Electronic component and method for manufacturing electronic component

Abstract

Provided is an electronic component capable of suppressing a structural change of the electronic component when the electronic component is mounted. An electronic component (10) is provided with: a lead member (4); a support member (5); an electronic component (1) disposed between the lead member (4) and the support member (5), the electronic component (1) having a first surface (11) disposed on the lead member (4) side and a second surface (12) disposed on the support member (5) side; a first bonding layer (31) that bonds the lead member (4) and the first surface (11), is configured from Sn and a first metal capable of forming an intermetallic compound with Sn and having a melting point higher than 1100 DEG C, and contains a first intermetallic compound having a melting point higher than 260 DEG C in a proportion of 80 vol% or more; and a second bonding layer (32) that bonds the support member (5) and the second surface (12), is configured from Sn and a second metal capable of forming an intermetallic compound with Sn and having a melting point higher than 1100 DEG C, and contains a second intermetallic compound having a melting point higher than 260 DEG C in a proportion of 80 vol% or more.

Description

Technical Field

[0001] The present disclosure relates to electronic components and a method for manufacturing electronic components. Background Art

[0002] For the purpose of rectification and surge absorption, diode components are widely used in general consumer, industrial equipment, automotive applications, railway applications, etc. Since the diode component is mounted on a printed circuit board at the customer's site, it is preferably capable of withstanding secondary mounting (e.g., about 260°C). Therefore, a high-lead solder with a melting point of about 300°C is used for the internal bonding of the diode component. The high-lead solder contains lead, and there is concern about its adverse effects on the human body. However, since there is no general substitute material, it was also excluded from the European RoHS directive in 2022.

[0003] For example, as lead-free bonding materials that can maintain bonding at about 260°C, there are Au-20Sn, Bi-Ag, etc. However, they all have problems of high cost and low thermal conductivity compared to lead solder, and it is difficult to apply them to diode products. As an Sn-based alloy having a melting point close to that of high-lead solder, there is an Sn-Ag-Cu-Sb-based solder. However, this solder is very hard compared to high-lead solder. Therefore, in a diode product of the type where electronic components such as semiconductor elements are bonded to, for example, the upper and lower surfaces using a bonding material, during the process of cooling after bonding, a large stress is applied to the electronic components, and structural changes such as cracking of the electronic components may occur.

[0004] As a technique capable of suppressing structural changes of electronic components, it is described in the abstract of Patent Document 1 that "a solder foil formed by rolling a solder material containing metal particles such as Cu particles and solder particles such as Sn particles, and an electronic device connected using the solder foil."

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-247742 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] When an electronic component is mounted on a substrate or the like by soldering, heat is applied to the electronic component. Therefore, the bonding portion of the electronic component provided in the electronic component is deformed by heat, and there is a possibility of structural changes in the electronic component.

[0010] The problem to be solved by the present disclosure is to provide an electronic component and a method for manufacturing an electronic component that can suppress structural changes of the electronic component when the electronic component is mounted.

[0011] Solution to the problem

[0012] The electronic component of the present disclosure includes: a first component; a second component; an electronic element disposed between the first component and the second component, having a first surface disposed on the first component side and a second surface disposed on the second component side; a first bonding layer that bonds the first component to the first surface, and is composed of a first metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn, and contains a first intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more; and a second bonding layer that bonds the second component to the second surface, and is composed of a second metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn, and contains a second intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more. Other solutions will be described later in the mode for carrying out the invention.

[0013] Advantageous effects of the invention

[0014] According to the present disclosure, it is possible to provide an electronic component and a method for manufacturing an electronic component that can suppress structural changes of the electronic component when the electronic component is mounted. Description of the drawings

[0015] Figure 1 is a cross-sectional view of the electronic component of the present disclosure.

[0016] Figure 2 is a cross-sectional view of an electronic component according to another embodiment.

[0017] Figure 3 is a flowchart showing a method for manufacturing the electronic component of the present disclosure.

[0018] Figure 4 is a cross-sectional view of a precursor of the electronic component during assembly in the placement process.

[0019] Figure 5 is a cross-sectional electron micrograph of a bonding portion where an electronic element is bonded to a lead component and a support component using a paste as a comparative example.

[0020] Figure 6 is a cross-sectional electron micrograph of a bonding portion where an electronic element is bonded to a lead component and a support component using a first sheet and a second sheet containing Cu as a high melting point metal as a comparative example.

[0021] Figure 7 is, as an example, a cross-sectional electron micrograph when Ni is used instead of Figure 6 Cu.

[0022] Figure 8A This is a cross-sectional electron micrograph of the first bonding layer when Ni is 20% by mass.

[0023] Figure 8B This is Figure 8A a binary-processed diagram of the cross-sectional electron micrograph of

[0024] Figure 9A This is a cross-sectional electron micrograph of the first bonding layer when Ni is 25% by mass.

[0025] Figure 9B This is Figure 9A a binary-processed diagram of the cross-sectional electron micrograph of

[0026] Figure 10A This is a cross-sectional electron micrograph of the first bonding layer when Ni is 30% by mass.

[0027] Figure 10B This is Figure 10A a binary-processed diagram of the cross-sectional electron micrograph of

[0028] Figure 11 This is a graph showing the relationship between the Ni content in the first sheet and the consumption thickness of the Ni-P coating on the Cu plate. Detailed implementation mode

[0029] Hereinafter, a mode for implementing the present disclosure (referred to as an implementation mode) will be described with reference to the accompanying drawings. In the following description of one implementation mode, the description of other implementation modes applicable to one implementation mode will also be appropriately given. The present disclosure is not limited to the following one implementation mode, and different implementation modes can be combined with each other, or arbitrarily deformed within the range not significantly impairing the effects of the present disclosure. In addition, the same reference numerals are assigned to the same components, and repeated descriptions are omitted. Also, components having the same function are given the same name. The content shown in the drawings is always schematic, and for the convenience of illustration, sometimes the actual structure is changed within the range not significantly impairing the effects of the present disclosure, or the illustration of some components is omitted or deformed between the drawings. In addition, in the same implementation mode, it is not necessary to have all the structures.

[0030] Figure 1It is a cross-sectional view of the electronic component 10 of the present disclosure. The electronic component 10 includes an electronic element 1 having electrodes 2, a bonding layer 3, a lead component 4 (an example of a first component), a support component 5 (an example of a second component), and a resin component 6. As will be described in detail later, the bonding layer 3 contains Sn, a metal (a first metal, a second metal) that can form an intermetallic compound with Sn and has a melting point higher than 1100°C, and an intermetallic compound (a first intermetallic compound, a second intermetallic compound) having a melting point higher than 260°C. Thus, even when the electronic component 10 is heated for mounting on a substrate or the like by soldering or the like, melting of the bonding layer 3 can be suppressed, and structural changes of the electronic component 10 caused by the melting can be suppressed.

[0031] The electronic element 1 is, for example, a semiconductor element such as a diode, but the electronic element 1 is not limited thereto. The electronic element 1 is disposed between the lead component 4 and the support component 5. The electronic element 1 includes a first surface 11 disposed on the side of the lead component 4 and a second surface 12 disposed on the side of the support component 5.

[0032] The electrodes 2 supply power to the electronic element 1 and include a first electrode 21 and a second electrode 22. Thus, the electronic element 1 includes: the first electrode 21 forming the first surface 11; and the second electrode 22 forming the second surface 12.

[0033] The first electrode 21 and the second electrode 22 each independently include a Ni layer 23 made of Ni (monomer) or a Ni-based alloy on the first surface 11 and the second surface 12, respectively. Thus, the Ni layer 23 is bonded to the first bonding layer 31 and the second bonding layer 32 on the first surface 11 and the second surface 12. The "each independently" described herein means that although it applies to both the first electrode 21 and the second electrode 22, it does not mean that the applicable content is the same. Hereinafter, the case of "each independently" has the same meaning. For example, both the first electrode 21 and the second electrode 22 may include a Ni layer 23 formed of Ni monomer, or the first electrode 21 may include a Ni layer 23 formed of Ni monomer, and the second electrode 22 may include a Ni layer 23 formed of a Ni-based alloy. The Ni-based alloy is not limited to this example and is, for example, at least one of Ni-P, Ni-B, Ni-V, etc. The Ni layer 23 can be formed, for example, on the surface of a conductive metal plate such as monomer Cu by plating or the like.

[0034] The thickness of the Ni layer 23 is 1.5 μm or more and 3.5 μm or less in each of the first electrode 21 and the second electrode 22. The thickness of the Ni layer 23 is preferably 1.5 μm or more and 3.5 μm or less in the entire extending direction of the first surface 11 and the second surface 12. The thickness can be measured, for example, by actually measuring the thickness of the Ni layer 23 in a cross-sectional microscope photograph.

[0035] By setting the thickness within this range, even when the electronic component 10 is mounted on a printed circuit board or the like and kept (used) at a high temperature for a long period, the disappearance of the electrode 2 can be suppressed, and the occurrence of structural changes can be suppressed. Thereby, the high-temperature reliability of the electronic component 10 can be improved. In particular, by setting it to 3.5 μm or less, the internal stress of the electronic element 1 is suppressed to a small value, and cracking caused by thermal shock or the like during the manufacture and after mounting of the electronic component 10 can be suppressed.

[0036] Among them, the thickness is preferably 2.0 μm or more and 2.5 μm or less. By setting the thickness within this range, the high-temperature reliability and the cracking of the electronic element 1 can be more stably suppressed.

[0037] In addition, the entirety of the first electrode 21 and the second electrode 22 may be made of Ni (monomer) or a Ni-based alloy. In this case, in the first electrode 21 and the second electrode 22, the Ni layer 23 and the layer other than the Ni layer 23 cannot be distinguished. However, in each of the first electrode 21 and the second electrode 22, if Ni (monomer) or a Ni-based alloy exists in a portion at a distance of 1.5 μm or more and 3.5 μm or less in the inward direction starting from the first surface 11 and the second surface 12, it can be considered that a Ni layer 23 of 1.5 μm or more and 3.5 μm or less is formed.

[0038] The bonding layer 3 is a layer that bonds the electronic element 1 to the lead component 4 and the support component 5. The bonding layer 3 can be formed, for example, by heating in a state where the following-described first sheet 301 and second sheet 302 (both are referred to Figure 4 ) are sandwiched between the electronic element 1 and the lead component 4 and the support component 5.

[0039] The bonding layer 3 includes a first bonding layer 31 and a second bonding layer 32. The first bonding layer 31 bonds the lead component 4 to the first surface 11. The first bonding layer 31 is composed of a first metal (for example, Ni) and Sn (usually the first metal and Sn are combined) and contains an intermetallic compound of the first metal (for example, Ni - Sn) at a ratio of 80% by volume or more. The content of the intermetallic compound of the first metal can be measured, for example, based on a cross-sectional electron microscope photograph. The first metal is a metal having a melting point higher than 1100 °C, preferably 1200 °C or more. The first metal is a metal that can form an intermetallic compound with Sn. The intermetallic compound of the first metal has a melting point higher than 260 °C. By including the intermetallic compound of the first metal having a melting point higher than 260 °C, when the electronic component 10 is mounted on a printed circuit board or the like, for example, even when soldering is performed by heating to a temperature of 260 °C, the deformation of the first bonding layer 31 can be suppressed, and peeling can be suppressed. The first bonding layer 31 contains the first metal and the intermetallic compound of the first metal.

[0040] In the first bonding layer 31, the first metal is preferably contained in a proportion of 4% by volume or more and 20% by volume or less. By containing the first metal within this range, when the electronic component 10 is used, even if the electronic component 10 is exposed to high temperatures, an undesirable reaction of the bonding layer 3 can be suppressed. The content of the first metal can be measured based on, for example, a cross-sectional electron micrograph.

[0041] The first metal is not limited to this example. For example, Ni is preferably contained. By containing Ni, an intermetallic compound of the first metal can be easily formed with Sn during the manufacture of the electronic component 10. The first metal may be contained in the first bonding layer 31 in the form of a monomer or in the form of a compound such as an alloy. As the alloy, for example, Ni-based alloys can be cited. As specific examples of Ni-based alloys, for example, at least one of Ni-B, Ni-P, etc. can be cited.

[0042] Also, the first metal is not limited to this example. For example, Au is also preferably contained. By containing Au, an intermetallic compound of the first metal can be easily formed with Sn during the manufacture of the electronic component 10. Similar to Ni, Au can also be contained in the first bonding layer 31 in the form of a monomer or in the form of a compound such as an alloy. As the alloy, Au-based alloys can be cited. As specific examples of Au-based alloys, for example, AuSn, AuSn2, AuSn4, ζ-phase (Zeta phase), etc. can be cited.

[0043] The shape of the first metal is not particularly limited, but a spherical shape is preferred. By having a spherical shape, the surface area of the first metal is increased, and an intermetallic compound of the first metal can be easily formed with Sn. In addition, when the electrode 2 is made of Ni or a Ni-based alloy, for example, when the electronic component is used at high temperatures, consumption (reduction in film thickness) of the electrode 2 can be suppressed. Furthermore, the first metal does not need to be spherical, as long as it has a shape without corners such as a circular shape or a flat shape in cross-section.

[0044] The first metal is preferably dispersed in the first bonding layer 31. Thereby, the intermetallic compound formed from the first metal can be dispersed throughout the first bonding layer 31, and the heat resistance of the entire first bonding layer 31 can be improved.

[0045] The first intermetallic compound preferably mainly contains Ni-Sn (a compound in which Ni and Sn are combined). By mainly containing Ni-Sn, it is difficult to melt even when the electronic component 10 is mounted (second mounting) on a printed circuit board or the like at a maximum temperature of 260°C, for example, and thus the bonding layer 3 can be maintained. The "mainly" mentioned here means 50% by volume or more in the whole of the first bonding layer 31, or the most material among the materials constituting the first bonding layer 31. Hereinafter, it is the same in the case of being referred to as "mainly". As Ni-Sn, for example, Ni3Sn4 can be cited.

[0046] Moreover, as the first intermetallic compound, it is also preferable to mainly contain Au-Sn (a compound in which Au and Sn are combined). By mainly containing Au-Sn, it is difficult to melt even when the electronic component 10 is mounted (second mounting) on a printed circuit board or the like at a maximum temperature of 260°C, for example, and thus the bonding layer 3 can be maintained.

[0047] The second bonding layer 32 bonds the support member 35 to the second surface 12. The material of the second bonding layer 32 can be the same as the material of the first bonding layer 31 described above. Therefore, the second bonding layer 32 is composed of a second metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C, preferably 1200°C or higher, and Sn (usually, the second metal is combined with Sn). At the same time, the second bonding layer 32 contains a second intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more. The second intermetallic compound is the same as the above-mentioned first intermetallic compound and is composed of a second metal and Sn. By containing the second intermetallic compound having a melting point higher than 260°C, when the electronic component 10 is mounted on a printed circuit board or the like, for example, even when soldering is performed by heating to a temperature of 260°C, deformation of the second bonding layer 32 can be suppressed, and peeling can be suppressed.

[0048] Regarding the second bonding layer 32, the description of the first bonding layer 31 described above can be similarly applied. For example, in the second bonding layer 32, it is preferable to contain the second metal in a proportion of 4% by volume or more and 20% by volume or less. For the second metal, the description of the first metal described above can be similarly applied. Therefore, the above-mentioned first metal and second metal preferably independently contain Ni respectively. In addition, the above-mentioned first metal and second metal also preferably independently contain Au respectively. Moreover, the above-mentioned first metal and second metal preferably both have a spherical shape, and the above-mentioned first metal and second metal are preferably independently dispersed in the first bonding layer 31 and the second bonding layer 32.

[0049] In addition, regarding the second intermetallic compound, the description of the above-mentioned first intermetallic compound can be equally applied. Therefore, for example, the above-mentioned first intermetallic compound and the second intermetallic compound preferably mainly contain Ni-Sn independently of each other. In addition, the above-mentioned first intermetallic compound and the second intermetallic compound also preferably mainly contain Au-Sn independently of each other.

[0050] When the electronic component 10 is mounted on a substrate (not shown) or the like, for example, the lead component 4 is electrically connected to another component (such as a power source). The lead component 4 can be made of any metal, for example. The support component 5 fixes the electronic element 1. The support component 5 can be made of metal or the like, for example. The electronic element 1, the bonding layer 3, the lead component 4, and the support component 5 are encapsulated by an encapsulating resin component 6. The resin component 6 is, for example, an epoxy resin in which silica spheres are dispersed.

[0051] The lead component 4 and the support component 5 preferably are each independently composed of at least one of Cu or a Cu-based alloy. Specific examples of the Cu-based alloy include at least one of a phosphor bronze-based alloy, a Cu-Fe-based alloy, a Cu-Zr-based alloy, a Cu-Cr-based alloy, a Cu-Ni-Si-based alloy, etc. The lead component 4 and the support component 5 are directly bonded to the first bonding layer 31 and the second bonding layer 32, respectively. In this way, heat of the electronic component 10 (such as a diode) that generates heat due to energization can be efficiently dissipated.

[0052] In another embodiment, the lead component 4 and the support component 5 are each independently composed of at least one of Cu or a Cu-based alloy. On the surfaces of the lead component 4 and the support component 5 (at least the side of the bonding surface with the lead component 4 and the support component 5), plating layers made of Ag are respectively formed. In this way, wetting can be easily ensured during bonding. Whether to form a plating layer on the surfaces of the lead component 4 and the support component 5 can be determined by observing the surfaces of the lead component 4 and the support component 5 with an electron microscope to confirm the surface conditions.

[0053] In other embodiments, the lead component 4 and the support component 5 are each independently composed of at least one of Cu or a Cu-based alloy. On the surfaces of the lead component 4 and the support component 5 (at least the side of the bonding surface with the lead component 4 and the support component 5), plating layers made of Ni or a Ni-based alloy are respectively formed. In this way, during use after mounting on a printed circuit board or the like, an undesired reaction at the interface of the bonding portion can be suppressed. Specific examples of the Ni-based alloy include at least one of Ni-P, Ni-B, etc.

[0054] In the example of the present disclosure, as described above, the first component is the lead component 4, and the second component is the support component 5. And, in the direction along the first surface 11 (in Figure 1The area of the first bonding layer 31 in the left - right direction (in the plane of the drawing) is smaller than the area of the first surface 11. Moreover, the area of the second bonding layer 32 in the direction along the second surface 12 is larger than the area of the second surface 12. In this way, the stress generated on the side surface of the electronic component 1 can be reduced. Therefore, during the manufacture of the electronic component 10, when thermal shock occurs, etc., the generation of cracks can be suppressed. Also, when the electronic component 10 generates heat when powered on, heat can be easily dissipated. In addition, the electronic component 10 has a shape that narrows in the direction from the support member 5 towards the lead member 4, so the electronic component 10 can be easily manufactured.

[0055] Figure 2 It is a cross - sectional view of the electronic component 10 of another embodiment. The area of the first bonding layer 31 in the direction along the first surface 11 is larger than the area of the first surface 11. Moreover, the area of the second bonding layer 32 in the direction along the second surface 12 is smaller than the area of the second surface 12. Even so, the stress generated on the side surface of the electronic component 1 can be reduced. Therefore, during the manufacture of the electronic component 10, when thermal shock occurs, etc., the generation of cracks can be suppressed. Also, when the electronic component 10 generates heat when powered on, heat can be easily dissipated.

[0056] Figure 3 It is a flowchart showing a method for manufacturing an electronic component of the present disclosure (hereinafter referred to as the manufacturing method of the present disclosure). The manufacturing method of the present disclosure includes a placement step S1 and a heating step S2.

[0057] Figure 4 It is a cross - sectional view of the precursor 110 of the electronic component 10 ( Figure 1 ) during assembly in the placement step S1. In the placement step S1, between the lead member 4 and the first surface 11 of the electronic component 1 having the first surface 11 and the second surface 12, a first sheet 301 containing a first metal and Sn is placed. As described above, the first metal can form an intermetallic compound with Sn and has a melting point higher than 1100 °C. At the same time, a second sheet 302 containing a second metal and Sn is placed between the support member 5 and the second surface 12. As described above, the second metal can form an intermetallic compound with Sn and has a melting point higher than 1100 °C.

[0058] As described above, the first sheet 301 and the second sheet 302 are transformed into the first bonding layer 31 and the second bonding layer 32 by heating. Specifically, for example, in the first sheet 301, Sn reacts with the first metal to generate a first intermetallic compound, and a first bonding layer 31 containing unreacted Sn and the first intermetallic compound is generated. The same applies to the second sheet 302.

[0059] The first sheet 301 preferably contains Ni as the first metal in a proportion of 15 mass% or more and 30 mass% or less. Ni reacts withFigure 1 The content described is the same, and it can also be included in the first sheet 301 in a monomeric form, or can be included in the first sheet 301 in the form of a compound such as an alloy. Further, the second sheet 302 preferably contains Ni as the second metal in a proportion of 15% by mass or more and 30% by mass or less. Ni is the same as that described with reference to the above Figure 1 The content described is the same, and it can also be included in the second sheet 302 in a monomeric form, or can be included in the second sheet 302 in the form of a compound such as an alloy. By the first sheet 301 and the second sheet 302 respectively containing the first metal and the second metal within this range, the bonding strength between the electronic element 1, the lead component 4, and the support component 5 can be improved during the manufacture of the electronic component 10. Further, in each of the first bonding layer 31 and the second bonding layer 32 (both are referred to Figure 1 ), the first intermetallic compound and the second intermetallic compound can be generated in most parts in a short time.

[0060] In particular, by setting it to 15% by mass or more, even when the electronic component 10 mounted on a printed circuit board or the like is used for a long time, the disappearance of the electrode 2 caused by the reaction between the metal constituting the electrode 2 and Ni can be suppressed, and the reliability of the electronic component 10 can be improved. On the other hand, by setting it to 30% by mass or less, when the first bonding layer 31 and the second bonding layer 32 are formed, the generation rate of the first intermetallic compound and the second intermetallic compound is prevented from becoming too fast, and unreacted Sn remains, and sufficient coatability can be exhibited.

[0061] Among them, the first sheet 301 preferably contains Ni as the first metal in a proportion of 20% by mass or more and 25% by mass or less. Further, the second sheet 302 preferably contains Ni as the second metal in a proportion of 20% by mass or more and 25% by mass or less. By the first sheet 301 and the second sheet 302 respectively containing the first metal and the second metal within this range, the generation of the first intermetallic compound and the second intermetallic compound quickly and the ensuring of wettability can be better balanced.

[0062] There are no particular limitations on the physical properties of the first sheet 301 and the second sheet 302. For example, by shaping metal materials respectively containing the first metal and the second metal into a sheet shape (including a foil shape), the first sheet 301 and the second sheet 302 can be manufactured. The thicknesses of the first sheet 301 and the second sheet 302 are not particularly limited, but are respectively independently, for example, 10 μm or more and 1 mm or less, preferably 100 μm or more and 500 μm or less.

[0063] The configuration can be executed, for example, by inserting the lead component 4, the first sheet 301, the electronic component 1, the second sheet 302, and the support component 5 from the side close to the alignment jig 41 into the alignment jig 41 having a desired shape and loading them with a heavy object 42 from above. In particular, it is preferable to make the lead component 4, the first sheet 301, the electronic component 1, the second sheet 302, and the support component 5 adhere to each other by loading.

[0064] The heating step S2 is a step of heating at least the first sheet 301 and the second sheet 302 in a state where the first sheet 301 and the second sheet 302 are clamped by the lead component 4, the electronic component 1, and the support component 5. By heating, the first bonding layer 31 ( Figure 1 ) and the second bonding layer ( Figure 1 ) are formed. As described above, the first bonding layer 31 bonds the lead component 4 to the first surface 11, is composed of a first metal and Sn (usually the first metal is combined with Sn), and contains an intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more. As described above, the second bonding layer 32 bonds the support component 5 to the second surface 12, is composed of a second metal and Sn (usually the second metal is combined with Sn), and contains an intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more.

[0065] The heating conditions are not particularly limited, and heating may be performed under the conditions capable of generating the first bonding layer 31 and the second bonding layer 32 with reference to the above Figure 1 description. For example, the heating temperature can be 235°C or higher and 270°C or lower. The heating time can be, for example, 5 minutes or more and 15 minutes or less. The heating ambient gas can be, for example, an inert ambient gas.

[0066] Figure 5 is a cross-sectional electron micrograph of the bonding portion where the electronic component 1 is bonded to the lead component 4 and the support component 5 using a paste as a comparative example. In the bonding of the paste using the conventional method, since the paste contains volatile components such as a solvent and a flux, the volatile components volatilize during heating. Therefore, in addition to the metal particles 103 related to the bonding, voids 101 are generated in the bonding portion. Since the voids 101 significantly reduce the heat dissipation performance, it is difficult to apply them to electronic components 10 (such as diodes) with a large amount of heat generation.

[0067] In addition, for example, as described above Figure 4As shown, when a load is applied, the paste is exposed, and a short circuit 102 between the pastes is generated on the side of the electronic component 1. Due to the short circuit 102, the electronic component 1 cannot be energized, and the reliability of the electronic component 10 is reduced. The generation of the short circuit 102 occurs significantly especially during pressure bonding. In addition, in the transient liquid phase sintering method (TLPS), although bonding can be performed without pressure, voids 101 are likely to be generated due to the use of the paste.

[0068] Therefore, in the manufacturing method of the present disclosure, the first sheet 301 and the second sheet 302 (both are referred to Figure 3 ) are used instead of the paste. Thereby, the generation of the voids 101 can be suppressed, and the generation of the short circuit 102 can also be suppressed in the case of load bonding.

[0069] Figure 6 is a cross-sectional electron micrograph of a bonding portion where the electronic component 1 is bonded to the lead component 4 and the support component 5 using the first sheet 301 and the second sheet 302 containing Cu as the first metal as a comparative example. Figure 7 is a cross-sectional electron micrograph in the case where Ni is used instead of the above Figure 6 Cu as an example. Figure 6 and Figure 7 respectively represent bonding portions where 20% by mass of Cu powder or Ni powder is used and heated at 250 °C for 5 minutes for bonding.

[0070] In the case of using Cu ( Figure 6 ), in addition to particles 220 of the intermetallic compound (Cu - Sn) of Cu and Sn, that is, Cu6Sn5, a relatively large amount of unreacted Cu powder 210 and Sn powder 230 remain. On the other hand, in the case of using Ni ( Figure 7 ), the structure 250 of the intermetallic compound (Ni - Sn) of Ni and Sn, that is, Ni3Sn4, is formed over substantially the entire region, and the unreacted Ni powder 240 and Sn powder 230 are extremely few. From this result, it can be seen that by using Ni, even if the amount of Ni used is small, the intermetallic compound can be generated efficiently in a short time. Therefore, compared with the amount of Ni, the amount of Sn can be relatively increased, and the amount of the melted component during bonding increases, so the wettability can be improved.

[0071] Example

[0072] <Evaluation 1>

[0073] Along Figure 3 the process shown, Figure 1The electronic component 10 shown. In the present embodiment, three types of electronic components 10 were fabricated using sheets (serving as the first sheet 301 and the second sheet 302) having different material compositions. The first one is a sheet containing 20 mass% of Ni (the first metal, the second metal), with the remaining portion (80 mass%) composed of Sn. The second one is a sheet containing 25 mass% of Ni (the first metal, the second metal), with the remaining portion (75 mass%) composed of Sn. The third one is a sheet containing 30 mass% of Ni (the first metal, the second metal), with the remaining portion (70 mass%) composed of Sn. The sheets were fabricated by molding Ni powder and Sn powder into sheet form.

[0074] Each used respective sheets as the first sheet 301 ( Figure 3 ) and the second sheet 302 ( Figure 3 ), and the electronic components 10 were fabricated respectively. In the configuration process S1 ( Figure 3 ), a load of 0.05 MPa was applied using a heavy object 42 ( Figure 3 ). In the heating process S2, it was heated at 250 °C for 5 minutes in an N2 ambient gas to form the first bonding layer 31 ( Figure 1 ) and the second bonding layer 32 ( Figure 1 ). Finally, the bonded portion was sealed with a resin component 6 ( Figure 1 ).

[0075] Figure 8A is a cross-sectional electron microscope photograph of the first bonding layer 31 when Ni is 20 mass% (hereinafter appropriately referred to as "photograph"). Figure 9A is a cross-sectional electron microscope photograph of the first bonding layer 31 when Ni is 25 mass%. Figure 10A is a cross-sectional electron microscope photograph of the first bonding layer 31 when Ni is 30 mass%. Since the first sheet 301 and the second sheet 302 have the same material composition and the same shape, for simplicity of explanation, hereinafter, mainly the second bonding layer 32 formed from the second sheet 302 will be described.

[0076] In Figure 8A , Figure 9A and Figure 10A , the portion 71 close to white (the lighter-colored portion) represents the intermetallic compound of Ni and Sn (Ni3Sn4, the second intermetallic compound), and the portion 72 close to black (the darker-colored portion) represents unreacted Ni. As shown in these photographs, it can be seen that the intermetallic compound of Ni and Sn occupies the majority, and the unreacted Ni is very little.

[0077] Each of the three photographs was subjected to monochromatic binarization processing. The results are shown in Figure 8B , Figure 9B andFigure 10B in

[0078] Figure 8B is a Figure 8A figure obtained by binarizing a cross-sectional electron micrograph. Figure 9B is a Figure 9A figure obtained by binarizing a cross-sectional electron micrograph. Figure 10B is a Figure 10A figure obtained by binarizing a cross-sectional electron micrograph. Regarding Figure 8B , Figure 9B and Figure 10B , the white portion 73 represents an intermetallic compound and corresponds to the portion 71 ( Figure 8A , Figure 9A , Figure 10A ) before binarization. The black portion 74 represents Ni and corresponds to the portion 72 ( Figure 8A , Figure 9A , Figure 10A ) before binarization.

[0079] Regarding each photograph, the areas of the white portion 73 and the black portion 74 are measured respectively, and the proportions of the portions 73 and 74 in the entire first bonding layer 31 are calculated. The proportion of the white portion 73 can be regarded as the volume proportion of the first intermetallic compound and the second intermetallic compound contained in the first bonding layer 31 and the second bonding layer 32 respectively. In addition, the proportion of the black portion 74 can be regarded as the volume proportion of the first metal and the second metal contained in the first bonding layer 31 and the second bonding layer 32 respectively.

[0080] As a result, when Ni is 20 mass% ( Figure 8B ), the proportion of the white portion 73 is 93.6% (93.6 volume%) and the proportion of the black portion 74 is 6.4% (6.4 volume%). In addition, when Ni is 25 mass% ( Figure 9B ), the proportion of the white portion 73 is 87.0% (87.0 volume%) and the proportion of the black portion 74 is 13.0% (13.0 volume%). And when Ni is 30 mass% ( Figure 10B ), the proportion of the white portion 73 is 80.1% (80.1 volume%) and the proportion of the black portion 74 is 19.9% (19.9 volume%). Therefore, in these examples, in the first bonding layer 31 and the second bonding layer 32, the first intermetallic compound and the second intermetallic compound are contained at a proportion of 80 volume% or more respectively.

[0081] Regarding three fabricated electronic components 10, they are heated to 260 °C and soldered onto a printed circuit board. During soldering, no structural changes were observed in the entirety of the electronic component 10 including the first bonding layer 31 and the second bonding layer 32. Therefore, according to the present disclosure, it is understood that structural changes in the electronic component 10 (especially the bonding layer 3) can be suppressed when installing the electronic component 10. In addition to this, it is also understood that the bonding within the electronic component 10 (such as the bonding layer 3) can be maintained.

[0082] In addition, as a comparative example, except for changing Ni to 35 mass%, it is the same as the example of Figure 8A and Figure 8B and the respective ratios of the partial regions 73 and 74 were calculated. As a result, the ratio of the white partial region 73 was 75.0% (75.0 volume %), and the ratio of the black partial region 74 was 25.0% (25.0 volume %). Therefore, in the comparative example, the first intermetallic compound and the second intermetallic compound were each contained in a ratio of less than 80 volume % in the first bonding layer 31 and the second bonding layer 32.

[0083] Three fabricated electronic components 10 were soldered onto a printed circuit board in the same manner as above. During soldering, the first bonding layer 31 and the second bonding layer 32 melted, and structural changes occurred in the electronic component 10. Therefore, it is understood that when installing the electronic component 10, structural changes occur in the electronic component 10 if the content ratios of the first intermetallic compound and the second intermetallic compound in each of the first bonding layer 31 and the second bonding layer 32 are less than 80 volume %.

[0084] <Evaluation 2>

[0085] Figure 11 is a graph showing the relationship between the Ni content rate in the first sheet 301 ( Figure 3 ) and the consumption thickness of the Ni - P plating layer on the Cu plate. First, two Cu plates (equivalent to the electrodes 2) having a Ni - P plating layer with a thickness of 3 μm (P content: 3 mass %) were joined using the above - mentioned first sheet 301 to fabricate samples. A plurality of first sheets 301 with different Ni content rates were prepared, and samples were fabricated respectively. The first sheet 301 was joined to the Ni - P plating layer. Each fabricated sample was maintained at 150 °C for 1000 hours. After maintaining for 1000 hours, the thickness of the Ni - P plating layer was measured.

[0086] As Figure 11As shown, when the Ni content rate is less than 15% by mass, the consumption thickness of the Ni-P coating significantly increases. This is considered to be caused by the insufficient formation of intermetallic compounds during the production of the sample due to the low Ni content rate. Since there is less Ni, almost no Ni remains in the first bonding layer 31 but a large amount of Sn remains. Therefore, it is considered that during the 1000-hour holding at 150°C, the large amount of remaining Sn reacts with the Ni in the Ni-P coating to form intermetallic compounds, consuming the Ni-P coating.

[0087] On the other hand, when the Ni content rate is 15% by mass or more and the consumption thickness is 1.0 μm or less, especially when it is 25% by mass or more, it is almost zero. Therefore, by using the first sheet 301 and the second sheet 302 with a Ni content rate of 15% by mass or more, during the production of the sample (when manufacturing the electronic component 10), the formation of intermetallic compounds can be more promoted. And afterwards, for example, at a high temperature such as holding at 150°C for 1000 hours, the reaction with the Ni-P coating can be suppressed, and the structural change can be more sufficiently suppressed.

[0088] As the upper limit of the Ni content rate, by setting it to a ratio of 30% by mass or less, the reduction of Sn caused by a large amount of Ni can be suppressed. Thus, it is considered that wettability can be ensured during soldering.

[0089] <Evaluation 3>

[0090] (Components used)

[0091] The electronic component 10 was produced in the same manner as in <Evaluation 1> above, using the first sheet 301 and the first electrode 21 composed of the first metal and a metal other than the first metal shown in Table 1 and Table 2 below. The second sheet 302 and the second electrode 22 used sheets and electrodes with the same materials and physical properties as the first sheet 301 and the first electrode 21, respectively. Five electronic components 10 were produced each and evaluated separately.

[0092] [Table 1]

[0093] Table 1 Examples 1 - 24

[0094]

[0095] [Table 2]

[0096] Table 2 Comparative Examples 1 - 6

[0097]

[0098] The first sheet 301 of Examples 1 and 2 contains Ni monomers at any value of 15 to 30% by mass (20% by mass), and Sn monomers as the remaining portion. The first sheet 301 of Examples 3 and 4 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and Sn monomers as the remaining portion. The first sheet 301 of Examples 5, 6, 25, and 26 contains Ni monomers at the same concentration as that of Examples 1 and 2, and a Sn-Ag alloy as the remaining portion. In addition, in Examples 5, 6 and Examples 25, 26, each first sheet is the same, but the thickness of the first electrode is different, which will be described in detail later. The first sheet 301 of Examples 7, 8, 27, and 28 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and a Sn-Ag alloy as the remaining portion. In addition, in Examples 7, 8 and Examples 27, 28, each first sheet is the same, but the thickness of the first electrode is different, which will be described in detail later. The first sheet 301 of Examples 9 and 10 contains Ni monomers at the same concentration as that of Examples 1 and 2, and a Sn-Ag-Cu alloy as the remaining portion.

[0099] The first sheet 301 of Examples 11 and 12 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and a Sn-Ag-Cu alloy as the remaining portion. The first sheet 301 of Examples 13 and 14 contains Ni monomers at the same concentration as that of Examples 1 and 2, and a Sn-Ag-Cu-In alloy as the remaining portion. The first sheet 301 of Examples 15 and 16 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and a Sn-Ag-Cu-In alloy as the remaining portion. The first sheet 301 of Examples 17 and 18 contains Ni monomers at the same concentration as that of Examples 1 and 2, and a Sn-Cu alloy as the remaining portion. The first sheet 301 of Examples 19 and 20 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and a Sn-Cu alloy as the remaining portion.

[0100] The first sheet 301 of Examples 21 and 22 contains Ni monomers at the same concentration as that of Examples 1 and 2, and a Sn-Sb alloy as the remaining portion. The first sheet 301 of Examples 23 and 24 contains a Ni-Fe alloy at the same Ni concentration as that of Examples 1 and 2, and a Sn-Sb alloy as the remaining portion. Therefore, in Examples 1 to 28, the Ni concentration in the first sheet 301 is the same.

[0101] The first sheet 301 of Comparative Examples 1 and 2 contains Cu monomers at the same concentration as that of Examples 1 and 2, and Sn monomers as the remaining portion.

[0102] In Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23 (hereinafter collectively referred to as Example Group A), a Ni - P plating layer (P content is 3% by mass) is formed on the Cu plate of the monomer as the first electrode 21 with a thickness of 1.5 μm or more and 3.5 μm or less (specifically 2.5 μm). Measuring any part, the thickness of the plating layer is 2.5 μm. The plated part is the Ni layer 23.

[0103] In addition, in Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 (hereinafter collectively referred to as Example Group B), as the first electrode 21, except for using a Ni plating layer (excluding P) instead of the Ni - P plating layer, the same first electrode 21 as in Example Group A is used.

[0104] In Examples 25 - 28, the composition and thickness are set as follows. In Examples 25 and 27, the same first electrode 21 as in the above Example Group A is used. However, in Examples 25 and 27, the thickness of the plating layer is 0.5 μm or more and 1.0 μm or less (specifically 0.75 μm). Measuring any part, it is 0.75 μm.

[0105] In addition, in Examples 26 and 28, as the first electrode 21, except for using a Ni plating layer (excluding P) instead of the Ni - P plating layer, the same first electrode 21 as in Examples 25 and 27 is used.

[0106] (Evaluation Method)

[0107] Regarding each of the five fabricated electronic components 10, by measuring the electrical characteristics, the presence or absence of cracking of the electronic element 1 was evaluated. As a result, in any of Examples 1 - 28 and Comparative Examples 1 and 2, no cracking was observed, and it was confirmed that the electronic component 10 operates normally.

[0108] Next, taking 10 seconds at 260°C as one cycle, a reflow test of three cycles was performed on each of the electronic components 10. After the reflow test, when the bonding of the bonding layer 3 could be maintained in all five electronic components 10, it was marked as a circle (○), and when the bonding of the bonding layer 3 could not be maintained in even one electronic component 10, it was marked as a cross (×). When it could be maintained, no structural change was observed on the electronic component 10, and when it could not be maintained, a structural change was observed on the electronic component 10. As a result, in Examples 1 - 28, especially the bonding of the bonding layer 3 was maintained, and no structural change was observed on the electronic component 10. However, in Comparative Examples 1 and 2, the bonding of the bonding layer 3 could not be maintained, and a structural change was observed on the electronic component 10.

[0109] In Examples 1 to 28, the first metal used was Ni. Ni can form an intermetallic compound with Sn and has a melting point higher than 1100°C. Therefore, it is known that the shape of the bonding layer 3 is maintained even during the reflow test at 260°C, and it has reflow resistance. Based on this result, it is considered that for the electronic component 10 of Examples 1 to 28, for example, by heating at 260°C, the structural change of the bonding layer 3 can be particularly suppressed even when mounted on a printed circuit board or the like. In addition, the same tendency is shown regardless of whether there is P (phosphorus) in the plating layer constituting the first electrode 21.

[0110] On the other hand, in Comparative Examples 1 and 2, the first metal used was Cu, and the melting point of Cu is 1100°C or lower. Therefore, Cu is not the first metal defined in the present disclosure. Thus, it is known that in Comparative Examples 1 and 2, when mounted at 260°C, the bonding layer 3 melts and deforms, and does not have reflow resistance.

[0111] This result is considered to be due to Figure 6 the insufficient formation of the intermetallic compound as shown above. From this, it is considered that a relatively large amount of unreacted Sn remains, and as a result of reacting with the Ni of the electrode during reflow, the electrode disappears, peeling occurs, and the bonding cannot be maintained. Therefore, it is considered that for the electronic component 10 of Comparative Examples 1 and 2, for example, due to heating at 260°C, a structural change occurs when mounted on a printed circuit board or the like, and it is difficult to mount.

[0112] From these results, it can be seen that by using the first metal and the second metal defined in the present disclosure, the structural change of the electronic component 10 can be suppressed when mounting the electronic component 10.

[0113] In addition, in Examples 1 to 24 where the thickness of the Ni layer 23 included in the first electrode 21 and the second electrode 22 is 1.5 μm or more and 3.5 μm or less, the shape during use is maintained even when assuming the actual use of a printed circuit board or the like on which the electronic component 10 is mounted. That is, even when the entire printed circuit board including the mounted electronic component 10 is held at 150°C for 1000 hours, the shape of the bonding layer 3 after holding is maintained, and in particular, no deformation is seen in the bonding layer 3. Therefore, it can be seen that according to the present disclosure, the reliability of the electronic component 10 can be maintained for a long time.

[0114] On the other hand, in Examples 25 to 28 where the thickness of the Ni layer 23 deviates from the range of more than 1.5 μm and 3.5 μm, after maintaining at 150°C for 1000 hours, deformation was seen in the shape of the bonding layer 3. This is considered to be because the Ni layer 23 is thin, and due to the reaction, the Ni layer 23 is thinned or disappears, and the electronic component 1 peels off. From these results, it can be seen that by making the thickness of the Ni layer 23 1.5 μm or more and 3.5 μm or less, the durability and reliability during use of the mounted electronic component 10 can be improved, and the structural change of the electronic component 10 can be suppressed.

[0115] Explanation of symbols

[0116] 1 - Electronic component, 10 - Electronic component, 100 - Electronic component, 101 - Void, 102 - Short circuit, 103 - Metal particle, 11 - First surface, 110 - Precursor, 12 Second surface, 2 - Electrode, 21 - First electrode, 22 - Second electrode, 23 - Ni layer, 3 - Bonding layer, 301 - First sheet, 302 - Second sheet, 31 - First bonding layer, 32 - Second bonding layer, 35 - Support member, 4 - Lead member (first member), 41 - Alignment jig, 42 - Weight, 5 - Support member (second member), 6 - Resin member, 71 - Portion, 72 - Portion, S1 - Configuration process, S2 - Heating process.

Claims

1. An electronic component, characterized in that, Comprising: A first component; A second component; An electronic component disposed between the above-mentioned first component and the above-mentioned second component, having a first surface disposed on the side of the above-mentioned first component and a second surface disposed on the side of the above-mentioned second component; A first bonding layer that bonds the above-mentioned first component to the above-mentioned first surface, comprising a first metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn, and comprising a first intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more; And A second bonding layer that bonds the above-mentioned second component to the above-mentioned second surface, comprising a second metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn, and comprising a second intermetallic compound having a melting point higher than 260°C in a proportion of 80% by volume or more.

2. The electronic component according to claim 1, wherein In the above-mentioned first bonding layer, the above-mentioned first metal is contained in a proportion of 4% by volume or more and 20% by volume or less, and In the above-mentioned second bonding layer, the above-mentioned second metal is contained in a proportion of 4% by volume or more and 20% by volume or less.

3. The electronic component according to claim 1, wherein The above-mentioned first component is a lead component, the above-mentioned second component is a support component, The area of the above-mentioned first bonding layer in the direction along the above-mentioned first surface is smaller than the area of the above-mentioned first surface, The area of the above-mentioned second bonding layer in the direction along the above-mentioned second surface is larger than the area of the above-mentioned second surface.

4. The electronic component according to claim 1, wherein The above-mentioned first component is a lead component, the above-mentioned second component is a support component, The area of the above-mentioned first bonding layer in the direction along the above-mentioned first surface is larger than the area of the above-mentioned first surface, The area of the above-mentioned second bonding layer in the direction along the above-mentioned second surface is smaller than the area of the above-mentioned second surface.

5. The electronic component according to claim 1, wherein The above-mentioned first metal and the above-mentioned second metal each independently contain Ni.

6. The electronic component according to claim 1, wherein The above-mentioned first metal and the above-mentioned second metal each independently contain Au.

7. The electronic component according to claim 1, wherein The above-mentioned electronic component includes a first electrode forming the above-mentioned first surface and a second electrode forming the above-mentioned second surface, The above-mentioned first electrode and the above-mentioned second electrode each have a Ni layer made of Ni or a Ni-based alloy on the above-mentioned first surface and the above-mentioned second surface respectively, The thickness of the above-mentioned Ni layer is 1.5 μm or more and 3.5 μm or less in each of the above-mentioned first electrode and the above-mentioned second electrode.

8. The electronic component according to claim 1, wherein The above-mentioned first component and the above-mentioned second component are each independently composed of at least one of Cu or a Cu-based alloy, The above-mentioned first component and the above-mentioned second component are directly bonded to the above-mentioned first bonding layer and the above-mentioned second bonding layer respectively.

9. The electronic component according to claim 1, wherein The above-mentioned first component and the above-mentioned second component are each independently composed of at least one of Cu or a Cu-based alloy. A plating layer made of Ag is formed on the surfaces of the above-mentioned first component and the above-mentioned second component, respectively.

10. The electronic component according to claim 1, wherein: The above-mentioned first component and the above-mentioned second component are each independently composed of at least one of Cu or a Cu-based alloy. A plating layer made of Ni or a Ni-based alloy is formed on the surfaces of the above-mentioned first component and the above-mentioned second component, respectively.

11. The electronic component according to claim 1, wherein: The above-mentioned first intermetallic compound and the above-mentioned second intermetallic compound each independently mainly contain Ni-Sn.

12. The electronic component according to claim 1, wherein: The above-mentioned first intermetallic compound and the above-mentioned second intermetallic compound each independently mainly contain Au-Sn.

13. The electronic component according to claim 1, wherein: The above-mentioned first metal and the above-mentioned second metal both have a spherical shape. The above-mentioned first metal and the above-mentioned second metal are each independently dispersed into the above-mentioned first bonding layer and the above-mentioned second bonding layer.

14. A method for manufacturing an electronic component, characterized in that, It includes the following steps: A placement step, in which a first sheet containing a first metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn is placed between the first component and the above-mentioned first surface of the electronic component having a first surface and a second surface, and a second sheet containing a second metal that can form an intermetallic compound with Sn and has a melting point higher than 1100°C and Sn is placed between the second component and the above-mentioned second surface. And A heating step, in which, in a state where the first sheet and the second sheet are clamped by the above-mentioned first component, the above-mentioned electronic component, and the above-mentioned second component, at least the first sheet and the second sheet are heated, thereby forming a first bonding layer and a second bonding layer. The first bonding layer joins the first component and the first surface, is composed of the above-mentioned first metal and Sn, and contains, in a proportion of 80% by volume or more, a first intermetallic compound having a melting point as high as 260°C. The second bonding layer joins the second component and the second surface, is composed of the above-mentioned second metal and Sn, and contains, in a proportion of 80% by volume or more, a second intermetallic compound having a melting point higher than 260°C.

15. The method for manufacturing an electronic component according to claim 14, wherein: The above-mentioned first sheet contains Ni as the above-mentioned first metal in a proportion of 15% by mass or more and 30% by mass or less. The above-mentioned second sheet contains Ni as the above-mentioned second metal in a proportion of 15% by mass or more and 30% by mass or less.

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