Package, electronic apparatus, and package manufacturing method

Abstract

In the present invention, a heat dissipating member (22) is made of a metal sintered material. A frame (21) is made of a ceramic material. An adhesive layer (40) includes: a first interface (FC1) in contact with the frame (21); and a second interface (FC2) in contact with the heat dissipating member (22). The adhesive layer (40) is made of a composite material containing both a metal and a ceramic. The composite material and the ceramic material of the frame (21) are mutually sintered at the first interface (FC1), and the composite material and the metal sintered material of the heat dissipating member (22) are mutually sintered at the second interface (FC 2).

Description

Package, electronic device, and method for manufacturing the package

[0001] The present invention relates to a package, an electronic device, and a method for manufacturing the package.

[0002] Japanese Patent Laid-Open Publication No. 2015-204426 (Patent Document 1) discloses a package. This package includes a heat sink plate and a ceramic frame. The heat sink plate is a rectangular metal plate that dissipates heat generated by electronic components mounted on its upper surface. The ceramic frame is joined to the heat sink plate so as to surround the area where the electronic components are mounted. This joining is performed by brazing. The brazing temperature is approximately 780°C. The ceramic frame is made of, for example, alumina or aluminum nitride.

[0003] The ceramic frame has a frame shape and is formed by joining an upper layer sheet and a lower layer sheet. A metallized film and a plated coating are provided on the lower surface of the lower layer sheet. The plated coating on the lower surface of the lower layer sheet is joined to the heat sink plate via a brazing material. The inner peripheral edge of the lower layer sheet is positioned more toward the outer periphery than the inner peripheral edge of the upper layer sheet. This allows the electronic component to be mounted close to the inner periphery of the upper layer sheet of the ceramic frame, avoiding the fillet of the brazing material.

[0004] The heat sink plate is a metal plate. A metal plate having high thermal conductivity and capable of mitigating package warpage due to differences in linear expansion coefficients during brazing with the ceramic frame is selected. For example, a composite metal plate or a clad metal plate is used. The composite metal plate is formed, for example, by an impregnation method. Specifically, it is formed by impregnating a porous high-melting-point metal plate with Cu. Since the linear expansion coefficient of high-melting-point metals such as tungsten or molybdenum is close to that of ceramic, the linear expansion coefficient of the heat sink plate can be made close to that of the ceramic frame. Furthermore, Cu has excellent thermal conductivity, which can improve the heat dissipation performance of the heat sink plate.

[0005] When the linear expansion coefficient of the heat sink plate needs to be close to that of the ceramic frame, composite metal plates or clad metal plates are widely used, as mentioned above. However, when matching the linear expansion coefficient is not important, simple metal materials are also widely used, such as pure copper, which can significantly increase thermal conductivity.

[0006] Japanese Patent Laid-Open Publication No. 51-132461 (Patent Document 2) discusses a manufacturing method that does not require brazing between a metal plate and a frame-shaped ceramic plate. Specifically, the publication discloses a first manufacturing method in which a frame-shaped unfired ceramic plate (green sheet) is placed on a Mo metal plate, directly bonded by hot pressing, and then fired. In this first manufacturing method, the flat surface of the metal plate makes it difficult for the metal and ceramic to interpenetrate during bonding. As a result, the bond strength between the metal plate and the ceramic plate is extremely weak. Therefore, the publication discloses a second manufacturing method in which an unfired ceramic plate is placed on one main surface of a metal plate made of a high-melting-point metal (e.g., molybdenum or tungsten) via a layer of metal powder made of the high-melting-point metal, followed by firing. According to the publication, the interposition of the metal powder layer facilitates the interpenetration. Furthermore, the metal plate and the metal powder layer are homogeneous, making them easy to bond, thereby increasing the bond strength. Therefore, the bonding strength is increased.

[0007] JP 2015-204426 A JP 51-132461 A

[0008] The above-mentioned Japanese Patent Laid-Open Publication No. 51-132461 claims that a high joint strength can be obtained between a metal plate (a heat dissipation member made of metal) and a ceramic plate (a frame made of a ceramic material) without the need for brazing. However, according to the inventors' investigations, this joint strength is still far below a practical joint strength. In fact, even decades after the disclosure of Japanese Patent Laid-Open Publication No. 51-132461, a heat dissipation member made of metal and a frame made of a ceramic material are typically joined by brazing, as disclosed in the above-mentioned Japanese Patent Laid-Open Publication No. 2015-204426, for example.

[0009] The present invention has been made to solve the above-mentioned problems, and its object is to provide a package, an electronic device, and a method for manufacturing a package that can ensure practically sufficient joint strength between a frame body made of a ceramic material and a heat dissipation member made of a metal, without requiring brazing between the frame body and the heat dissipation member.

[0010] Aspect 1 is a package having a cavity for housing an electronic component. The package includes a heat dissipation member made of a metal sintered material, a frame made of a ceramic material, and an adhesive layer. The heat dissipation member has an upper surface facing the cavity and a lower surface opposite the upper surface. The frame has an opposing surface facing the upper surface of the heat dissipation member in the thickness direction, a surface opposite the opposing surface, an inner surface surrounding the cavity, and an outer surface opposite the inner surface. The adhesive layer has a first interface in contact with the opposing surface of the frame, a second interface opposite the first interface and in contact with the upper surface of the heat dissipation member, and an outer wall surface connecting the upper surface and the lower surface. The adhesive layer is made of a composite material containing both ceramic and metal, and the composite material is sintered to the ceramic material of the frame at the first interface and to the metal sintered material of the heat dissipation member at the second interface.

[0011] Aspect 2 is the package according to aspect 1, wherein the metal sintered material includes copper and at least one high-melting-point metal selected from the group consisting of tungsten and molybdenum.

[0012] Aspect 3 is the package according to aspect 2, wherein the metal of the composite material of the adhesive layer includes copper and at least one high-melting-point metal selected from the group consisting of tungsten and molybdenum.

[0013] Aspect 4 is a package according to aspect 2 or 3, further comprising a metallized layer provided on the surface of the frame body and made of a sintered material containing copper at a higher volume ratio than the metal sintered material of the heat dissipation member.

[0014] Aspect 5 is a package described in any one of aspects 1 to 4, wherein the composite material of the adhesive layer does not contain silver, the adhesive layer has an inner end extending into the cavity, and a space is provided in the thickness direction between the inner end of the adhesive layer and the opposing surface of the frame body or the top surface of the heat dissipation member.

[0015] A sixth aspect is the package according to any one of the first to fifth aspects, wherein the lower surface of the heat dissipation member and the outer wall surface form an obtuse angle.

[0016] A seventh aspect is the package according to any one of the first to sixth aspects, wherein the lower surface of the heat dissipation member has a convex shape at the center of the heat dissipation member.

[0017] Aspect 8 is the package according to aspect 7, wherein the lower surface of the heat dissipation member has a concave shape outside the central portion.

[0018] Aspect 9 is the package of any one of aspects 1 to 8, wherein the adhesive layer does not contain silver.

[0019] Aspect 10 is a package described in any one of aspects 1 to 9, wherein, in a cross-sectional view parallel to the thickness direction, the outer surface of the frame body has a lower end, the outer wall surface of the heat dissipation member has an upper end, and the positional deviation between the lower end and the upper end in a direction perpendicular to the thickness direction is within 0.1 mm.

[0020] Aspect 11 is the package according to any one of aspects 1 to 10, wherein a corner formed by the surface and the outer surface of the frame has a radius of curvature of 0.1 mm or more and 0.5 mm or less.

[0021] A twelfth aspect is the package according to any one of the first to eleventh aspects, further comprising a metal terminal provided on the surface of the frame.

[0022] Aspect 13 is an electronic device comprising the package described in aspect 5, the electronic component housed within the cavity of the package, and a mounting material containing silver for mounting the electronic component onto the package.

[0023] Aspect 14 is a method for manufacturing a package for manufacturing a package described in any one of Aspects 1 to 12, and includes a step of forming a green structure that combines a first green member that will become the heat dissipation member when fired, a second green member that will become the frame body when fired, and a third green member that will become the adhesive layer when fired, and a step of firing the green structure.

[0024] According to the first aspect, the adhesive layer is made of a composite material containing both ceramic and metal, and the composite material is sintered to the ceramic material of the frame and to the metal sintered material of the heat dissipation member. This makes it possible to ensure a practically sufficient bonding strength between the ceramic frame and the metal heat dissipation member without requiring brazing between the frame and the heat dissipation member.

[0025] According to the second aspect, the thermal conductivity of the heat dissipation component can be improved by including copper, and the linear expansion coefficient of the heat dissipation component can be reduced by including a high-melting-point metal, which can be appropriately adjusted depending on the application of the package. Furthermore, according to the third aspect, the composite material of the adhesive layer contains a material similar to the metal sintered material of the heat dissipation component. This can more reliably ensure bonding strength.

[0026] According to the fourth aspect, the metallization layer on the surface of the frame is made of a sintered material containing copper at a higher volume ratio than the metal sintered material of the heat dissipation member. This makes the linear expansion coefficient of the metallization layer higher than that of the heat dissipation member. Considering that the thickness of the metallization layer is usually smaller than that of the heat dissipation member, in a configuration in which a frame made of a ceramic material is disposed between the metallization layer and the heat dissipation member, the above-mentioned relationship in linear expansion coefficients makes it easier to balance thermal stress in the package. This makes it possible to suppress warping of the package under temperature changes.

[0027] According to the above-mentioned aspects 5 and 13, the adhesive layer has an inner end portion extending into the cavity, and a space is provided in the thickness direction between the inner end portion of the adhesive layer and the opposing surface of the frame body or the upper surface of the heat dissipation member. As a result, when an electronic component is mounted using a mounting material containing silver, silver migration from the mounting material must proceed by bypassing the space. Therefore, a decrease in electrical insulation between the heat dissipation member and the surface of the frame body due to silver migration is suppressed. In particular, when a metal terminal is provided on the surface of the frame body as in the above-mentioned aspect 12, it is possible to avoid insufficient electrical insulation between the heat dissipation member and the metal terminal due to the migration.

[0028] According to the sixth aspect, the lower surface of the heat dissipation member and the outer wall surface form an obtuse angle, which makes it possible to make the bonding layer for bonding the heat dissipation member to another member less likely to peel off.

[0029] According to the seventh aspect, the lower surface of the heat dissipation member has a convex shape at the center of the heat dissipation member. This allows the convex shape to spread the bonding material outward from the center of the heat dissipation member when the heat dissipation member is bonded to another member by forming a bonding layer using a fluid bonding material. This facilitates ensuring the bonding strength of the bonding layer in the peripheral portion around the center. Since peeling of the bonding layer is more likely to occur from the peripheral portion than from the center, ensuring the bonding strength of the bonding layer in the peripheral portion can prevent peeling of the bonding layer. Furthermore, according to the eighth aspect, the lower surface of the heat dissipation member has a concave shape outside the center. If the lower surface of the heat dissipation member has a simple convex shape, the lower surface of the heat dissipation member is prone to unintentional tilting around the protruding portion of the convex shape. However, by having the concave shape of the lower surface of the heat dissipation member, this tilting can be suppressed.

[0030] According to the above-mentioned Aspect 9, the adhesive layer does not contain silver. This makes it possible to prevent silver migration from the adhesive layer. In particular, when a metal terminal is provided on the surface of the frame body as in the above-mentioned Aspect 12, it is possible to prevent the migration from causing insufficient electrical insulation between the heat dissipation member and the metal terminal.

[0031] According to the above-mentioned aspect 10, the misalignment between the lower end of the outer surface of the frame and the upper end of the outer wall surface of the heat dissipation member in the direction perpendicular to the thickness direction is within 0.1 mm. This makes it possible to suppress stress concentration due to the misalignment. Therefore, peeling between the lower end of the outer surface of the frame and the upper end of the outer wall surface of the heat dissipation member is prevented.

[0032] According to the above-mentioned aspect 11, the corners formed by the surface and outer surface of the frame body have a radius of curvature of 0.1 mm or more and 0.5 mm or less. A radius of curvature of 0.1 mm or more makes the corners of the frame body less likely to chip when subjected to impact. A radius of curvature of 0.5 mm or less prevents excessive reduction in the surface area of ​​the frame body due to rounded corners. In particular, when a metal terminal is provided on the surface of the frame body as in the above-mentioned aspect 12, ensuring a sufficient surface area of ​​the frame body makes it easier to ensure a bonding area between the surface of the frame body and the metal terminal. Therefore, they can be bonded to each other with high strength.

[0033] According to the above-mentioned fourteenth aspect, the heat dissipation member, the frame, and the adhesive layer can be formed by simultaneous firing.

[0034] The objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

[0035] FIG. 1 is a schematic cross-sectional view showing the configuration of an electronic device according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing the configuration of a package according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing a first step of a method for manufacturing the package of FIG. 2. FIG. 4 is a schematic cross-sectional view showing a second step of a method for manufacturing the package of FIG. 2. FIG. 5 is a schematic cross-sectional view showing a third step of a method for manufacturing the package of FIG. 2. FIG. 6 is a schematic cross-sectional view showing a fourth step of a method for manufacturing the package of FIG. 2. FIG. 7 is a schematic partial cross-sectional view showing one example of a configuration in the vicinity of an outer end surface of an adhesive layer of a package according to the first embodiment. FIG. 8 is a schematic partial cross-sectional view showing another example of a configuration in the vicinity of an outer end surface of an adhesive layer of a package according to the first embodiment. FIG. 9 is a schematic partial cross-sectional view showing the occurrence of silver migration in the electronic device of FIG. 1. FIG. 10 is a schematic cross-sectional view showing the configuration of an electronic device according to a second embodiment. FIG. 11 is a schematic cross-sectional view showing the configuration of an electronic device according to a third embodiment. FIG. 12 is a schematic partial cross-sectional view showing stress on a bonding layer in the electronic device of FIG. 1. FIG. 13 is a schematic partial cross-sectional view showing the configuration of an electronic device according to a fourth embodiment. FIG. 14 is a schematic cross-sectional view showing the configuration of an electronic device according to a fifth embodiment. FIG. 15 is a schematic cross-sectional view showing the configuration of an electronic device according to a sixth embodiment. FIG. 16 is a schematic partial cross-sectional view showing an example of the configuration of a corner formed between the surface and outer surface of the frame body in the package of FIG. 2 and its vicinity. FIG. 17 is a schematic partial cross-sectional view showing an example of the configuration of a corner formed between the surface and outer surface of the frame body in the package according to the seventh embodiment. FIG. 18 is a schematic cross-sectional view showing the configuration of a package according to an eighth embodiment. FIG. 19 is a schematic cross-sectional view showing the configuration of a package according to a first modification of the eighth embodiment. FIG. 20 is a schematic cross-sectional view showing the configuration of a package according to a second modification of the eighth embodiment. FIG. 21 is a schematic cross-sectional view showing the configuration of a package according to a third modification of the eighth embodiment. FIG. 22 is a schematic cross-sectional view showing the configuration of a package according to a fourth modification of the eighth embodiment. FIG. 23 is a schematic cross-sectional view showing the configuration of an electronic device according to a ninth embodiment. FIG. 24 is a schematic perspective view showing the configuration of a package according to a tenth embodiment.

[0036] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, the term "metal" can refer to either a pure metal or an alloy. The term "alloy" can refer to a solid solution of multiple metal components, a mixture of multiple metals that has not been solidified, or an intermetallic compound. The term "green" refers to the state before firing. Therefore, a component labeled "green" is to be fired, but has not yet been fired. The terms "upper" and "lower" are used to distinguish relative directions and do not imply limitations related to the direction of gravity, unless otherwise specified.

[0037] First Embodiment Fig. 1 is a schematic cross-sectional view showing the configuration of an electronic device 100 according to a first embodiment. Fig. 2 is a schematic cross-sectional view showing the configuration of a package 51 included in the electronic device 100. The electronic device 100 (Fig. 1) includes a semiconductor module 90 (electronic device), a heat sink 99, and a solder layer 98 (bonding layer). The solder layer 98 bonds the semiconductor module 90 to the heat sink 99.

[0038] The semiconductor module 90 includes a package 51 having a cavity CV, a semiconductor element 8 (electronic component) housed in the cavity CV, and a mounting material 7 for mounting the semiconductor element 8 on the package 51. The semiconductor module 90 may also include wires 9 as wiring members for the semiconductor element 8. The wires 9 may be formed by wire bonding. In the example shown in FIG. 1 , the wires 9 electrically connect the semiconductor element 8 and the lead frame 30 to each other. The semiconductor module 90 may also include a lid 80 ( FIG. 1 ) for sealing the cavity CV. The lid 80 may be attached to the package 51 by an adhesive 70.

[0039] The package 51 may be plated at an appropriate timing after the firing step described below. The plating typically involves forming a nickel plating film (not shown) as a base and a gold plating film (not shown).

[0040] The semiconductor element 8 is mounted on a cavity surface SW1a of the upper surface SW1 of the heat dissipation member 22 of the package 51 via a mounting material 7. The mounting material 7 is electrically conductive. The mounting material 7 may contain silver (Ag). The mounting material 7 may be formed by sintering an Ag paste, which may contain a solvent and nano-sized Ag powder dispersed therein. Alternatively, the mounting material 7 may be formed by curing an epoxy resin in which Ag powder is dispersed. Alternatively, the mounting material 7 may be formed by soldering. This mounting process is typically performed at a mounting temperature of about 300°C.

[0041] The distance (horizontal distance in FIG. 1 ) between the semiconductor element 8 mounted in the package 51 and the inner surface SF3 of the frame body 21 may be 25 μm or less. This distance may even be zero. In other words, the semiconductor element 8 may be in contact with the inner surface SF3 of the frame body 21. The reason why the semiconductor element 8 can be placed close to the inner surface SF3 of the frame body 21 in this manner is because brazing is not used to connect the frame body 21 and the heat dissipation member 22 in the package 51. If brazing were used, a fillet of brazing material would be formed near the inner surface SF3 within the cavity CV, which would likely prevent the semiconductor element 8 from being placed close to the inner surface SF3. In contrast, in this embodiment, the semiconductor element 8 can be mounted close to the frame body 21, thereby ensuring a larger mounting area within the cavity CV. Furthermore, by mounting the semiconductor element 8 close to the frame body 21, the length of the wires 9 is reduced, which usually leads to improved electrical characteristics.

[0042] The adhesive portion 70 may be, for example, a thermosetting resin. The adhesive portion 70 is provided on the frame body 21 so as to surround the cavity CV. The adhesive portion 70 may have a portion that is provided on the frame body 21 via the lead frame 30 (metal terminal). The thickness of the adhesive portion 70 between the lid body 80 and the package 51 (the vertical dimension in FIG. 1 ) is, for example, not less than 100 μm and not more than 360 μm.

[0043] 2 , the package 51 has a cavity CV in which the semiconductor element 8 ( FIG. 1 ) is housed. The package 51 includes a heat dissipation member 22, a frame 21, and an adhesive layer 40. The package 51 may further include a metallization layer 31, a brazing material layer 32, and a lead frame 30.

[0044] The heat dissipation member 22 has an upper surface SW1, a lower surface SW2 opposite the upper surface SW1, and an outer wall surface SW4 connecting the upper surface SW1 and the lower surface SW2. The upper surface SW1 faces the cavity CV. Specifically, the upper surface SW1 includes a cavity surface SW1a facing the cavity CV. The upper surface SW1 also has a peripheral surface SW1b located outside the cavity surface SW1a. The peripheral surface SW1b may surround the cavity surface SW1a. The cavity surface SW1a may be an approximately flat surface. The peripheral surface SW1b may be an approximately flat surface. In the example shown in FIG. 2, the upper surface SW1 is an approximately flat surface.

[0045] The heat dissipation member 22 is made of a metal sintered material. In this specification, the metal sintered material means a sintered material that is substantially made of metal. As described above, the metal sintered material is substantially a metal material, but may also contain ceramic as an additive. The volume percentage of the metal in the metal sintered material is preferably 95 volume % or more. The volume percentage may be 100%, in which case the metal sintered material contains only metal.

[0046] The metal sintered material may contain copper (Cu) and at least one high-melting-point metal selected from the group consisting of tungsten (W) and molybdenum (Mo). High thermal conductivity can be ensured by including a sufficient proportion of Cu. Meanwhile, the linear expansion coefficient of the heat dissipation member can be made closer to that of ceramics such as alumina by including a sufficient proportion of Cu. This similarity in linear expansion coefficient is useful for suppressing thermal stress between the heat dissipation member 22 and the frame 21. The Cu proportion is, for example, 10% by volume or more and 60% by volume or less. The volume proportions are calculated by combining the weight percentages obtained by elemental analysis with the density values ​​of each element (Cu: 8.96, W: 19.3, Mo: 10.28 (unit: g / cm). ３)) can be calculated. For the sake of simplicity of composition, the metal sintered material may contain only one of W and Mo. In other words, the metal sintered material may be a copper-tungsten alloy or a copper-molybdenum alloy. The copper-tungsten alloy or copper-molybdenum alloy metal sintered material is, of course, a different material from the copper / tungsten clad material.

[0047] The frame 21 has an opposing surface SF2 that faces the peripheral surface SW1b of the upper surface SW1 of the heat dissipation member 22 in the thickness direction (the vertical direction in FIGS. 1 and 2 ), a surface SF1 opposite the opposing surface SF2, an inner surface SF3 that surrounds the cavity CV, and an outer surface SF4 opposite the inner surface SF3. The outer edge of the frame 21 may have a rectangular shape in an in-plane direction perpendicular to the thickness direction. The size of each side of the rectangular shape is, for example, 4 mm to 40 mm. The thickness of the frame 21 is, for example, 0.1 mm to 1 mm. The frame 21 is made of a ceramic material. This improves the heat resistance of the package 51 compared to when the frame 21 is made of a resin material. Because the ceramic material is an insulator, the surface SF1 of the frame 21 can be electrically insulated from the heat dissipation member 22. The ceramic material may contain, for example, alumina as a main component. In that case, the ceramic material may also include additives, such as silicon oxide, manganese oxide, or both.

[0048] The adhesive layer 40 has an interface FC1 (first interface) in contact with the opposing surface SF2 of the frame 21 and an interface FC2 (second interface) opposite the interface FC1 and in contact with the top surface SW1 of the heat dissipation member 22. The adhesive layer 40 also has an outer end surface SA4 facing the outside of the package 51. At least a portion of the adhesive layer 40 is in contact with the peripheral surface SW1b of the top surface SW1 of the heat dissipation member 22. In the example shown in FIG. 2, the adhesive layer 40 also is in contact with a portion of the cavity surface SW1a of the top surface SW1 of the heat dissipation member 22. As shown in FIG. 2, the adhesive layer 40 may be arranged so as to be in contact with only a portion (rather than the entire) of the cavity surface SW1a. In this case, the adhesive layer 40 has an inner end surface SA3 facing the cavity CV.

[0049] The adhesive layer 40 is made of a composite material containing both metal and ceramic. The composite material is sintered to the ceramic material of the frame body 21 at interface FC1 and to the metal sintered material of the heat dissipation member 22 at interface FC2. Because Cu has a low melting point, the Cu of the adhesive layer 40 and the Cu of the heat dissipation member 22 may be fused together and bonded. The frame body 21 and the heat dissipation member 22 are fixed to each other by sintering at interfaces FC1 and FC2. This eliminates the need for brazing filler metal to bond the frame body 21 and the heat dissipation member 22 to each other. While brazing filler metals typically contain Ag, avoiding the use of brazing filler metal prevents the presence of Ag, an element prone to migration, between the frame body 21 and the heat dissipation member 22. The volume fraction of the metal in the composite material of the adhesive layer 40 is smaller than the volume fraction of the metal in the heat dissipation member 22.

[0050] The metal of the composite material may include Cu and at least one high-melting-point metal selected from the group consisting of W and Mo. The ceramic of the composite material may include, for example, alumina as a main component. The ceramic may include additives in addition to alumina as the main component, such as silicon oxide and manganese oxide.

[0051] The composite material may contain a material that is the same as the ceramic material of the frame body 21. This makes it possible to reduce the difference in sintering temperature between the adhesive layer 40 and the frame body 21 when they are co-fired. Furthermore, the composite material of the adhesive layer 40 may contain a material that is the same as the metal sintering material of the heat dissipation member 22. This makes it possible to more reliably ensure the bonding strength between the adhesive layer 40 and the heat dissipation member 22 when they are co-fired.

[0052] The linear expansion coefficient of the composite material of the adhesive layer 40 may be greater than the linear expansion coefficient of the ceramic material of the frame 21 and less than the linear expansion coefficient of the heat dissipation member 22. Such a relationship between the linear expansion coefficients can be easily obtained, for example, by making the ceramic of the composite material of the adhesive layer 40 the same as the ceramic material of the frame 21 and making the metal of the composite material of the adhesive layer 40 the same as the sintered metal material of the heat dissipation member.

[0053] The composite material preferably contains 20% by volume or more and 80% by volume or less of ceramic. By containing 20% ​​by volume or more of ceramic, the bonding strength to the ceramic material of the frame body 21 is increased. Furthermore, the composite material of the adhesive layer 40 preferably contains 20% by volume or more and 80% by volume or less of metal. By containing 20% ​​by volume or more of metal, the bonding strength to the metal sintered material of the heat dissipation member 22 is increased. The adhesive layer 40 may be made only of ceramic material and metal material. Therefore, the adhesive layer 40 does not need to contain an organic material. It is preferable that the adhesive layer 40 does not contain Ag.

[0054] The thickness of the adhesive layer 40 (the vertical dimension in FIG. 2 ) may be 5 μm or more and 50 μm or less. A thickness of 5 μm or more allows the layer thickness to be roughly uniform while using commonly used ceramic powders and metal powders with thicknesses of approximately 0.5 μm or more and 2 μm or less for forming the adhesive layer 40. A thickness of 50 μm or less makes it easy to apply a screen printing method as a method for forming the adhesive layer 40.

[0055] The lead frame 30 is disposed on the surface SF1 of the frame 21 via a brazing material layer 32 and a metallized layer 31. The metallized layer 31 is provided on the surface SF1 of the frame 21. Specifically, the lead frame 30 is joined to the metallized layer 31 using the brazing material layer 32. The metallized layer 31 may be made of a sintered material containing Cu at a higher volume ratio than the metallic sintered material of the heat dissipation member 22.

[0056] The lid 80 (FIG. 1) may be made of a ceramic material, which may contain alumina as a main component, e.g., be substantially alumina. Alternatively, the lid 80 may contain a resin, e.g., a liquid crystal polymer. The resin may have an inorganic filler dispersed therein, e.g., silica particles. Dispersing the inorganic filler in the resin can increase the strength and durability of the lid 80.

[0057] 3 to 6 are schematic cross-sectional views showing first to fourth steps of the method for manufacturing the package of FIG. 2, respectively.

[0058] Referring to Fig. 3, a green sheet 21G is formed, including a portion that will become the frame 21 (Fig. 2) when fired. Generally, the green sheet is formed from a slurry using a doctor blade method. The slurry is obtained by mixing powders that will become the components of the sintered body with resin, plasticizer, solvent, etc. in a ball mill. The powder for the slurry that forms the frame 21 contains, for example, 50 wt % or more of Al as the main component. ２ O ３ powder and SiO ２ The slurry may be a mixed powder of a Si-containing powder corresponding to 5 to 17% by weight in terms of SiO and a Mn-containing powder corresponding to 3 to 14% by weight in terms of MnO. Using this slurry, a green sheet 21G can be formed by a doctor blade method. Next, a green metallization layer 31G, which will become the metallization layer 31 upon firing, is formed on one side (the upper surface in FIG. 3 ) of the green sheet 21G. A green adhesive layer 40G, which will become the adhesive layer 40 upon firing, is formed on the other side (the lower surface in FIG. 3 ). These layers may be formed by printing a paste using a screen printing method. The paste is produced by kneading a metal powder, a resin, and a solvent. The printed paste is dried, for example, at a temperature of 110°C for 5 minutes. If the metallization layer 31 (FIG. 2) is not required, the formation of the green metallization layer 31G is omitted.

[0059] The paste for the green metallization layer 31G contains a metal powder. The metal powder may include Cu powder and a powder of at least one high-melting-point metal selected from the group consisting of W and Mo. Ceramic powder may also be added as needed. Alternatively, instead of printing the paste, green sheets formed from a slurry made of a material similar to the paste may be laminated.

[0060] The paste for the green adhesive layer 40G contains a metal powder and a ceramic powder. The metal powder may contain Cu powder and a powder of at least one high-melting-point metal selected from the group consisting of W and Mo. As a modified example, instead of printing the paste, green sheets formed from a slurry made of a material similar to the paste may be laminated.

[0061] Next, through holes HL for forming the cavities CV (FIG. 2) are formed by, for example, punching.

[0062] Referring to Figure 4, a green sheet 22G is formed, which will become the heat dissipation member 22 (Figure 2) when fired. The powder for the slurry used to form the heat dissipation member 22 may be a mixed powder containing Cu powder and a high-melting-point metal powder. Therefore, in this manufacturing method, unlike the impregnation method in which Cu is provided by impregnating an already sintered high-melting-point metal, the Cu and the high-melting-point metal are mixed together in a powdered state. The mixed powder may also contain ceramic powder as an additive.

[0063] Next, the green sheet 22G and the structure shown in Fig. 3 are laminated together to form a green structure KG. The green structure KG is a structure combining a green sheet 22G (first green member), a green sheet 21G (second green member), and a green adhesive layer 40G (third green member), and in this example, a green metallized layer 31G is also combined. When breaking is performed as described below, trenches (not shown) may be formed on each of the upper and lower surfaces of the green structure KG at the position where the breaking will occur by mechanical processing using a cutting edge CT or laser processing using a laser processing device (not shown).

[0064] Next, the green structure KG is fired. The firing temperature is, for example, 1100°C or higher and 1400°C or higher. A firing temperature of 1100°C or higher allows the laminate to be heated to a temperature higher than the melting point of Cu. This allows the heat dissipation member 22 containing Cu to be formed with high quality. On the other hand, a firing temperature of 1400°C or lower avoids process difficulties caused by an excessively high firing temperature. For example, excessive evaporation of Cu during firing can be avoided. As described above, a plating process may be performed at any timing after the firing process. Furthermore, the mounting of the semiconductor element 8 ( FIG. 1 ) may be performed at any timing after the firing process (or after the plating process, if performed).

[0065] If the green adhesive layer 40G were laminated on a flat metal plate serving as a heat dissipation member, as in the technique of JP 51-132461 A, the bond strength between the heat dissipation member and the adhesive layer would be extremely low after firing the green adhesive layer 40G. Furthermore, if the green adhesive layer 40G were laminated on a metal plate made of a metal sintered material, rather than a flat metal plate, with microscopic irregularities, the metal powder in the green adhesive layer 40G would come into contact with the metal plate's surface more frequently. Therefore, the bond strength between the adhesive layer 40G and the metal plate obtained by firing the green adhesive layer 40G would be slightly higher than in the previous case, but there is still room for improvement. In contrast to these methods, in this embodiment, the green adhesive layer 40G is laminated on a green sheet 22G serving as the heat dissipation member 22, and then the two are fired simultaneously. This allows the metal powder in the green adhesive layer 40G to penetrate more deeply into the green sheet 22G. Therefore, the bond strength between the adhesive layer 40 and the heat dissipation member 22 after firing is significantly improved compared to the two methods described above.

[0066] Referring to FIG. 5, the sintered body KF is obtained from the green structure KG by the above-mentioned firing. In other words, the heat dissipation member 22, the frame 21, the adhesive layer 40, and the metallized layer 31 are formed by simultaneous firing. Next, a breaking process is performed on the sintered body KF, in which cracks originating from the trenches described above are generated along the dashed lines BR. Referring also to FIG. 6, this breaking process obtains a sintered body KFp from the sintered body KF (FIG. 5). As a variant, instead of forming trenches before firing in place of the breaking process, a cutting process may be performed. Note that, in order to improve manufacturing efficiency, multiple sintered bodies KFp may be obtained from one sintered body KF.

[0067] 2, a brazing step is performed so that the lead frame 30 is joined to the sintered body KFp via the brazing material layer 32. In this way, the package 51 is obtained.

[0068] 7 and 8 are schematic partial cross-sectional views, taken parallel to the thickness direction, showing one example and another example of the configuration of the package 51 near the outer end surface SA4 of the adhesive layer 40. In these cross-sectional views, the outer surface SF4 of the frame 21 has a lower end JF4, and the outer wall surface SW4 of the heat dissipation member 22 has an upper end JW4. As described above, the breaking process (or cutting process) is performed along the dashed line BR ( FIG. 5 ). As a result, at least before the firing process, the lower end JF4 and the upper end JW4 are positioned approximately the same in the direction perpendicular to the thickness direction (the horizontal direction in FIGS. 7 and 8 ), i.e., the in-plane direction. However, due to factors such as sintering shrinkage during the firing process, a slight misalignment between the lower end JF4 and the upper end JW4 in the in-plane direction may occur, as shown in FIG. 8 . Even in such cases, the misalignment can be easily reduced to within 0.1 mm by applying the breaking or cutting process. It is also easy to keep all four positions, including the lower end JF4, the upper end JW4, and the upper end JA4a and the lower end JA4b of the adhesive layer 40, within a range of 0.1 mm in the in-plane direction.

[0069] According to the first embodiment, the adhesive layer 40 (FIG. 2) is made of a composite material containing both ceramic and metal, and the composite material is sintered to the ceramic material of the frame 21 and to the metallic sintered material of the heat dissipation member 22. This makes it possible to ensure a practically sufficient bonding strength between the frame 21 made of a ceramic material and the heat dissipation member 22 made of a metal, without requiring brazing between the frame 21 and the heat dissipation member 22.

[0070] By including both Cu and a high-melting-point metal in the heat dissipation member 22, the improvement in thermal conductivity of the heat dissipation member 22 due to the inclusion of Cu and the suppression of the linear expansion coefficient of the heat dissipation member 22 due to the inclusion of a high-melting-point metal can be appropriately adjusted depending on the application of the package. If the composite material of the adhesive layer 40 also includes a material similar to such a metal sintered material, the similarity of the materials can more reliably ensure the bonding strength between the heat dissipation member 22 and the adhesive layer 40.

[0071] The metallized layer 31 on the surface of the frame 21 is made of a sintered material containing Cu at a higher volume ratio than the metal sintered material of the heat dissipation member 22. This results in a higher linear expansion coefficient for the metallized layer 31 than for the heat dissipation member 22. Considering that the thickness of the metallized layer 31 is typically smaller than that of the heat dissipation member 22, in a configuration in which the frame 21 made of a ceramic material is disposed between the metallized layer 31 and the heat dissipation member 22, the above-described linear expansion coefficient relationship facilitates balancing thermal stresses in the package 51. This reduces warpage of the package 51 under temperature changes. The thickness of the metallized layer 31 is preferably 5 μm or more and 200 μm or less. A thickness of 5 μm or more facilitates balancing thermal stresses, thereby more effectively suppressing warpage of the package 51. Furthermore, the metallized layer 31 can fully function as a conductive layer. A thickness of 200 μm or less reduces peeling of the metallized layer 31.

[0072] Unlike general brazing filler metals, the adhesive layer 40 does not need to contain Ag. This makes it possible to prevent Ag migration from the adhesive layer 40. In particular, when the lead frame 30 is provided on the surface SF1 of the frame 21, it is possible to prevent the electrical insulation between the heat dissipation member 22 and the lead frame 30 from becoming insufficient due to the migration. If the adhesive layer 40 contained Ag like a general brazing filler metal layer, Ag migration would be likely to occur if a negative potential was applied to the lead frame 30 for a long period of time relative to the potential of the heat dissipation member 22.

[0073] 7 and 8, the misalignment between the lower end JF4 of the outer surface SF4 of the frame 21 and the upper end JW4 of the outer wall surface SW4 of the heat dissipation member 22 in the direction perpendicular to the thickness direction is within 0.1 mm. This makes it possible to suppress stress concentration due to the misalignment. Therefore, peeling is prevented from occurring between the lower end JF4 of the outer surface SF4 of the frame 21 and the upper end JW4 of the outer wall surface SW4 of the heat dissipation member 22.

[0074] Second Embodiment Figure 9 is a schematic partial cross-sectional view showing the occurrence of Ag migration in an electronic device 100 having a package 51 according to the first embodiment described above. The adhesive layer 40 has an inner end EI extending into the cavity CV. As described above, the adhesive layer 40 does not need to contain Ag, but the mounting material 7 often needs to contain Ag. Therefore, Ag migration may occur along the path MG (indicated by the dashed arrow in Figure 9).

[0075] 10 is a schematic cross-sectional view showing the configuration of electronic device 100 according to the second embodiment, in which electronic device 100 has package 52 instead of package 51 (FIG. 9). In both package 51 and package 52, the composite material of adhesive layer 40 does not need to contain Ag. However, unlike package 51, package 52 has a space PS in the thickness direction (vertical direction in the figure) between inner end EI of adhesive layer 40 and opposing surface SF2 of frame 21. Note that the rest of the configuration is substantially the same as the configuration of the first embodiment described above, and therefore the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0076] According to the second embodiment, Ag migration from the mounting material 7 must proceed along a path MG (indicated by the dashed arrow in FIG. 10 ) that bypasses the space PS. This prevents a decrease in electrical insulation between the heat dissipation member 22 and the surface SF1 of the frame 21 due to Ag migration. In particular, when a lead frame 30 is provided on the surface SF1, it is possible to prevent the electrical insulation between the heat dissipation member 22 and the lead frame 30 from becoming insufficient due to the migration.

[0077] Third Embodiment Figure 11 is a schematic cross-sectional view showing the configuration of an electronic device 100 according to a third embodiment, in which the electronic device 100 has a package 52 instead of the package 51 (Figure 9). In both the package 51 and the package 53 (Figures 9 and 11), the composite material of the adhesive layer 40 does not need to contain Ag. However, unlike the package 51, in the package 53, a space PS is provided in the thickness direction (the vertical direction in the figure) between the inner end EI of the adhesive layer 40 and the upper surface SW1 of the heat dissipation member 22. Note that the configuration is otherwise substantially the same as the configuration of the first embodiment described above. Therefore, the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0078] According to the third embodiment, Ag migration from the mounting material 7 must proceed along a path MG (indicated by the dashed arrow in FIG. 11 ) that bypasses the space PS. This prevents a decrease in electrical insulation between the heat dissipation member 22 and the surface SF1 of the frame 21 due to Ag migration. In particular, when a lead frame 30 is provided on the surface SF1, it is possible to prevent the electrical insulation between the heat dissipation member 22 and the lead frame 30 from becoming insufficient due to the migration.

[0079] 12 is a schematic partial cross-sectional view showing stress TS caused by temperature changes in solder layer 98 in electronic device 100 having package 51 according to the first embodiment. Stress TS tends to occur roughly along the in-plane direction (horizontal direction in the figure). In package 51, bottom surface SW2 and outer wall surface SW4 of heat dissipation member 22 may form a roughly right angle AGr. In this case, stress TS occurs perpendicular to the interface between outer wall surface SW4 and solder layer 98. As a result, stress TS tends to lead to peeling at the interface.

[0080] FIG. 13 is a schematic cross-sectional view showing the configuration of an electronic device 100 according to the fourth embodiment. The electronic device 100 has a package 54 instead of the package 51 ( FIG. 12 ). In the package 54, the lower surface SW2 of the heat dissipation member 22 and the outer wall surface SW4 form an obtuse angle AGo. The obtuse angle AGo is, for example, 92° or greater and 100° or less. The obtuse angle AGo can be obtained, for example, by buffing the package 51 ( FIG. 12 ), which has a right angle AGr, while holding it by hand or the like. Note that the remaining configuration is substantially the same as that of any of the first to third embodiments described above. Therefore, the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0081] According to the fourth embodiment, the outer wall surface SW4 is inclined rather than perpendicular to the in-plane direction. This makes it less likely that stress TS will lead to peeling at the interface between the outer wall surface SW4 and the solder layer 98. This makes it possible to make the solder layer 98 less likely to peel.

[0082] Fifth Embodiment FIG. 14 is a schematic cross-sectional view showing the configuration of an electronic device 100 according to a fifth embodiment. The electronic device 100 has a package 55 instead of the package 51 ( FIG. 2 ). Note that this cross-sectional view is a cross-sectional view parallel to the thickness direction and passing through the center of the heat dissipation member 22. In the package 51 ( FIGS. 1 and 2 : first embodiment), the lower surface SW2 of the heat dissipation member 22 may be flat. In contrast, in the package 55 ( FIG. 14 ), the lower surface SW2 of the heat dissipation member 22 has a convex shape VX at the center of the heat dissipation member 22. Note that the configuration is otherwise substantially the same as that of any of the first to fourth embodiments described above. Therefore, the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0083] According to the fifth embodiment, when the heat dissipation member 22 is joined to the heat sink 99 (or more generally, another member) by forming a solder layer 98 using solder (or, more generally, a fluid material for forming a bonding layer) that melts when heated, the convex shape VX causes the bonding material to spread outward from the center of the heat dissipation member 22 toward the outer periphery. This makes it easier to ensure the bonding strength of the solder layer 98 in the peripheral portion around the center. Because peeling of the solder layer 98 is more likely to occur from the periphery than from the center, ensuring the bonding strength of the solder layer 98 in the peripheral portion can prevent peeling of the solder layer 98.

[0084] The reference line LS ( FIG. 14 ) is a straight line connecting one end and the other end (the right end and the left end in the figure) of the heat dissipation member 22. The convex shape VX protrudes from the reference line LS. The height difference of the lower surface SW2 in a direction perpendicular to the reference line LS, based on the reference line LS, is preferably 10 μm or more and 100 μm or less. A height difference of 10 μm or more can more fully achieve the above-mentioned effect. A height difference of 100 μm or less can prevent the formation of areas where the thickness of the solder layer 98 is locally excessive. Because the thermal conductivity of the solder layer 98 is not necessarily higher than that of the heat dissipation member 22, an excessive thickness of the solder layer 98 can degrade the heat dissipation characteristics.

[0085] Unlike the sixth embodiment described later, in the fifth embodiment, the underside SW2 does not have a portion recessed from the reference line LS (a portion above the reference line LS in FIG. 11 ). Therefore, the height difference in the fifth embodiment is equal to the dimension by which the convex shape VX protrudes from the reference line LS in the direction perpendicular to the reference line LS.

[0086] Sixth Embodiment FIG. 15 is a schematic cross-sectional view showing the configuration of an electronic device 100 according to a sixth embodiment. The electronic device 100 has a package 56 instead of the package 55 ( FIG. 14 ). Note that, like the aforementioned FIG. 14 , this cross-sectional view is a cross-sectional view taken along a plane parallel to the thickness direction and passing through the center of the heat dissipation member 22. In the package 57 ( FIG. 15 ), the lower surface SW2 of the heat dissipation member 22 has a concave shape VC outside the center in addition to the convex shape VX in the fifth embodiment. The concave shape VC can be obtained, for example, by performing a heat treatment in the cavity CV of the package 55 ( FIG. 14 : fifth embodiment) while placing a weight at the position where the concave shape VC is to be formed. Note that the remaining configuration is substantially the same as that of the fifth embodiment. Therefore, the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0087] According to the sixth embodiment, the convex shape VX provides an effect similar to that of the fifth embodiment. Here, in the package 51 (FIG. 14: first embodiment), the lower surface SW2 of the heat dissipation member 22 has a simple convex shape. Therefore, when the heat dissipation member 22 is joined to a heat sink 99 (or more generally, another component) by forming a solder layer 98 using solder (more generally, a fluid material for forming a bonding layer) that melts upon heating, the lower surface SW2 of the package 51 is likely to unintentionally tilt from the horizontal plane, as shown by arrow NC (FIG. 14), with the protruding portion of the convex shape VX serving as a fulcrum. In contrast, according to the sixth embodiment, the lower surface SW2 of the heat dissipation member 22 also has a concave shape VC, which allows the edge of the lower surface SW2 of the heat dissipation member 22 to be closer to the heat sink 99. This prevents the heat dissipation member 22 from tilting.

[0088] The concave shape VC is located further back than the reference line LS (above the reference line LS in FIG. 12 ). Therefore, the height difference in this sixth embodiment is the sum of the dimension by which the convex shape VX protrudes from the reference line LS in a direction perpendicular to the reference line LS and the dimension by which the concave shape VC recedes from the reference line LS in a direction perpendicular to the reference line LS. In this sixth embodiment, as in the fifth embodiment described above, the height difference in the direction perpendicular to the reference line LS is preferably 10 μm or more and 100 μm or less.

[0089] Seventh Embodiment FIG. 16 is a schematic partial cross-sectional view showing an example of the configuration of a corner AS formed between the surface SF1 and the outer surface SF4 of the frame 21 in the package 51 according to the first embodiment. The corner AS may be an unrounded corner. FIG. 17 is a schematic partial cross-sectional view showing an example of the configuration of a corner AP formed between the surface SF1 and the outer surface SF4 of the frame 21 in the package 57 according to the seventh embodiment. The corner AP is rounded, specifically, has a radius of curvature of 0.1 mm or more and 0.5 mm or less. The remaining configuration is substantially the same as that of any of the first to sixth embodiments described above. Therefore, the same or corresponding elements are designated by the same reference numerals, and description thereof will not be repeated.

[0090] According to this embodiment, the corners AP of the frame body 21 have a radius of curvature of 0.1 mm or more and 0.5 mm or less. A radius of curvature of 0.1 mm or more makes the corners AP less likely to chip when subjected to impact. A radius of curvature of 0.5 mm or less prevents the area of ​​the surface SF1 of the frame body 21 from being excessively reduced due to the rounded corners AP. In particular, when a lead frame 30 is provided on the surface SF1 of the frame body 21, ensuring a sufficient area of ​​the surface SF1 of the frame body 21 makes it easier to ensure a bonding area between the surface SF1 of the frame body 21 and the lead frame 30. This allows them to be bonded to each other with high strength.

[0091] Eighth Embodiment FIG. 18 is a schematic cross-sectional view showing the configuration of a package 58 according to an eighth embodiment. The package 58 has a configuration similar to that of the frame 21, the heat dissipation member 22, and the adhesive layer 40 of the package 51 ( FIG. 3 ) according to the first embodiment. A lead frame 30 may be applied to the package 58 and the modified examples described below, as with the package 51 ( FIG. 2 ), and a metallization layer 31 for the lead frame 30 may also be applied. Furthermore, a metallization layer for a purpose other than the lead frame 30 may be formed on the surface SF1 of the frame 21 of the package 58 instead of or together with the metallization layer 31 for the lead frame 30. The material of the metallization layer may be the same as that described above as the material of the metallization layer 31.

[0092] FIG. 19 is a schematic cross-sectional view showing the configuration of a package 58A according to a first modification of the eighth embodiment. The package 58A has a frame 21A instead of the frame 21 ( FIG. 18 ). The frame 21A (specifically, its inner portion) is disposed on the peripheral surface SW1b of the upper surface SW1 of the heat dissipation member 22 via an adhesive layer 40. In terms of its position in the thickness direction, the frame 21A extends from a position above the upper surface SW1 of the heat dissipation member 22 into the range between the upper surface SW1 and the lower surface SW2 of the heat dissipation member 22. The frame 21A may extend further; in the example shown in FIG. 19 , it extends to the position of the lower surface SW2 of the heat dissipation member 22. The frame 21A is spaced apart from the heat dissipation member 22.

[0093] FIG. 20 is a schematic cross-sectional view showing the configuration of a package 58B according to a second modification of the eighth embodiment. The package 58B includes a frame 21B instead of the frame 21 (FIG. 17). The frame 21B includes a plate-shaped base 21h disposed on the upper surface SW1 of the heat dissipation member 22 via an adhesive layer 40, and a frame 21i positioned on the base 21h. The boundary between the base 21h and the frame 21i (shown by the dashed line in the figure) may be imaginary. In this second modification, the frame 21i defines the inner surface SF3 of the frame 21B. Unlike the eighth embodiment (FIG. 18), in this second modification, the cavity surface SW1a of the upper surface SW1 of the heat dissipation member 22 faces the cavity CV via the adhesive layer 40 and the base 21h of the frame 21B.

[0094] FIG. 21 is a schematic cross-sectional view showing the configuration of a package 58C according to a third modification of the eighth embodiment. The package 58C has a frame 21C instead of the frame 21 (FIG. 18). The frame 21C (specifically, its inner portion) is disposed on the peripheral surface SW1b of the upper surface SW1 of the heat dissipation member 22. With respect to its position in the thickness direction, the frame 21C extends from a position above the upper surface SW1 of the heat dissipation member 22 into the range between the upper surface SW1 and the lower surface SW2 of the heat dissipation member 22. The frame 21C may extend further; in the example shown in FIG. 21, it extends to the position of the lower surface SW2 of the heat dissipation member 22. The outer wall surface SW4 of the heat dissipation member 22 is in contact with the frame 21C.

[0095] The package 58C can be manufactured by firing a laminate of the lower layer LY1 and the upper layer LY2. The lower layer LY1 is formed, for example, as follows: First, a first unfired layer made of a material that will become the frame 21C when fired is formed. Next, a through hole corresponding to the area where the heat dissipation member 22 will be located is formed in the first unfired layer using a mold. Next, a second unfired layer including a portion that will become the heat dissipation member 22 and the adhesive layer 40 when fired is laminated on the first unfired layer so as to cover the through hole. Next, the mold is used again to press the portion of the second unfired layer into the through hole. Next, the portion of the second unfired layer that was not pressed by the mold, in other words, the portion remaining on the top surface of the first unfired layer, is removed. This results in the lower layer LY1. The upper layer LY2 is obtained by removing a portion corresponding to the cavity CV from the unfired layer made of a material that will become the frame 21C when fired. The package 58C is obtained by firing the laminate of the lower layer LY1 and the upper layer LY2.

[0096] As a further modification of the third modification, an adhesive layer (not shown) made of a ceramic material may be provided between the portion of the frame 21C included in the lower layer LY1 and the portion of the frame 21C included in the upper layer LY2. The adhesive layer may be formed by applying a ceramic paste to the first unfired layer before the second unfired layer is laminated on the first unfired layer. This application may be performed, for example, before the through-holes are formed.

[0097] FIG. 22 is a schematic cross-sectional view showing the configuration of a package 58D according to a fourth variation of the eighth embodiment. The package 58D includes a heat dissipation member 22D and a frame 21D instead of the heat dissipation member 22 and frame 21 (FIG. 18). The frame 21D (specifically, its inner portion) is disposed on a peripheral surface SW1b of the upper surface SW1 of the heat dissipation member 22D. The heat dissipation member 22D includes a support portion 22i and a cavity portion 22h provided on a portion of the support portion 22i. The boundary between the cavity portion 22h and the support portion 22i (indicated by the dashed line in FIG. 22) may be imaginary. The upper surface SW1 of the heat dissipation member 22D includes a cavity surface SW1a formed by the cavity portion 22h and a peripheral surface SW1b formed by the support portion 22i. On the upper surface SW1 of the heat dissipation member 22D, the positions of the cavity surface SW1a and the peripheral surface SW1b are different in the thickness direction, with the latter being closer to the lower surface SW2. The cavity surface SW1a and the peripheral surface SW1b may be approximately parallel to each other. The upper surface SW1 may further have a sidewall surface SW1c formed by a cavity portion 22h and connecting the cavity surface SW1a and the peripheral surface SW1b. The sidewall surface SW1c may extend approximately along the thickness direction. The sidewall surface SW1c may have a portion that contacts the frame body 21D. The lower portion of the sidewall surface SW1c (the end portion connected to the peripheral surface SW1b) may contact the end surface of the adhesive layer 40. The outer wall surface SW4 of the support portion 22i may contact the frame body 21D. The package 58D can be manufactured by a manufacturing method similar to the manufacturing method of the package 58C (FIG. 21) described above.

[0098] 23 is a schematic cross-sectional view showing the configuration of a semiconductor module 91 (electronic device) according to a ninth embodiment. The semiconductor module 91 includes a package 59 having a cavity CV, a semiconductor element 8 housed in the cavity CV, and a mounting material 7 for mounting the semiconductor element 8 on the package 59. The semiconductor module 91 may also include wires 9 as wiring members for the semiconductor element 8. The semiconductor module 91 does not include a lid 80 (FIG. 1: first embodiment) and therefore does not include an adhesive portion 70 for bonding the lid 80. The semiconductor module 91 may be used in place of the semiconductor module 90 in the electronic device 100 (FIG. 1: first embodiment).

[0099] Like the package 51 ( FIG. 2 : first embodiment), the package 59 includes a heat dissipation member 22, a frame 21, and an adhesive layer 40. The package 59 further includes an electrode layer 35 on the surface SF1. Like the package 51 ( FIG. 2 : first embodiment), the package 59 may also be plated. In other words, a plating film (not shown) may also be provided on the package 59.

[0100] Unlike package 51 ( FIG. 2 : first embodiment), package 59 does not have a lead frame 30, and therefore does not have a brazing material layer 32 or a metallization layer 31 for bonding. While in package 51, lead frame 30 functions as an external terminal, in package 59, electrode layer 35 may also function as an external terminal. For this purpose, electrode layer 35 may extend further from surface SF1 as necessary. The function of electrode layer 35 is not limited to functioning as an external terminal. For example, electrode layer 35 may function as a circuit pattern in addition to or instead of this function, as shown in FIG. 24 (first embodiment, described below). Depending on the application of the package, electrode layer 35 may be omitted.

[0101] In a semiconductor module 91 having a package 59, the electrode layer 35 and the semiconductor element 8 may be electrically connected to each other by a wire 9. In the process of attaching the wire 9, the surface (top surface in FIG. 23 ) of the electrode layer 35 of the package 59 is exposed. If the package 59 is plated, the exposed surface of the electrode layer 35 may also be plated. However, the wire 9 does not necessarily have to be connected to the electrode layer 35. Furthermore, the wire 9 may be omitted depending on the design of the electronic device.

[0102] The material of the electrode layer 35 may be the same as that of the metallized layer 31 (FIG. 2: Embodiment 1). The method of forming the electrode layer 35 may also be the same as that of the metallized layer 31.

[0103] The other configurations are substantially the same as those of any of the above-described first to seventh embodiments, and therefore the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, the electrode layer 35 of the ninth embodiment may be applied to the eighth embodiment.

[0104] Tenth Embodiment Fig. 24 is a schematic perspective view showing the configuration of a package 59M according to a tenth embodiment. In Fig. 24, a dot pattern is applied to the electrode layer 35 to make the drawing easier to see. The package 59M has a frame 21M. The frame 21M has an inner surface that surrounds a plurality of cavities CV1 and CV2. In the example shown in Fig. 24, the electrode layer 35 functions as a wiring pattern. As a modified example, a wire 9 may be connected to the electrode layer 35, as shown in Fig. 23 (ninth embodiment).

[0105] Since the configuration other than the above is substantially the same as that of the above-described embodiment 9, the same or corresponding elements are denoted by the same reference numerals and description thereof will not be repeated. Furthermore, in the package according to any of the above-described embodiments, multiple cavities may be provided instead of one cavity, as in the tenth embodiment.

[0106] The above-described embodiments may be freely combined with each other. Although the present invention has been described in detail, the above description is illustrative in all respects and does not limit the present invention. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present invention.

[0107] 7: Mounting material 8: Semiconductor element (electronic component) 21, 21M: Frame 21G: Green sheet (second green member) 22: Heat dissipation member 22G: Green sheet (first green member) 22i: Support 30: Lead frame (metal terminal) 31: Metallized layer 32: Brazing material layer 40: Adhesive layer 40G: Green adhesive layer (third green member) 51-59, 58A-58D, 59M: Package 90, 91: Semiconductor module (electronic device) 98: Solder layer 99: Heat sink 100: Electronic device CV: Cavity KG: Green structure PS: Space SF1: Surface SF2: Opposing surface SF3: Inner surface SF4: Outer surface SW1: Upper surface SW1a : Cavity surface SW1b : Peripheral surface SW2 : Bottom surface SW4 : Outer wall surface VC : Concave shape VX : Convex shape

Claims

1. A package having a cavity in which an electronic component will be housed, comprising: a heat dissipation member made of a metal sintered material, the heat dissipation member having a top surface facing the cavity, a bottom surface opposite the top surface, and an outer wall surface connecting the top surface and the bottom surface; a frame made of a ceramic material, the frame having an opposing surface facing the top surface of the heat dissipation member in the thickness direction, a surface opposite the opposing surface, an inner surface surrounding the cavity, and an outer surface opposite the inner surface; and an adhesive layer having a first interface in contact with the opposing surface of the frame, and a second interface opposite the first interface in contact with the top surface of the heat dissipation member, the adhesive layer being made of a composite material containing both ceramic and metal, the composite material being sintered to the ceramic material of the frame at the first interface, and being sintered to the metal sintered material of the heat dissipation member at the second interface.

2. The package according to claim 1, wherein said metallic sintered material comprises at least one high melting point metal selected from the group consisting of tungsten and molybdenum, and copper.

3. A package according to claim 2, wherein the metal of the composite material of the adhesive layer includes at least one high melting point metal selected from the group consisting of tungsten and molybdenum, and copper.

4. A package according to claim 2 or 3, further comprising a metallization layer provided on the surface of the frame and made of a sintered material containing copper at a volume ratio higher than that of the metallic sintered material of the heat dissipation member.

5. A package as claimed in any one of claims 1 to 3, wherein the composite material of the adhesive layer does not contain silver, the adhesive layer has an inner end extending into the cavity, and a space is provided in the thickness direction between the inner end of the adhesive layer and the opposing surface of the frame or the top surface of the heat dissipation member.

6. A package according to any one of claims 1 to 3, wherein the lower surface of the heat dissipation member and the outer wall surface form an obtuse angle.

7. A package according to any one of claims 1 to 3, wherein the lower surface of the heat dissipation member has a convex shape at the center of the heat dissipation member.

8. The package according to claim 7, wherein the lower surface of the heat dissipation member has a concave shape outside the central portion.

9. A package according to any one of claims 1 to 3, wherein the adhesive layer does not contain silver.

10. A package as claimed in any one of claims 1 to 3, wherein, in a cross-sectional view parallel to the thickness direction, the outer surface of the frame has a lower end, the outer wall surface of the heat dissipation member has an upper end, and the positional deviation between the lower end and the upper end in a direction perpendicular to the thickness direction is within 0.1 mm.

11. A package according to any one of claims 1 to 3, wherein a corner formed by the surface and the outer surface of the frame has a radius of curvature of 0.1 mm or more and 0.5 mm or less.

12. The package according to any one of claims 1 to 3, further comprising a metal terminal provided on the surface of the frame.

13. An electronic device comprising: the package according to claim 5; the electronic component housed in the cavity of the package; and a mounting material containing silver for mounting the electronic component on the package.

14. A method for manufacturing a package for producing a package as claimed in any one of claims 1 to 3, comprising the steps of: forming a green structure that combines a first green member that will become the heat dissipation member when fired, a second green member that will become the frame body when fired, and a third green member that will become the adhesive layer when fired; and firing the green structure.

Images