1B ) in the stacking direction (indicated by the arrow Z in FIG. 1B ) is １ The length indicated by is preferably 5 μm or more and 5,000 μm or less.

[0022] Hereinafter, each component of the ceramic substrate according to the first embodiment of the present invention will be described in detail.

[0023] (Ceramic Layer) In the ceramic substrate 1, the ceramic layer may be a sintered body of a ceramic green sheet. The ceramic green sheet can be formed, for example, by applying a doctor blade method or the like to a ceramic slurry on a carrier film.

[0024] The ceramic slurry may contain, for example, ceramic powder, a binder, a plasticizer, etc. As the ceramic material, for example, a low-temperature co-fired ceramic (LTCC) material can be used. The low-temperature co-fired ceramic material is a ceramic material that can be sintered at a temperature of 1000°C or less and can be co-fired with Au, Ag, Cu, etc., which have low resistivity. Specific examples of the low-temperature co-fired ceramic material include glass composite low-temperature co-fired ceramic materials obtained by mixing ceramic powder such as alumina, zirconia, magnesia, forsterite, etc. with borosilicate glass, and ZnO-MgO-Al ２ O ３ -SiO ２ Glass-ceramic low-temperature sintering ceramic material using BaO-Al ２ O ３ -SiO ２ Ceramic powder, Al ２ O ３ -CaO-SiO ２ -B２ O ３ Al-based ceramic powder, etc. ２ O ３ -CaO-SiO ２ -MgO-B ２ O ３ Examples of suitable materials include non-glass-based low-temperature sintered ceramic materials using ceramic powders.

[0025] The thickness of the ceramic layer is not particularly limited, but is preferably 5 μm or more and 200 μm or less, and is preferably designed appropriately depending on the number of laminated ceramic layers, the overall thickness of the ceramic substrate, etc.

[0026] (Heat Dissipation Member) As shown in FIGS. 1B and 1C , in the ceramic substrate 1, the heat dissipation member 40 is in a sheet shape. However, in the ceramic substrate according to the first embodiment of the present invention, the shape of the heat dissipation member is not particularly limited as long as it can be in a columnar or rod shape or the like and can form an inner portion and an outer portion.

[0027] In the ceramic substrate 1, the protruding direction of the outer portion 42 (arrow P in FIG. 1B) ４２ In the direction indicated by ( ), the length of the heat dissipation member 40 is preferably 1 mm or more and 100 mm or less, and more preferably 5 mm or more and 50 mm or less.

[0028] In the ceramic substrate 1, the protruding direction P of the outer portion 42 ４２ In FIG. 1B, the length of the inner portion 41 (reference symbol L ４１ 1B) relative to the length of the outer portion 42 (the length indicated by the symbol L ４２ The ratio of the length (L ４２ / L ４１ ) is preferably 0.01 or more and 19 or less, and more preferably 0.1 or more and 9 or less.

[0029] In the ceramic substrate 1, the thermal conductivity of the heat dissipation member made of a carbon material is preferably 100 W / m·K or more and 2000 W / m·K or less. When the thermal conductivity of the heat dissipation member is in the above range, heat from the heat-generating component can be suitably dissipated to the outside.

[0030] Examples of carbon materials include graphite, graphene, and carbon nanotubes.

[0031] (Surface Electrode, Internal Electrode, Internal Conductor, and Wiring Via) The surface electrode, internal electrode, internal conductor, and wiring via may be formed by firing a conductive paste. The conductive paste is not particularly limited, but may contain, for example, a conductive metal material, a binder, a plasticizer, etc. The conductive paste may also contain a co-base (ceramic powder) for adjusting the shrinkage rate. Examples of the conductive metal material contained in the conductive paste include metals primarily composed of at least one of Ag, Ag—Pt alloy, Ag—Pd alloy, Cu, Ni, Pt, Pd, W, Mo, and Au. Among these conductive metal materials, Ag, Ag—Pt alloy, Ag—Pd alloy, and Cu have low resistivity and are therefore more preferably used in conductor patterns for high frequencies. The conductive paste may or may not contain a glass component. If the conductive paste contains a glass component, the sintering properties of the surface electrode, internal conductor, and wiring via with the electronic component body can be improved. On the other hand, when the conductive paste does not contain a glass component, the purity of the metal contained in the conductive paste increases, and the purity of the metal contained in the formed surface electrodes, internal electrodes, internal conductors, and wiring vias also increases. Therefore, the resistance values ​​of the surface electrodes, internal electrodes, internal conductors, and wiring vias can be reduced. By adjusting the proportion of the glass component contained in the conductive paste, surface electrodes, internal electrodes, internal conductors, and wiring vias with desired electrical properties and structures can be obtained.

[0032] (External Heat Dissipation Mechanism) In the ceramic substrate 1, the external heat dissipation mechanism 60 is not particularly limited, and may be a heat sink, a heat dissipation fin, a vapor chamber, etc. Alternatively, the external heat dissipation mechanism 60 may be a housing of an electronic device.

[0033] (Heat-Generating Component) The heat-generating component 50 is an electrical component that generates heat when in operation, and examples thereof include well-known components such as a processor, an LED, a power amplifier, and a camera module.

[0034] [Second Embodiment] A ceramic substrate according to a second embodiment of the present invention differs from the ceramic substrate according to the first embodiment of the present invention in that the heat dissipation member has multiple outer portions, each of which protrudes from a different portion of the side surface.

[0035] The ceramic substrate according to the second embodiment of the present invention will be described in detail with reference to the drawings. Fig. 2A is a perspective view schematically showing an example of the ceramic substrate according to the second embodiment of the present invention. Fig. 2B is a cross-sectional view taken along line CC of Fig. 2A.

[0036] 2A and 2B, in the ceramic substrate 101, the heat dissipation member 140 has an inner portion 141 and first and second outer portions 142a and 142b. The first outer portion 142a protrudes from the first side surface 13a, and the second outer portion 142b protrudes from the second side surface 13b. In other words, as shown in FIG. 2B, the heat dissipation member 140 has an L-shape in a plan view.

[0037] The ceramic substrate and the heat dissipation member made of a carbon material have low adhesion, and when pulled in the protruding direction of the outer portion of the heat dissipation member, the heat dissipation member may come off the laminate. However, when the heat dissipation member 140 is L-shaped in plan view, the first outer portion 142a is pulled in the protruding direction (arrow P in FIG. 2B ). １４２ａ Even if the heat dissipation member 140 is pulled in the direction indicated by the arrow P in FIG. 2B , the second outer portion 142 b acts as a support, preventing the heat dissipation member 140 from coming off the laminated body 10. １４２ｂ Even if the heat dissipation member 140 is pulled in the direction indicated by the arrow (the direction indicated by the arrow), the first outer portion 142 a acts as a support, and the heat dissipation member 140 can be prevented from coming off the laminate 10 .

[0038] When the heat dissipation member 140 has two outer portions, the number of heat dissipation paths increases, and the heat generated from the heat-generating components can be dissipated efficiently.

[0039] In the ceramic substrate according to the second embodiment of the present invention, when the heat dissipation member has two outer portions, the two outer portions may protrude from any two of the first side surface, the second side surface, the third side surface, and the fourth side surface. In this case, in order to prevent the heat dissipation member from coming off the laminate, it is preferable that the protruding directions of the first outer portion and the second outer portion are not parallel to each other, and it is preferable that the protruding directions of the first outer portion and the second outer portion are perpendicular to each other.

[0040] In the ceramic substrate 101 shown in FIGS. 2A and 2B, the heat dissipation member 140 has two outer portions, but in the ceramic substrate of the present invention, the heat dissipation member may have three or more outer portions.

[0041] 2A and 2B, the laminate 10 is rectangular parallelepiped. However, in the ceramic substrate of the present invention, the shape of the laminate is not particularly limited and may be an L-shaped columnar shape in a plan view, a trapezoidal columnar shape in a plan view, a triangular columnar shape, a cylindrical columnar shape, or the like. It is preferable to design it appropriately depending on the location where the ceramic substrate is to be placed. Similarly, it is preferable to design the number and positions of the outer portions of the heat dissipation member appropriately depending on the location where the ceramic substrate is to be placed.

[0042] [Third Embodiment] A ceramic substrate according to a third embodiment of the present invention differs from the ceramic substrate according to the first embodiment of the present invention in that, when the ceramic substrate is viewed in a plane, the direction in which the outer portion protrudes outward from the side surface is defined as the protruding direction, and the direction perpendicular to the protruding direction is defined as the width direction, the inner portion includes a first region having a first width in the width direction and a second region having a second width in the width direction that is longer than the first width, and the first region is located between the second region and the outer portion when the ceramic substrate is viewed in a plane.

[0043] The ceramic substrate according to the third embodiment of the present invention will be described in detail with reference to the drawings. Fig. 3 is a cross-sectional view schematically showing an example of a cross section of the ceramic substrate according to the third embodiment of the present invention, taken in a direction perpendicular to the stacking direction and passing through the heat dissipation member.

[0044] 3 has the following features. First, when the ceramic substrate 201 is viewed from above, the direction in which the outer portion 242 of the heat dissipation member 240 protrudes outward from the first side surface 13 a is referred to as the protruding direction (indicated by the arrow P in FIG. 3 ). ２４２ The direction of protrusion P ２４２ The direction perpendicular to the arrows W and Y in FIG. 3 is the width direction (the direction indicated by the arrow Y in FIG. 3). ２４１ａ a first region 241a having a first width W ２４１ａ A second width W in the longer width direction Y ２４１ｂ and a second region 241b having a protruding direction P ２４２ 3, the second region 241b, the first region 241a, and the outer portion 242 are located in this order. That is, the first region 241a is located between the second region 241b and the outer portion 242. As shown in FIG. 3, the heat dissipation member 240 has a T-shape in a plan view.

[0045] The ceramic substrate and the heat dissipation member made of a carbon material have low adhesion, and when pulled in the protruding direction of the outer portion of the heat dissipation member, the heat dissipation member may come off the laminate. However, as described above, when the heat dissipation member 240 is T-shaped in plan view, the protruding direction P of the outer portion 242 ２４２ Even if the heat dissipation member 240 is pulled, the second region 241b provides support and prevents the heat dissipation member 240 from coming off the laminate 10. Furthermore, when manufacturing the ceramic substrate or handling the heat dissipation member, the heat dissipation member is less likely to move, and gaps are less likely to occur between the ceramic layer and the heat dissipation member. Therefore, high heat dissipation performance can be achieved.

[0046] In the ceramic substrate according to the third embodiment of the present invention, the shape of the heat dissipation member is not particularly limited as long as the first region and the second region are included in the inner portion of the heat dissipation member as described above. Examples of such heat dissipation members are shown below with reference to the drawings.

[0047] 4A to 4H are plan views each showing a schematic diagram of another example of a heat dissipation member in a ceramic substrate according to the third embodiment of the present invention.

[0048] 4A includes a heat dissipation member 240A. The heat dissipation member 240A is L-shaped, and the outer portion 242 and the first region 241a have the same length in the width direction Y, i.e., a first width W. ２４１ａ and the second width W ２４１ｂ is the first width W ２４１ａ longer than.

[0049] 4B includes a heat dissipation member 240B. The heat dissipation member 240B has a cross shape, and the outer portion 242 and the first region 241a have the same length in the width direction Y, i.e., a first width W. ２４１ａ and the second width W ２４１ｂ is the first width W ２４１ａ The heat dissipation member 240B is longer than the protruding direction P ２４２ and a third region 241c connected to the second region 241b extending in the direction opposite to the second width W of the second region 241b in the width direction Y. ２４１ｂ is the third width W of the third region 241c in the width direction Y. ２４１ｃ longer than.

[0050] The ceramic substrate 201C shown in FIG. 4C includes a heat dissipation member 240C. The heat dissipation member 240C has a U-shaped shape with one long side partially cut out. The remaining cut-out portion of the heat dissipation member 240C is a first region 241a. The heat dissipation member 240C has an outer portion 242 and a second region 241b in the width direction Y, both of which have the same length, a second width W. ２４１ｂ and the second width W ２４１ｂ is the first width W ２４１ａ longer than.

[0051] The ceramic substrate 201D shown in FIG. 4D includes a heat dissipation member 240D. The heat dissipation member 240D has a dumbbell-like shape with two long sides partially cut out. The remaining cut-out portions of the heat dissipation member 240D are the first region 241a. The heat dissipation member 240D has an outer region 242 and a second region 241b in the width direction Y, both of which have the same length, and a second width W ２４１ｂ and the second width W ２４１ｂ is the first width W ２４１ａ longer than.

[0052] 4E includes a heat dissipation member 240E. The heat dissipation member 240E extends in a protruding direction P ２４２ The first region 241a has a first width W in the width direction Y. The second region 241b, the first region 241a, the second region 241b, the first region 241a, the second region 241b, the first region 241a, and the second region 241b are formed in this order from the inside. ２４１ａ The second region 241b has a second width W ２４１ｂ Also, the second width W ２４１ｂ is the first width W ２４１ａ In the ceramic substrate of the present invention, a plurality of second regions 241b and first regions 241a may be formed in this manner.

[0053] 4F includes a heat dissipation member 240F. The heat dissipation member 240F has an inner portion 241 that projects in the protruding direction P ２４２ In the heat dissipation member 240F, if the longest portion in the width direction Y is considered to be the second region 241b, the remaining portion is the first region 241a.

[0054] 4G includes a heat dissipation member 240G. The heat dissipation member 240G has an inner portion 241 that projects in the protruding direction P ２４２ In the heat dissipation member 240G, if the longest portion in the width direction Y is considered to be the second region 241b, the remaining portion is the first region 241a.

[0055] 4H includes a heat dissipation member 240H. The heat dissipation member 240H has an arrowhead shape. In the heat dissipation member 240H, if the longest portion in the width direction Y is considered to be the second region 241b, the longest portion in the protruding direction P ２４２ The side portion becomes the first region 241a.

[0056] In heat dissipation members having these shapes, even if the heat dissipation member is pulled in the direction in which the outer portion protrudes, the second region acts as a support and prevents the heat dissipation member from coming off the laminate.

[0057] In the ceramic substrate according to the third embodiment of the present invention, a through hole may be formed in the inner portion of the heat dissipation member, penetrating the substrate in the stacking direction. Such a ceramic substrate will be described with reference to the drawings.

[0058] 5 is a cross-sectional view schematically illustrating an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, taken in a direction perpendicular to the stacking direction and passing through a heat dissipation member having a through hole. The ceramic substrate 201I shown in FIG. 5 includes a laminate 10 and a heat dissipation member 240I. The heat dissipation member 240I has the same shape as the heat dissipation member 240, except that a through hole 245I is formed in an inner portion 241 of the heat dissipation member 240I, penetrating the heat dissipation member 240I in the stacking direction Z.

[0059] When manufacturing a ceramic substrate, a heat dissipation member is sandwiched between ceramic green sheets and fired. In this case, if a heat dissipation member 240I having a through hole 245I formed therein is used as the heat dissipation member, the ceramic green sheets arranged above and below the heat dissipation member 240I come into contact with each other via the through hole 245I and are sintered. Alternatively, another ceramic green sheet may be placed inside the through hole 245I and fired. As a result, the ceramic green sheets arranged above and below the heat dissipation member 240I and the ceramic green sheet arranged inside the through hole 245I are sintered. Therefore, in the manufactured ceramic substrate 201I, sintered ceramic S is present inside the through hole 245I. In the ceramic substrate 201I, the protruding direction P of the outer portion 242 of the heat dissipation member 240I is ２４２ Even if the heat dissipation member 240I is pulled, the ceramic S inside the through-hole 245I acts as a support, preventing the heat dissipation member 240I from coming off the laminate 10.

[0060] The shape of the through holes is not particularly limited, and may be an equilateral triangle, a regular rectangle, a pentagon, a regular hexagon, a regular octagon, a circle, an ellipse, or the like when the heat dissipation member is viewed from above.

[0061] In the ceramic substrate according to the third embodiment of the present invention, the heat dissipation member may have a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes. Such a ceramic substrate will be described with reference to the drawings.

[0062] 6A is a cross-sectional view schematically illustrating an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, taken along a direction perpendicular to the stacking direction and passing through a heat dissipation member. FIG. 6B is a cross-sectional view taken along line DD of FIG. 6A.

[0063] 6A and 6B, the ceramic substrate 201J includes a laminate 10 and a heat dissipation member 240J. As shown in FIG. 6A and FIG. 6B, the heat dissipation member 240J has an inner portion 241J having a thickness T ２４１Ｊ Therefore, the thickness T of the outer portion 242J in the stacking direction Z is ２４２Ｊ The heat dissipation member 240J has the same shape as the heat dissipation member 240 except that the outer portion 242J is thicker than the inner portion 241J in both directions in the Z direction.

[0064] As shown in FIG. 6B, the heat dissipation member 240J has a thickness T ２４２Ｊ Since the outer portion 242J is thick, a part of the outer portion 242J contacts the first side surface 13a from which the outer portion 242J protrudes.

[0065] In this case, even if stress is applied to the outer portion 242J in the lateral direction (the direction indicated by the arrow Y in FIG. 6A ), the contact portion between the outer portion 242J and the first side surface 13a acts as a support, making it difficult for the heat dissipation member 240J to move. This prevents the heat dissipation member 240J from being damaged or coming loose.

[0066] In the ceramic substrate according to the third embodiment of the present invention, a recess may be formed in the laminate on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion. Such a ceramic substrate will be described with reference to the drawings.

[0067] FIG. 7 is a cross-sectional view schematically showing an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the side surface protruding toward the outer portion of the heat dissipation member and perpendicular to the first main surface of the laminate.

[0068] 7 includes a laminate 210K and a heat dissipation member 240. The ceramic substrate 201K has the same configuration as the ceramic substrate 201, except that a recess 215K exposing a part of the inner portion 241 is formed in the laminate 210K on the first side surface 213a from which the outer portion 242 protrudes.

[0069] 7, the recess 215K is formed so as to expose a part of the upper and lower surfaces of the heat dissipation member 240. In the cross section shown in FIG. ２４２ The slits are formed linearly and widen as they approach the slits.

[0070] In the ceramic substrate 201 described above, stress tends to concentrate at the boundary between the inner portion 241 and the outer portion 242 of the heat dissipation member 240. Therefore, the heat dissipation member 240 is prone to breakage at the boundary between the inner portion 241 and the outer portion 242. However, when the recess 215K is formed as in the ceramic substrate 201K, the heat dissipation member 240 can move at the boundary between the inner portion 241 and the outer portion 242, and stress is less likely to concentrate. Therefore, the heat dissipation member 240 is less likely to breakage.

[0071] The shape of the recess is not limited to the shape shown in FIG. 7, but may be any of the shapes exemplified below.

[0072] 8A to 8D are cross-sectional views schematically showing examples of other recess shapes in the ceramic substrate according to the third embodiment of the present invention.

[0073] The ceramic substrate 201L shown in FIG. 8A has the same shape as the ceramic substrate 201K, except that the recess 215L is formed so as to expose only the upper surface of the heat dissipation member 240. The ceramic substrate 201M shown in FIG. 8B has the same shape as the ceramic substrate 201K, except that the recess 215M is formed so as to expose only the lower surface of the heat dissipation member 240. The ceramic substrate 201N shown in FIG. 8C has the same shape as the ceramic substrate 201K, except that the recess 215N is formed in a curved shape (R-chamfered), in cross section. The ceramic substrate 201O shown in FIG. 8D has the same shape as the ceramic substrate 201K, except that the recess 215O is formed from a bottom 215Ob parallel to the first side surface 213a and a side 215Os perpendicular to the first side surface 213a, in cross section.

[0074] In a ceramic substrate according to a third embodiment of the present invention, the heat dissipation member may have two outer portions, and one of the outer portions may protrude in a direction opposite to the direction of the other outer portion. Such a ceramic substrate will be described with reference to the drawings.

[0075] 9 is a cross-sectional view schematically illustrating an example of a cross section of a ceramic substrate according to a third embodiment of the present invention, cut in a direction perpendicular to the stacking direction and passing through a heat dissipation member. As shown in FIG. 9, a ceramic substrate 201P includes a laminate 10 and a heat dissipation member 240P. The heat dissipation member 240P has an inner portion 241P and two outer portions (242P-a, 242P-b). One outer portion 242P-a protrudes from the first side surface 13a, and the other outer portion 242P-b protrudes from the third side surface 13c. The protruding direction of the outer portion 242P-a (indicated by an arrow P in FIG. 9) is 1 / 2. ２４２Ｐ－ａ ) and the protruding direction of the outer portion 242P-b (the direction indicated by the arrow P ２４２Ｐ－ｂ This is the opposite direction to the direction indicated by .

[0076] 9, the heat dissipation member 240P has a cross shape in a plan view. An inner portion 241P of the heat dissipation member 240P has a first width W ２４１Ｐ－ａ a first region 241P-a having a first width W ２４１Ｐ－ａ A second width W in the longer width direction Y２４１Ｐ－ｂ a second region 241P-b having a first width W ２４１Ｐ－ａ and a first region '241P-a' having the same length as the protruding direction P ２４２－ａ , the outer portion 242P-b, the first region '241P-a', the second region 241P-b, the first region 241P-a and the outer portion 242P-a are positioned in this order.

[0077] In the ceramic substrate 201P, the heat dissipation member 240P has two outer portions (242P-a, 242P-b), which increases the number of heat dissipation paths and allows the heat generated by the heat-generating components to be dissipated efficiently.

[0078] In addition, in the ceramic substrate 201P, the protruding direction P ２４２Ｐ－ａ and the protruding direction P ２４２Ｐ－ｂ In either direction, the heat dissipation member 240P is pulled, and the second region 241P-b acts as a support, preventing the heat dissipation member 240P from coming off the laminate 10.

[0079] The heat dissipation member 240P has a cross shape in plan view, but the shape of the heat dissipation member in such a case is not particularly limited, and may be, for example, a diamond or ellipse in plan view.

[0080] Fourth Embodiment A ceramic substrate according to a fourth embodiment of the present invention differs from the ceramic substrate according to the first embodiment of the present invention in that a through hole penetrating in the stacking direction is formed in the inner portion of the heat dissipation member.

[0081] The ceramic substrate according to the fourth embodiment of the present invention will be described in detail with reference to the drawings. Fig. 10 is a cross-sectional view schematically illustrating an example of a cross section of the ceramic substrate according to the fourth embodiment of the present invention, taken in a direction perpendicular to the stacking direction and passing through the heat dissipation member. The ceramic substrate 301I shown in Fig. 10 includes a laminate 10 and a heat dissipation member 340I. The heat dissipation member 340I has the same shape as the heat dissipation member 40, except that a through-hole 345I is formed in an inner portion 341I, penetrating the heat dissipation member 340I in the stacking direction Z.

[0082] When manufacturing a ceramic substrate, a heat dissipation member is sandwiched between ceramic green sheets and fired. In this case, if a heat dissipation member 340I having a through hole 345I formed therein is used as the heat dissipation member, the ceramic green sheets arranged above and below the heat dissipation member 340I come into contact with each other via the through hole 345I and are sintered. Alternatively, another ceramic green sheet may be placed inside the through hole 345I and fired. As a result, the ceramic green sheets arranged above and below the heat dissipation member 340I and the ceramic green sheet arranged inside the through hole 345I are sintered. Therefore, in the manufactured ceramic substrate 301I, sintered ceramic S is present inside the through hole 345I. In the ceramic substrate 301I, the protruding direction P of the outer portion 342I of the heat dissipation member 340I is ３４２ Even if the heat dissipation member 340I is pulled, the ceramic S inside the through-hole 345I provides support, preventing the heat dissipation member 340I from coming off the laminate 10. Furthermore, the adhesion between the ceramic layer and the heat dissipation member is improved, making it less likely that gaps will form between the ceramic layer and the heat dissipation member. As a result, high heat dissipation performance can be achieved.

[0083] The shape of the through holes is not particularly limited, and may be an equilateral triangle, a regular rectangle, a pentagon, a regular hexagon, a regular octagon, a circle, an ellipse, or the like when the heat dissipation member is viewed from above.

[0084] In the ceramic substrate according to the fourth embodiment of the present invention, as in the ceramic substrate according to the third embodiment of the present invention shown in Figures 6A to 6B, the heat dissipation member may have a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

[0085] In the ceramic substrate according to the fourth embodiment of the present invention, as in the ceramic substrate according to the third embodiment of the present invention shown in Figures 7 and 8A to 8D, a recess that exposes at least a part of the inner portion may be formed in the laminate on the side surface from which the outer portion protrudes.

[0086] In the ceramic substrate according to the fourth embodiment of the present invention, like the ceramic substrate according to the third embodiment of the present invention shown in Figure 9, the heat dissipation member may have two outer portions, and the protruding direction of one outer portion may be opposite to the protruding direction of the other outer portion.

[0087] Fifth Embodiment A ceramic substrate according to a fifth embodiment of the present invention differs from the ceramic substrate according to the first embodiment of the present invention in that the heat dissipation member has a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

[0088] The ceramic substrate according to the fifth embodiment of the present invention will be described in detail with reference to the drawings. Fig. 11A is a cross-sectional view schematically showing an example of a cross section of the ceramic substrate according to the fifth embodiment of the present invention, taken in a direction perpendicular to the stacking direction and passing through the heat dissipation member. Fig. 11B is a cross-sectional view taken along line E-E of Fig. 11A.

[0089] 11A and 11B, the ceramic substrate 401J includes a laminate 10 and a heat dissipation member 440J. As shown in FIG. 11A and FIG. 11B, the heat dissipation member 440J has an inner portion 441J having a thickness T ４４１Ｊ Therefore, the thickness T of the outer portion 442J in the stacking direction Z is ４４２Ｊ The heat dissipation member 440J has the same shape as the heat dissipation member 40 except that the outer portion 442J is thicker than the inner portion 441J in both directions in the Z direction.

[0090] As shown in FIG. 11B, the heat dissipation member 440J has a thickness T ２４２Ｊ Since the outer portion 442J is thick, a part of the outer portion 442J contacts the first side surface 13a from which the outer portion 442J protrudes.

[0091] In this case, even if stress is applied to the outer portion 442J in the lateral direction (the direction indicated by arrow Y in FIG. 11A ), the portion where the outer portion 442J contacts the first side surface 13a provides support, making the heat dissipation member 440J less likely to move. This prevents the heat dissipation member 440J from being damaged or coming loose. Furthermore, during the manufacture of the ceramic substrate or when handling the heat dissipation member, the heat dissipation member is less likely to move, making it less likely that a gap will form between the ceramic layer and the heat dissipation member. This results in high heat dissipation performance.

[0092] In the ceramic substrate according to the fifth embodiment of the present invention, the heat dissipation member may have any of the following shapes.

[0093] 12A to 12C are cross-sectional views schematically showing examples of a ceramic substrate according to the fifth embodiment of the present invention having heat dissipation members with different shapes.

[0094] In the ceramic substrate 401Q shown in Fig. 12A, the heat dissipation member 440Q has an outer portion 442Q that is thicker than the inner portion 441Q only on the upper side in the Z direction. In the ceramic substrate 401R shown in Fig. 12B, the heat dissipation member 440R has an outer portion 442R that is thicker than the inner portion 441R only on the lower side in the Z direction. In the ceramic substrate 401S shown in Fig. 12C, the heat dissipation member 440S has an overall crank-shaped bent shape. In the heat dissipation member 440S, the inner portion 441S is linear and the outer portion 442S is L-shaped, with a portion of the outer portion 442S in contact with the first side surface 13a.

[0095] In the ceramic laminate according to the fifth embodiment of the present invention, a recess may be formed in the laminate on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion. Such a ceramic substrate will be described with reference to the drawings.

[0096] FIG. 13 is a cross-sectional view schematically illustrating an example of a cross section of a ceramic substrate according to a fifth embodiment of the present invention, cut in a direction perpendicular to the side surface protruding toward the outer portion of the heat dissipation member and perpendicular to the first main surface of the laminate.

[0097] 13 includes a laminate 410T and a heat dissipation member 440Q. As described above, the heat dissipation member 440Q is thicker than the inner portion 441Q only on the upper side of the outer portion 442Q in the Z direction. In the ceramic substrate 401T, a recess 415T exposing a portion of the inner portion 441Q is formed in the laminate 410T on the first side surface 413a from which the outer portion 442Q protrudes.

[0098] 13, the recess 415T is formed so as to expose a part of the lower surface of the inner portion 441Q. In the cross section shown in FIG. 13, the recess 415T is formed in the protruding direction P of the outer portion 442Q. ４４２Ｑ The slits are formed linearly and widen as they approach the slits.

[0099] In the ceramic substrate 401Q described above, stress tends to concentrate at the boundary between the inner portion 441Q and the outer portion 442Q of the heat dissipation member 440Q. As a result, the heat dissipation member 440Q is prone to breakage at the boundary between the inner portion 441Q and the outer portion 442Q. However, when a recess 415T is formed as in the ceramic substrate 401T, the heat dissipation member 440Q can move at the boundary between the inner portion 441Q and the outer portion 442Q, making it less likely that stress will concentrate. As a result, the heat dissipation member 440Q is less likely to break.

[0100] In the ceramic substrate according to the fifth embodiment of the present invention, the cross-sectional shape of the recess may be curved (chamfered) or may have a shape consisting of a bottom portion parallel to the side surface of the laminate and a side portion perpendicular to the side surface of the laminate.

[0101] In the ceramic laminate according to the fifth embodiment of the present invention, the heat dissipation member has two outer portions, one of which protrudes in a direction opposite to the direction of protrusion of the other outer portion, and each outer portion may have a shape such that a part of the outer portion contacts the side surface from which the other outer portion protrudes. Such a ceramic substrate will be described with reference to the drawings.

[0102] FIG. 14 is a cross-sectional view schematically illustrating an example of a cross section of a ceramic substrate according to a fifth embodiment of the present invention, cut in a direction perpendicular to the side surface protruding toward the outer portion of the heat dissipation member and perpendicular to the first main surface of the laminate.

[0103] As shown in Figure 14, the ceramic substrate 401P includes a laminate 10 and a heat dissipation member 440P. The heat dissipation member 440P has an inner portion 441P and two outer portions (442P-a, 442P-b). One outer portion 442P-a protrudes from the first side surface 13a, and the other outer portion 442P-b protrudes from the third side surface 13c. The protruding direction of the outer portion 442P-a (indicated by the arrow P in Figure 14) is ４４２Ｐ－ａ ) and the protruding direction of the outer portion 442P-b (the direction indicated by the arrow P ４４２Ｐ－ｂ This is the opposite direction to the direction indicated by .

[0104] The heat dissipation member 440P has a thickness T ４４１Ｐ Therefore, the thickness T of the outer portion 442P-a in the stacking direction Z is ４４２Ｐ－ａ and the thickness T of the outer portion 442P-b ４４２Ｐ－ｂ The thickness T of the outer portion 442P-a is ４４２Ｐ－ａ and outer portion 442P-b have the same thickness and are thicker than inner portion 441P in both Z directions.

[0105] As shown in FIG. 14, the heat dissipation member 440P has thick outer portions 442P-a and 442P-b, which are in contact with the first side surface 13a and the third side surface 13c, respectively.

[0106] In the ceramic substrate 401P, the heat dissipation member 440P has a protruding direction P of the outer portion 442P-a. ４４２Ｐ－ａ In the ceramic substrate 401P, when the heat dissipation member 440P is pulled in the protruding direction P of the outer portion 442P-b, the outer portion 442P-b acts as a support, preventing the heat dissipation member 440P from coming off. ４４２Ｐ－ｂ When the heat dissipation member 440P is pulled, the outer portion 442P-a acts as a support and prevents the heat dissipation member 440P from coming off.

[0107] Sixth Embodiment Next, a method for manufacturing a ceramic substrate according to a sixth embodiment of the present invention will be described. The method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention includes (1) a pre-firing laminate preparation step and (2) a firing step. The method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention will be described below using, as an example, the heat dissipation member 240D according to the third embodiment of the present invention.

[0108] (1) Pre-Firing Laminate Preparation Step FIGS. 15A to 15D are process diagrams sequentially illustrating an example of a pre-firing laminate preparation step in the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention.

[0109] In the pre-firing laminate preparation process, for example, LTCC material, binder, and plasticizer are mixed in desired amounts to prepare a slurry. Next, the slurry is applied to a carrier film (not shown) to form multiple ceramic green sheets 20 as shown in FIG. 15A. A lip coater or doctor blade can be used to apply the slurry. Note that the ceramic green sheets 20 shrink when fired in the firing process described below. It is preferable to appropriately determine the size of the ceramic green sheets 20, taking into account the shrinkage caused by firing.

[0110] 15B, a portion where the heat dissipation member 240D will be accommodated is determined, and a hole 30a is formed in the ceramic green sheet 20. At this time, holes such as via holes for wiring vias may also be formed. The hole 30a and via holes for wiring vias may be formed by laser processing, cutter processing, drilling, or the like. It is preferable to appropriately determine the sizes of the hole 30a and via holes for wiring vias, taking into account shrinkage due to firing.

[0111] Next, a conductive paste may be placed on the surface of the ceramic green sheet or in predetermined positions such as via holes for wiring vias so that surface electrodes, internal electrodes, internal conductors, and wiring vias are formed in the fired ceramic substrate (not shown).

[0112] 15C, the constraining layer 70 is prepared. The constraining layer 70 is a layer containing an inorganic material that is not substantially sintered at the firing temperature. ２ O ３ It is preferable that the aluminum alloy contains 100% by weight of Al (impurities are allowed). ２ O ３ The constraining layer 70, which includes the above-mentioned polymer, is a sheet that does not substantially sinter at the temperature at which the ceramic green sheet 20 is sintered. Since the constraining layer 70 does not substantially sinter during firing, it does not shrink and acts to suppress shrinkage in the main surface direction of the pre-fired laminate. As a result, the dimensional accuracy of various components after firing can be improved.

[0113] 15D, the ceramic green sheet 20 is peeled off from the carrier film (not shown) and laminated. At this time, the heat dissipation member 240D is placed in the hole 30a. In addition, the constraining layer 70 is laminated on both ends in the lamination direction Z.

[0114] 16 is a plan view schematically illustrating an example of a ceramic green sheet in which a heat dissipation member 240D is disposed in the hole 30a, with an inner portion 241D of the heat dissipation member 240D accommodated in the hole 30a and an outer portion 242D of the heat dissipation member 240D protruding outward.

[0115] Through the above steps, a pre-fired laminate 201Da shown in FIG. 17 can be produced. FIG. 17 is a cross-sectional view schematically illustrating an example of a pre-fired laminate produced by a method for producing a ceramic laminate according to a sixth embodiment of the present invention. The pre-fired laminate 201Da shown in FIG. 17 includes a ceramic green sheet laminate 10a including a plurality of stacked ceramic green sheets 20 and having holes 30a therein, and a heat dissipation member 240D made of a carbon material and disposed in the holes 30a. The ceramic green sheet laminate 10a also includes a first main surface 16a, a second main surface 17a opposing the first main surface 16a, and a side surface 18a connecting the first main surface 16a and the second main surface 17a. The heat dissipation member 240D has an inner portion 241D accommodated in the holes 30a and an outer portion 242D protruding from the side surface 18a.

[0116] (2) Firing Step FIG. 18A is a cross-sectional view schematically illustrating an example of the firing step of the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. FIG. 18B is a cross-sectional view schematically illustrating an example of a ceramic substrate on which a constraining layer has been formed after the firing step of the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention. Next, as shown in FIG. 18A , the pre-firing laminate 201Da is fired by heating while applying pressure. The firing temperature is not particularly limited as long as it is a temperature at which the constraining layer 70 does not sinter, but is preferably 1000° C. or less. Note that applying pressure is not essential in the firing step of the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention.

[0117] By firing under these conditions, it is possible to produce a ceramic substrate in which the ceramic green sheet 20 serves as a ceramic layer, the hole 30a serves as a receiving portion 30, and a heat dissipation member is disposed in the receiving portion.

[0118] After the firing step, a ceramic substrate 201D having ceramic layers formed thereon as shown in FIG. 18B can be produced.

[0119] After the firing, the constraining layer 70 is removed by sandblasting or other treatment. Through the above steps, the ceramic substrate can be manufactured.

[0120] In the description of the method for manufacturing a ceramic substrate according to the sixth embodiment of the present invention, the case where the heat dissipation member 240D according to the third embodiment of the present invention is used as the heat dissipation member has been given as an example, but the shape of the heat dissipation member is not particularly limited, and heat dissipation members of various shapes exemplified in the description of the ceramic substrates according to the first to fifth embodiments of the present invention can be used. Furthermore, by appropriately changing the shape of the holes in the ceramic green sheets according to the shape of the heat dissipation member, a desired ceramic substrate can be manufactured.

[0121] This specification describes the following:

[0122] The present invention (1) comprises a laminate including a plurality of stacked ceramic layers, the laminate having a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, a housing portion formed inside the laminate, and a heat dissipation member made of a carbon material and placed in the housing portion, wherein the heat dissipation member is a ceramic substrate having an inner portion housed in the housing portion and an outer portion protruding to the outside from the side surface.

[0123] The present invention (2) is the ceramic substrate according to the present invention (1), wherein the heat dissipation member has a plurality of outer portions, each of which protrudes from a different portion of the side surface.

[0124] The present invention (3) is the ceramic substrate according to the present invention (1) or (2), wherein the heat dissipation member is in the form of a sheet.

[0125] The present invention (4) is the ceramic substrate according to any one of the present inventions (1) to (3), wherein, when the ceramic substrate is viewed in a plane, the direction in which the outer portion protrudes outward from the side surface is defined as the protruding direction, and the direction perpendicular to the protruding direction is defined as the width direction, the inner portion includes a first region having a first width in the width direction, and a second region having a second width in the width direction that is longer than the first width, and the first region is located between the second region and the outer portion when the ceramic substrate is viewed in a plane.

[0126] The present invention (5) is the ceramic substrate according to the present invention (4), wherein a through hole penetrating in the stacking direction is formed in the inner portion.

[0127] The present invention (6) is the ceramic substrate according to the present invention (4) or (5), wherein the heat dissipation member has a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

[0128] The present invention (7) is the ceramic substrate according to any one of the present inventions (4) to (6), wherein the laminate has a recess on the side surface from which the outer portion protrudes, the recess exposing at least a part of the inner portion.

[0129] The present invention (8) is the ceramic substrate according to any one of the present inventions (4) to (7), wherein the heat dissipation member has two outer portions, and the protruding direction of one outer portion is opposite to the protruding direction of the other outer portion.

[0130] The present invention (9) is the ceramic substrate according to any one of the present inventions (1) to (3), wherein the inner portion has a through-hole formed therethrough in the stacking direction.

[0131] A present invention (10) is the ceramic substrate according to the present invention (9), wherein the heat dissipation member has a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

[0132] The present invention (11) is the ceramic substrate according to the present invention (9) or (10), wherein the laminate has a recess formed on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion.

[0133] The present invention (12) is a ceramic substrate according to any one of the present inventions (9) to (11), wherein the heat dissipation member has two outer portions, the protruding direction of one outer portion is opposite to the protruding direction of the other outer portion, and a portion of each outer portion has a shape that contacts the side surface from which the outer portion protrudes.

[0134] The present invention (13) is the ceramic substrate according to any one of the present inventions (1) to (3), wherein the heat dissipation member has a shape in which a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

[0135] The present invention (14) is the ceramic substrate according to the present invention (13), wherein the laminate has a recess formed on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion.

[0136] The present invention (15) is the ceramic substrate according to the present invention (13) or (14), wherein the heat dissipation member has two outer portions, and the protruding direction of one outer portion is opposite to the protruding direction of the other outer portion.

[0137] The present invention (16) is a method for manufacturing a ceramic substrate, the method including: a pre-fired laminate preparation step of preparing a pre-fired laminate, the pre-fired laminate including a plurality of stacked ceramic green sheets and having a hole therein; and a heat dissipation member made of a carbon material disposed in the hole; and a firing step of firing the pre-fired laminate to produce a ceramic substrate in which the ceramic green sheets are made into ceramic layers, the hole is made into an accommodation portion, and the heat dissipation member is disposed in the accommodation portion, wherein the ceramic green sheet laminate prepared in the pre-fired laminate preparation step has a first main surface, a second main surface opposite to the first main surface, and a side surface connecting the first main surface and the second main surface, and the heat dissipation member has an inner portion that is accommodated in the hole and an outer portion that protrudes to the outside from the side surface.

[0138] EXAMPLES Hereinafter, examples will be given that more specifically disclose the present invention, but the present invention is not limited to these examples.

[0139] (Example 1) (1) Pre-firing laminate preparation step First, as shown in Fig. 19, a graphite sheet having dimensions of length x width x thickness = 20.0 mm x 50.0 mm x 0.04 mm was prepared as the heat dissipation member according to Example 1. Fig. 19 is a plan view schematically showing the heat dissipation member according to Example 1.

[0140] Next, alumina powder was prepared, and SiO ２ :59% by weight, B ２ O ３ : 10% by weight, CaO: 25% by weight, Al ２ O ３ A borosilicate glass powder containing 6% by weight of alumina powder and 6% by weight of glass powder was prepared. The alumina powder and glass powder were mixed in a weight ratio of 40:60, and appropriate amounts of binder, dispersant, plasticizer, organic solvent, etc. were added to the mixed powder and mixed to prepare a ceramic slurry. The ceramic slurry was then degassed and cut using a doctor blade to produce 15 ceramic green sheets measuring 30.0 mm x 30.0 mm x 0.08 mm.

[0141] A hole was formed in one of the prepared ceramic green sheets by laser processing. The planar shape of the hole was a rectangle measuring 20.05 mm x 25.05 mm, and the hole was formed by cutting inward from the edge of the ceramic green sheet. Taking into account the shrinkage of the ceramic green sheet during firing, the shape of the hole was determined so that a gap of 0.05 mm would be left when placing a heat dissipation member in the hole.

[0142] Next, two alumina sheets were prepared as constraining layers, and a constraining layer sheet was placed on the outermost layer. Seven unprocessed ceramic green sheets were then stacked, and a ceramic green sheet with holes formed therein was then stacked on top of that, with heat dissipation members placed in the holes. Next, seven unprocessed ceramic green sheets were stacked, and a constraining layer sheet was then stacked on the innermost layer. Through the above steps, a pre-fired laminate was prepared, which included a ceramic green sheet laminate with holes inside and heat dissipation members placed in the holes.

[0143] (2) Firing Step Next, the pre-fired laminate was pressed in the thickness direction. The pre-fired laminate was then fired at 1000°C to form a ceramic substrate with a constraining layer formed on the outermost layer. In this firing step, the 80 μm-thick ceramic green sheet was fired so as to be in contact with the heat dissipation member. The hole was also fired to form a housing portion.

[0144] Thereafter, the constraining layer was removed by sandblasting, and the ceramic substrate according to Example 1 was manufactured.

[0145] (Example 2) Fig. 20 is a plan view schematically showing a heat dissipation member according to Example 2. The heat dissipation member according to Example 2 shown in Fig. 20 has the same shape as the heat dissipation member according to Example 1, except that a notch measuring 2.5 mm x 15.0 mm is formed on both sides at a position 5.0 to 20.0 mm from the end. The portion with the notch becomes the inner portion of the heat dissipation member in the manufactured ceramic substrate.

[0146] Using this heat dissipation member of Example 2, a ceramic substrate of Example 2 was manufactured in the same manner as Example 1, except that the holes formed in the ceramic green sheet were formed to match the shape of the heat dissipation member of Example 2. In the ceramic substrate of Example 2, the portion of the heat dissipation member with the notch is the first region, and the area inside is the second region. The width of the second region is wider than the width of the first region. In the ceramic substrate of Example 2, the second region, first region, and outer portion are aligned in this order in the protruding direction of the outer portion of the heat dissipation member.

[0147] (Example 3) A heat dissipation member according to Example 3 was fabricated in the same manner as in Example 1, except that the thickness of the outer portion was set to 0.06 mm. In the heat dissipation member according to Example 3, the inner portion is uniformly thinner than the outer portion both vertically. In the ceramic substrate according to Example 3, a portion of the outer portion of the heat dissipation member is in contact with the side surface of the laminate from which the outer portion protrudes.

[0148] Comparative Example 1 A ceramic substrate according to Comparative Example 1 was manufactured in the same manner as in Example 1, except that no holes were formed in the ceramic green sheets and no heat dissipation members were disposed.

[0149] (Comparative Example 2) Fig. 21 is a plan view schematically showing a heat dissipation member according to Comparative Example 2. The heat dissipation member according to Comparative Example 2 shown in Fig. 21 is the same as the heat dissipation member according to Example 1, except that it is a square with dimensions of 20.0 mm x 20.0 mm.

[0150] A ceramic substrate according to Comparative Example 2 was manufactured in the same manner as in Example 1, except that a hole measuring 20.05 mm x 20.05 mm was formed in the center of the ceramic green sheet and the heat dissipation member according to Comparative Example 2 was placed in the hole. In the ceramic substrate according to Comparative Example 2, the heat dissipation member was inside the laminate and not exposed to the outside.

[0151] (Evaluation of Heat Dissipation) The ceramic substrates according to Examples 1 to 3 were used to evaluate heat dissipation using the following method. FIG. 22 is a schematic diagram of the test method for evaluating heat dissipation. As shown in FIG. 22, a 5 mm x 5 mm heater 50 was installed at the center of the first main surface 11 of each ceramic substrate (indicated by the reference symbol 1 in FIG. 22) via a thermal interface material (TIM). A 20 mm x 20 mm heat sink 60 was also installed via a TIM on the outer portion 42 of the heat dissipation member 40. These were then covered with absorbent cotton for thermal insulation from the surroundings. The heat sink was water-cooled to maintain a temperature of 25°C, and the heater was turned on at 2.5 W. Once the heater temperature stabilized, the heater temperature was measured using a thermocouple attached to the heater surface. The results are shown in Table 1.

[0152] The heater temperatures were obtained in the same manner as above, except that no heat sink was provided, using the ceramic substrates according to Comparative Examples 1 and 2. The results are shown in Table 1.

[0153]

[0154] As shown in Table 1, it was found that heat dissipation performance is improved when the heat dissipation member is protruded to the outside. In particular, the ceramic substrate of Example 2, which has a notch, and the ceramic substrate of Example 3, which has a thicker outer portion than the inner portion, had higher heat dissipation performance. This is thought to be because, in the ceramic substrates of Examples 2 and 3, the adhesion between the ceramic layer and the heat dissipation member is strong, making it less likely that a gap will form between the ceramic layer and the heat dissipation member.

[0155] Example 4 First, a ceramic substrate was manufactured in the same manner as in Example 1. Next, a recess was formed on the side surface of the laminate from which the outer portion protruded, so that the upper and lower surfaces of the inner portion were exposed, thereby manufacturing a ceramic substrate according to Example 4. The recess had a bottom parallel to the side surface of the laminate and a side perpendicular to the side surface of the laminate. The depth of the recess (the distance from the side surface of the laminate to the bottom) was 0.1 mm, and the width of the recess (the distance from the heat dissipation member to the side) was 0.1 mm.

[0156] (Evaluation of Tensile Stress) The tensile stress when the outer portion of the heat dissipation member was bent upward was simulated for the ceramic substrates according to Examples 1 and 4. The results are shown in Table 2. The simulation was performed using FEMTET (stress analysis) manufactured by Murata Software Co., Ltd.

[0157]

[0158] As shown in Table 2, it was found that forming a recess in the laminate that exposes part of the inner portion of the heat dissipation member reduces the tensile stress when the heat dissipation member is bent.

[0159] 1, 101, 201, 201A, 201B, 201C, 201D, 201E, 201F, 201G, 201H, 201I, 201J, 201K, 201L, 201M, 201N, 201O, 201P, 301I, 401J, 401P, 401Q, 401R, 401S, 401T Ceramic substrate 10, 210K, 210M, 410T Laminate 10a Ceramic green sheet laminate 11 First main surface 12 Second main surface 13 Side surface 13a, 213a, 413a First side surface 13b Second side surface 13c Third side surface 13d Fourth side surface 16a First main surface 17a Second main surface 18a Side surface 20 Ceramic green sheet 30 Storage part 30a Hole part 40, 140, 240, 240A, 240B, 240C, 240D, 240E, 240F, 240G, 240H, 240I, 240O, 240P, 440J, 440P, 440Q, 440R, 440S Heat dissipation member 41, 141, 241, 241D, 241J, 241P, 341I, 441J, 441P, 441Q, 441R, 441S Inner part 42, 242, 242D, 242J, 242P-a, 242P-b, 442J, 442P-a, 442P-b, 442Q, 442R, 442S Outer portion 50 Heat generating parts 60 External heat dissipation mechanism 70 Constraint layer 142a First outer portion 142b Second outer portion 201Da Pre-fired laminate 215K, 215L, 215M, 215N, 215O, 415T Recess 215Ob Bottom 215Os Side 241a, 241P-a First region 241P-a' First region' 241b, 241P-b Second region 241c Third region 245I, 345I Through hole

Claims

1. A ceramic substrate comprising: a laminate including a plurality of laminated ceramic layers, the laminate having a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface; a housing portion formed inside the laminate; and a heat dissipation member made of a carbon material placed in the housing portion, the heat dissipation member having an inner portion housed in the housing portion and an outer portion protruding to the outside from the side surface.

2. The ceramic substrate according to claim 1, wherein the heat dissipation member has a plurality of outer portions, each of the outer portions protruding from a different portion of the side surface.

3. The ceramic substrate according to claim 1 or 2, wherein the heat dissipation member is in the form of a sheet.

4. A ceramic substrate according to any one of claims 1 to 3, wherein, when the ceramic substrate is viewed in a plane, the direction in which the outer portion protrudes outward from the side surface is defined as a protruding direction, and the direction perpendicular to the protruding direction is defined as a width direction, the inner portion includes a first region having a first width in the width direction, and a second region having a second width in the width direction that is longer than the first width, and when the ceramic substrate is viewed in a plane, the first region is located between the second region and the outer portion.

5. The ceramic substrate according to claim 4, wherein a through hole is formed in the inner portion, penetrating in the stacking direction.

6. The ceramic substrate according to claim 4 or 5, wherein the heat dissipation member has a shape such that a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

7. The ceramic substrate according to any one of claims 4 to 6, wherein the laminate has a recess formed on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion.

8. A ceramic substrate according to any one of claims 4 to 7, wherein the heat dissipation member has two outer portions, and one of the outer portions protrudes in a direction opposite to the direction of protrusion of the other outer portion.

9. The ceramic substrate according to any one of claims 1 to 3, wherein a through hole is formed in the inner portion, penetrating in the stacking direction.

10. The ceramic substrate according to claim 9, wherein the heat dissipation member has a shape such that a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

11. The ceramic substrate according to claim 9 or 10, wherein the laminate has a recess formed on the side surface from which the outer portion protrudes, exposing at least a part of the inner portion.

12. A ceramic substrate according to any one of claims 9 to 11, wherein the heat dissipation member has two outer portions, one of which protrudes in a direction opposite to the other of which, and a portion of each of the outer portions is shaped to contact the side surface from which the outer portion protrudes.

13. The ceramic substrate according to any one of claims 1 to 3, wherein the heat dissipation member has a shape such that a part of the outer portion is in contact with the side surface from which the outer portion protrudes.

14. The ceramic substrate according to claim 13, wherein the laminate has a recess formed on the side surface from which the outer portion protrudes, exposing at least a portion of the inner portion.

15. The ceramic substrate according to claim 13 or 14, wherein the heat dissipation member has two outer portions, and one of the outer portions protrudes in a direction opposite to the direction of protrusion of the other outer portion.

16. A method for manufacturing a ceramic substrate, comprising: a pre-fired laminate preparation step of preparing a pre-fired laminate comprising a ceramic green sheet laminate containing a plurality of stacked ceramic green sheets and having holes therein, and a heat dissipation member made of a carbon material placed in the holes; and a firing step of firing the pre-fired laminate to produce a ceramic substrate in which the ceramic green sheets are turned into ceramic layers, the holes are used as receiving sections, and the heat dissipation member is placed in the receiving sections, wherein the ceramic green sheet laminate prepared in the pre-fired laminate preparation step has a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, and the heat dissipation member has an inner portion that is received in the hole and an outer portion that protrudes to the outside from the side surface.

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