Electronic component with heat dissipation section and method of manufacturing same

Abstract

This electronic component with a heat dissipating part comprises an electronic component (1), a heat dissipating part (2), and a joining member (4). The electronic component (1) generates heat while in operation. The heat dissipating part (2) dissipates heat generated by the electronic component (1) to an atmospheric fluid. The joining member (4) joins the electronic component (1) and the heat dissipating part (2). The joining area of the electronic component (1) and the heat dissipating part (2) is 100 mm2 or more. The joining member (4) forms a porous metal layer (40) in which pores (41) are homogeneously distributed throughout.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2022-79355 filed on May 13, 2022, the contents of which are incorporated herein by reference. [Technical field]

[0002] The present disclosure relates to an electronic component with a heat dissipation portion and a method for manufacturing the same. [Background technology]

[0003] Conventionally, electronic components with heat dissipation parts have been developed in which the electronic component and the heat dissipation part for dissipating heat from the electronic component are integrally formed. For example, Patent Document 1 discloses a technique for making the void ratio of the solder 10% or less when the heat dissipation part and the electronic component are joined by soldering in an electronic component with a heat dissipation part. This makes it possible to reduce the thermal resistance of the joint, thereby improving the heat dissipation performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-282770 A Summary of the Invention

[0005] However, the technology described in Patent Document 1 of As mentioned above, if the solder void ratio of the joint is reduced, it becomes difficult for the joint to absorb the thermal stress when it is applied, which may cause the joint to crack more easily.

[0006] In view of the above, an object of the present disclosure is to provide an electronic component with a heat dissipation portion that can achieve both improved heat dissipation performance and improved durability, and a manufacturing method thereof.

[0007] In order to achieve the above object, an electronic component with a heat dissipation unit according to one embodiment of the present disclosure includes an electronic component (1) that generates heat when in operation; A heat dissipation unit (2) that dissipates heat generated by the electronic component to an ambient fluid; A joining member (4) that joins the electronic component and the heat dissipation portion, The bonding area between the electronic component and the heat sink is 100 mm 2 That's all. The joining member forms a porous metal layer (40) in which pores (41) are uniformly distributed throughout. And, The joining material is solder. .

[0008] According to this, since the joining member forms a porous metal layer, it is possible to reduce the temperature distribution over the entire surface of the joining member. Even if a crack occurs in the joining member, the crack can be absorbed by the pores, so the crack can be prevented from spreading. As a result, it is possible to achieve both improved heat dissipation performance and improved durability. [Brief description of the drawings]

[0011] [Figure 1] 1 is an explanatory diagram illustrating an overall configuration of a semiconductor device according to an embodiment; [Diagram 2] FIG. 4 is an explanatory diagram showing a surface of a joining member in one embodiment. [Diagram 3] FIG. 4 is a characteristic diagram showing the relationship between the pore distance and the durability index in a porous metal layer. [Figure 4] FIG. 4 is a characteristic diagram showing the relationship between the thickness dimension and the void ratio in a porous metal layer. [Diagram 5] FIG. 4 is an explanatory diagram showing a joint surface of a heat dissipation portion according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. As shown in Fig. 1, in this embodiment, a semiconductor device 1 having a heat dissipation portion 2 integrally formed therewith is used as an electronic component with a heat dissipation portion. The semiconductor device 1 of this embodiment includes a substrate 10, a semiconductor element 20, and a lid 30. The semiconductor device 1 of this embodiment corresponds to an electronic component.

[0013] The substrate 10 functions as an interposer for the semiconductor element 20 when the semiconductor device 1 is mounted on a motherboard 3, which is an external member. The substrate 10 is mounted on the upper surface of the motherboard 3 via solder bumps 60. More specifically, the substrate 10 is mounted on the upper surface of the motherboard 3 via the solder bumps 60 with the lower surface of the substrate 10 facing the upper surface of the motherboard 3. The substrate 10 may be, for example, a ceramic substrate, a printed circuit board, a glass epoxy substrate, or the like.

[0014] The semiconductor element 20 is mounted on the upper surface of the substrate 10 via bump electrodes (not shown). More specifically, the semiconductor element 20 is mounted on the upper surface of the substrate 10 via bump electrodes with the surface (i.e., the lower surface) of the semiconductor element 20 facing the upper surface of the substrate 10.

[0015] The semiconductor element 20 is flip-chip bonded onto the upper surface of the substrate 10. An IC chip formed by a general semiconductor process can be used as the semiconductor element 20. In addition, bump electrodes are provided on the surface of the semiconductor element 20 and are made of solder, gold, Cu, or the like.

[0016] The lid 30 is a sealing member that seals the semiconductor element 20. The lid 30 is fixed onto the upper surface of the substrate 10 via a sealing material (not shown). Furthermore, the rear surface (i.e., the upper surface) of the semiconductor element 20 and the lid 30 are joined by an adhesive material 50. The sealing material and adhesive material 50 can be made of a material having a higher melting temperature than the bump electrodes.

[0017] The heat dissipation section 2 is a heat dissipation member that dissipates heat generated by the semiconductor device 1 to air, which is an ambient fluid. The heat dissipation section 2 is made of a material with excellent thermal conductivity. In this embodiment, the heat dissipation section 2 is made of a metal such as aluminum or copper. The heat dissipation section 2 has a plate section 21 and a fin section 22.

[0018] The plate portion 21 is formed in a plate shape. The plate portion 21 is disposed so as to contact the upper surface of the lid 30 of the semiconductor device 1 (i.e., the surface opposite to the surface to which the semiconductor element 20 is bonded). The fin portion 22 is a heat transfer member that increases the heat transfer area with the air and promotes heat exchange between the air and the semiconductor device 1. A plurality of fin portions 22 are provided so as to protrude upward from the upper surface of the plate portion 21 (i.e., the surface opposite to the surface in contact with the lid 30).

[0019] The semiconductor device 1 and the heat dissipation section 2 are joined by a joining member 4. In this embodiment, the joining member 4 is made of solder. That is, the semiconductor device 1 and the heat dissipation section 2 are solder-joined. At least one of the joining surface of the semiconductor device 1 with the joining member 4 and the joining surface of the heat dissipation section 2 with the joining member 4 is plated with nickel.

[0020] The bonding area between the semiconductor device 1 and the heat sink 2 is 100 mm 2 In this embodiment, the joint between the semiconductor device 1 and the heat sink 2 is 30 mm square, and the joint area between the semiconductor device 1 and the heat sink 2 is 900 mm 2 It states that:

[0021] As shown in Fig. 2, the bonding member 4 forms a porous metal layer 40 in which pores 41 are uniformly distributed throughout. Note that Fig. 2 shows the surface of the bonding member 4 of this embodiment as viewed from above (i.e., the heat dissipation portion 2 side).

[0022] Here, the distance between adjacent pores 41 in the porous metal layer 40 is defined as the pore distance Lp. The relationship between the pore distance Lp in the porous metal layer 40 and durability is shown in FIG. 3. The durability index on the vertical axis of FIG. 3 is an index showing the level of durability against damage to the bonding members 4 and the substrate 10 due to long-term use. The higher the durability index value, the higher the durability. Note that "damage to the bonding members 4 and the substrate 10 due to long-term use" here is caused by thermal distortion, thermal deterioration, pressure fluctuation, swelling, etc.

[0023] As is clear from Fig. 3, when the inter-pore distance Lp is greater than 1 mm, durability drops sharply. For this reason, the porous metal layer 40 is formed so that the inter-pore distance Lp is smaller than 1 mm at any point. That is, the porous metal layer 40 is formed so that the inter-pore distance Lp is smaller than 1 mm at any point within the porous metal layer 40. In other words, the porous metal layer 40 is formed so that the inter-pore distance Lp is smaller than 1 mm at any point within the porous metal layer 40 when viewed from a direction perpendicular to the bonding surface between the semiconductor device 1 and the heat dissipation portion 2. 2 At least one pore 41 is formed inside the material, which can improve durability.

[0024] Here, the length of the porous metal layer 40 in the arrangement direction of the semiconductor device 1 and the heat dissipation part 2 is defined as the thickness dimension Wp. 2 The area ratio of the pores 41 contained per 100 mm is defined as the void fraction Rv. In this embodiment, the arrangement direction of the semiconductor device 1 and the heat dissipation portion 2 in the porous metal layer 40 is parallel to the direction perpendicular to the bonding surface in the porous metal layer 40.

[0025] According to the study by the present inventors, it was found that in the semiconductor device 1 of this embodiment, if the thickness dimension Wp and the void fraction Rv of the porous metal layer 40 satisfy the relationship Rv≦−6.23Wp+1, the heat dissipation performance can be improved, as shown in the shaded area in Fig. 4. In this case, in the porous metal layer 40, the temperature difference dT is 1°C, the heat transfer coefficient λ is 64.2 W / (m K), and the heat flow rate q is 400 kW / m 2 For this reason, in this embodiment, the thickness dimension Wp and the void fraction Rv of the porous metal layer 40 are set to satisfy the relationship Rv≦−6.23Wp+1.

[0026] 5, a groove 23 is formed on the joint surface of the plate portion 21 of the heat dissipation portion 2 with the joint member 4. An end of the groove 23 is open to the outside of the heat dissipation portion 2. That is, the inside of the groove 23 communicates with the outside of the heat dissipation portion 2 (that is, air which is the atmospheric fluid). In this embodiment, two linear grooves 23 are formed so as to intersect in a cross shape on the joint surface of the plate portion 21 with the semiconductor device 1.

[0027] Next, a description will be given of a method for manufacturing the semiconductor device 1 in this embodiment that is integrally provided with the heat dissipation portion 2. First, a preparation step is performed to prepare the semiconductor device 1 and the heat dissipation portion 2.

[0028] Next, a printing process is performed. In the printing process, a paste solder is applied to at least one of the bonding surface of the semiconductor device 1 and the bonding surface of the heat dissipation part 2 through a screen mesh. The paste solder contains a flux material that improves the bonding property of the solder. In this embodiment, the content of the flux material in the solder is about 50%.

[0029] Next, a bonding process is performed to solder the bonding portions of the semiconductor device 1 and the heat dissipation portion 2. In this embodiment, the bonding portions of the semiconductor device 1 and the heat dissipation portion 2 are soldered by reflow soldering.

[0030] Specifically, first, the heat dissipation unit 2 is placed at a predetermined position on the joining surface of the substrate 10, and then the substrate 10 is carried into a heating furnace. Then, after a preheating process at about 180°C, the temperature is raised to about 220°C to melt the solder. Thereafter, the substrate 10 is cooled until the solder solidifies, whereby the heat dissipation unit 2 is solder-joined to the joining surface of the substrate 10.

[0031] As described above, the heat dissipation portion 2 is soldered to the semiconductor device 1. Other processes such as finishing are then performed. In this manner, the semiconductor device 1 integrally provided with the heat dissipation portion 2 is completed.

[0032] As described above, in the semiconductor device 1 of this embodiment, the bonding member 4 forms a porous metal layer 40 in which the pores 41 are uniformly distributed throughout. Therefore, the bonding between the semiconductor device 1 and the heat dissipation section 2 is spotted. This makes it possible to reduce the temperature distribution over the entire surface of the bonding section. Even if a crack occurs in the bonding member 4, it can be absorbed by the pores 41, so that the crack can be prevented from spreading. Furthermore, since the distance between the spotted bonding sections is reduced, the thermal stress can be reduced. As a result, it is possible to achieve both improved heat dissipation performance and improved durability.

[0033] In the semiconductor device 1 of this embodiment, the porous metal layer 40 has a surface area of ​​1 mm2 or less when viewed from a direction perpendicular to the bonding surface between the semiconductor device 1 and the heat sink 2. 2 ) has at least one pore 41 formed therein. This can improve durability, as shown in FIG. 2 above.

[0034] In the semiconductor device 1 of this embodiment, the porous metal layer 40 is configured so that the thickness dimension Wp and the void fraction Rv satisfy the relationship Rv≦−6.23Wp+1. This can improve the heat dissipation performance as shown in FIG.

[0035] In the semiconductor device 1 of the present embodiment, the grooves 23 are formed on the bonding surface of the heat dissipation portion 2 with the bonding member 4. This allows the gas in the bonding member 4 to easily escape to the outside through the grooves 23 in the bonding process, so that the pores 41 can be uniformly distributed in the bonding member 4.

[0036] By the way, when a component that requires heat dissipation (such as an electronic component) is joined to a heat dissipation part, and the joining area of ​​the joining part is 100 mm 2When the area is as large as above, a sheet-like solder that does not contain flux material is usually used as the joining material. Since the soldering is performed by heating in a reducing atmosphere, almost no voids are generated in the joining material. Therefore, when thermal stress acts on the joining material, it becomes difficult for the stress to be absorbed, and the joining material is likely to crack.

[0037] In contrast, the manufacturing method of the semiconductor device 1 of this embodiment includes a printing step of applying a solder paste containing a flux material through a screen mesh to at least one of the bonding surfaces of the semiconductor device 1 and the bonding surface of the heat dissipation part 2. This allows the pores 41 to be uniformly distributed in the bonding member 4. As a result, even if a crack occurs in the bonding member 4, it can be absorbed by the pores 41, thereby improving durability.

[0038] The present disclosure is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit and scope of the present disclosure.

[0039] (1) In the above embodiment, an example has been described in which air is used as the atmospheric fluid and the heat dissipation section 2 is configured to dissipate heat generated by the semiconductor device 1 to the air, but the present invention is not limited to this embodiment. For example, a refrigerant liquid may be used as the atmospheric fluid and the heat dissipation section 2 may be immersed in the refrigerant liquid to dissipate heat generated by the semiconductor device 1 to the refrigerant liquid. In this case, an insulating fluid may be used as the refrigerant liquid. Specifically, a fluorine-based inert liquid may be used as the refrigerant liquid. The fluorine-based inert liquid is a refrigerant liquid that has excellent insulation properties, heat transfer properties, and stability.

[0040] (2) In the above embodiment, an example has been described in which two linear grooves 23 are formed on the bonding surface of the plate portion 21 of the heat dissipation portion 2 so as to intersect in a cross shape, but the present invention is not limited to this. For example, one groove 23 or three or more grooves 23 may be formed. In addition, the groove 23 may be formed at any position on the bonding surface of the heat dissipation portion 2 with the semiconductor device 1, as long as the end of the groove 2 is open to the outside of the heat dissipation portion 2.

[0041] (others) The features of the electronic component with a heat dissipation portion and the manufacturing method thereof disclosed in this specification are as follows. (Item 1) An electronic component (1) that generates heat when in operation; a heat dissipation section (2) that dissipates heat generated by the electronic components to an ambient fluid; a joining member (4) that joins the electronic component and the heat dissipation portion, The bonding area between the electronic component and the heat sink is 100 mm 2 That's all. The electronic component with a heat dissipation part, wherein the joining member forms a porous metal layer (40) having pores (41) uniformly distributed throughout. (Item 2) the porous metal layer has at least one pore formed per unit area when viewed from a direction perpendicular to a bonding surface between the electronic component and the heat dissipation portion, The unit area is 1 mm 2 and The length of the porous metal layer in the arrangement direction of the electronic component and the heat dissipation part is defined as a thickness dimension (Wp); When the area ratio of the pores contained in the unit area when the porous metal layer is viewed from a direction perpendicular to the bonding surface is defined as a void ratio (Rv), 2. An electronic component with a heat dissipation part according to item 1, wherein the thickness dimension and the void ratio satisfy the relationship: Rv≦−6.23Wp+1. (Item 3) 3. The electronic component with a heat dissipation part according to item 1 or 2, wherein the joining member is solder. (Item 4) 4. The electronic component with a heat dissipation portion according to any one of items 1 to 3, wherein at least one of a joint surface of the electronic component with the joint member and a joint surface of the heat dissipation portion with the joint member is plated with nickel. (Item 5) 5. The electronic component with a heat dissipation portion according to any one of items 1 to 4, wherein a groove (23) is formed on a surface of the heat dissipation portion to be joined with the joining member. (Item 6) A method for manufacturing an electronic component with a heat dissipation part formed by joining an electronic component (1) that generates heat during operation to a heat dissipation part (2) that dissipates the heat generated by the electronic component to an atmospheric fluid, comprising the steps of: The bonding area between the electronic component and the heat sink is 100 mm 2 That's all. A method for manufacturing an electronic component with a heat dissipation portion, comprising a printing process for applying paste solder, which is a joining material for joining the electronic component and the heat dissipation portion, via a screen mesh to at least one of the joining surfaces of the electronic component and the joining surface of the heat dissipation portion.

[0042] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of the present disclosure.

Claims

1. An electronic component (1) that generates heat when in operation; A heat dissipation section (2) that dissipates heat generated by the electronic component to an atmospheric fluid; A joining member (4) that joins the electronic component and the heat dissipation portion, The bonding area between the electronic component and the heat dissipation portion is 100 mm ２ That's all. The joining member forms a porous metal layer (40) having pores (41) uniformly distributed throughout the layer, The joining member is solder.

2. the porous metal layer has at least one pore formed per unit area when viewed from a direction perpendicular to a bonding surface between the electronic component and the heat dissipation portion, The unit area is 1 mm ２ and The length of the porous metal layer in the arrangement direction of the electronic component and the heat dissipation portion is defined as a thickness dimension (Wp); When the area ratio of the pores contained in the unit area when the porous metal layer is viewed from a direction perpendicular to the bonding surface is defined as a void ratio (Rv), 2. The electronic component with a heat sink according to claim 1, wherein the thickness dimension and the void ratio satisfy the relationship: Rv≦−6.23Wp+1.

3. 3. The electronic component with a heat dissipation portion according to claim 1, wherein at least one of a joint surface of the electronic component with the joint member and a joint surface of the heat dissipation portion with the joint member is plated with nickel.

4. 3. The electronic component with a heat sink according to claim 1, wherein a groove (23) is formed on a surface of the heat sink to be joined to the joining member.

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