Zn-Al eutectoid alloy bonding material, bonded body, and method for producing bonded body

Abstract

Disclosed is a Zn-Al eutectoid alloy bonding material that can solve either or both of the technical problems of improving the physical properties of a bonding material and improving the bonding quality of a bonded body, a bonded body formed using the Zn-Al eutectoid alloy bonding material, and a method for manufacturing a bonded body. The Zn-Al eutectoid alloy bonding material comprises a Zn-Al eutectoid alloy that contains Zn and Al as essential components, and is characterized by containing Al in an amount of 25 mass% or more and 28 mass% or less, and the remainder containing Zn and unavoidable impurities.

Description

Technical Field

[0001] This invention relates to ZnAl eutectoid alloy bonding materials, bonding bodies, and methods for manufacturing bonding bodies. Background Technology

[0002] In recent years, devices using SiC and GaN in the semiconductor division have attracted considerable attention, replacing those using Si. SiC and GaN, as semiconductors, exhibit superior properties compared to Si. Devices using Si in the semiconductor division operate at approximately 150°C, while devices using SiC and GaN can operate at temperatures of approximately 200°C to 250°C or higher. Therefore, materials with high melting points are required as bonding materials for devices operating at such high temperatures.

[0003] Lead-containing solders are used as bonding materials in high-temperature environments. However, considering the adverse effects of lead on the environment and health, it is desirable to avoid using lead-containing solders as much as possible. Specifically, in Europe, according to the RoHS Directive, the use of lead-containing solders is prohibited in equipment operating in low-temperature ranges, and lead-free bonding materials that can also be used in equipment operating in high-temperature ranges are required.

[0004] To meet this need, ZnAl eutectoid alloy materials have attracted attention as a bonding material that can replace lead-containing solder, as disclosed in Patent Document 1 below. The ZnAl eutectoid alloy bonding material disclosed in Patent Document 1 is composed of 17wt% to 30wt% Al-0wt% to 1.5wt% Cu-0wt% to 0.5wt% Mg-Zn, and utilizes superplasticity to bond objects.

[0005] The ZnAl eutectoid alloy bonding material disclosed in Patent Document 1 is formed by rapidly cooling a ZnAl eutectoid alloy to refine its grains, then cutting it into a plate shape, and using it as a welding sheet. Furthermore, when bonding the ZnAl eutectoid alloy bonding material disclosed in Patent Document 1 to a bonding object, by applying pressure of 5 MPa to 50 MPa while maintaining a temperature of 200°C to 275°C for a specified time at which the ZnAl eutectoid alloy exhibits superplasticity, thereby ensuring close contact between the bonding object and the ZnAl eutectoid alloy bonding material, the temperature is then raised to 280°C to 410°C to perform diffusion bonding.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2009-113050 Summary of the Invention

[0009] Here, the inventors have conducted in-depth research on bonding materials composed of ZnAl eutectoid alloys. As a result, the inventors discovered a first technical problem: the desire to further improve the physical properties of bonding materials composed of ZnAl eutectoid alloys.

[0010] Furthermore, the inventors have discovered a second technical problem: to further improve the bonding quality when using bonding materials made of ZnAl eutectoid alloys. Specifically, the inventors have discovered a second technical problem: from the viewpoint of bonding quality, it is desirable to further improve the shear strength when using bonding materials made of ZnAl eutectoid alloys, and to improve the amount of bonding material flowing out from the edges of the joined portion during bonding.

[0011] Further research by the inventors has yielded the following insights: Given the recent trend of rapidly increasing mounting density of electronic components such as semiconductor chips, the suppression of outflow, particularly from the perspective of bonding quality, is a technical problem that needs significant improvement in the second technical problem. Specifically, the inventors envisioned using a bonding material made of ZnAl eutectoid alloy as a grain bonding material to fix the die (chip) to the substrate, and conducted in-depth research. It was found that the bonding material made of ZnAl eutectoid alloy melts during bonding and flows out from the outer edge of the chip, potentially causing short circuits between adjacent chips. In particular, when bonding multiple chips, such as power semiconductor chips (5mm x 15mm square) or larger rectangular chips, to a substrate, the spacing between adjacent chips is small, making it crucial to suppress the outflow of the bonding material. Therefore, the inventors discovered the following technical problem: when using a bonding material made of ZnAl eutectoid alloy to bond an object to a substrate, it is desirable to minimize the outflow of the bonding material from the outer edge of the object to bond, thereby improving the bonding quality.

[0012] Therefore, the object of the present invention is to provide a ZnAl eutectoid alloy bonding material capable of solving either or both of the improvement of physical properties as a bonding material and the improvement of bonding quality as addressed in the first technical problem described above, a bond formed using the ZnAl eutectoid alloy bonding material, and a method for manufacturing the bond.

[0013] (A1) The ZnAl eutectoid alloy bonding material of the present invention is a ZnAl eutectoid alloy bonding material comprising Zn and Al as basic components, wherein it contains Al in the range of 25% by mass or more and 28% by mass or less, and the remainder contains Zn and unavoidable impurities.

[0014] (A2) The ZnAl eutectoid alloy bonding material of the present invention preferably contains, as the basic composition, either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

[0015] (A3) The preferred ZnAl eutectoid alloy bonding material of the present invention has a solidus temperature of 450°C or less.

[0016] (A4) The preferred ZnAl eutectoid alloy bonding material of the present invention has a liquidus temperature and solidus temperature difference of 50°C or more and 150°C or less.

[0017] (B1) The joint of the present invention comprises a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, wherein the ZnAl eutectoid alloy bonding material is based on Zn and Al, contains Al in the range of 25% by mass or more and 28% by mass or less, and the remainder contains Zn and unavoidable impurities.

[0018] (B2) Preferably, the ZnAl eutectoid alloy bonding material, as the basic composition, further comprises either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

[0019] (B3) In the joint of the present invention, the joint is formed by joining the object to the substrate via a ZnAl eutectoid alloy bonding material disposed between the substrate and the object to be joined with the substrate. In the joint, the amount of ZnAl eutectoid alloy bonding material overflowing from the outer edge of the object to be joined is preferably 3 mm or less, more preferably 2 mm or less.

[0020] (B4) Preferably, the solidus temperature of the ZnAl eutectoid alloy bonding material is below 450°C.

[0021] (B5) Preferably, the difference between the liquidus temperature and the solidus temperature of the ZnAl eutectoid alloy bonding material is 50°C or more and 150°C or less.

[0022] (C1) The manufacturing method of the joint of the present invention is a method for manufacturing a joint comprising a substrate and a joint comprising a ZnAl eutectoid alloy bonding material, characterized in that: the ZnAl eutectoid alloy bonding material is a ZnAl eutectoid alloy bonding material having Zn and Al as basic components, containing 25% by mass or more and 28% by mass or less of Al, with the remainder containing Zn and unavoidable impurities, and the manufacturing method of the joint includes: a contact improvement step, wherein pressure is applied while the substrate is in contact with the ZnAl eutectoid alloy bonding material in a non-heated state to improve the contact between the substrate and the ZnAl eutectoid alloy bonding material; and a bonding step, wherein the substrate and the bonding material are bonded by heating at a temperature condition that allows the substrate and the ZnAl eutectoid alloy bonding material to be bonded in the contact improvement step.

[0023] (C2) Preferably, the manufacturing method of the joint of the present invention is carried out in an atmosphere with an oxygen concentration of less than 30 ppm.

[0024] (C3) Preferably, in the method for manufacturing the joint of the present invention, the pressure applied to the substrate and the joint material is increased at a rate of less than 1 mm / min during the process of improving the tightness of the joint.

[0025] (C4) Preferably, the manufacturing method of the joint of the present invention includes a preheating treatment in the bonding improvement process, wherein the preheating treatment refers to applying pressure to the substrate and the joint material at a temperature lower than the bonding temperature at which the bonding can be performed in the bonding process.

[0026] (C5) Preferably, in the manufacturing method of the joint of the present invention, when the pressure applied to the substrate and the joint material in the joining process is set as the joining pressure, the pressure applied to the substrate and the joint material in the preheating treatment is a preheating pressure lower than the joining pressure.

[0027] (C6) The preferred method for manufacturing the joint of the present invention includes a heating step after the contact improvement step, wherein the heating step is performed to achieve a temperature condition that enables the joining step to be performed, and wherein the temperature of the atmosphere exposed to the substrate and the joining material is continuously increased in the heating step.

[0028] (C7) Preferably, in the manufacturing method of the joint of the present invention, in a step after the step of improving the tightness, the pressure applied to the substrate and the joint material is reduced during the heating of the substrate and the joint material.

[0029] The aforementioned ZnAl eutectoid alloy bonding material is preferably manufactured by a manufacturing method having some or all of the following characteristics (D1) to (D6).

[0030] (D1) The above-mentioned ZnAl eutectoid alloy bonding material is preferably manufactured using the following manufacturing method, which includes: an alloy ingot making process, which makes an alloy ingot comprising a ZnAl eutectoid alloy; an alloy ingot making process, which makes an alloy ingot from the alloy ingot by machining the alloy ingot made in the alloy ingot making process, wherein the volume of the alloy ingot is determined according to the volume of the ZnAl eutectoid alloy bonding material; a heat treatment process, which heats the alloy ingot in a temperature atmosphere above the solution temperature and below the melting point; and a cooling process, which cools the alloy ingot heated in the heat treatment process.

[0031] (D2) The preferred feature of the manufacturing method of the above-mentioned ZnAl eutectoid alloy bonding material is that the alloy ingot is rolled into an alloy rolled body by rolling the alloy ingot before the heat treatment process.

[0032] (D3) The preferred feature of the manufacturing method of the above-mentioned ZnAl eutectoid alloy bonding material is that it includes a surface grinding process for grinding the surface of the ZnAl eutectoid alloy that is cooled in the cooling process.

[0033] (D4) The preferred feature of the manufacturing method of the above-mentioned ZnAl eutectoid alloy bonding material is that, as a step after the cooling step, a surface coating step is included to coat the surface of the ZnAl eutectoid alloy.

[0034] (D5) A preferred feature of the manufacturing method of the ZnAl eutectoid alloy bonding material of the present invention is that, in the alloy ingot manufacturing process, the alloy ingot is made into a plate shape.

[0035] (D6) A preferred feature of the manufacturing method of the above-mentioned ZnAl eutectoid alloy bonding material is that the ZnAl eutectoid alloy is cooled by water cooling in the cooling process.

[0036] (E1) The ZnAl eutectoid alloy bonding material of the present invention is a ZnAl eutectoid alloy bonding material comprising Zn and Al as basic components, characterized in that it contains 20% by mass or more and 30% by mass of Al, contains at least one additive element selected from the group consisting of Ag, Co, Ge, Mn, Mo, Ni, Sb and V, and the remainder contains Zn and unavoidable impurities.

[0037] (E2) A preferred feature of the ZnAl eutectoid alloy bonding material of the present invention is that the added element is selected from the group consisting of Ge, Mn, Ni and V.

[0038] (F1) The joint of the present invention is characterized in that it has a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, wherein the ZnAl eutectoid alloy bonding material is the ZnAl eutectoid alloy bonding material involved in the present invention described above.

[0039] (F2) The preferred feature of the bonding body of the present invention is that the substrate is a copper substrate or a low-phosphorus nickel-plated substrate.

[0040] (G1) The manufacturing method of the joint of the present invention is a method for manufacturing a joint having a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, characterized in that: the ZnAl eutectoid alloy bonding material according to claim 17 or 18 is used as the ZnAl eutectoid alloy bonding material, and the manufacturing method of the joint includes: a contact improvement step, wherein pressure is applied while the substrate is in contact with the ZnAl eutectoid alloy bonding material to improve the contact between the substrate and the ZnAl eutectoid alloy bonding material; and a joining step, wherein the substrate and the ZnAl eutectoid alloy bonding material are joined by heating at a temperature condition that allows the substrate and the ZnAl eutectoid alloy bonding material to be joined in the contact improvement step.

[0041] (H1) The ZnAl eutectoid alloy bonding material of the present invention comprises a ZnAl eutectoid alloy with Zn and Al as its basic components, characterized in that it contains Ge in the range of 1.0% by mass or more and 5.0% by mass or less, the remainder of which contains Zn and unavoidable impurities, and exhibits a shear strength of 40 MPa or more in bonding at 350°C.

[0042] (H2) The joint of the present invention is a joint using the ZnAl eutectoid alloy joint material described in (H1), characterized in that the substrate is a copper substrate or a nickel-plated substrate.

[0043] (Invention effect)

[0044] According to the present invention, a ZnAl eutectoid alloy bonding material, a bonding body, and a method for manufacturing the bonding body can be provided, which can solve the above-mentioned technical problems. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a method for manufacturing a ZnAl eutectoid alloy bonding material according to one embodiment of the present invention.

[0046] Figure 2 This is an explanatory diagram showing the configuration of a manufacturing apparatus for producing a bonded body using a ZnAl eutectoid alloy bonding material according to one embodiment of the present invention.

[0047] Figure 3 This is a flowchart illustrating a method for manufacturing a bonded body using a ZnAl eutectoid alloy bonding material according to one embodiment of the present invention.

[0048] Figure 4 It is a schematic representation according to Figure 3 The diagram illustrates the changes in temperature and pressure conditions during the fabrication of a bonded body using a ZnAl eutectoid alloy bonding material, as well as the bonding state between the substrate and the ZnAl eutectoid alloy bonding material.

[0049] Figure 5 This is a table relating to the chemical composition, physical properties of the alloy, and bonding properties of the sample involved in Example 1.

[0050] Figure 6 This is an explanatory diagram used to illustrate the method for deriving outflow.

[0051] Figure 7 This is a photograph showing the cross-section of the joint formed by bonding the ZnAl eutectoid alloy bonding material of Sample 6 from Example 1 between oxygen-free copper plates, as observed using a scanning electron microscope.

[0052] Figure 8 (a) and (b) in the text are respectively... Figure 7 An enlarged photograph of the main part.

[0053] Figure 9 This is a photograph showing the results of the outflow characteristic evaluation test conducted in Example 3 using a copper substrate.

[0054] Figure 10 This is a photograph showing the results of the bonding interface state evaluation test conducted in Example 3 with a copper substrate.

[0055] Figure 11 This is a graph showing the results of evaluating the relationship between heating time and shear strength by measuring the shear strength of the ZnAl eutectoid alloy bonding material involved in Example 3 with a copper substrate and a low-phosphorus nickel-plated substrate.

[0056] Figure 12 This is a photograph showing the results of the outflow characteristic evaluation test conducted in Example 3 using a low-phosphorus nickel-plated substrate.

[0057] Figure 13 This is a photograph showing the results of the bonding interface state evaluation test conducted in Example 3 using a low-phosphorus nickel-plated substrate.

[0058] Figure 14 This is a photograph showing the results of the bonding interface state evaluation test conducted in Example 3 using a low-phosphorus nickel-plated substrate.

[0059] (Symbol Explanation)

[0060] 10: Manufacturing equipment

[0061] 20: Main body

[0062] 24: Introduction Section

[0063] 26: Discharge section

[0064] 30: Gas supply source

[0065] 40: Oxygen Concentration Meter

[0066] 50: Pressurization device

[0067] 52: First clamping part

[0068] 54: Second clamping part

[0069] 56: Setting Department

[0070] 60: Heating device

[0071] 62: Fever element

[0072] 64: Fever-generating body

[0073] 66: Temperature measuring instrument

[0074] 68: Heating control device Detailed Implementation

[0075] The following describes a ZnAl eutectoid alloy bonding material, a bonding body, and a method for manufacturing the bonding body according to one embodiment of the present invention.

[0076] On ZnAl Eutectoid Alloy Bonding Materials

[0077] One embodiment of the present invention relates to a ZnAl eutectoid alloy bonding material comprising a ZnAl eutectoid alloy with Zn and Al as its basic components. The ZnAl eutectoid alloy bonding material of this embodiment may, in addition to materials with Zn and Al as their basic components, also include either or both of Cu and Mg as basic components. That is, the ZnAl eutectoid alloy bonding material of this embodiment may be a material with Zn and Al as its basic components, a material with Zn, Al, and Cu as its basic components, a material with Zn, Al, and Mg as its basic components, or a material with Zn, Al, Cu, and Mg as its basic components.

[0078] The ZnAl eutectoid alloy bonding material involved in this embodiment can be optimized in terms of the content (combination amount) of Al, Zn, Cu and Mg as basic components according to the required physical properties and bonding properties.

[0079] Here, assuming that ZnAl eutectoid alloy bonding material is used as a bonding material in various applications, such as grain bonding materials for fixing grains (chips) to substrates, the following physical properties are considered: (α1) solidus temperature, (α2) liquidus temperature, (α3) the difference between the liquidus temperature and the solidus temperature, (α4) maximum load, (α5) strength, (α6) elongation, and (α7) hardness. The solidus temperature is the lower limit of the temperature at which a ZnAl eutectoid alloy changes from a solid to a liquid, and it is an indicator for setting the bonding temperature. The liquidus temperature is the upper limit of the temperature at which a ZnAl eutectoid alloy completely changes from a solid to a liquid, and it is an indicator for appropriately determining the heating temperature during bonding.

[0080] Here, the maximum load of a ZnAl eutectoid alloy bond refers to the maximum force that the ZnAl eutectoid alloy bond can withstand before failure, and is considered an important indicator for evaluating the mechanical strength of the bond. Furthermore, the strength of a ZnAl eutectoid alloy bond represents its resistance to external forces and is an important indicator for judging the durability and reliability of the bond. Elongation represents the rate of increase in the relative length that a ZnAl eutectoid alloy bond can elongate before fracture, and can be used as an indicator of durability relative to deformation, impact, or vibration. Hardness is an indicator of the resistance of a ZnAl eutectoid alloy bond to damage from other objects and is an important indicator for judging the wear resistance and lifespan of the bond.

[0081] When ZnAl eutectoid alloy bonding materials are envisioned as bonding materials, such as those used to fix grains (chips) to substrates, it is preferable that some or all of the above-mentioned physical properties meet the following criteria.

[0082] (α1) Solidus temperature: below 450℃

[0083] (α2) Liquidus temperature: below 540℃

[0084] (α3) The difference between the liquidus temperature and the solidus temperature: above 50℃ and below 150℃

[0085] (α4) Maximum load: 2500 [N] or more

[0086] (α5) Strength: 100 MPa or higher (at room temperature)

[0087] (α6) Elongation: 1% or more

[0088] (α7) Hardness: 10 [Hv] or higher

[0089] Furthermore, when considering the use of ZnAl eutectoid alloy bonding materials as bonding materials for various applications, such as die bonding materials used to fix chips to substrates, characteristics such as (β1) maximum load, (β2) shear strength, and (β3) outflow are considered as bonding properties. Here, maximum load is the maximum force that the joint can withstand before failure, and it is an important indicator for evaluating the durability and reliability of joints formed using ZnAl eutectoid alloy bonding materials. Shear strength indicates the strength of the joint relative to the force per unit area, and it is an important indicator for evaluating the reliability and durability of the joint. In this specification, "shear strength" refers to the bonding strength measured by an lap joint test. Outflow indicates the amount of ZnAl eutectoid alloy bonding material that flows out of the joint during the bonding process. Excessive outflow may lead to a decrease in the mechanical strength of the joint and adverse effects on adjacent components, such as short circuits and mechanical interference. Therefore, by keeping the outflow rate below an appropriate value, the quality and performance of the joint can be optimized, and the overall reliability of the product can be improved.

[0090] When ZnAl eutectoid alloy bonding materials are envisioned as bonding materials, such as those used to fix grains (chips) to a substrate, it is preferable that some or all of the above-mentioned bonding properties meet the following criteria.

[0091] (β1) Maximum load: 1400 [N] or more

[0092] (β2) Shear strength: ≥50 [MPa] (room temperature)

[0093] (β3) Outflow rate: less than 2.00 mm

[0094] ZnAl eutectoid alloy bonding materials can have their basic composition (alloying amount) of Al, Zn, Cu, and Mg optimized to satisfy some or all of the aforementioned physical properties (α1) to (α7) and bonding properties (β1) to (β3). Specifically, if the aim is to lower the aforementioned solidus temperature and liquidus temperature, the ZnAl eutectoid alloy bonding material can contain at least one of Cu and Mg as a basic composition, and can contain either or both of Cu in the range of 2.0 wt% or less and Mg in the range of 2.0 wt% or less. Furthermore, if the aim is to improve the maximum load and strength, which are physical properties of the ZnAl eutectoid alloy bonding material, the ZnAl eutectoid alloy bonding material can have an Al content greater than 22 wt%, and further, can contain 25 wt% or more. Additionally, if the aim is to improve hardness and suppress elongation, the ZnAl eutectoid alloy bonding material can contain not only Al and Zn, but also at least one of Cu and Mg as a basic composition.

[0095] Furthermore, if the purpose is to suppress the outflow of bonding material when bonding the joint object to the substrate, then, under the condition that it contains Al and Zn as a basic component and does not contain Cu and Mg, the ZnAl eutectoid alloy bonding material may contain Al in the range of 22% by mass or more and 28% by mass, preferably 25% by mass or more and 28% by mass. Alternatively, under the condition that, in addition to Al and Zn, it also contains either or both of Cu and Mg as a basic component, the ZnAl eutectoid alloy bonding material may contain Al in the range of 22% by mass or more and less than 28% by mass, and contain Cu and Mg in the range of less than 2.0% by mass, respectively. If the purpose is to improve the maximum load and shear strength when bonding the joint object to the substrate, then the ZnAl eutectoid alloy bonding material may contain Al in the range of 22% by mass or more and less than 28% by mass.

[0096] Manufacturing Method of ZnAl Eutectoid Alloy Bonding Material

[0097] The following describes one embodiment of a method for manufacturing a ZnAl eutectoid alloy bonding material having the above-described characteristics.

[0098] like Figure 1 As shown in the flowchart, the manufacturing method of the ZnAl eutectoid alloy bonding material of this embodiment generally consists of multiple steps, including an alloy ingot manufacturing step, an alloy small ingot manufacturing step, a heat treatment step, a cooling step, a surface oxide film removal step, and a surface coating step. Hereinafter, refer to... Figure 1 The flowchart illustrates step by step the manufacturing method of ZnAl eutectoid alloy bonding materials.

[0099] Alloy Ingot Manufacturing Process

[0100] In the manufacturing method of the ZnAl eutectoid alloy bonding material of this embodiment, firstly, in the alloy ingot manufacturing process of step 1-1, an alloy ingot containing a ZnAl eutectoid alloy is manufactured. The alloy ingot containing the ZnAl eutectoid alloy can be manufactured as follows: for example, raw materials containing Al, Zn, Cu, and Mg as basic components are prepared in a specified ratio. Furthermore, the prepared raw materials of the ZnAl eutectoid alloy bonding material are placed in a crucible or sagger in a melting furnace such as a high-frequency melting furnace, melted under an inert gas atmosphere such as argon or nitrogen, and then cast into a mold or the like in the atmosphere, thereby manufacturing the alloy ingot.

[0101] Alloy ingots containing ZnAl eutectoid alloys can have specific shapes such as plates, cuboids, cubes, and spheres, or unspecified shapes. In the manufacturing method of the ZnAl eutectoid alloy bonding material of this embodiment, from the viewpoint of ease of processing in processes following the alloy ingot manufacturing process and ensuring the stability of quality, the alloy ingot manufacturing process can produce alloy ingots containing ZnAl eutectoid alloys into plates with a predetermined thickness.

[0102] Alloy Ingot Manufacturing Process

[0103] When an alloy ingot containing a ZnAl eutectoid alloy is prepared in the alloy ingot manufacturing process described in step 1-1 above, the manufacturing process proceeds to the alloy ingot manufacturing process in step 1-2. The alloy ingot manufacturing process involves machining the alloy ingot produced in the alloy ingot manufacturing process to create an alloy ingot. The volume of this alloy ingot is determined based on the volume of the ZnAl eutectoid alloy bonding material ultimately obtained from the alloy ingot. When the alloy ingot containing the ZnAl eutectoid alloy is made into a plate with a predetermined thickness in the alloy ingot manufacturing process described above, alloy ingots of a predetermined volume can be easily and stably manufactured by determining the longitudinal and transverse lengths in a manner that results in a predetermined area and then performing cutting.

[0104] Heat Treatment Process

[0105] When an alloy ingot containing a ZnAl eutectoid alloy is prepared in the alloy ingot manufacturing process described in steps 1-2 above, the manufacturing process proceeds to the heat treatment process in steps 1-3. The heat treatment process involves heating the alloy ingot in a temperature atmosphere above the solution temperature but below the melting point. The heat treatment process can be a process of heating the alloy ingot containing the ZnAl eutectoid alloy at atmospheric pressure, but it can also be a process of producing an alloy rolled body by pressure rolling in addition to heating the alloy ingot containing the ZnAl eutectoid alloy.

[0106] Cooling Process

[0107] When the alloy ingot containing the ZnAl eutectoid alloy is heated and rolled in the heat treatment processes involved in steps 1-3 above, the manufacturing process proceeds to the cooling process in steps 1-4. The cooling process is the process of cooling the alloy ingot and alloy rolled body that were heated in the heat treatment process. The cooling of the alloy ingot and alloy rolled body in the cooling process can be achieved through various methods, such as furnace cooling within the heating furnace used in the heat treatment process, air cooling after removal from the heating furnace, natural cooling under a unique gas atmosphere outside the heating furnace, and cooling using water or liquid nitrogen as a coolant. Considering that water is a coolant with high thermal conductivity and specific heat, the cooling of the alloy rolled body can be achieved by water cooling using water as the coolant.

[0108] Surface Oxide Layer Removal Process

[0109] When the cooling of the ZnAl eutectoid alloy is completed in the cooling processes described in steps 1-4 above, the manufacturing process proceeds to the surface oxide layer removal process in steps 1-5. The surface oxide layer removal process removes the oxide film covering the surface of the ZnAl eutectoid alloy that was cooled in the cooling process. This can be performed using methods such as grinding to remove the oxide film from the surface of the ZnAl eutectoid alloy. The surface oxide layer removal process only needs to remove the oxide layer located on the surface of the ZnAl eutectoid alloy. For example, mechanical methods such as mechanical grinding or chemical methods such as using high-temperature hydrogen or reducing agents can be appropriately used to remove the surface oxide layer.

[0110] Surface Coating Process

[0111] When the surface grinding of the ZnAl eutectoid alloy is completed in the surface grinding process described in steps 1-5 above, the manufacturing process proceeds to the surface coating process in steps 1-6. The surface coating process involves coating the surface of the ZnAl eutectoid alloy, after the surface oxide film has been removed in the surface oxide film removal process, with another substance to inhibit oxidation of the ZnAl eutectoid alloy surface. The coating material used to coat the ZnAl eutectoid alloy surface in the surface coating process can be a substance whose adhesion and durability to the ZnAl eutectoid alloy, conductivity when used as a bonding material for the ZnAl eutectoid alloy, bonding characteristics, and ease of use do not exceed permissible limits and cause adverse effects. From this perspective, the coating material used in the surface coating process can be, for example, composed of metals such as gold, silver, copper, platinum, and nickel, or conductive non-metals. Furthermore, the surface coating process can use evaporation methods such as vacuum evaporation, CVD, and EVD, or methods such as plating and sputtering, and utilizes a coating material to coat the surface of the ZnAl eutectoid alloy containing the ZnAl eutectoid alloy.

[0112] The ZnAl eutectoid alloy bonding material manufactured by the above-described method can form a bonded body comprising a specified substrate and a bonding portion, wherein the bonding portion is composed of the ZnAl eutectoid alloy bonding material. The formation (bonding) of a bonded body using the above-described ZnAl eutectoid alloy bonding material can be achieved by the following method for manufacturing the bonded body. The method for manufacturing a bonded body using the ZnAl eutectoid alloy bonding material will be described in further detail below.

[0113] Method for manufacturing joints using ZnAl eutectoid alloy bonding materials

[0114] The following describes a method for manufacturing a joint using a ZnAl eutectoid alloy bonding material according to this embodiment. A joint using a ZnAl eutectoid alloy bonding material can, for example, be manufactured by using... Figure 2 The manufacturing apparatus 10 shown is used for manufacturing. Specifically, the manufacturing apparatus 10 has a hollow main body 20.

[0115] An inlet section 24 and an outlet section 26 are connected to the main body 20 via piping. A gas supply source 30 for supplying inert gases such as nitrogen and argon is connected to the inlet section 24. An oxygen concentration measuring instrument 40 is connected to the outlet section 26. Thus, the manufacturing apparatus 10 can simultaneously supply inert gas from the inlet section 24 and discharge gas present inside the main body 20 from the outlet section 26, thereby replacing the interior of the main body 20 with inert gas.

[0116] A pressurizing device 50 is provided inside the main body 20. The pressurizing device 50 includes a first clamping part 52 and a second clamping part 54 that are arranged opposite to each other and are movable relative to each other. In this embodiment, the first clamping part 52 is connected to a power source (not shown), and the first clamping part 52 is movable relative to the second clamping part 54 in a moving direction and a moving direction. In the pressurizing device 50, the area between the first clamping part 52 and the second clamping part 54 is a setting part 56 for setting a substrate and a ZnAl eutectoid alloy bonding material. By bringing the first clamping part 52 and the second clamping part 54 closer together, the pressurizing device 50 can pressurize the substrate and the ZnAl eutectoid alloy bonding material set in the setting part 56 located between them. In addition, the pressurizing device 50 can control the operation of the power source using a pressurizing control device (not shown), thereby controlling the magnitude and rate of increase or decrease of the pressure applied to the substrate and the ZnAl eutectoid alloy bonding material set in the setting part 56.

[0117] Additionally, the manufacturing apparatus 10 includes a heating device 60 for heating the substrate and the ZnAl eutectoid alloy bonding material disposed in the setting section 56 of the pressurizing device 50. In the illustrated example, the heating elements 62 and 64, built into the first clamping section 52 and the second clamping section 54, function as the heating device 60. The heating device 60 includes a temperature measuring instrument 66, such as a thermocouple, and a heating control device 68. The temperature measuring instrument 66 can directly or indirectly measure the temperature of the substrate and the ZnAl eutectoid alloy bonding material disposed in the setting section 56. By controlling the heating of the heating elements 62 and 64 (electrical control) according to the temperature of the substrate and the ZnAl eutectoid alloy bonding material measured by the temperature measuring instrument 66, the heating device 60 can heat the substrate and the ZnAl eutectoid alloy bonding material under predetermined conditions.

[0118] The method for manufacturing a bonded body using a ZnAl eutectoid alloy bonding material in this embodiment can be performed by pressing and heating the substrate and the ZnAl eutectoid alloy bonding material simultaneously, as described in the manufacturing apparatus 10 above, thereby manufacturing a bonded body. Figure 3 As shown in the flowchart, the manufacturing method of this embodiment can be implemented through multiple steps, including a process for setting up the mating object, a process for reducing oxygen concentration, a process for increasing the tightness of the seal, a process for heating, and a process for joining. Furthermore, the manufacturing method of this embodiment can be achieved through methods such as... Figure 4 This is achieved by changing the temperature and applying pressure, as shown. The following is based on... Figure 3 The flowchart illustrates step-by-step the manufacturing method of the joint using ZnAl eutectoid alloy bonding material.

[0119] Setting up the mating objects

[0120] In the manufacturing method of the joint using ZnAl eutectoid alloy bonding material in this embodiment, the joint object is first set in the joint object setting step 2-1. When using... Figure 2 In the case of the manufacturing apparatus 10 shown, the bonding object, including the substrate and the ZnAl eutectoid alloy bonding material, is disposed on the setting part 56 of the pressure device 50 in such a way that the first clamping part 52 and the second clamping part 54 are close to or far apart.

[0121] Oxygen Concentration Reduction Process

[0122] When the joining object setting process is completed in the above-mentioned joining object setting process, the manufacturing process proceeds to the oxygen concentration reduction process in step 2-2. In the oxygen concentration reduction process, a treatment is performed to reduce the oxygen concentration in the area where the joining object is set. In use... Figure 2 In the case of the manufacturing apparatus 10 shown, while using an oxygen concentration meter 40 to confirm the residual oxygen concentration inside the main body 20 where the object to be joined is disposed, an inert gas such as nitrogen or argon is supplied from a gas supply source 30 via an inlet 24. As a result, the air present inside the main body 20 is replaced by the inert gas, and the oxygen concentration in the area where the object to be joined is disposed is reduced to below a predetermined value (e.g., below 30 ppm).

[0123] Process for Improving Sealing Density

[0124] When the oxygen concentration in the area where the bonding object is located is sufficiently reduced during the oxygen concentration reduction process described above, the manufacturing process proceeds to the adhesion improvement process in steps 2-3. In the adhesion improvement process, pressure is applied while the substrate is in contact with the ZnAl eutectoid alloy bonding material, thereby improving the adhesion between the substrate and the ZnAl eutectoid alloy bonding material. In use... Figure 2 In the case of the manufacturing apparatus 10 shown, after the substrate and the ZnAl eutectoid alloy bonding material are arranged on the setting part 56 of the pressure device 50 in such a way that the first clamping part 52 and the second clamping part 54 are close to or far away from each other, the substrate and the ZnAl eutectoid alloy bonding material are clamped by the first clamping part 52 and the second clamping part 54 constituting the pressure device 50.

[0125] Here, in the process of improving the adhesion, the temperature and pressure conditions of the substrate and the ZnAl eutectoid alloy bonding material can be optimized to improve the adhesion between the substrate and the ZnAl eutectoid alloy bonding material. Specifically, the adhesion improvement process can, for example, apply pressure while the substrate and the ZnAl eutectoid alloy bonding material are in contact without heating (at room temperature), however, as... Figure 4As shown, heating and pressurization can be performed simultaneously at a temperature range that is lower than the bonding temperature (or the heating start temperature in the heating process described later) and higher than the unheated state (room temperature) (hereinafter also referred to as the "bonding improvement temperature range"), or at a specified temperature within the bonding improvement temperature range (hereinafter also referred to as the "bonding improvement temperature"). Specifically, the bonding improvement process can be performed by heating within a temperature range that is lower than the bonding temperature (or the heating start temperature in the heating process described later) and higher than the unheated state (room temperature), i.e., a temperature range of 100°C to 150°C, while applying pressure with a relatively light load (e.g., less than 1 [MPa]), thereby achieving a tight bond between the ZnAl eutectoid alloy bonding material and the substrate in a softened state.

[0126] Furthermore, the pressure applied to the substrate and the ZnAl eutectoid alloy bonding material can be increased at a rate below a predetermined upper limit of pressure. The upper limit of pressure can be appropriately set, for example, as a value determined experimentally or derived through calculation based on a predetermined formula. Based on the examination in the embodiments described later, the upper limit of pressure can be 1 [mm / min] or less. In this embodiment, the adhesion improvement process increases the adhesion between the substrate and the ZnAl eutectoid alloy bonding material by increasing the pressure applied to the substrate and the ZnAl eutectoid alloy bonding material at a rate below 1 [mm / min]. This minimizes the gap between the substrate and the ZnAl eutectoid alloy bonding material and suppresses the amount of oxygen present between them to a minimum. Additionally, in cases where, as described above, pressure is applied while heating the ZnAl eutectoid alloy bonding material to soften it within the adhesion improvement temperature range or at the adhesion improvement temperature, pressure can be applied as follows... Figure 4 As shown in the example, the pressure increase is stopped for a specified time within the temperature range of increased contact density or at the temperature of increased contact density, or the rate of pressure increase is lower than the rate of increase under temperature conditions outside the temperature range of increased contact density.

[0127] Furthermore, in the bonding strength improvement process, by increasing the pressure applied to the substrate and the ZnAl eutectoid alloy bonding material to a predetermined set pressure, a sufficient bond is achieved between the substrate and the ZnAl eutectoid alloy bonding material. Here, the set pressure in the bonding strength improvement process can be appropriately set, for example, to a value determined experimentally or derived through calculation using a predetermined formula. For example, referring to the embodiments described later, it can be set to 0.005 [mm / min] or less. Specifically, the lower limit of the set pressure in the bonding strength improvement process can be set to a pressure of 3 [MPa] or more. Furthermore, the upper limit of the set pressure in the bonding strength improvement process can be set, for example, taking into account the strength of the substrate being bonded using the ZnAl eutectoid alloy bonding material, or the bonding object such as a semiconductor component.

[0128] Heating Process

[0129] When the adhesion improvement process described in steps 2-3 above reaches a state where the adhesion between the substrate and the ZnAl eutectoid alloy bonding material has been improved, the manufacturing process proceeds to the heating process in steps 2-4. The heating process involves raising the temperature of the atmosphere exposed to the bonding objects, including the substrate and the ZnAl eutectoid alloy bonding material, from a non-heated state (room temperature) to a temperature condition suitable for bonding in the subsequent bonding process. For example, when the ZnAl eutectoid alloy bonding material contains ZnAl eutectoid alloy as its main component, bonding can be performed at around 395°C via diffusion bonding or similar methods. Therefore, the heating process raises the atmosphere temperature to a target temperature of 395°C or higher. The target temperature in the heating process can be set to a temperature higher than or equal to the temperature at which bonding can be performed using the ZnAl eutectoid alloy bonding material. Furthermore, the target temperature can be set taking into account errors caused by the characteristics of the manufacturing apparatus 10, the bonding environment, etc.

[0130] In the heating process, the temperature of the atmosphere exposed to the substrate and the ZnAl eutectoid alloy bonding material is continuously increased. During this heating process, the target temperature can be rapidly reached without slowing down the heating rate within the 200°C–275°C temperature range disclosed in Patent Document 1, where the ZnAl eutectoid alloy exhibits superplasticity.

[0131] Joining Process

[0132] When the temperature of the atmosphere exposed to the substrate and the ZnAl eutectoid alloy bonding material is raised to a temperature sufficient to bond the substrate and the ZnAl eutectoid alloy bonding material during the heating process described in steps 2-4 above, the manufacturing process proceeds to the bonding process in steps 2-5. The bonding process involves maintaining the substrate and bonding material at the temperature at which they were bonded in the adhesion enhancement process using the ZnAl eutectoid alloy bonding material for a predetermined holding time, thereby bonding the substrate and the bonding material. In the bonding process, the bonding temperature is maintained while the pressure applied to the substrate and bonding material in the adhesion enhancement process is maintained, and bonding is performed. The holding time in the bonding process can be appropriately set, for example, to a value determined experimentally or derived through calculation based on a prescribed formula.

[0133] The ZnAl eutectoid alloy bonding material, the method for manufacturing the ZnAl eutectoid alloy bonding material, the bond, and the method for manufacturing the bond illustrated in this embodiment of the present invention have the following features. Therefore, the unique effects described below can be achieved.

[0134] (a1) The ZnAl eutectoid alloy bonding material of this embodiment is a ZnAl eutectoid alloy bonding material composed of Zn and Al as basic components, characterized in that it contains Al in the range of 25% by mass or more and 28% by mass or less, and the remainder contains Zn and unavoidable impurities.

[0135] By employing the above-described (a1) configuration, the ZnAl eutectoid alloy bonding material of this embodiment can achieve either or both improvements in the physical properties of the bonding material and improvements in the bonding quality.

[0136] (a2) The ZnAl eutectoid alloy bonding material of this embodiment is characterized in that, as the basic composition, it further comprises either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

[0137] By employing the configuration described in (a2) above, the ZnAl eutectoid alloy bonding material of this embodiment can achieve either or both improvements in the physical properties of the bonding material and improvements in the bonding quality.

[0138] (a3) The ZnAl eutectoid alloy bonding material of this embodiment is characterized in that the solidus temperature is below 450°C.

[0139] The ZnAl eutectoid alloy bonding material of this embodiment, by adopting the above-described (a3) ​​configuration, can be bonded at a bonding temperature set based on a solidus temperature of 450°C or below.

[0140] (a4) The ZnAl eutectoid alloy bonding material of this embodiment is characterized in that the difference between the liquidus temperature and the solidus temperature is 50°C or more and 150°C or less.

[0141] The ZnAl eutectoid alloy bonding material of this embodiment exists in a paste or semi-solid state within the temperature range between the liquidus temperature and the solidus temperature, exhibiting fluidity while maintaining an appropriate viscosity. In this state, the ZnAl eutectoid alloy bonding material spreads substantially uniformly across the bonding surface, thereby achieving a high-quality bond. As shown in (a4) above, the difference between the liquidus temperature and the solidus temperature of the ZnAl eutectoid alloy bonding material of this embodiment is 50°C or more and 150°C or less. Therefore, even if there are some temperature changes during bonding, it can spread substantially uniformly across the bonding surface, achieving a high-quality bond.

[0142] (b1) The joint body of this embodiment is characterized in that it has a substrate and a joint portion, the joint portion being composed of a ZnAl eutectoid alloy bonding material, the ZnAl eutectoid alloy bonding material being composed of Zn and Al as basic components, containing Al in the range of 25% by mass or more and 28% by mass or less, the remainder containing Zn and unavoidable impurities.

[0143] By adopting the configuration described in (b1) above, the joint of this embodiment can achieve either or both of the improvement of physical properties in the joint and the improvement of joint quality.

[0144] (b2) The joint of this embodiment is characterized in that the ZnAl eutectoid alloy bonding material, as the basic composition, further comprises either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

[0145] By adopting the configuration described in (b2) above, the joint of this embodiment can achieve either or both of the improvement of physical properties in the joint and the improvement of joint quality.

[0146] (b3) The joint body of this embodiment is formed as follows: the joint is formed by joining the joint object to the substrate via the ZnAl eutectoid alloy bonding material disposed between the substrate and the joint object to be joined to the substrate, wherein the amount of ZnAl eutectoid alloy bonding material overflowing from the outer edge of the joint object in the joint is preferably 3 [mm] or less, more preferably 2 [mm] or less.

[0147] By employing the configuration described in (b3) above, the joint of this embodiment can suppress adverse effects such as reduced mechanical strength of the joint due to excessive outflow, and short circuits and mechanical interference to adjacent components. Therefore, the joint of this embodiment optimizes the quality and performance of the joint, thereby improving the overall reliability of the product.

[0148] (b4) The joint of this embodiment is characterized in that the solidus temperature of the ZnAl eutectoid alloy joint material is below 450°C.

[0149] By employing the configuration described in (b4) above, the joint of this embodiment can be joined at a joining temperature set based on a solidus temperature of 450°C or below.

[0150] (b5) The joint of this embodiment is characterized in that the difference between the liquidus temperature and the solidus temperature of the ZnAl eutectoid alloy joint material is 50°C or more and 150°C or less.

[0151] By employing the configuration described above (b5), the joint of this embodiment can expand approximately uniformly on the joint surface even when the temperature changes during the jointing process, thereby enabling high-quality jointing in the joint.

[0152] (c1) The manufacturing method of the joint body in this embodiment is a method for manufacturing a joint body having a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material. The manufacturing method of the joint body is characterized in that, as the ZnAl eutectoid alloy bonding material, a ZnAl eutectoid alloy bonding material is used, which has Zn and Al as basic components, contains Al in the range of 25% by mass or more and 28% by mass or less, and the remainder contains Zn and unavoidable impurities. Furthermore, the manufacturing method of the joint body includes: a contact improvement step, which improves the contact between the substrate and the ZnAl eutectoid alloy bonding material by applying pressure while contacting the substrate with the ZnAl eutectoid alloy bonding material; and a bonding step, which bonds the substrate and the bonding material by heating at a temperature condition that allows the substrate and the ZnAl eutectoid alloy bonding material to be bonded in the contact improvement step.

[0153] The method for manufacturing the joint in this embodiment uses the aforementioned ZnAl eutectoid alloy bonding material. Therefore, the method for manufacturing the joint in this embodiment can produce a joint that achieves either or both of improved physical properties of the joint and improved bonding quality.

[0154] (c2) The method for manufacturing the joint in this embodiment is characterized in that at least the joining process is carried out in an atmosphere with an oxygen concentration of 30 ppm or less.

[0155] The manufacturing method of the joint in this embodiment, by performing it as described in (c2) above, can suppress the oxidation of the ZnAl eutectoid alloy joint material and suppress the decrease in shear strength caused by the oxidation of the ZnAl eutectoid alloy joint material.

[0156] (c3) The manufacturing method of the joint in this embodiment is characterized in that, in the process of improving the tightness, the pressure applied to the substrate and the joint material is increased at a rate of less than 1 [mm / min].

[0157] The method for manufacturing the bond in this embodiment, performed as described in (c3) above, can reduce the yield stress of the ZnAl eutectoid alloy bonding material. Therefore, the method for manufacturing the bond in this embodiment can both suppress the pressure required for bonding and further improve the shear strength.

[0158] (c4) The manufacturing method of the joint in this embodiment is characterized in that a preheating treatment is performed in the bonding improvement process, wherein the preheating treatment refers to applying pressure to the substrate and the joint material at a temperature lower than the bonding temperature at which the bonding can be performed in the bonding process and higher than the ambient temperature.

[0159] The manufacturing method of the bond in this embodiment is carried out as described in (c4). In the bonding improvement step, by heating and pressurizing at a temperature below the bonding temperature but above room temperature, the ZnAl eutectoid alloy bonding material can be bonded to the substrate in a softened state. As a result, the bonding strength between the substrate and the ZnAl eutectoid alloy bonding material is further improved, which helps to further improve the bonding quality.

[0160] (c5) The manufacturing method of the joint in this embodiment is characterized in that, when the pressure applied to the substrate and the joint material in the joining process is set as the joining pressure, the pressure applied to the substrate and the joint material in the preheating treatment is a preheating pressure lower than the joining pressure.

[0161] The method for manufacturing the joint in this embodiment, performed as described in (c5), allows for heating while applying pressure under conditions that do not become excessively high during the adhesion improvement process. Therefore, the method for manufacturing the joint in this embodiment enables the bonding material to fully adhere to the substrate during the adhesion improvement process, thus contributing to improved bonding quality.

[0162] (c6) The manufacturing method of the joint in this embodiment is characterized by a heating step after the contact improvement step, wherein the heating step is performed to raise the temperature to a temperature condition that enables the joining to be performed in the joining step, and wherein the temperature of the atmosphere exposed to the substrate and the joining material is continuously raised in the heating step.

[0163] The manufacturing method of the joint in this embodiment is carried out as described above (c6), which, for example, can shorten the time until the joining process compared to the case where the holding period is set in the temperature range in which the ZnAl eutectoid alloy exhibits superplasticity for a specified time, as described in the prior art.

[0164] (c7) The manufacturing method of the joint in this embodiment is characterized in that, in the process after the contact improvement process, the pressure applied to the substrate and the joint material is reduced during the heating of the substrate and the joint material.

[0165] The manufacturing method of the joint in this embodiment is carried out as described above (c7), for example, it is possible to manufacture a high-value joint that ensures sufficient shear strength while minimizing deformation of the substrate.

[0166] (d1) The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment is characterized by comprising: an alloy ingot manufacturing step, wherein an alloy ingot comprising a ZnAl eutectoid alloy is manufactured; an alloy ingot manufacturing step, wherein an alloy ingot is manufactured from the alloy ingot by machining the alloy ingot manufactured in the alloy ingot manufacturing step, wherein the volume of the alloy ingot is determined according to the volume of the ZnAl eutectoid alloy bonding material; a heat treatment step, wherein the alloy ingot is heated in a temperature atmosphere above the solution temperature and below the melting point; and a cooling step, wherein the alloy ingot heated in the heat treatment step is cooled.

[0167] The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, having the characteristics described above (d1), can reduce the grain size of the ZnAl eutectoid alloy. This, in turn, reduces the yield stress of the ZnAl eutectoid alloy bonding material. Therefore, according to the method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, the pressure required for bonding using this ZnAl eutectoid alloy bonding material can be suppressed.

[0168] (d2) The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment can be achieved by rolling the alloy ingot into an alloy rolled body. The rolling temperature can be maintained at room temperature or heated.

[0169] The manufacturing method of the ZnAl eutectoid alloy bond exemplified in this embodiment is carried out as described in (d2) above, in which a very thin alloy rolled body for the bond material is formed from an alloy ingot during the heat treatment process. This increases the surface area to volume ratio and maximizes the cooling rate in the subsequent cooling process. As a result, the grain size of the ZnAl eutectoid alloy can be further refined, reducing the yield stress of the ZnAl eutectoid alloy bond. It is expected to exhibit superplasticity even at room temperature, forming a state that allows for easy deformation. In other words, the ZnAl eutectoid alloy bond can exhibit greater deformation capacity at room temperature.

[0170] (d3) The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, as described above, may include a step of removing the oxide layer from the surface of the ZnAl eutectoid alloy that has been cooled in the cooling process. The step of removing the surface oxide layer may be simply mechanically grinding the surface or using high-temperature hydrogen, a reducing agent, or the like.

[0171] The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, when performed as described in (d3) above, can suppress the reduction in shear strength caused by oxidation of the surface of the ZnAl eutectoid alloy.

[0172] (d4) The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, as described above, may include a surface coating process for coating the surface of the ZnAl eutectoid alloy as a process following the cooling process.

[0173] The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment is carried out as described above (d4). By utilizing the coating layer formed through the surface coating process, the oxidation of the ZnAl eutectoid alloy surface can be suppressed, and the shear strength can be suppressed from decreasing due to surface oxidation.

[0174] (d5) The method for manufacturing ZnAl eutectoid alloy bonding material illustrated in this embodiment is characterized in that, as described above, the alloy ingot is made into a very thin plate shape during the alloy ingot manufacturing process.

[0175] The method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, when performed as described above (d5), enables the formation of an alloy ingot with an extremely high surface area to volume ratio. Therefore, even during the alloy ingot manufacturing process, the grain size of the ZnAl eutectoid alloy can be made very small.

[0176] (d6) The method for manufacturing ZnAl eutectoid alloy bonding material illustrated in this embodiment is characterized in that, as described above, the cooling process cools the ZnAl eutectoid alloy by water cooling.

[0177] Water is a refrigerant characterized by its extremely high latent heat of vaporization and high specific heat. In particular, the latent heat of vaporization of water is about 11 times that of liquid nitrogen, and it carries away a large amount of heat during cooling, thus contributing significantly to the cooling effect. In addition, the thermal conductivity of water is about 5 times that of liquid nitrogen, participating in heat transfer. Therefore, the method for manufacturing the ZnAl eutectoid alloy bonding material illustrated in this embodiment, when carried out as described above (d6), achieves higher cooling efficiency and can reduce the grain size of the ZnAl eutectoid alloy compared to using other refrigerants in the cooling process.

[0178] (e1) The ZnAl eutectoid alloy bonding material of the present invention is a ZnAl eutectoid alloy bonding material comprising Zn and Al as basic components, characterized in that it contains 20% by mass or more and 30% by mass of Al, contains at least one additive element selected from the group consisting of Ag, Co, Ge, Mn, Mo, Ni, Sb and V, and the remainder contains Zn and unavoidable impurities.

[0179] The ZnAl eutectoid alloy bonding material of the present invention, by employing the structure described in (e1) above, significantly improves bonding characteristics such as shear strength and fluidity compared to existing ZnAl eutectoid alloy bonding materials. In particular, by setting the Al content to a range of 20% by mass or more and 30% by mass or less, the ZnAl eutectoid alloy bonding material of the present invention maximizes the properties of the ZnAl eutectoid alloy while effectively activating the effects of the additive elements. Furthermore, by containing at least one additive element selected from the group consisting of Ag, Co, Ge, Mn, Mo, Ni, Sb, and V in a range of 0.001% by mass or more and 2.0% by mass or less, the bonding characteristics can be improved by utilizing the properties of each additive element. Therefore, the ZnAl eutectoid alloy bonding material of the present invention provides a high-performance ZnAl eutectoid alloy bonding material that can cope with various substrates and bonding conditions.

[0180] (e2) The ZnAl eutectoid alloy bonding material of the present invention is characterized in that the added element is selected from the group consisting of Ge, Mn, Ni and V.

[0181] The ZnAl eutectoid alloy bonding material of the present invention, by employing the composition described above (e2), achieves particularly excellent bonding properties. It has been confirmed that Ge, Mn, Ni, and V, when added to ZnAl eutectoid alloys, exhibit particularly high effectiveness in improving shear strength, suppressing outflow, and inhibiting the formation of Kirkendal voids. By selectively adding these elements, high shear strength and stable bonding interfaces can be achieved for both copper substrates and low-phosphorus nickel-plated substrates. Furthermore, these elements are also excellent in terms of environmental safety and availability; therefore, from a practical point of view, this provides a very useful bonding material.

[0182] (f1) The joint of the present invention is characterized in that it has a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, wherein the ZnAl eutectoid alloy bonding material is the ZnAl eutectoid alloy bonding material of the present invention.

[0183] The joint of the present invention, by employing the configuration described above (f1), achieves a joint with high shear strength and excellent reliability. By using the ZnAl eutectoid alloy bonding material described above, the shear strength of the joint is significantly improved, and the stability of the bonding interface is also enhanced. Therefore, the joint of the present invention can maintain stable performance over a long period under various operating environments. Furthermore, compared to conventional joints, the joint of the present invention can be bonded at lower temperatures, thus also having the advantage of being suitable for bonding components that are not heat-resistant.

[0184] (f2) The bonding body of the present invention is characterized in that the substrate is a copper substrate or a low-phosphorus nickel-plated substrate.

[0185] The joint of the present invention, by employing the configuration described above (f2), exhibits particularly superior bonding characteristics. The copper substrate or low-phosphorus nickel-plated substrate has the following characteristics: good compatibility with the ZnAl eutectoid alloy bonding material, facilitating the formation of a stable bonding interface. It has been confirmed that the ZnAl eutectoid alloy bonding material of the present invention exhibits particularly high shear strength relative to these substrates, effectively suppressing the formation of Kirkendal voids at the bonding interface. Therefore, according to the present invention, a particularly useful joint can be provided in fields requiring high reliability, such as electronic components and automotive components.

[0186] (g1) The manufacturing method of the joint of the present invention is a method for manufacturing a joint having a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, characterized in that the ZnAl eutectoid alloy bonding material as described in claim 17 or 18 is used as the ZnAl eutectoid alloy bonding material, and the manufacturing method of the joint includes: a contact improvement step, wherein pressure is applied while the substrate is in contact with the ZnAl eutectoid alloy bonding material to improve the contact between the substrate and the ZnAl eutectoid alloy bonding material; and a bonding step, wherein the substrate and the ZnAl eutectoid alloy bonding material are bonded by heating at a temperature condition that allows the substrate and the ZnAl eutectoid alloy bonding material to be bonded in the contact improvement step.

[0187] The method for manufacturing the bonded body of the present invention, by employing the configuration described in (g1) above, enables the stable manufacture of high-quality bonded bodies. By incorporating a contact improvement process, the adhesion between the bonding material and the substrate is enhanced, enabling improved shear strength and stabilization of the bonding interface in subsequent bonding processes. Furthermore, compared to conventional bonding materials, the ZnAl eutectoid alloy bonding material of the present invention can be bonded at low temperatures, thus minimizing the thermal impact during the bonding process. Consequently, the method for manufacturing the bonded body of the present invention enables the manufacture of bonded bodies using heat-sensitive components, reduces energy consumption in the manufacturing process, and also contributes to reducing environmental impact.

[0188] (h1) The ZnAl eutectoid alloy bonding material of the present invention is composed of a ZnAl eutectoid alloy with Zn and Al as the basic components, characterized in that it contains Ge in the range of 1.0% by mass or more and 5.0% by mass or less, the remainder of which contains Zn and unavoidable impurities, and exhibits a shear strength of 40 MPa or more in bonding at 350°C.

[0189] The ZnAl eutectoid alloy bonding material of the present invention (h1) is based on Zn and Al, and contains Ge in the range of 1.0% by mass or more and 5.0% by mass or less, thereby achieving particularly high shear strength. Specifically, as illustrated in the examples described later, the ZnAl eutectoid alloy bonding material of the present invention (h1) can exhibit a shear strength of more than 40 MPa even when bonded at a low temperature such as 350°C. Thus, the ZnAl eutectoid alloy bonding material of the present invention (h1) achieves reliable shear strength even when bonded at a low temperature. Furthermore, as illustrated in the examples described later, the ZnAl eutectoid alloy bonding material of the present invention (h1) can achieve sufficient shear strength even in short-time bonding such as 90 seconds. This is very helpful in improving the productivity of bonding processes using the ZnAl eutectoid alloy bonding material of the present invention (h1).

[0190] (h2) The joint of the present invention is a joint using the ZnAl eutectoid alloy joint material described in (h1), characterized in that the substrate is a copper substrate or a nickel-plated substrate.

[0191] The joint according to (h2) of the present invention uses the ZnAl eutectoid alloy bonding material described in (h1) and achieves particularly high shear strength by using a copper substrate or a nickel-plated substrate as the base material. Specifically, as illustrated in the embodiments described later, the joint according to (h2) of the present invention achieves a shear strength exceeding 40 MPa in bonding at 350°C when using a copper substrate as the base material. Furthermore, as illustrated in the embodiments described later, even when using a nickel-plated substrate as the base material, a shear strength exceeding 50 MPa can be stably obtained in bonding at 400°C. Thus, the joint according to (h2) of the present invention can achieve high shear strength regardless of the type of base material and can be appropriately used as a practical joint. In addition, the nickel-plated substrate includes at least a low-phosphorus nickel-plated substrate and a medium-phosphorus nickel-plated substrate.

[0192] This invention is not limited to the embodiments shown above, and appropriate modifications can be conceived without departing from the spirit of the invention. For example, this embodiment shows an example of performing an oxygen concentration reduction process before the adhesion improvement process, but from the viewpoint of reducing the oxygen concentration between the substrate and the ZnAl eutectoid alloy bonding material, the oxygen concentration reduction process can be performed in parallel with the adhesion improvement process, provided that there are no problems in accordance with the spirit of the invention.

[0193] The ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all the structures described in (a1) to (a4) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Furthermore, the bonding body and the method for manufacturing the bonding body of the present invention do not need to satisfy all the structures described in (b1) to (b5) and (c1) to (c7) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Furthermore, the method for manufacturing the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all of (d1) to (d6) above, and may not satisfy some of (d1) to (d6) without departing from the spirit of the present invention.

[0194] Furthermore, the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all the configurations mentioned in (e1) and (e2) above, and may not satisfy some of the configurations without departing from the spirit of the present invention. Furthermore, the bond and the method for manufacturing the bond of the present invention do not need to satisfy all the configurations mentioned in (f1) and (f2) above, and may not satisfy some of the configurations without departing from the spirit of the present invention. Furthermore, the method for manufacturing the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all of (g1) above, and may not satisfy some of (g1) without departing from the spirit of the present invention.

[0195] Furthermore, the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all the structures involved in (e1) and (e2) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Furthermore, the bond and the method for manufacturing the bond of the present invention do not need to satisfy all the structures involved in (f1) and (f2) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Furthermore, the method for manufacturing the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all of (g1) above, and may not satisfy some of (g1) without departing from the spirit of the present invention. Further, the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all the structures involved in (h1) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Further, the ZnAl eutectoid alloy bonding material of the present invention does not need to satisfy all the structures involved in (h1) above, and may not satisfy some of the structures without departing from the spirit of the present invention. Furthermore, the bond of the present invention does not need to satisfy all the structures involved in (h2) above, and may not satisfy some of the structures without departing from the spirit of the present invention.

[0196] Example 1

[0197] Hereinafter, specific embodiments of the present invention will be described. In this embodiment, a ZnAl eutectoid alloy bonding material was prepared according to the preparation method of the ZnAl eutectoid alloy bonding material described in [1] below. In addition, a bond was prepared according to the preparation method of the bond body described in [2] below. Further, as described in [3] below, the physical properties of the sample of the ZnAl eutectoid alloy bonding material prepared by the method of [1] were tested. In addition, as described in [4] below, the bonding properties of the bond body prepared by the method of [2] were tested.

[0198] [1] Preparation method of ZnAl eutectoid alloy bonding material

[0199] In this embodiment, as Figure 5 As shown, to prepare ZnAl eutectoid alloy bonding materials with Zn and Al as the basic components, and ZnAl eutectoid alloy bonding materials with Zn, Al, Cu, and Mg as the basic components (samples 1 to 6), raw materials were prepared by mixing pure Zn, pure Al, pure Cu, and pure Mg in a proportion (blending ratio) based on the chemical composition of each sample. These prepared raw materials were placed in a graphite crucible in a high-frequency melting furnace and heated to approximately 12.5 kW (500°C to 550°C) under an argon atmosphere until completely melted. After maintaining the molten state for 5 minutes, the mixture was cast into a boat-shaped mold in atmospheric pressure, thus producing the alloy ingots with ZnAl eutectoid alloy as the main component (alloy ingot manufacturing process).

[0200] In addition, when making ZnAl eutectoid alloy bonding materials, the alloy ingots made as described above, which are mainly composed of ZnAl eutectoid alloys, are processed into alloy ingots by cutting and other mechanical processing (alloy ingot manufacturing process). Then, they are prepared by heat treatment process (heat treatment process) and cooling process (cooling process).

[0201] The ZnAl eutectoid alloy cooled in the cooling process is then processed into a ZnAl eutectoid alloy bonding material through the following steps: a process of removing the oxide film by grinding with P1200 to P2500 sandpaper (surface grinding process), and a process of ultrasonically cleaning the surface-ground ZnAl eutectoid alloy for a specified time (3 minutes in this embodiment) and depositing gold of a specified thickness (50 nm in this embodiment) to implement anti-oxidation measures (surface coating process).

[0202] [2] Preparation method of the joint

[0203] Using the ZnAl eutectoid alloy bonding material prepared as described above, and employing the manufacturing apparatus 10 exemplified in the above embodiment, a bond body was prepared by bonding a copper substrate made of copper plate to the ZnAl eutectoid alloy bonding material. The copper plate constituting the copper substrate was made of commercially available oxygen-free copper plate and was prepared as follows: the bonding surface with the ZnAl eutectoid alloy bonding material was polished with P1200 to P2500 sandpaper to remove the oxide film, and after ultrasonic cleaning for a specified time (3 minutes in this embodiment), the surface was coated with gold of a specified thickness (50 nm in this embodiment).

[0204] Here, ZnAl eutectoid alloys are metals that are very easily oxidized, exhibiting the characteristic that even at high temperatures with oxygen concentrations below 40 ppm, a relatively thick oxide film can easily form. Therefore, the key is to ensure a high degree of contact between the ZnAl eutectoid alloy and the copper substrate (base material) at room temperature, preventing the bonding surface from contacting gas. Therefore, in this embodiment, when preparing the bond, as illustrated in the above embodiments, according to... Figure 3 The flowchart shown indicates that before reaching the heating process (steps 2-4), the oxygen concentration in the environment where the ZnAl eutectoid alloy bonding material and the copper substrate (substrate) are configured is reduced, while the ZnAl eutectoid alloy bonding material and the copper substrate (substrate) are made to achieve a high degree of adhesion at room temperature.

[0205] Specifically, the process begins with a bonding object setting step (step 2-1) in which the ZnAl eutectoid alloy bonding material and the copper substrate (substrate) are placed in an overlapping state in the setting part 56 of the pressurizing device 50. In the oxygen concentration reduction step (step 2-2), the interior of the main body 20 is purged with an inert gas (nitrogen in this embodiment) until the oxygen concentration reaches below 1 [ppm]. Then, in the contact improvement step (step 2-3), the laminate of the ZnAl eutectoid alloy bonding material and the copper substrate (substrate) is clamped by the first clamping part 52 and the second clamping part 54 constituting the pressurizing device 50, and the pressure is increased at a predetermined pressurization rate until a predetermined pressure (3 [MPa] in this embodiment) is reached, thereby achieving a high degree of contact between the ZnAl eutectoid alloy bonding material and the copper substrate (substrate).

[0206] When the bonding strength improvement process (steps 2-3) is completed at room temperature as described above, a heating process (steps 2-4) is performed. That is, in a nitrogen atmosphere with an oxygen concentration of less than 1 ppm, the ZnAl eutectoid alloy bonding material is clamped by two copper substrates (substrates) and the first clamping part 52 and the second clamping part 54 constituting the pressurizing device 50, and the atmosphere temperature is raised to the bonding temperature (395°C in this embodiment). After the atmosphere temperature reaches the bonding temperature, the material is heated for a predetermined holding time while maintaining the temperature and pressure conditions that allow bonding to be performed in the bonding process, thereby producing a bond (hereinafter also referred to as a "joint test piece").

[0207] [3] Physical properties of ZnAl eutectoid alloy bonding materials involved in samples 1 to 6

[0208] The test methods and results for the physical properties of the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6 are described. In this embodiment, tests were conducted on the physical properties from the perspectives of (α1) solidus temperature, (α2) liquidus temperature, (α3) the difference between the liquidus temperature and the solidus temperature (hereinafter also referred to as "solid-liquid temperature difference"), (α4) maximum load, (α5) strength (tensile strength), (α6) elongation, and (α7) hardness. The test methods for each test are as follows.

[0209] (α1) Conditions and methods for determining solidus temperature

[0210] • Sample weight: Approximately 10 mg

[0211] • Measuring apparatus: Differential scanning calorimeter (Rigaku Corporation, Thermo Plus DSC 8230)

[0212] • Heating rate: 2℃ / min

[0213] • Measurement temperature range: 100℃~600℃

[0214] • Standard based on: JIS Z 3198-1 (Method A)

[0215] • Measurement method: Approximately 10 mg of the test sample was measured using a differential scanning calorimeter (Rigaku, Thermo Plus DSC 8230) and measured within the range of 100℃ to 600℃ at a heating rate of 2℃ / min. The solidus temperature was determined from the obtained DSC curve according to the method in JIS Z 3198-1 (Method A).

[0216] (α2) Conditions and methods for determining the liquidus temperature

[0217] • Sample weight: Approximately 150g

[0218] • Measuring apparatus: Data logger (Keyence, NR-500), K-type thermocouple, personal computer, stainless steel container

[0219] • Measurement temperature: 700℃~200℃

[0220] • Standard based on: JIS Z 3198-1 "Test methods for lead-free solders - Part 1: Method for determining melting temperature range"

[0221] • Measurement Method: Insert a type K thermocouple into the center of a completely molten sample (approximately 150g) inside a stainless steel container and allow it to stand. Allow it to cool naturally from 700°C, recording the sample temperature over time using a data logger (Keyence NR-500) until it reaches 200°C, obtaining a time-temperature curve, also known as the cooling curve. Determine the liquidus temperature from the obtained cooling curve according to the melting temperature range determination method (Method B) described in JIS Z 3198-1.

[0222] (α3) Method for deriving the difference between the liquidus temperature and the solidus temperature (solid-liquid temperature difference)

[0223] The solid-liquid phase temperature difference is derived by subtracting the solid phase temperature from the liquidus temperature derived from (α1) and (α2) above.

[0224] (α4) Determination conditions and methods for maximum load

[0225] • Sample dimensions: Total length 85mm, gripping part length 15mm

[0226] Gauge length 25mm, gauge diameter 5mm

[0227] • Measuring apparatus: Universal testing machine (Shimadzu Corporation, Autograph AG-IS 10kN)

[0228] • Test speed: 5 mm / min

[0229] • Test method: A cylindrical alloy ingot with a diameter of 15 mm and a length of 85 mm was obtained by casting, and a specimen of the specified size was prepared by machining on a lathe. The specimen was placed in an electric furnace at 375°C for 1 hour, and then immediately immersed in water at 20°C. After cooling, the specimen was held in a universal testing machine and stretched along its length at a test speed of 5 mm / min at room temperature. The maximum load [N] recorded until fracture was measured.

[0230] Methods for deriving (α5) strength and (α6) elongation

[0231] Divide the maximum load obtained by (α4) by the area along the diameter of the gauge length of the ZnAl eutectoid alloy specimen before the test (19.6 mm). 2 The value obtained is taken as the strength [MPa] of the alloy composition. Further, the elongation is obtained by subtracting the gauge length before the test from the gauge length at the fracture surface of the tested specimen, dividing the result by the gauge length before the test, and then multiplying by 100.

[0232] (α7) Hardness testing conditions and methods

[0233] • Sample dimensions: Diameter 20mm, thickness 3mm

[0234] • Testing apparatus: Vickers hardness tester (AKASHI MVK-F, manufactured by Akashi Seisakusho)

[0235] • Standard followed: JIS Z 2244 "Vickers Hardness Test - Test Method"

[0236] • Test Method: An alloy ingot of specified composition was obtained by casting. A cylindrical specimen with a diameter of 20 mm and a thickness of 3 mm was prepared by lathe machining. After grinding the test surface with 800-grit sandpaper, the specimen was placed in an electric furnace at 375°C for 1 hour, then immediately immersed in water at 20°C. After cooling, the specimen was used for testing after 24 hours at room temperature. The determination and hardness calculation were performed according to the method described in JIS Z 2244.

[0237] The results of the physical property tests (α1) to (α7) conducted on samples 1 to 6 are shown below. Figure 5 The physical properties of each sample were evaluated based on the criteria illustrated in the above embodiments, and the results are as follows.

[0238] (α1) Regarding the solidus temperature

[0239] Studies related to solidus temperature were conducted on samples 1 through 6. The results showed that the solidus temperature of all samples was below 450°C. Therefore, the ZnAl eutectoid alloy bonding materials involved in samples 1 through 6 all meet the solidus temperature evaluation criteria illustrated in the above embodiments. Furthermore, the effect of the presence or absence of Cu and Mg as basic components on the solidus temperature was investigated when the Al content was the same. The results showed that samples 2, 4, and 6, which contained Cu and Mg as basic components, exhibited significantly lower solidus temperatures compared to samples 1, 3, and 5, which had the same Al content. This indicates that the solidus temperature of ZnAl eutectoid alloy bonding materials tends to decrease when Cu and Mg are included as basic components.

[0240] (α2) Regarding the liquidus temperature

[0241] Studies related to the liquidus temperature were conducted on samples 1 through 6. The results showed that the liquidus temperature of all samples was below 540°C. Therefore, the ZnAl eutectoid alloy bonding materials involved in samples 1 through 6 all meet the evaluation criteria for liquidus temperature illustrated in the above embodiments. Furthermore, the effect of the presence or absence of Cu and Mg as basic components on the solidus temperature was investigated when the Al content was the same. The results showed that samples 2, 4, and 6, which contained Cu and Mg as basic components, had lower liquidus temperatures compared to samples 1, 3, and 5, which had the same Al content. This indicates that the presence of Cu and Mg as basic components leads to a decreasing trend in the liquidus temperature of ZnAl eutectoid alloy bonding materials.

[0242] (α3) Regarding the difference between the liquidus temperature and the solidus temperature (solid-liquid temperature difference)

[0243] Regarding samples 1 to 6, the trend of the solid-liquid phase temperature difference was investigated. The results showed that all samples had a solid-liquid phase temperature difference between 50°C and 150°C, meeting the evaluation criteria for solid-liquid phase temperature difference illustrated in the above embodiments. Furthermore, the effect of the presence or absence of Cu and Mg as basic components on the solid-liquid phase temperature difference was investigated when the Al content was the same. The results showed that samples 2, 4, and 6, which contained Cu and Mg as basic components, exhibited a significantly larger solid-liquid phase temperature difference compared to samples 1, 3, and 5, which had the same Al content. This indicates that the presence of Cu and Mg as basic components leads to a larger solid-liquid phase temperature difference in ZnAl eutectoid alloy bonding materials.

[0244] (α4) Regarding the maximum load

[0245] Regarding samples 1 to 6, the trend of maximum load was investigated. The results showed that all samples achieved a maximum load of 2500 N or higher, meeting the evaluation criteria for maximum load illustrated in the above embodiments. Furthermore, when studying samples 1, 3, and 5, which contain Zn and Al as basic components but do not contain Cu or Mg, it was found that the higher the Al content, the higher the maximum load. Additionally, the effect of the presence or absence of Cu and Mg as basic components on the maximum load was investigated when the Al content was the same. The results showed that samples 2 and 4, which contain Cu and Mg as basic components, had a higher maximum load compared to samples 1 and 3, which had the same Al content. While sample 6, which contains Cu and Mg as basic components, had a lower maximum load compared to sample 5, which had the same Al content, it still met the evaluation criteria for maximum load, demonstrating sufficient maximum load as a bonding material.

[0246] (α5) Regarding strength (tensile strength)

[0247] Regarding samples 1 through 6, the trend of tensile strength was investigated. The results showed that all samples had a tensile strength of 100 MPa or higher, meeting the strength evaluation criteria illustrated in the above embodiments. Furthermore, when studying samples 1, 3, and 5, which contain Zn and Al as basic components but do not contain Cu or Mg, it was found that the higher the Al content, the higher the tensile strength. Additionally, the effect of the presence or absence of Cu and Mg as basic components on tensile strength was investigated when the Al content was the same. The results showed that samples 2 and 4, which contain Cu and Mg as basic components, had increased tensile strength compared to samples 1 and 3, which had the same Al content. While sample 6, which contains Cu and Mg as basic components, had a lower tensile strength compared to sample 5, which had the same Al content, it still met the tensile strength evaluation criteria, demonstrating sufficient tensile strength as a bonding material.

[0248] (α6) Regarding elongation

[0249] Regarding samples 1 to 6, the trend of elongation was investigated. The results showed that samples 1 to 5 had an elongation of 1% or more, meeting the strength evaluation criteria illustrated in the above embodiments. On the other hand, sample 6 had an elongation of 0%. Therefore, it was concluded that samples 1 to 5 were optimal when elongation-related properties were required.

[0250] (α7) Regarding hardness

[0251] Regarding samples 1 through 6, the trend in hardness was investigated. The results showed that all samples achieved a hardness of 10 [Hv] or higher, meeting the hardness evaluation criteria illustrated in the above embodiments. Furthermore, the effect of the presence of Cu and Mg as basic components on hardness was investigated when the Al content was the same. The results showed that samples 2 and 4, which contained Cu and Mg as basic components, exhibited increased hardness compared to samples 1 and 3, which had the same Al content.

[0252] [4] Regarding the bonding characteristics of the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6

[0253] The test methods and results for the bonding characteristics of the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6 are described. In this embodiment, tests were conducted on the bonding characteristics from the viewpoints of (β1) maximum load, (β2) shear strength, and (β3) outflow rate. The test methods for each test are as follows. Furthermore, the test piece (hereinafter also referred to as the "joint test piece") used for the bonding characteristic tests of the ZnAl eutectoid alloy bonding materials was prepared by placing the ZnAl eutectoid alloy bonding material (5mm × 5mm × 0.5mm) involved in Samples 1 to 6 between two oxygen-free copper substrates (10mm × 20mm × 3mm) and bonding them using a pressure sintering apparatus (Model HTM-3000 manufactured by Meichang Machinery Co., Ltd.).

[0254] (β1) Measurement conditions and methods for maximum load

[0255] • Measuring apparatus: Universal testing machine (Shimadzu Corporation, Autograph AG-IS)

[0256] • Stretching speed: 1mm / min

[0257] • Test method: Place the joint test piece in a universal testing machine (Shimadzu Corporation, Autograph AG-IS), and stretch it along the length of the joint test piece at a test speed of 1 mm / min. Measure the maximum load [N] recorded until the joint test piece breaks.

[0258] (β2) Method for deriving shear strength

[0259] Regarding shear strength, the maximum load obtained from the above-mentioned test will be divided by the area of ​​the ZnAl eutectoid alloy bonding material before bonding (25 mm²). 2 The value obtained is taken as the shear strength [MPa] of the alloy composition.

[0260] (β3) Determination conditions and methods for outflow

[0261] For the joint test piece that fractured during a tensile test conducted to determine the aforementioned maximum load, images of the joint are obtained. For example... Figure 6 As shown, the fracture surface region X (the dotted area in the figure) and the outflow region Y (the diagonal line in the figure) from which the ZnAl eutectoid alloy bonding material flows out are identified in the image. The outflow region Y is divided into four regions (outflow region Y1 to outflow region Y4) with the diagonal of the fracture surface region as the boundary, and the outflow amount [mm] is obtained by dividing the area of ​​the largest region among outflow regions Y1 to outflow region Y4 (maximum area S) by the length of one side of the bonding material before bonding (5 [mm]).

[0262] The results of the bonding characteristic related tests (β1) to (β7) conducted on samples 1 to 6 are shown below. Figure 5 The bonding characteristics of each sample were evaluated according to the criteria illustrated in the above embodiments, and the results are as follows.

[0263] (β1) Regarding the maximum load

[0264] The bonding characteristics of the joints formed using the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6 were studied from the perspective of maximum load. The results showed that all samples achieved a maximum load of 1400 N or more, meeting the evaluation criteria for maximum load illustrated in the above embodiments. Furthermore, the influence of the presence or absence of Cu and Mg as basic components on the maximum load was investigated when the Al content was the same. The results indicated that Samples 2, 4, and 6, which contained Cu and Mg as basic components, exhibited maximum loads of the same degree or higher than those of Samples 1, 3, and 5, which had the same Al content, respectively. This suggests that the presence of Cu and Mg as basic components does not adversely affect the maximum load. Additionally, it was found that for samples with an Al content (content) of 28% (mass%) as basic components, the maximum loads of Sample 5 (containing no Cu and Mg) and Sample 6 (containing Cu and Mg) were slightly lower than those of Samples 1 to 4 (containing less than 28% (mass%) of Al. However, the maximum loads of samples 5 and 6 are both above 1400 [N], which shows that they are sufficient values ​​for bonding characteristics.

[0265] (β2) Regarding shear strength

[0266] The bonding characteristics of the joints formed using the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6 were studied from the perspective of shear strength. The results showed that all samples achieved a shear strength of 50 MPa or higher, meeting the shear strength evaluation criteria illustrated in the above embodiments. Furthermore, the effect of the presence or absence of Cu and Mg as basic components on shear strength was investigated when the Al content was the same. The results indicated that Samples 2, 4, and 6, which contained Cu and Mg as basic components, exhibited shear strengths of the same degree or higher than those of Samples 1, 3, and 5, which had the same Al content, respectively. This suggests that the presence of Cu and Mg as basic components does not adversely affect the shear strength. Additionally, it was found that for samples with an Al content (content) of 28% (mass%) as basic components, the shear strengths of Sample 5 (containing no Cu and Mg) and Sample 6 (containing Cu and Mg) were slightly lower than those of Samples 1 to 4 (containing less than 28% (mass%) of Al. However, the shear strength of both samples 5 and 6 is above 50 [MPa], which shows that they are sufficient values ​​for bonding properties.

[0267] (β3) Regarding outflow

[0268] The bonding characteristics of the joints formed using the ZnAl eutectoid alloy bonding materials involved in Samples 1 to 6 were studied from the perspective of outflow rate. The results showed that the outflow rate for Samples 1 to 5 was 2.00 mm or less, meeting the evaluation criteria for outflow rate illustrated in the above embodiments. On the other hand, the outflow rate for Sample 6 was 2.42 mm. Therefore, it was concluded that Samples 1 to 5 were optimal from the viewpoint of minimizing outflow rate.

[0269] Example 2

[0270] Next, the second embodiment will be described. In this embodiment, the cross-section of the resulting bond was observed using a scanning electron microscope (SEM). The bond was obtained by placing the ZnAl eutectoid alloy bonding material (mass ratio Zn:Al:Cu:Mg = 68.0:28.0:2.0:2.0) involved in Sample 6 of the first embodiment between two oxygen-free copper plates (copper substrate: 10mm × 20mm × 3mm) and bonding them using a pressure sintering apparatus (Model HTM-3000 manufactured by Meichang Machinery Co., Ltd.). The scanning electron microscope used for observation and the measurement conditions are shown below.

[0271] • Measuring device: JSM-IT700HR (manufactured by Nippon Electronics Co., Ltd.)

[0272] • Signal: BED-S

[0273] • Incident voltage: 15.0 kV

[0274] WD: 10.1 [mm]

[0275] Multiplier: 300x

[0276] • Observation range: 426.7 × 320.0 [μm]

[0277] • Irradiation current, Std.: 75.0

[0278] • Scan rotation: 0.0 [degrees]

[0279] • Vacuum mode: Low Vacuum

[0280] Vacuum level: 30 Pa

[0281] SEM observation was performed under the above measurement conditions, and the results were obtained. Figure 7 and Figure 8 The SEM images involved. Figure 7 The SEM image shows a photograph of the boundary between the joint and the outflow area of ​​the copper substrate bonded using a ZnAl eutectoid alloy bonding material. Figure 8 (a) and (b) in the text are respectively... Figure 7 A magnified photograph of the main part.

[0282] Reference Figure 7 and Figure 8 The SEM images confirmed that the copper substrate could be bonded using the ZnAl eutectoid alloy bonding material described in Sample 6. Furthermore, the SEM images also confirmed that the outflow portion was not bonded and that the microstructure of the bonded portion differed from that of the outflow portion.

[0283] Example 3

[0284] In Example 3 of the present invention, the properties of the ZnAl eutectoid alloy bonding material with the newly added trace element were evaluated. Specifically, a ternary alloy (Zn-21.78Al-1X eutectoid alloy bonding material) was prepared by adding 1 part by mass of an additive element (hereinafter also referred to as "X component") to a Zn-22Al eutectoid alloy (99 parts by mass). Here, 12 elements were used as X component: Ag, Bi, Co, Cu, Ga, Ge, Mn, Mo, Ni, Sb, Si, and V. When selecting these elements, environmental safety (toxicity level), availability (rarity, whether precious metals are used), and workability (ease of melting) were considered.

[0285] The bonding material is made in a shape with dimensions of 5×5×0.5 [mm]. A copper substrate or a low-phosphorus nickel-plated substrate is used as the substrate. As for the bonding conditions, the temperature is set to three levels: 330℃, 350℃, and 400℃, the holding time is set to 90 seconds, and the pressure is set to 4 [MPa].

[0286] The evaluation of the joint was conducted through observation of the fracture surface and shear tests on the joint interface. Thus, the effects of each X component on shear strength and the properties of the joint material were investigated in detail.

[0287] In this embodiment, a shear strength test was conducted to evaluate the shear strength of the ZnAl eutectoid alloy bond material with X component added when using a copper substrate. The test apparatus and test conditions used for the shear strength test are as follows.

[0288] The joint test piece for evaluating the shear strength of the ZnAl eutectoid alloy bonding material with added X component is prepared as follows: the ZnAl eutectoid alloy bonding material with added X component (5mm×5mm×0.5mm) is placed between two oxygen-free copper plates (copper substrate: 10mm×20mm×3mm), and the bonding is performed using a pressure sintering apparatus (Model HTM-3000 manufactured by Meichang Machinery Co., Ltd.).

[0289] (γ1) Measurement conditions and methods for maximum load

[0290] • Measuring apparatus: Universal testing machine (Shimadzu Corporation, Autograph AG-IS)

[0291] • Stretching speed: 1mm / min

[0292] • Test method: Place the joint test piece in a universal testing machine (Shimadzu Corporation, Autograph AG-IS), and stretch it along the length of the joint test piece at a test speed of 1 mm / min. Measure the maximum load [N] recorded before the joint test piece breaks.

[0293] (γ2) Method for deriving shear strength

[0294] Regarding shear strength, the maximum load obtained by testing using the above method will be divided by the area of ​​the ZnAl eutectoid alloy bonding material with added X component before bonding (25 mm²). 2 The value obtained is taken as the shear strength [MPa] of the alloy composition.

[0295] (Shear strength test with copper substrate)

[0296] Table 1 shows the results of the shear strength tests obtained through the above-described shear strength tests. As shown in Table 1, it was found that at a bonding temperature of 400℃, alloys with the addition of Ge, Mn, Mo, Ni, Si, and V generally exhibited higher shear strength than ZnAl eutectoid alloys. In particular, alloys with the addition of Ni and V showed a trend of exhibiting shear strength more than 10% higher than that of ZnAl eutectoid alloys.

[0297] [Table 1]

[0298]

[0299] Based on the bonding test results at a bonding temperature of 350℃, it was found that alloys with added Ge, Mo, and V generally exhibited higher shear strength than ZnAl eutectoid alloys. This confirms that the addition of Ge, Mo, and V is also effective in low-temperature bonding processes. In particular, alloys with added Ge, Ni, and V showed shear strength more than 10% higher than that of ZnAl eutectoid alloys. Therefore, the addition of Ge, Ni, and V elements can maintain high strength even at low bonding temperatures, which is effective for achieving low-temperature bonding processes.

[0300] Based on the bonding test results at a bonding temperature of 330°C, it was found that alloys with added Ge, Ni, and V exhibited shear strengths exceeding 30.0 MPa. In particular, it was discovered that the addition of Ge, Ni, and V elements maintained high strength even at low bonding temperatures, which is effective for achieving low-temperature processing.

[0301] The above results show that adding Ge, Mn, Mo, Ni, Si, and V as X components in Zn-21.78Al-1X eutectoid alloy bonding materials helps improve shear strength. The addition of Ge, Ni, and V also maintains high strength at low bonding temperatures, effectively enabling low-temperature bonding processes. Therefore, the following conclusion is drawn: In scenarios requiring low-temperature bonding, adding Ge, Ni, and V as X components to ZnAl alloys is effective.

[0302] (Evaluation test of effluent characteristics when using copper substrate)

[0303] In addition, in this embodiment, an experiment was conducted to evaluate the flow characteristics when bonding a copper substrate with the aforementioned Zn-21.78Al-1X eutectoid alloy. Furthermore, the sample used in this experiment was prepared with the bonding temperature set to 350°C, the holding time set to 90 seconds, and the applied pressure set to 4 MPa.

[0304] Figure 9 The image shows photographs illustrating the results of the relevant experiments. (Refer to...) Figure 9 It can be seen that when using ZnAl eutectoid alloys with elements other than Cu (Ag, Co, Ge, Mn, Mo, Ni, Si, V), the outflow of the bonding material is approximately the same as when no elements are added, confirming that it falls within the preferred range. This indicates that adding elements Ag, Co, Ge, Mn, Mo, Ni, Si, and V as component X does not have a significant adverse effect on the outflow characteristics of the bonding material.

[0305] On the other hand, when Cu was added as component X, it was found that, unlike when other elements were added, the outflow of the bonding material tended to increase. This indicates that the addition of Cu increases the fluidity of the bonding material, which may lead to excessive outflow at the joint. From the viewpoint of suppressing outflow, it was found that other elements such as Ag, Co, Ge, Mn, Mo, Ni, Si, and V are preferred as component X, rather than Cu.

[0306] The above results confirm that for bonding materials composed of Zn-21.78Al-1X eutectoid alloys, adding appropriate amounts of Ag, Co, Ge, Mn, Mo, Ni, Si, and V can both suppress outflow and improve the performance of the bonding materials.

[0307] (Evaluation test of the bonding interface state when using copper substrate as substrate)

[0308] In this embodiment, an experiment was conducted to evaluate the interface state of the Zn-21.78Al-1X eutectoid alloy bonding material with a copper substrate (interface state evaluation experiment). The X composition used in the experiment was Ag, Co, Cu, Ge, Mn, Mo, Ni, Si, and V. The bonded body formed by bonding the Zn-21.78Al-1X eutectoid alloy with a copper substrate at a bonding temperature of 400°C, a holding time of 90 seconds, and a pressure of 4 MPa was used as a sample for the experiment. The results are shown below. Figure 10 .

[0309] The structure of the diffusion layer at the interface remains the same regardless of any element used as a trace element in this experiment. Specifically, as Figure 10 As shown, the structure of the diffusion layer at the bonding interface of the samples involved in this experiment was confirmed to be a layer structure consisting of Cu-Zn layer, Cu-Al layer, and Zn-Al bonding material layer stacked sequentially from the Cu substrate side. Since this layered structure is the same regardless of the type of added element, it was determined that a diffusion layer can be stably formed regardless of which element is added as X component. This diffusion layer is formed by the diffusion of Zn and Al from the copper substrate.

[0310] More specifically, in Figure 10In the example of the bonding interface using a ZnAl eutectoid alloy with added V, the elemental distributions of Cu, Zn, Al, and V were confirmed by EDS elemental mapping. On the other hand, the same experiment was performed on the bonding interface state of a Zn-22Al eutectoid alloy, and the results were compared with those of Zn-21.78Al-1V, but no significant difference was found in the formation of the diffusion layer. Therefore, in ZnAl alloys, even with the addition of V, no significant impact on the structure of the diffusion layer was observed.

[0311] (A study on the relationship between holding time and shear strength)

[0312] In this embodiment, a ZnAl eutectoid alloy bonding material with Zn-22Al as its basic composition was used. The shear strength with a copper substrate and with a low-phosphorus nickel-plated substrate (a substrate formed by applying a 5 μm thick low-phosphorus nickel plating to the entire surface of a copper substrate) were measured, and their bonding characteristics with the substrate were compared. The bonding temperature was set to 400°C, and the applied pressure was set to 4 MPa. The relationship between holding time and shear strength was evaluated.

[0313] like Figure 11 As shown, regarding the shear strength with the copper substrate, it was confirmed that the shear strength increases with increasing holding time. Based on the experimental results, the shear strength depends on the holding time, based on y = 13.542ln(x) - 43.701(R). 2 Based on the relationship (=0.9685), the shear strength reached 40 [MPa] after heating for approximately 630 seconds.

[0314] On the other hand, regarding the shear strength with the low-phosphorus nickel-plated substrate, it was determined that a longer holding time is required to obtain the same strength as the copper substrate. Based on y = 9.3416ln(x) + 6.1567(R... 2 According to the relationship (=0.919), the increase in shear strength in low-phosphorus nickel-plated substrates increases slowly with increasing holding time. In low-phosphorus nickel-plated substrates, it takes more than 630 seconds of heating to achieve a shear strength of 40 MPa.

[0315] These results show that, when using ZnAl eutectoid alloy bonding materials, higher shear strength is achieved with a shorter holding time compared to copper substrates, while a longer holding time is required compared to low-phosphorus nickel-plated substrates. Therefore, it is clear that the holding time and other bonding conditions need to be appropriately adjusted according to the substrate material.

[0316] (Shear strength test when using low-phosphorus nickel-plated substrate)

[0317] In this embodiment, a Zn-21.78Al-1X eutectoid alloy bonding material was used to evaluate the shear strength with a low-phosphorus nickel-plated substrate. The bonding temperature was set to 400°C, the applied pressure was set to 4 MPa, and the holding time was set to 630 seconds for the shear strength measurement.

[0318] The results of the above measurements are shown in Table 2. Figure 2 As shown, it was confirmed that adding all X components (Ag, Co, Cu, Ga, Ge, Mg, Mn, Mo, Ni, Sb, V) except Bi resulted in shear strengths equal to or higher than those without addition. Specifically, the shear strengths with the addition of Ag, Mg, Mn, Ni, and V were 59.6 [MPa], 54.3 [MPa], 59.8 [MPa], 54.2 [MPa], and 56.3 [MPa], respectively, which are more than 10% higher than the shear strength of the ZnAl eutectoid alloy bond. On the other hand, the result with the addition of Bi was a shear strength of 41.4 [MPa], which is more than 10% lower than the shear strength of the ZnAl eutectoid alloy bond.

[0319] [Table 2]

[0320]

[0321] The results indicate that the addition of Ag, Mg, Mn, Ni, and V improves the shear strength. This clearly demonstrates that selecting an appropriate X composition is effective in optimizing shear strength during bonding with low-phosphorus nickel-plated substrates.

[0322] (Evaluation test of effluent characteristics when using low-phosphorus nickel-plated substrate)

[0323] In this embodiment, a ZnAl eutectoid alloy bonding material with Zn-21.78Al as the basic composition and 1% by mass of trace elements was used to evaluate the outflow when bonding with a low-phosphorus nickel-plated substrate. The bonding conditions were as follows: bonding temperature of 400°C, pressure of 4 MPa, and holding time of 630 seconds.

[0324] Reference Figure 12 It was found that when all trace elements (Ag, Bi, Co, Cu, Ga, Ge, Mg, Mn, Mo, Ni, Sb, V) were added, the outflow rate was the same as or sometimes exceeded that without addition. This leads to the conclusion that the addition of trace elements (component X) improves the flowability of the bonding material, especially when bonding with low-phosphorus nickel-plated substrates. Therefore, it is confirmed that suppressing outflow is an important factor in bonding with low-phosphorus nickel-plated substrates, and the impact on flowability needs to be considered when selecting trace elements.

[0325] (Evaluation test of bonding interface condition when using low phosphorus nickel-plated substrate)

[0326] In this embodiment, the bonding interface state of a ZnAl eutectoid alloy bonding material with a basic composition of Zn-21.78Al and the addition of 1% by mass of trace elements was evaluated with a low-phosphorus nickel-plated substrate. The structure and bonding characteristics of the bonding interface were investigated under the conditions of a bonding temperature of 400°C, a pressure of 4 MPa, and a holding time of 630 seconds, with the addition of Ge, Bi, Cu, Co, Mn, Ni, Sb, Ag, Mo, Ga, Mg, and V, respectively.

[0327] Reference Figure 13 and Figure 14 It can be seen that, regardless of the trace element added, a layer structure consisting of Cu (substrate), Ni (plating), Ni-Al layer, and Zn-Al (bonding material) is confirmed to be stacked from the substrate side in the bonding interface. In addition, it was observed that the bonding fracture sites mainly occur at the interface between Ni and Ni-Al layer, or at the interface between Ni-Al layer and Zn-Al layer.

[0328] exist Figure 13 In the example of the bonding interface using a ZnAl eutectoid alloy bonding material with added Ge, stable bonding was confirmed at the interface between the Ni-Al and Zn-Al layers, but fracture occurred along the interface. The same phenomenon was also confirmed in the bonding interface using a ZnAl eutectoid alloy bonding material with added Bi, Cu, Co, Mn, Ni, and Sb.

[0329] On the other hand, Figure 14 In the case of ZnAl eutectoid alloy bonding materials with added Ag and Mo, voids, believed to be Kirkendal pores, were confirmed to form within the Ni-Al layer. This indicates that the formation of these pores may affect shear strength, especially with the addition of Ag or Mo, making process control to suppress pore formation important. The same phenomenon was also observed when using ZnAl eutectoid alloy bonding materials with added Ga, Mg, and V.

[0330] The interface between the ZnAl eutectoid alloy bonding material with 1% by mass of trace elements and a low-phosphorus nickel-plated substrate showed no significant difference in basic layer structure compared to the interface between the ZnAl eutectoid alloy bonding material without trace elements and the low-phosphorus nickel-plated substrate. However, Kirkendal voids were observed when specific trace elements (Ag or Mo) were added. Therefore, this should be considered when optimizing bonding conditions when using ZnAl eutectoid alloy bonding materials with trace elements.

[0331] (Summary of Example 3)

[0332] As described above, in this embodiment, a ZnAl eutectoid alloy bonding material with a basic composition of Zn-21.78Al and the addition of 1% by mass of trace elements was used to evaluate the bonding characteristics relative to a copper substrate and a low-phosphorus nickel-plated substrate. The experimental results are summarized in Table 3 below. (Refer to...) Figure 3 It is known that ZnAl eutectoid alloy bonding materials with trace elements such as Ge, Mn, Ni, and V exhibit particularly excellent bonding properties.

[0333] [Table 3]

[0334]

[0335] In bonding tests with copper substrates, it was found that the shear strength of the bonded material was improved compared to that of the ZnAl eutectoid alloy by adding Ge, Ni, and V. These elements were also highly effective in suppressing outflow and voids. Furthermore, in bonding tests with copper substrates, it was found that while the shear strength of the bonded material was inferior to that of the material containing Ge, Ni, and V, the addition of Mn and Mo resulted in higher effectiveness in suppressing outflow and voids.

[0336] In bonding tests with low-phosphorus nickel-plated substrates, it was found that adding Mn and Ni was effective in both improving shear strength and suppressing porosity compared to Zn-22Al eutectoid alloy bonding materials. Furthermore, while adding Co, Cu, Ge, and Sb resulted in lower shear strength compared to adding Mn and Ni, both exhibited good shear strength and porosity suppression properties.

[0337] These results lead to the following conclusions: Ternary alloys (Zn-21.78Al-1X) with trace elements added (Ge, Mn, Ni, and V) can significantly improve bonding properties compared to Zn-22Al eutectoid alloy bonding materials.

[0338] Example 4

[0339] To investigate the effects of additive elements in the ZnAl eutectoid alloy bonding material of this invention in more detail, the inventors evaluated the types and amounts of additive elements, and further evaluated the influence of bonding conditions on bonding characteristics. The ZnAl eutectoid alloy bonding material of Example 4 was prepared using the same method as in Example 1. Furthermore, the shear strength was measured under the same conditions as in Example 1.

[0340] The inventors first evaluated the effects of bonding temperature and holding time on the bonding characteristics of ZnAl eutectoid alloy bonding materials with a basic composition of 78% by mass and 22% by mass. The results are shown in Table 4.

[0341] [Table 4]

[0342]

[0343] As shown in Table 4, in this Example 4, the ZnAl eutectoid alloy bonding material with the basic composition exhibited a shear strength of 36.3 MPa during bonding at 350°C with a holding time of 5430 seconds. Furthermore, it was confirmed that by setting the bonding temperature to 400°C, a shear strength of 38.2 MPa was obtained with a holding time of 1830 seconds, and a shear strength of 51.6 MPa was obtained with a holding time of 3630 seconds.

[0344] The inventors then used a copper substrate as the base material and set the holding time to 90 seconds to evaluate the effect of adding elements when bonding at a relatively low temperature of 350°C. The results are shown in Table 5.

[0345] [Table 5]

[0346]

[0347] As shown in Table 5, in this Example 4, when Ge was added, the shear strength was around 20 MPa to 30 MPa when the addition was 0.01% by mass and 0.1% by mass, while a high shear strength of over 90 MPa was obtained when the addition was increased to 1.0% by mass. It was further confirmed that even when the amount of Ge added was set to 3.0% by mass, a high strength of over 85 MPa could be maintained.

[0348] On the other hand, in this Example 4, when V was added, a shear strength of 17 MPa to 30 MPa was observed in the range of 0.01% to 0.1% by mass. Furthermore, it was confirmed that in the comparison of Ni addition, the strength was 19.3 MPa when 0.1% by mass was added and 0.2 MPa when 5.0% by mass was added.

[0349] The inventors further evaluated the effects of various added elements at a bonding temperature of 400°C. The holding time was 90 seconds. The results are shown in Table 6.

[0350] [Table 6]

[0351]

[0352] As shown in Table 6, in Example 4, when the bonding temperature was set to 400°C, the ZnAl eutectoid alloy bond with 1.0% by mass of Ge exhibited shear strengths of 42.8 MPa and 49.3 MPa at Al contents of 24.75% by mass and 27.72% by mass, respectively. It was further confirmed that by increasing the amount of Ge to 3.0% by mass and 5.0% by mass, the shear strength increased to 51.6 MPa and 57.0 MPa, respectively.

[0353] On the other hand, regarding the Ni addition evaluated as a comparative example, it was confirmed that a shear strength of 53.9 MPa was observed when 0.01% by mass was added, but as the addition amount increased to 0.10% by mass and 1.00% by mass, the shear strength decreased to 37.1 MPa and 28.6 MPa, respectively.

[0354] Thus, based on the insights gained in Example 4, it was confirmed that the ZnAl eutectoid alloy bonding material of the present invention, by adding approximately 1.0% by mass of Ge as an additive element, exhibits a high shear strength exceeding 90 MPa even in low-temperature bonding at 350°C. Furthermore, it was confirmed that when the bonding temperature is set to 400°C, a shear strength exceeding 50 MPa can be stably obtained by setting the amount of Ge added to 3.0% to 5.0% by mass. In contrast, it was confirmed that when the amount of V added is in the range of 0.01% to 0.1% by mass, the shear strength remains between 17 MPa and 30 MPa. Regarding the addition of Ni, it was confirmed that adding a trace amount (0.01% by mass) yields a certain effect, but the shear strength shows a decreasing trend with increasing addition amount.

[0355] It has been further confirmed that the ZnAl eutectoid alloy bonding material of the present invention can achieve practical shear strength even at its basic composition by appropriately setting the bonding temperature and holding time. These results demonstrate that the ZnAl eutectoid alloy bonding material of the present invention can achieve a shorter holding time by adding Ge, and possesses excellent properties as a practical bonding material capable of achieving stable shear strength.

[0356] This invention is not limited to the embodiments and variations shown above, and other embodiments can be obtained within the scope of its teachings and spirit without departing from the spirit of this invention. The constituent elements of the above embodiments can be arbitrarily selected and combined. Furthermore, any constituent element of the embodiments, any constituent element described in the technical solution for solving the problem, or a embodied constituent element described in the technical solution for solving the problem can be arbitrarily combined to form the invention. In this regard, it is intended to obtain patent rights in amendments or divisional applications of this application.

[0357] (Industrial availability)

[0358] The method for manufacturing the ZnAl eutectoid alloy bonding material of the present invention can be suitably used to manufacture bonding materials for devices operating under high-temperature conditions, and can replace lead-containing solder. Furthermore, the bonding body of the present invention can be suitably used to construct devices operating under high-temperature conditions. The method for manufacturing the bonding body of the present invention can be suitably used to manufacture bonding bodies required for manufacturing devices operating under high-temperature conditions.

Claims

1. A ZnAl eutectoid alloy bonding material, comprising a ZnAl eutectoid alloy with Zn and Al as basic components, characterized in that, It contains more than 25% by mass and less than 28% by mass of Al, with the remainder containing Zn and unavoidable impurities.

2. The ZnAl eutectoid alloy bonding material according to claim 1, characterized in that, As part of the basic composition, it also contains either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

3. The ZnAl eutectoid alloy bonding material according to claim 1 or 2, characterized in that, The solidus temperature is below 450℃.

4. The ZnAl eutectoid alloy bonding material according to claim 1 or 2, characterized in that, The difference between the liquidus temperature and the solidus temperature is greater than 50°C and less than 150°C.

5. A joint, characterized in that, It comprises a substrate and a bonding portion, the bonding portion being constructed from a ZnAl eutectoid alloy bonding material. The ZnAl eutectoid alloy bonding material is based on Zn and Al, containing more than 25% by mass and less than 28% by mass of Al, with the remainder containing Zn and unavoidable impurities.

6. The joint according to claim 5, characterized in that, The ZnAl eutectoid alloy bonding material, as part of the basic composition, also contains either or both of Cu in the range of less than 2.0% by mass and Mg in the range of less than 2.0% by mass.

7. The joint according to claim 5 or 6, characterized in that, The joint is formed by joining the object to the substrate via a ZnAl eutectoid alloy bonding material disposed between the substrate and the object to be joined to the substrate. In the joint, the amount of ZnAl eutectoid alloy bonding material overflowing from the outer edge of the joint object is less than 3 mm.

8. The joint according to claim 5 or 6, characterized in that, The solidus temperature of the ZnAl eutectoid alloy bonding material is below 450℃.

9. The joint according to claim 5 or 6, characterized in that, The difference between the liquidus temperature and the solidus temperature of the ZnAl eutectoid alloy bonding material is above 50°C and below 150°C.

10. A method for manufacturing a joint, the joint comprising a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, characterized in that... As the ZnAl eutectoid alloy bonding material, a ZnAl eutectoid alloy bonding material with Zn and Al as the basic components, containing more than 25% by mass and less than 28% by mass of Al, and the remainder containing Zn and unavoidable impurities is used. The method for manufacturing the joint includes: The process for improving the adhesion involves applying pressure while bringing the substrate into contact with the ZnAl eutectoid alloy bonding material, thereby increasing the adhesion between the substrate and the ZnAl eutectoid alloy bonding material. as well as The bonding process involves heating the substrate, which was bonded to the ZnAl eutectoid alloy bonding material in the bonding improvement process, at a temperature that allows the substrate to be bonded to the ZnAl eutectoid alloy bonding material.

11. The method for manufacturing the joint according to claim 10, characterized in that, At least the bonding process is carried out in an atmosphere with an oxygen concentration of less than 30 ppm.

12. The method for manufacturing the joint according to claim 10 or 11, characterized in that, In the process of improving the tightness of the bond, the pressure applied to the substrate and the bonding material is increased at a rate of less than 1 mm / min.

13. The method for manufacturing the joint according to claim 10 or 11, characterized in that, The process for improving the tightness of the joint involves a preheating treatment, which refers to applying pressure to the substrate and the bonding material at a temperature lower than the bonding temperature at which the bonding can be performed in the bonding process but higher than the ambient temperature.

14. The method for manufacturing the joint according to claim 13, characterized in that, When the pressure applied to the substrate and the bonding material in the bonding process is defined as the bonding pressure, The pressure applied to the substrate and the bonding material during the preheating treatment is a preheating pressure lower than the bonding pressure.

15. The method for manufacturing the joint according to claim 10 or 11, characterized in that, Following the contact improvement process is a heating process, in which the temperature is increased to achieve the temperature conditions necessary for the bonding process to proceed. In the heating process, the temperature of the atmosphere exposed to the substrate and the bonding material is continuously increased.

16. The method for manufacturing the joint according to claim 10 or 11, characterized in that, In the process following the bonding improvement process, the pressure applied to the substrate and the bonding material is reduced during the heating of the substrate and the bonding material.

17. A ZnAl eutectoid alloy bonding material, comprising a ZnAl eutectoid alloy with Zn and Al as its basic components, characterized in that, Containing more than 20% by mass and less than 30% by mass of Al, It contains at least one additive element selected from the group consisting of Ag, Co, Ge, Mn, Mo, Ni, Sb, and V, in a concentration ranging from 0.001% by mass to 2.0% by mass. The remainder contains Zn and unavoidable impurities.

18. The ZnAl eutectoid alloy bonding material according to claim 17, characterized in that, The added elements are selected from the group consisting of Ge, Mn, Ni, and V.

19. A ZnAl eutectoid alloy bonding material, comprising a ZnAl eutectoid alloy with Zn and Al as basic components, characterized in that, Containing 1.0% by mass and less than 5.0% by mass of Ge. The remaining portion contains Zn and unavoidable impurities. It exhibits a shear strength of over 40 MPa in the bond at 350°C.

20. A joint, characterized in that, It comprises a substrate and a bonding portion, the bonding portion being constructed from a ZnAl eutectoid alloy bonding material. The ZnAl eutectoid alloy bonding material is the ZnAl eutectoid alloy bonding material as described in claim 17 or 18.

21. The joint according to claim 20, characterized in that, The substrate is a copper substrate or a low-phosphorus nickel-plated substrate.

22. A joint, comprising a ZnAl eutectoid alloy bonding material as described in claim 19, characterized in that, The substrate is a copper substrate or a nickel-plated substrate.

23. A method for manufacturing a joint, the joint comprising a substrate and a joint portion comprising a ZnAl eutectoid alloy bonding material, characterized in that... The ZnAl eutectoid alloy bonding material according to claim 17 or 18 is used as the bonding material for the ZnAl eutectoid alloy. The method for manufacturing the joint includes: The process for improving the adhesion involves applying pressure while bringing the substrate into contact with the ZnAl eutectoid alloy bonding material, thereby increasing the adhesion between the substrate and the ZnAl eutectoid alloy bonding material. as well as The bonding process involves heating the substrate, which was bonded to the ZnAl eutectoid alloy bonding material in the bonding improvement process, at a temperature that allows the substrate to be bonded to the ZnAl eutectoid alloy bonding material.

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