Components for electrical and electronic equipment

Abstract

An electrical and electronic device component is provided, which is formed by welding multiple plates of copper-based material and exhibits high weld strength. The component comprises multiple plates containing 90% by mass or more Cu and has a welded portion that integrates the multiple plates by welding them together in a linear or point-like manner in an interlocking or overlapping state. The welded portion extends throughout the thickness of the plates, and in a cross-section cut along the direction of the extension of the welded portion, the Vickers hardness of the welded portion, measured at a position equivalent to half the thickness of the plates, is 60 or higher.

Description

Technical Field

[0001] This invention relates to components for electrical and electronic equipment. Background Technology

[0002] In recent years, with the increasing functionality and performance of electrical and electronic equipment, the heat generation of these devices has tended to increase. Furthermore, with the miniaturization of electrical and electronic equipment, the heat density also increases, making the heat generated for cooling increasingly important. Components used to cool this heat include, for example, vapor chambers as planar heat pipes. Copper-based materials (pure copper, copper alloys) with high thermal conductivity are preferred for vapor chamber materials.

[0003] Here, the vapor chamber has a sealed structure in which working fluid is added to the internal space formed by joining multiple plates at their outer periphery in an overlapping state, and then the joining is achieved by sealing under reduced pressure. Examples of relevant joining methods include laser welding, resistance welding, diffusion bonding, and TIG welding.

[0004] When joining materials through these welds, the weld is formed by heating the material to a high temperature, temporarily melting it, and then solidifying it. Therefore, similar to annealing sheet metal, this process softens the material, resulting in a reduction in strength relative to the material's inherent strength. When strength decreases, the material becomes more prone to deformation.

[0005] Regarding this issue, Patent Document 1 discloses the following technology: In a method for manufacturing a heat spreader by joining multiple components through diffusion bonding and solder bonding, a precipitation-hardening copper alloy is used as the material of the outer shell, and precipitation hardening is achieved through aging treatment, thereby improving the strength of the outer shell, etc.

[0006] However, the technology in Patent Document 1 has the following problems: it requires the use of precipitation-hardening copper alloys and cannot use non-precipitation copper alloys or pure copper. Additionally, the technology in Patent Document 1 has the following problems: it requires aging treatment, which leads to a decrease in productivity as the number of processes increases.

[0007] Therefore, it is desirable to improve the strength of welds by methods other than precipitation-hardening copper alloys and aging treatment.

[0008] The problem of reduced strength in the aforementioned welded parts exists not only in heat spreaders, but also in other electrical and electronic equipment such as busbars.

[0009] It should be noted that although Patent Document 2 discloses a technique for improving bonding strength by irradiating a laser along a specific trajectory, the technique in Patent Document 2 pertains to the bonding of aluminum and copper, and is difficult to apply to the bonding of copper-based materials. Specifically, copper-based materials have high thermal conductivity, resulting in easy heat dissipation. Furthermore, because laser light is easily reflected, copper-based materials are difficult to bond using laser welding. Therefore, in simple laser welding as described in Patent Document 2, the bonding strength is low and the bond cannot be fully established.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: International Publication No. 2017 / 164013

[0013] Patent Document 2: Japanese Patent Application Publication No. 2017-168340 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] The present invention was made in view of the above circumstances, and the objective is to provide an electrical and electronic component in which multiple plates formed of copper-based materials are joined by welding, and the welded joint has high strength.

[0016] Furthermore, the present invention also aims to provide an electrical and electronic component with rigidity and resistance to local deformation of the welded portion by controlling the hardness of the welded plate and the slope of the overall hardness of the plate in components such as heat spreaders and busbars that have welded portions.

[0017] Methods for solving problems

[0018] Through repeated and in-depth research, the inventors of this application discovered that by using a plate composed of more than 90% Cu by mass and controlling the laser welding conditions, the Vickers hardness (HV) of the welded part can be increased. In addition, the inventors of this application discovered that by controlling the appropriate hardness and the slope of the hardness from the welded part to the non-welded part, it becomes rigid and the welded part is less prone to local deformation, thus completing the component for electrical and electronic equipment of the present invention.

[0019] That is, the main structure of the present invention is as follows.

[0020] (1) A component for electrical and electronic equipment, comprising multiple plates containing 90% by mass or more Cu, wherein the aforementioned component for electrical and electronic equipment has a welded part that integrates the aforementioned multiple plates into a linear or dotted shape by welding them together in a mutually facing or overlapping state.

[0021] The aforementioned welded portion extends throughout the thickness of the aforementioned plate.

[0022] In the cross-section when the aforementioned weld portion is cut in the direction in which the aforementioned plurality of plates are joined,

[0023] The Vickers hardness HV1 of the aforementioned welded part, measured at a position at the center of the weld mark (i.e., the weld width) at a dimension equivalent to half the thickness of the aforementioned plate, is 60 or higher.

[0024] (2) The electrical and electronic equipment component as described in (1), wherein, in the aforementioned cross section, when measuring the GAM value obtained from crystal orientation analysis data by SEM-EBSD method in a rectangular area divided by the weld width of the aforementioned welded part and the thickness of the aforementioned plate, the area ratio of the aforementioned grains with a GAM value of 0.5° or more and less than 2.0° relative to all grains present in the measurement area is 25% or more.

[0025] (3) The electrical and electronic equipment component as described in (1) or (2) is composed of multiple plates containing 90% by mass or more Cu. The component has a welded portion that integrates the multiple plates by welding them together in a linear or dotted manner, with the welded portion extending throughout the thickness of the plates. In a cross-section cut along the direction of the extended portion of the joined plates, a measurement is taken at a position corresponding to half the thickness of the plate, at the center of the width of the weld mark (i.e., the weld width) on the surface of the plate. When the Vickers hardness at the aforementioned welded portion is set to HV1 at a fixed time, and the Vickers hardness at the aforementioned non-welded portion is set to HV2 at a position separated from the center of the aforementioned welded portion by a distance equivalent to only 1.5 times the half-width of the weld along the direction of the weld width, the Vickers hardness HV2 at the aforementioned non-welded portion is 75 or higher, and the hardness slope ((HV2-HV1) / X) when the difference between the Vickers hardness HV2 at the aforementioned non-welded portion and the Vickers hardness HV1 at the aforementioned welded portion is divided by the indentation spacing X (μm) between the positions where the Vickers hardness HV1 and HV2 are measured is 0.2 / μm or lower.

[0026] (4) The electrical and electronic equipment component described in any one of (1) to (3), wherein the aforementioned plate contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P.

[0027] (5) The electrical and electronic equipment component described in any of (1) to (3), wherein the aforementioned plate material is 99.96% by mass or more of Cu and unavoidable impurities.

[0028] (6) The electrical and electronic equipment component described in any of (1) to (5), wherein the aforementioned electrical and electronic equipment component is a heat exchange plate.

[0029] (7) The electrical and electronic equipment component described in any of (1) to (5), wherein the aforementioned electrical and electronic equipment component is a busbar.

[0030] The effects of the invention

[0031] According to the present invention, it is possible to provide an electrical and electronic component that is formed by welding multiple plates of a copper-based material containing more than 90% by mass of Cu, and the welded portion has high strength.

[0032] Furthermore, according to the present invention, by obtaining appropriate hardness at the welded portion and controlling the slope of hardness from the welded portion to the non-welded portion, it is possible to provide a component for electrical and electronic equipment that is rigid and whose welded portion is not prone to local deformation. Attached Figure Description

[0033] [ Figure 1 (a) is a schematic perspective view of two Cu plates constituting an electrical and electronic device component according to an embodiment of the present invention being laser-welded into a line in an apposed state; (b) is a schematic perspective view of two Cu plates constituting an electrical and electronic device component according to an embodiment of the present invention being laser-welded into a line in an overlapping state.

[0034] [ Figure 2 This is an optical microscope photograph taken from the Z-axis showing the surface condition of the side of a Cu joint (a joint of two Cu plates) that has been laser-welded with a laser.

[0035] [ Figure 3 [Optical micrographs showing the surface state of a Cu joint obtained by laser welding of mating Cu plates, with the side opposite to the side irradiated by the laser.]

[0036] [ Figure 4 This is an optical microscope photograph showing the cross-sectional state of a Cu joint obtained by laser welding of Cu plates from the X-axis.

[0037] [ Figure 5 (a) is a schematic perspective view of two Cu plates laser-welded into a dotted shape when they are in an apposed state, and (b) is a schematic perspective view of two Cu plates laser-welded into a dotted shape when they are overlapping. Both views are shown in a state where the cross-section of the welded part can be seen in the direction in which the Cu joint extends.

[0038] [ Figure 6This diagram illustrates the general structure of a laser welding apparatus.

[0039] [ Figure 7 [A diagram showing the laser spot diameter of the laser welding device.]

[0040] [ Figure 8 (a) is a schematic perspective view of two Cu plates constituting a component for an electrical or electronic device according to another embodiment of the present invention joined together in a folded state to form a linear shape; (b) is a schematic perspective view of two Cu plates constituting a component for an electrical or electronic device according to another embodiment of the present invention joined together in an overlapping state to form a linear shape.

[0041] [ Figure 9 [This is an optical microscope photograph taken when observing the cross-sectional state of the joined Cu plates.] Detailed Implementation

[0042] The embodiments of the present invention will be described below. These descriptions are examples of embodiments of the present invention and do not limit the scope of the claims.

[0043] As one embodiment of the present invention, the component for electrical and electronic equipment is composed of multiple plates containing 90% by mass or more Cu, and has a welded portion that integrates the multiple plates by welding them together in a linear or dotted manner in a mutually facing or overlapping state. The welded portion extends throughout the thickness of the plates, and in a cross section when the welded portion is cut in the direction of the extension of the joined plates, the Vickers hardness of the welded portion measured at a position corresponding to half the thickness of the plates is 60 or more.

[0044] Figure 1 (a) is a schematic perspective view of a Cu joint 10 (a joint of two Cu plates) formed by laser welding two Cu plates 1 and 2 in a line-joined state. Figure 1 (b) is a schematic three-dimensional view of a Cu joint 10A formed by laser welding two Cu plates 1 and 2 in an overlapping state in a linear manner. Figure 1 In the embodiment shown in (a), a welded portion 3 is formed by joining Cu plates 1 and 2 together in a linear manner in an apposed state to create an integral welded portion, which is then joined by laser welding. Furthermore, Figure 1 In the embodiment shown in (b), a welded portion 3A is provided to integrate the Cu plates 1 and 2 in an overlapping state, and this portion is joined by laser welding. Furthermore, the welded portion 3A extends throughout the thickness of the plates 1 and 2. That is, Figure 1 (a) and Figure 1In (b), the welded portion 3 exists in such a way that it melts and solidifies in a manner that penetrates from the surface on the side irradiated by the laser to the opposite surface (back side), thereby penetrating through the plates 1 and 2 in the thickness direction. It should be noted that the term "Cu plate" here refers to a plate containing more than 90% by mass of Cu (copper).

[0045] Here, "plate containing more than 90% Cu by mass" means any plate with a Cu content of more than 90% by mass. It can be pure Cu or any Cu alloy, without any special restrictions.

[0046] When the sheet metal is a Cu alloy, it preferably has the following composition: containing one or more elements selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P as alloying elements, with Cu accounting for 90% by mass or more as the balance. The Cu alloy can be either a precipitation-hardening Cu alloy or a non-precipitation-hardening Cu alloy. When the sheet metal is a Cu alloy, the Vickers hardness (HV) varies depending on the type and amount of alloying elements added, and is therefore not particularly limited; for example, it is generally between 75 and 240.

[0047] Furthermore, when the plate material is pure Cu, the Cu content is 99.96% by mass or higher, and the total of unavoidable impurities Cd, Mg, Pb, Sn, Cr, Bi, Se, and Te is less than 5 ppm, and the total of Ag and O is less than 400 ppm. Since pure Cu exhibits excellent thermal conductivity, it can perform well as a heat-exothermic / cooling component. It should be noted that examples of "pure Cu" include electrolytic copper, oxygen-free copper (OFC), and TPC. When the plate material is pure Cu, the Vickers hardness is not particularly limited; it is generally between 65 and 120.

[0048] Furthermore, in this invention, the term "sheet material" refers to a sheet material processed into a specified shape, such as a plate, strip, foil, rod, or flat wire, and is a sheet material with a specified thickness. In a broader sense, it includes strip materials. In this invention, the thickness (sheet thickness) of the sheet material is not particularly limited, but is preferably 0.05–1.0 mm, more preferably 0.1–0.8 mm. It should be noted that the shapes and thicknesses (sheet thicknesses) of the multiple sheets material joined together can be the same or different.

[0049] Figure 2This photograph shows the surface condition of the side of the Cu joint 10 obtained by laser welding two mating Cu plates 1 and 2, on which the laser was irradiated. The X-axis direction indicates the laser scanning direction, i.e., the welding direction. Furthermore, it can be seen that there are portions where the rolling marks of the Cu plates disappear after laser irradiation. Also, there are portions where the Cu plates 1 and 2 melt and then solidify again; these are referred to as the welded portion 3.

[0050] Figure 3 An optical microscope photograph taken to observe the surface condition of the Cu joint 10 obtained by laser welding two Cu plates 1 and 2, opposite to the side irradiated by the laser. Figure 2 An optical microscope photograph of the surface condition of the back side.

[0051] like Figure 2 and Figure 3 As shown, the weld portion 3 extends across the entire thickness of plates 1 and 2, therefore laser weld marks appear on the surface of the Cu joint 10 on the side irradiated by the laser (front side) and on the surface opposite to the side irradiated by the laser (back side). Furthermore, as... Figure 2 and Figure 3 As shown, the width of the laser weld mark on the surface irradiated by the laser is typically wider than the width of the laser weld mark on the surface opposite to the irradiated side. The width of the laser weld mark on the irradiated surface is defined as the weld width in this invention, and the section is cut at the dashed cross-sectional observation position for cross-sectional microstructure observation.

[0052] Figure 4 An optical microscope photograph showing the cross-sectional state of a Cu joint formed by laser welding of Cu plates. (e.g.) Figure 4 As shown, the width of the laser-irradiated side of the weld, which melts and then solidifies again after being irradiated by a laser, is equivalent to the weld width. From Figure 4 The cross-sectional view shown also confirms the weld width.

[0053] In this invention, at the cross-section where the weld portion is cut along the direction extending from the two joined plates, the Vickers hardness of the weld portion measured at a position equivalent to half the thickness of the plates is 60 or higher. It should be noted that in this specification, the Vickers hardness HV is measured according to the method specified in JIS Z2244 (2009).

[0054] In detail, such as Figure 1As shown in (a), when a welded portion 3 is used to linearly join two Cu plates 1 and 2 in a mutually opposing state to form an integral unit, if the welding direction (laser scanning direction) is set to the X-axis direction, the direction perpendicular to the welding direction (the width direction of the plates) is set to the Y-axis direction, and the normal direction of the plates (the thickness direction of the plates) is set to the Z-axis direction, the direction L in which the two joined plates 1 and 2 extend is the direction that brings the plates close together to form an opposing state, which is the Y-axis direction. In the case of the electrical and electronic equipment component of this embodiment with such a joint body 10, the Vickers hardness of the welded portion 3 at position b, which is equivalent to half the thickness a of the Cu plates 1 and 2, when the Cu joint body 10 is cut along the Y-axis direction, needs to be 60 or higher.

[0055] In addition, such as Figure 1 As shown in (b), in the case of a welded portion 3A that integrates two Cu plates 1 and 2 by linearly joining them in a mutually overlapping state, the direction in which the two joined plates 1 and 2 extend is perpendicular to the welding direction, i.e., the Y-axis direction. In the case of the electrical and electronic equipment component of this embodiment with such a joint 10A, the Vickers hardness of both the position b1, which corresponds to half the thickness a1 of the Cu plate 1 in the welded portion of the Cu plate 1 at cross section A1 of the Cu plate 1, and the position b2, which corresponds to half the thickness a2 of the Cu plate 2 in the welded portion of the Cu plate 2 at cross section A2 of the Cu plate 2, when the Cu joint 10A is cut along the Y-axis direction, needs to be 60 or higher.

[0056] In welding, the weld is formed by temporarily melting and then solidifying the material at a high temperature. Therefore, similar to annealing the sheet metal, conventional welding methods result in softening, leading to a reduction in strength relative to the sheet's inherent strength. This reduced strength makes the material more prone to deformation.

[0057] However, as shown in the embodiments described later, by using a plate composed of 90% or more Cu by mass and controlling the laser welding conditions, the strength reduction caused by softening of the welded portion can be suppressed. It should be noted that, depending on the laser welding conditions, it is also possible to achieve a strength higher than that of the plate itself.

[0058] Therefore, in this embodiment, the Vickers hardness of the welded portion can be 60 or higher, and more specifically 65 or higher. Since the Vickers hardness of the welded portion is as high as 60 or higher, it is possible to provide electrical and electronic equipment components with high strength and excellent resistance to deformation. Vickers hardness and strength are proportional; therefore, when the Vickers hardness is high, the strength is high. It should be noted that, when aging treatment is performed as in Patent Document 1, it is considered that unless a hardening type copper alloy is not used, the Cu joint including the welded portion tends to soften upon heating, making it difficult to maintain the Vickers hardness of the welded portion at 60 or higher.

[0059] There is no particular upper limit to the Vickers hardness (HV) of the welded part. In the case of pure Cu, it is, for example, below 90. In the case of Cu alloy, it is, for example, below 130.

[0060] The above explanation pertains to line laser welding, while... Figure 5 (a) and (b) show the case of spot laser welding. Figure 5 (a) is a schematic three-dimensional view of a Cu joint 10B formed by spot laser welding of two Cu plates 1 and 2 in an aligning state. Figure 5 (b) is a schematic three-dimensional view of a Cu joint 10C formed by spot laser welding of two Cu plates 1 and 2 in an overlapping state.

[0061] like Figure 5 As shown in (a), in the case of the electrical and electronic equipment component of this embodiment with the Cu joint 10B, the Vickers hardness needs to be 60 or more at position b, which is half the thickness a of the Cu plates 1 and 2 present in the weld portion 3B of the cross section A. The Cu joint 10B has a weld portion 3B that is joined in a point-like manner to form an integral part when they are in a mating state. The cross section A is formed when the joint 10B is cut through the center c of the weld portion 3B on the surface of the plate along the extending direction L of the Cu plates 1 and 2.

[0062] In addition, such as Figure 5 As shown in (b), in the case of the electrical and electronic equipment component of this embodiment with the Cu joint 10C, the Vickers hardness at both positions b1 (equivalent to half the thickness a1 of the Cu plate 1 at the weld portion in cross section A1 of the Cu plate 1) and b2 (equivalent to half the thickness a2 of the Cu plate 2 at the weld portion in cross section A2 of the Cu plate 2) needs to be 60 or higher. The Cu joint 10C has weld portions 3B that are joined together in a point-like manner in an overlapping state, thus forming an integral part. Cross sections A1 and A2 are formed when the weld portion is cut along the lamination direction of the plate through the center c of the weld portion on the plate surface.

[0063] It should be noted that, in this specification, the Vickers hardness HV in the case of linear laser welding is measured in 5 cross sections A (YZ planes) obtained by cutting at 1mm intervals along the welding direction (X-axis direction), and the average value of their measurement results is used as the result.

[0064] In this invention, it is preferable that when the weld portion is cut in the cross section extending along the direction of the joined plates, and the GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is measured in a rectangular area divided by the weld width of the weld portion and the thickness of the plates, the area ratio of grains with a GAM value of 0.5° or higher and less than 2.0° relative to all grains present in the measurement area is 25% or higher.

[0065] The GAM (grain average orientation difference) value is obtained from crystal orientation analysis data by SEM-EBSD method. It is calculated by measuring the distance between measurement points (hereinafter also called step size) at 0.1 μm within a grain that is distinguished by large-angle grain boundaries with an orientation difference of more than 15°, calculating the orientation difference of each adjacent measurement point, and using the calculated orientation difference as the average value within the same grain.

[0066] A small GAM value indicates a small average orientation difference within the grain, uniform grains with very little strain, and a continuous orientation gradient, etc., meaning small strain within a single grain. Conversely, a large GAM value indicates a large average orientation difference within the grain, meaning large strain within a single grain. Grains with a GAM value of 0.5° or higher but less than 2.0° exhibit characteristics between these values, indicating a relatively large strain within a single grain. It should be noted that when annealing the sheet material, the GAM value is typically 0° or higher but less than 0.5°, indicating a decrease in localized strain within a single grain.

[0067] In this way, when the area ratio of grains with a GAM value of 0.5° or higher and less than 2.0° is 25% or higher, that is, when the area ratio of grains with a relatively large strain within a single grain is 25% or higher, in the case of pure Cu, the Vickers hardness of the welded part can be made to be 65 or higher.

[0068] The area ratio of grains with a GAM value of 0.5° or higher and less than 2.0° is preferably 45% or higher, more preferably 65% ​​or higher. Furthermore, there is no particular upper limit to the area ratio of grains with a GAM value of 0.5° or higher and less than 2.0°, for example, it is 95% or lower, preferably 90% or lower.

[0069] The GAM value can be obtained from the following crystal orientation analysis data, which is calculated using analysis software (TSL, OIM Analysis) based on crystal orientation data obtained by continuous measurement using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA). "EBSD" is short for Electron Backscatter Diffraction, a crystal orientation analysis technique that utilizes the Kikuchi line diffraction of reflected electrons generated when a copper plate as a sample is irradiated with an electron beam within a scanning electron microscope (SEM). "OIM Analysis" is the analysis software that uses the data measured using EBSD.

[0070] In this invention, the measurement area refers to the rectangular area defined by the weld width of the welded portion and the thickness of the plate on the surfaces of the aforementioned cross-sections A, A1, and A2, after mirror finishing through electrolytic polishing. The area ratio of grains with GAM values ​​within the specified range can be calculated as follows: GAM values ​​above 0° and below 0.25° are designated as the first partition; 15 partitions are defined with a scale of 0.25°; and GAM values ​​from 0° to below 3.75° are designated as the measurement objects. The area ratio of grains in each partition within the overall SEM image obtained using the SEM-EBSD method is used to calculate the measurement area ratio.

[0071] Preferably, the Cu sheet used in this electrical and electronic equipment component contains 90% by mass or more Cu, a Cu alloy containing other metallic elements, or 99.96% by mass or more Cu and unavoidable impurities of pure Cu. By using a Cu sheet with 90% by mass or more Cu, thermal conductivity is achieved. Cu inherently possesses high thermal conductivity, but due to the addition of more elements and the appearance of a second phase, thermal conductivity decreases. Therefore, the Cu sheet used in the electrical and electronic equipment component of this embodiment, by containing 90% by mass or more Cu, can suppress the decrease in thermal conductivity and possess high strength.

[0072] Furthermore, when observing the cross-section of multiple integral plates cut along the direction of the transverse weld, in the welded portion and the non-welded portion adjacent to the welded portion, for the welded portion, at the center of the weld width (where the width of the weld mark on the plate surface is taken as the weld width), and for the non-welded portion, at a distance of 1.5 times the weld width along the width direction from the center of the welded portion, the Vickers hardness HV1 and HV2 at the heat-affected portion are 75 or higher, and the value of dividing the difference between the Vickers hardness HV2 at the heat-affected portion and the Vickers hardness HV1 at the welded portion by the indentation spacing X (μm) between the positions where the Vickers hardness HV1 and HV2 are measured (hereinafter referred to as "hardness slope") ((HV2-HV1) / X) is 0.2 / μm or less.

[0073] (Linear welding)

[0074] like Figure 8 (a) (only in) Figure 8 As shown in the description (with added numbers), this is a Cu component 10D consisting of two Cu plates 101 and 102 arranged in an mating state. The two Cu plates 101 and 102 are linearly welded by irradiating and scanning their center with a laser, joining them at the center 121 of the weld portion 12. Here, the linear joint is formed by scanning the laser. The portion irradiated with a strong laser forms molten liquid Cu. Then, after the laser passes through, due to Cu's high thermal conductivity, the liquid Cu rapidly cools and transforms into solid Cu. When this operation is performed continuously, a weld portion 12 with a wavy weld bead is formed. Due to temporary melting and solidification, it is clearly in a different state from the base material 11 of the Cu plates 101 and 102. Furthermore, a heat-affected portion 13, which is in a different state from the surface of the base material 11 of the Cu plates 101 and 102, is formed around this weld portion 12 due to the heat. For the heat-affected portion 13, the properties of the base material 11 of the Cu plates 101 and 102 also change due to the heat. The heat affecting the heat-affected portion 13 includes heat from laser irradiation and heat generated from the weld 12. For example... Figure 8 As shown in (b), by irradiating and scanning two Cu plates 101 and 102 in an overlapping state, a Cu component 10D is obtained by welding the surfaces of the Cu plates in a linear manner. In order to obtain sufficient bonding strength, the welding is performed such that the width of the overlapped Cu plates 101 and 102 in the Y-axis direction is more than 1 / 2 of the welding width of the surface.

[0075] (Point welding)

[0076] By irradiating the center of two Cu plates together with a laser instead of scanning it, a point-like joint can be formed. The laser can be any shape, such as circular, elliptical, barrel-shaped, or rectangular. Alternatively, the point can be a dashed line, as long as the welded parts are separated. In point welding, the Cu plates can be joined along their thickness direction, or the melting of the Cu metal can be stopped midway. Alternatively, two Cu plates can be joined by irradiating them with a laser while they are overlapping. In this case, to obtain sufficient joint strength, the width of the weld along the Y-axis of the overlapping Cu plates should be at least half the width of the weld surface.

[0077] (Surface condition of Cu component)

[0078] Figure 2 This photograph shows the surface condition of a Cu component joined by laser welding of mating Cu sheets, with the X-axis indicating the laser scanning direction. It also shows areas where the rolling marks of the Cu sheets disappear after laser irradiation. Furthermore, it clearly shows areas where the Cu sheets melted and then solidified again; these are the welded areas. The width of the welded area showing the laser welding marks in the figure is defined as the weld width in this invention, and the cross-sectional structure is observed by cutting at the dashed-line viewpoint.

[0079] (Location for measuring Vickers hardness of linear joints)

[0080] Figure 9 An optical microscope photograph showing the cross-sectional view of a Cu component joined by laser welding of Cu sheets. (e.g.) Figure 9 As shown, the weld width is represented by the portion joined by melting and solidifying after being irradiated by a laser. From Figure 9 The cross-sectional view clearly shows the width of the weld mark on the Cu plate surface on the side irradiated by the laser. The portion extending forward from the center of the weld along the weld width direction, a distance equal to 1.5 times the weld width (weld half-width), is called the non-welded portion. In the thickness direction at these two locations, such as... Figure 9 As indicated by the arrows, the Vickers hardness HV1 and HV2 of the welded and non-welded portions are measured at a depth of 1 / 2 of the plate thickness in the center of the weld width.

[0081] (Vickers hardness)

[0082] Vickers hardness refers to the test method standardized by JIS Z 2244. Vickers hardness (HV) uses a rigid diamond indenter to press against the test material, and the size of the resulting indentation (grooving) is used to numerically represent hardness or softness. Because the indenter has a pyramidal shape, like an inverted pyramid, the ideal indentation is square. The test force is variable, specified in the JIS standard as 10 gf to 100 kgf.

[0083] (Slope of hardness)

[0084] For the measurement of non-welded parts, Figure 8 In the case of mating shown in (a), the Vickers hardness of the non-welded part is set as HV2 by measuring the average value of the two positions relative to the center of the welded part, perpendicular to the direction of laser propagation. Additionally, in Figure 8 In the case of overlap shown in (b), the position perpendicular to the direction of laser propagation and opposite to the adjacent end is measured relative to the center of the welded part and is set as the Vickers hardness HV2 of the non-welded part.

[0085] For the Cu plate at this time, the Vickers hardness HV1 and HV2 are measured at the center of the weld and the non-welded part. The difference between the Vickers hardness HV2 at the non-welded part and the Vickers hardness HV1 at the center of the weld is divided by the indentation spacing X μm between the locations where the Vickers hardness HV1 and HV2 are measured ((HV2-HV1) / X) as the hardness slope.

[0086] (Location for measuring Vickers hardness of point-bonded joints)

[0087] In spot welding, the widest part of the spot weld is taken as the weld width, and the cross-section of this part is taken as the measured surface. Therefore, the non-welded part is the part adjacent to the spot weld, located 1.5 times the weld half-width from the center of the weld along the width direction.

[0088] Therefore, the hardness is measured at the center point of the widest part of the dotted surface and at a point on the non-welded portion separated from that point by a certain distance. From this, the Vickers hardness HV1 and HV2 can be measured, and the hardness slope can be calculated.

[0089] (Distribution of hardness)

[0090] Hardness indicates the difficulty of deformation and damage to a Cu sheet, particularly its surface, when deformation and scratches are possible. Especially in joints formed by welding two Cu sheets together, a distribution of hardness can make them more prone to cracking. This is because when stress is applied to a sheet containing a mixture of hard and soft portions, stress concentration can occur, making the softer portions more susceptible to deformation and cracking. Therefore, Cu sheets where the thermal effects of laser welding (heat and cold) differ significantly from those of the molten and solidified weld portion become more prone to deformation and cracking under stress. Consequently, in the manufacture of electrical and electronic equipment components, a high hardness gradient can sometimes lead to cracking and breakage.

[0091] Therefore, it is desirable to have a small hardness slope that represents the change in hardness between the base material, non-welded portion, and welded portion of the Cu sheet. A larger hardness slope results in a greater difference in hardness between the base material, non-welded portion, and welded portion of the Cu sheet, leading to brittleness due to stress concentration and a higher likelihood of cracking. Therefore, the hardness slope ((HV2-HV1) / X), calculated by dividing the difference between the Vickers hardness HV1 used in the welded portion and the Vickers hardness HV2 located in the non-welded portion adjacent to the welded portion by the indentation spacing X (μm) between the locations where Vickers hardness HV1 and HV2 are measured, is set to 0.2 / μm or less, more preferably 0.15 / μm or less.

[0092] Furthermore, there is a practical problem that components used in electrical and electronic equipment are prone to deformation during actual use, requiring rigidity from the hardness of the Cu sheet material itself. Therefore, in this invention, it is preferable that the Vickers hardness HV2 of the Cu sheet portion other than the welded portion, especially the non-welded portion located adjacent to the welded portion, be 75 or higher.

[0093] (Cu alloy sheet)

[0094] Any sheet material with a Cu content of 90% or more by mass is acceptable; it can be pure Cu or any Cu alloy, with no particular restrictions.

[0095] When the Cu sheet used as a component in electrical and electronic equipment is a Cu alloy, it preferably has the following composition: containing one or more elements selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P as alloying elements, with Cu accounting for 90% by mass or more as the balance. The Cu alloy can be a precipitation-hardening Cu alloy or a non-precipitation-hardening Cu alloy. When the sheet is a Cu alloy, the Vickers hardness HV2 at the non-welded areas is in the range of 75 to 240.

[0096] By using Cu alloy as the Cu sheet material, the hardness slope can be kept below 0.2 / μm, thus suppressing crack formation. Furthermore, not only the hardness slope, but also the base material, non-welded portions, and welded portions of the Cu sheet material are preferably hard, especially the Vickers hardness HV2 at the non-welded portions, which is preferably in the range of 75 to 240. When the Vickers hardness HV2 at the non-welded portions of the Cu alloy sheet is less than 75, it becomes easily deformed during processing. When the Vickers hardness HV2 at the non-welded portions is greater than 240, deformation of the welded portion and cracks easily appear at the boundaries between the non-welded portion and the base material / welded portion.

[0097] (Pure Cu plate)

[0098] Furthermore, when the Cu sheet used as a component for electrical and electronic equipment is pure Cu containing 99.96% by mass or more of Cu and unavoidable impurities, a Vickers hardness HV2 of 75 to 120 is preferred for the non-welded portion. It is preferable that the hardness slope of the Cu sheet material, the welded portion, and the non-welded portion is small. By using pure Cu sheet material, a hardness slope of 0.1 / μm or less can be achieved, thereby making local deformation of the welded portion difficult. In particular, in pure Cu sheet material, when the Vickers hardness HV2 at the non-welded portion is less than 75, deformation becomes easier during processing. When the Vickers hardness HV2 at the non-welded portion is greater than 120, deformation of the welded portion, and cracks easily appear at the boundaries between the non-welded portion and the base material, and between the welded portion and the non-welded portion.

[0099] Next, the reasons for the limitation of the preferred composition of the sheet metal constituting the electrical and electronic equipment component of the present invention will be explained below.

[0100] The plate material constituting the electrical and electronic equipment component of the present invention can be any plate material containing 90% by mass or more of Cu, and can be a Cu alloy or pure Cu, either is acceptable.

[0101] First, let's explain the composition of the plate material when it is a Cu alloy.

[0102] (1) Case where the plate is a Cu alloy

[0103] The sheet material preferably contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P.

[0104] (Ag: 0.05–5.00% by mass)

[0105] Silver (Ag) is a component that improves mechanical properties without compromising electrical properties. To achieve this effect, an Ag content of 0.05% by mass or more is preferred. Furthermore, no specific upper limit needs to be set for the Ag content. However, due to the high price of Ag, from a material cost perspective, an upper limit of 5.0% by mass is preferred.

[0106] (Fe: 0.05–0.50% by mass)

[0107] Iron (Fe) is a component that improves mechanical properties. To achieve this effect, an Fe content of 0.05% by mass or more is preferred. However, even with a Fe content exceeding 0.50% by mass, a greater improvement cannot be expected, and a decrease in corrosion resistance may occur. Therefore, an Fe content of 0.05 to 0.50% by mass is preferred.

[0108] (Ni: 0.05–5.00% by mass)

[0109] Ni (nickel) is a component that functions as follows: in the parent phase (matrix) of Cu, it precipitates as second-phase particles formed from elemental matter or compounds with Si, for example, in fine particles of about 50 to 500 nm in size. These precipitates inhibit dislocation movement, causing precipitation hardening, and also inhibit grain growth, thereby increasing material strength through grain refinement. To achieve this effect, a Ni content of 0.05% by mass or more is preferred. On the other hand, when the Ni content exceeds 5.00% by mass, the decrease in electrical conductivity and thermal conductivity becomes significant; therefore, an upper limit of 5.00% by mass for the Ni content is preferred.

[0110] (Co: 0.05–2.00% by mass)

[0111] Co (cobalt) is a component that functions as follows: in the Cu matrix, it precipitates as a second-phase particle, formed from elemental matter or a compound with Si, in a fine size of approximately 50 to 500 nm. This precipitate inhibits dislocation movement, causing precipitation hardening, and also inhibits grain growth, thereby increasing material strength through grain refinement. To achieve this effect, a Co content of 0.05% by mass or more is preferred. On the other hand, when the Co content exceeds 2.00% by mass, the decrease in electrical conductivity and thermal conductivity becomes significant; therefore, an upper limit of 2.00% by mass or less of the Co content is preferred.

[0112] (Si: 0.05–1.10% by mass)

[0113] Silicon (Si) is an important component that functions as follows: in the parent phase (matrix) of Cu, it precipitates finely as a second-phase particle formed by compounds, along with Ni, Co, etc. This precipitate hardens by inhibiting dislocation movement and, by suppressing grain growth and refining the grains, increases the material's strength. To achieve this effect, a Si content of 0.05% by mass or more is preferred. On the other hand, when the Si content exceeds 1.10% by mass, the decrease in electrical conductivity and thermal conductivity becomes significant; therefore, an upper limit of 1.10% by mass for the Si content is preferred.

[0114] (Cr: 0.05–0.50% by mass)

[0115] Cr (chromium) is a component that functions as a compound or element in the Cu matrix, precipitating finely as a precipitate with a size of approximately 10 to 500 nm. This precipitation hardens the material by inhibiting dislocation movement and, by suppressing grain growth and refining the grains, increases the material's strength. To achieve this effect, a Cr content of 0.05% by mass or more is preferred. Furthermore, when the Cr content exceeds 0.50% by mass, the decrease in electrical conductivity and thermal conductivity becomes significant; therefore, a Cr content of 0.05 to 0.50% by mass is preferred.

[0116] (Sn: 0.05~9.50% by mass)

[0117] Sn (tin) is a component dissolved in the matrix phase of Cu, which helps to improve the strength of Cu alloys. It is preferable that the Sn content is 0.05% by mass or more. On the other hand, when the Sn content is greater than 9.50% by mass, embrittlement becomes more likely. Therefore, it is preferable that the Sn content is 0.05 to 9.50% by mass. Furthermore, since the presence of Sn tends to decrease electrical conductivity and thermal conductivity, it is more preferable that the Sn content is 0.05 to 0.50% by mass while suppressing the decrease in electrical conductivity and thermal conductivity.

[0118] (Zn: 0.05-0.50% by mass)

[0119] Zinc (Zn) is a component that improves the adhesion and migration properties of Sn plating and solder plating. To achieve this effect, a Zn content of 0.05% by mass or more is preferred. On the other hand, when the Zn content exceeds 0.50% by mass, the amount of zinc vapor increases during welding, which may cause defects in the weld. Therefore, a Zn content of 0.05 to 0.50% by mass is preferred.

[0120] (Mg: 0.01–0.50% by mass)

[0121] Magnesium (Mg) is a component that improves mechanical properties. To achieve this effect, it is preferable that the Mg content is 0.01% by mass or more. On the other hand, when the Mg content exceeds 0.50% by mass, there is a tendency for a decrease in electrical conductivity and thermal conductivity. Therefore, it is preferable that the Mg content is 0.01 to 0.50% by mass.

[0122] (P: 0.01–0.50% by mass)

[0123] Phosphorus (P) not only contributes to the deoxidation of Cu alloys, but also precipitates finely as compounds with Fe, Ni, etc., in the form of precipitates with a size of about 20-500 nm. These precipitates inhibit dislocation movement, thus promoting precipitation hardening, and further, inhibit grain growth and increase material strength through grain refinement. To achieve this effect, a P content of 0.01% by mass or more is preferred. On the other hand, when the P content is greater than 0.50% by mass, there is a tendency for cracking to occur in the solidified portion after welding. Therefore, a P content of 0.01-0.50% by mass is preferred.

[0124] (2) When the plate material is pure Cu with excellent electrical conductivity and heat dissipation.

[0125] The plate is preferably made of pure Cu with a composition of more than 99.96% Cu and unavoidable impurities. The unavoidable impurities, such as Cd, Mg, Pb, Sn, Cr, Bi, Se and Te, are totaled at less than 5 ppm and Ag and O are each less than 400 ppm.

[0126] (Manufacturing methods for components used in electrical and electronic equipment)

[0127] A method for manufacturing a component for electrical and electronic equipment according to one embodiment of the present invention includes the following welding process: after setting multiple plates containing 90% or more Cu to be in an adjacent or overlapping state, the parts to be joined are irradiated with a first laser having a wavelength of 400 to 500 nm with a spot diameter of 100 to 500 μm, and irradiated with a second laser having a wavelength of 800 to 1200 nm with a spot diameter of 10 to 300 μm, and welding is performed while injecting an inactive gas containing 1 to 50 ppm oxygen into the molten part at a flow rate of 10 to 50 L / min, thereby joining the multiple plates together in a linear manner to form an integral unit.

[0128] This welding process makes it easier to weld Cu plates together, which was previously difficult, and enables the welded part to have a Vickers hardness of 60 or higher, thus resulting in a high-strength welded part.

[0129] Furthermore, the hardness gradient is controlled by setting the irradiation time of a first laser with a wavelength of 400-500 nm with a spot diameter of 100-500 μm and a second laser with a wavelength of 800-1200 nm with a spot diameter of 10-300 μm to 0.1-10 msec / spot (in the case of linear pattern, the scanning speed is equivalent to the distance of 1 spot diameter; in the case of dot pattern, the irradiation time is the time per spot).

[0130] (Laser welding method)

[0131] Laser welding is a welding method that uses a lens to focus a highly directional and concentrated wavelength of light, using a laser with extremely high energy density as a heat source. By adjusting the laser's output power, narrow-width penetration welds relative to depth can also be performed. Furthermore, compared to the electric arc in arc welding, the laser can be minimized. Through the high-density energy achieved using a focusing lens, laser welding devices can perform localized welding and join materials with different melting points. Because of the minimal heat-affected zone, fine weld lines, and absence of processing reaction forces, it is also suitable for micro-welding.

[0132] (Laser welding equipment)

[0133] Figure 6 This figure illustrates an example of the general configuration of a laser welding apparatus. The laser welding apparatus 20 includes a laser control unit 21, oscillators 221 and 222, a laser head 29, a processing table 24, and a gas supply nozzle 30. On the processing table 24, the materials to be processed, i.e., Cu plates 111 and 112, are arranged in a mating or overlapping state. The laser control unit 21 controls the laser oscillators 221 and 222 (not shown), a scanner, the laser head 29, the processing table, and the like. For example, the control unit 21 controls the forward direction of the materials to be processed, i.e., the Cu plates 111 and 112, by controlling the rotation of X-axis and Y-axis motors (not shown). Alternatively, the control unit 21 can also control the movement of lasers 231 and 232. This can be appropriately selected according to the size of the materials to be processed. The control unit 21 oscillates multiple first and second lasers 231 and 232 emanating from the oscillators 221 and 222. The oscillating first and second lasers 231 and 232 pass through glass fiber 25 and are focused into parallel light by the first and second focusing lenses 261 and 262 within the laser head 29. The first and second lasers 231 and 232 are redirected to the direction of the processing table using the first and second lenses 271 and 272. Welding is performed by focusing the first and second lasers 231 and 232 through the focusing lens 28 and irradiating the Cu plates 111 and 112 at the positions to be joined. At this time, to prevent oxidation due to laser heating, an inert gas is supplied from the gas supply nozzle 30. The inert gas can be appropriately selected from argon, helium, nitrogen, etc.

[0134] The laser used for welding can be appropriately selected from known lasers. Examples of lasers include CO2 lasers, Nd:YAG lasers, semiconductor lasers, and fiber lasers. Considering factors such as output and laser focusing properties, fiber lasers are preferred. Other components of the laser welding apparatus can be selected from any previously known configurations.

[0135] (Laser welding)

[0136] Figure 7 This diagram illustrates an example of the laser spot diameter in a laser welding apparatus. (See figure.) Figure 7 As shown, a first laser 231 with a wavelength of 400-500 nm is irradiated with a spot diameter of 100-500 μm. Furthermore, a second laser 232 with a wavelength of 800-1200 nm is irradiated with a spot diameter of 10-300 μm. Figure 7 The diagram shows an example where the first laser 231 and the second laser 232 irradiate the surface of the plate in an overlapping manner. By simultaneously irradiating multiple lasers with specific wavelengths and spot diameters, previously difficult Cu plates can be easily welded. Furthermore, by simultaneously welding while injecting an inert gas containing 1 to 50 ppm oxygen into the molten portion at a rate of 10 to 50 L / min, a weld with a Vickers hardness of 60 or higher can be obtained.

[0137] The inert gas supplied to the molten section contains 10–50 ppm of oxygen. Examples of inert gases include nitrogen and argon. It is hypothesized that by simultaneously performing laser welding with such an inert gas containing 10–50 ppm oxygen at a flow rate of 10–50 L / min, the molten section can be covered with the inert gas, and a suitable amount of oxygen can be supplied to the interior of the molten section. This generates fine oxides, thereby increasing the hardness of the weld and introducing a suitable strain into the grains through rapid cooling. When the oxygen content of the inert gas is less than 10 ppm, the hardness decreases because sufficient oxygen cannot be supplied. On the other hand, when it is greater than 50 ppm, excessive oxidation occurs internally, leading to embrittlement. Furthermore, when the flow rate of the inert gas containing 10–50 ppm oxygen is less than 10 L / min, insufficient shielding effect is achieved, excessive oxidation occurs, and the cooling rate of the molten section decreases, thus insufficient strain cannot be obtained within the crystallization. In addition, when the flow rate exceeds 50 L / min, the shape of the molten pool becomes unstable due to the large amount of gas injected into the molten section, which may result in poor solidification.

[0138] Furthermore, the irradiation time for irradiating a first laser 231 with a wavelength of 400-500 nm with a spot diameter of 100-500 μm, and for irradiating a second laser 232 with a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, is set to 0.1-10 msec / spot (milliseconds / spot). (In the case of linear irradiation, this is the scanning speed equivalent to the distance of one spot diameter; in the case of point irradiation, this is the irradiation time per spot.) When the irradiation time is shorter than 0.1 msec, bonding becomes difficult, and the hardness slope tends to become steep. On the other hand, when the irradiation time exceeds 10 msec, the metal may melt away from the weld, resulting in defects, softening, and insufficient strength.

[0139] The electrical and electronic equipment component of the present invention involves irradiating the joint areas of multiple plates together with first and second lasers 231 and 232 after the plates are positioned in an overlapping or mating state, thereby joining the multiple plates together in a linear or dot-like manner to form an integral unit. By heating the Cu plate with the first laser 231, which only efficiently penetrates the surface of the Cu plate, over a larger area than the second laser 232, and irradiating the Cu plate with the second laser 232, which deeply penetrates the Cu plate, almost simultaneously with the heating, welding processes with virtually no defects such as porosity or internal defects can be performed.

[0140] When the wavelengths and spot diameters of the first and second lasers 231 and 232 are outside the range, the surface quality deteriorates or welding becomes impossible, making it unsuitable. Furthermore, controlling the heating based on the first laser 231 affects the cooling rate during the melting and solidification of the plate using the second laser 232. In-depth research revealed that by setting the wavelength to below 0.1–10 msec / spot, changes in hardness in the base material, non-welded portions, and welded portions of the Cu plate can be suppressed. Furthermore, the hardness slope of the non-welded portions and welded portions of the Cu plate can be suppressed more effectively.

[0141] (The effect of welding)

[0142] In this way, by controlling the base material, non-welded parts, and welded parts of Cu sheet with a specified composition, it is possible to obtain electrical and electronic equipment components that have hardness, rigidity, and are not prone to local deformation of the welded parts.

[0143] (Applications in electrical and electronic equipment)

[0144] The electrical and electronic equipment components of the present invention are intended to be used in semiconductor devices, LSIs, or many electronic devices that utilize them, and are intended for use in, for example, connectors, battery terminals, sockets, relays, switches, autofocus camera modules, lead frames, and other electrical and electronic equipment that require miniaturization and high integration, such as home game consoles, medical devices, workstations, servers, personal computers, car navigation systems, mobile phones, and robots.

[0145] (Heat spreader)

[0146] One embodiment of the present invention provides an electrical and electronic component formed from pure Cu or Cu alloy, which has excellent thermal conductivity, high strength, and excellent resistance to deformation. Therefore, it is preferably used in heat pipes and heat spreaders.

[0147] Other embodiments of the present invention provide electrical and electronic equipment components with high rigidity and, in particular, low crack formation, making them preferably applicable to heat pipes and vapor chambers. Especially as a structural material for vapor chamber products, they are less prone to cracking, thus reducing leakage and corrosion during use caused by cracks, suppressing the decline in thermal conductivity, and contributing to the inhibition of vapor chamber product aging and extending service life.

[0148] (busbar)

[0149] One embodiment of the present invention provides an electrical and electronic component made of pure Cu or a Cu alloy, which has excellent thermal conductivity and high strength and excellent resistance to deformation. Therefore, it is preferably used as a busbar. The busbar can be used as an electrical path for electrical connection, and can also be used as a heat dissipation transport path. In particular, by connecting the busbar from the heat-generating part to the heat-dissipating part or an external path, it can also be used as a cooling device.

[0150] Furthermore, the busbars formed by the electrical and electronic equipment components according to other embodiments of the present invention have excellent characteristics in terms of local deformation, and therefore can be used as electrical paths for electrical connections. In addition, they can also be used as transport paths for heat dissipation. In particular, by connecting the busbar from the heat-generating part to the heat-dissipating part or the outside, they can also be used as cooling devices.

[0151] Example

[0152] The following describes embodiments of the present invention. The present invention may have various forms and is not limited to the following embodiments.

[0153] (Examples 1-6 and Comparative Examples 1-9) Joining of two identical plates formed of pure Cu

[0154] In Examples 1-5 and Comparative Examples 1-9, a sheet material formed from pure Cu having the composition described in Table 1 was cut into two sheets with a thickness of 0.15 mm, a width of 20 mm, and a length of 1000 mm. The two cut sheets were then arranged such that their end faces extending along the length direction were moved towards each other in a direction that brought them closer together. Figure 1 The alignment is shown in (a). Furthermore, the first laser with a wavelength of 400–500 nm and a spot diameter (hereinafter also referred to as "beam diameter") of 100–500 μm, and the second laser with a wavelength of 800–1200 nm and a spot diameter of 10–300 μm are maintained as follows: Figure 8 Laser welding is performed simultaneously with the positional relationship of the laser spot diameters shown. The laser conditions are shown in Table 1. Laser welding is performed while supplying the molten section with an oxygen-containing inert gas as described in Table 1. As the inert gas, a mixture of nitrogen (G1 Grade) produced by Taiyo Hitsuzan and oxygen is used.

[0155] In addition, in Example 6, with Figure 1 The overlapping configuration shown in (b) replaces the mating configuration, and laser welding is performed under the same conditions as in Example 1.

[0156] Then, for the welded part, the Vickers hardness and GAM value were measured by the following method. The results are shown in Table 1. In addition, in Table 1, the case where the proportion of grains with a Vickers hardness Hv1 of 60 or above and a GAM value of 0.5° or above and less than 2.0° to the total area of ​​all grains present in the measurement area is 25% or above, is recorded as excellent deformation resistance and marked with "◎"; the case where the proportion of grains with a Vickers hardness Hv1 of 60 or above and a GAM value of 0.5° or above and less than 2.0° to the total area of ​​all grains present in the measurement area is less than 25%, is recorded as good deformation resistance and marked with "〇"; and the case where the Vickers hardness Hv1 is less than 60 is recorded as poor deformation resistance and marked with "×".

[0157] In addition, the local deformation characteristics of the welded part were also evaluated. When the hardness slope obtained from the hardness of the non-welded part, the hardness of the welded part, and the indentation spacing was less than 0.2 / μm, the material became a small tilted material between the welded and non-welded parts, thus becoming less prone to local deformation, and was rated as having good resistance to local deformation, and was rated as "○". On the other hand, when it was greater than 0.2 / μm, it was rated as being prone to local deformation, and was rated as "△".

[0158] Vickers hardness

[0159] Vickers hardness (HV) was determined according to the method specified in JIS Z2244 (2009). The load (test force) was selected from 20 to 100 gf, within the range where the diagonal length of the indentation was no greater than 0.03 mm. It should be noted that the indenter pressing time (extrusion time) was 15 seconds.

[0160] In Examples 1-5 and Comparative Examples 1-9, where the plates are joined together, as shown... Figure 1 As shown in (a), with the welding direction set as the X-axis, the direction perpendicular to the welding direction set as the Y-axis, and the normal direction of the sheet metal set as the Z-axis, the Vickers hardness Hv1 is measured at position b, which is equivalent to half the thickness a of the sheet metal in section A when the welded portion is cut along the Y-axis. The measurements are performed on five sections A (YZ planes) obtained by cutting along the welding direction (X-axis) at 1 mm intervals, and the average value of these measurements is calculated.

[0161] In addition, in Example 6 where the plates are overlapped, such as Figure 1 As shown in (b), the Vickers hardness Hv1 was measured at position b1, which corresponds to half the thickness a1 of the weld portion in section A1 when the weld portion is cut along the Y-axis, and at position b2, which corresponds to half the thickness a2 of the weld portion in section A2 when the weld portion is cut along the Y-axis. The measurements were performed on each of the five sections A1 and A2 (YZ planes) obtained by cutting along the welding direction (X-axis direction) at 1 mm intervals, and the average value of these measurements was calculated.

[0162] [GAM value]

[0163] The GAM value was obtained from the following crystal orientation analysis data, which was obtained by continuously measuring crystal orientation data using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA) and calculated using analysis software (TSL Ltd., OIM Analysis). Measurements were performed in 0.1 μm increments. The measurement area was a rectangular region defined by the weld width of the welded portion and the thickness of the sheet metal on the surfaces of sections A, A1, and A2, obtained through mirror finishing via electrolytic polishing.

[0164] The area ratio of grains with GAM values ​​within the specified range is calculated as follows: GAM values ​​above 0° and below 0.25° are set as the first partition, and 15 partitions are made with 0.25° as the scale. GAM values ​​above 0° and below 3.75° are set as the measurement objects. The area ratio of grains in each partition in the overall SEM image obtained by SEM-EBSD method is calculated by summing the area ratio of grains in each partition.

[0165] It should be noted that in Example 6, the average value of the grain area ratio of the GAM values ​​measured for the two plates was obtained, and this average value is recorded in Table 1.

[0166] [Table 1]

[0167]

[0168] According to Examples 1-6, it is known that in the joining of two identical plates formed of pure Cu, by irradiating the molten portion with a first laser having a wavelength of 400-500 nm with a spot diameter of 100-500 μm, and irradiating the molten portion with a second laser having a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, while simultaneously injecting an inert gas containing 1-50 ppm oxygen into the molten portion at a flow rate of 10-50 L / min, and welding at a spot rate of 0.1-3 msec / s, the Vickers hardness Hv1 of the welded portion can be 60 or higher. In Examples 1-3, 5, and 6, where the area ratio of GAM grains is 25% or higher, the Vickers hardness Hv1 is particularly high, reaching 65 or higher. Furthermore, it is known that the slope decreases when the irradiation time is 2 msec or higher.

[0169] On the other hand, in Comparative Example 1, where the oxygen content of the inert gas was less than 10 ppm, the Vickers hardness was low. Furthermore, in Comparative Example 2, where the oxygen content of the inert gas was more than 50 ppm, and in Comparative Example 3, where the flow rate of the inert gas was less than 10 L / min, internal oxidation became excessive, leading to embrittlement and significant damage. In Comparative Example 4, where the flow rate of the inert gas was more than 50 L / min, poor solidification occurred, resulting in a significant reduction in the thickness of the welded portion. In Comparative Examples 5-9, where the laser conditions were not a 100-500 μm spot diameter irradiation with a first laser with a wavelength of 400-500 nm and a 10-300 μm spot diameter irradiation with a second laser with a wavelength of 800-1200 nm, plates formed of pure Cu could not be joined together.

[0170] (Examples 7-26 and Comparative Examples 10-12) Joining of two identical plates formed of Cu alloy

[0171] In Examples 7-26 and Comparative Examples 10-12, two plates formed of a Cu alloy having the composition described in Table 2 were used and welded under the welding conditions described in Table 2. Otherwise, the same method as in Example 1 was used. The results are shown in Table 2.

[0172] [Table 2]

[0173]

[0174] According to Examples 7-26, it is known that in the joining of two identical plates formed of Cu alloy, by irradiating the molten portion with a first laser having a wavelength of 400-500 nm with a spot diameter of 100-500 μm and irradiating the molten portion with a second laser having a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, and simultaneously injecting an inactive gas containing 1-50 ppm oxygen into the molten portion at a flow rate of 10-50 L / min, while welding is performed at a spot rate of 0.2-10 msec / spot, the Vickers hardness Hv1 of the welded portion can be 60 or higher. In Examples 7, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, and 26, where the area ratio of GAM grains is 25% or higher, the ratio of the Vickers hardness of the welded portion to the plate (Vickers hardness of the welded portion / Vickers hardness of the plate) can be 0.5 or higher, and the decrease in the Vickers hardness of the welded portion can be particularly suppressed.

[0175] In Comparative Example 10, the strength of the weld could not be improved due to the low oxygen content. In Comparative Example 11, welding was not performed due to the short irradiation time. Furthermore, in Comparative Example 12, the weld melted due to the long irradiation time, and an aesthetically pleasing cross-section could not be obtained due to thinning.

[0176] (Examples 27-28) Joining two plates made of pure Cu with different compositions

[0177] In Example 27, a plate made of Cu alloy having the composition described in Table 3 was used and welded under the welding conditions described in Table 3. Otherwise, the same method as in Example 1 (combination) was used.

[0178] In Example 28, a sheet material formed from a Cu alloy having the composition described in Table 3 was used, and welding was performed under the welding conditions described in Table 3. Otherwise, the same method as in Example 6 (overlapping) was employed. It should be noted that the overlap was performed with the sheet material described in the upper part of Table 3 as the laser irradiation side.

[0179] The results are shown in Table 3.

[0180] [Table 3]

[0181]

[0182] According to Examples 27-28, it is known that in the joining of two plates formed of pure Cu with different compositions, by irradiating a first laser with a wavelength of 400-500 nm with a spot diameter of 100-500 μm and irradiating a second laser with a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, and simultaneously spraying an inactive gas containing 1-50 ppm oxygen into the molten part at a flow rate of 10-50 L / min, and performing welding for an irradiation time of 1 msec / spot, the Vickers hardness Hv1 of the welded part can be 60 or more.

[0183] (Examples 29-31) Joining of two plates made of Cu alloy with different compositions

[0184] In Examples 29-31, plates formed from Cu alloys having the composition described in Table 4 were used, and welding was performed under the welding conditions described in Table 4, except that the same method as in Example 1 was employed. The results are shown in Table 4.

[0185] [Table 4]

[0186]

[0187] According to Examples 29-31, it is known that in the joining of two plates formed of Cu alloy with different compositions, by irradiating a first laser with a wavelength of 400-500 nm with a spot diameter of 100-500 μm and irradiating a second laser with a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, and simultaneously spraying an inactive gas containing 1-50 ppm oxygen into the molten part at a flow rate of 10-50 L / min, and performing welding for an irradiation time of 1 msec / spot, the Vickers hardness Hv1 of the welded part can be 60 or more.

[0188] (Examples 32-33) Joining of a sheet made of pure Cu and a sheet made of Cu alloy

[0189] In Example 32, a plate made of pure Cu and a plate made of Cu alloy with the composition described in Table 5 were used for welding under the welding conditions described in Table 5. Otherwise, the same method as in Example 1 (combination) was used.

[0190] In Example 33, a plate made of pure Cu and a plate made of Cu alloy with the compositions described in Table 5 were used for welding under the welding conditions described in Table 5. Otherwise, the same method as in Example 6 (overlapping) was employed. It should be noted that the overlap was performed with the first plate described in the upper part of Table 5 as the laser irradiation side.

[0191] The results are shown in Table 5.

[0192] [Table 5]

[0193]

[0194] According to Examples 32-33, it is known that in the joining of a plate formed of pure Cu and a plate formed of Cu alloy, by irradiating a first laser with a wavelength of 400-500 nm with a spot diameter of 100-500 μm and irradiating a second laser with a wavelength of 800-1200 nm with a spot diameter of 10-300 μm, and simultaneously spraying an inactive gas containing 1-50 ppm oxygen into the molten part at a flow rate of 10-50 L / min, and performing welding for an irradiation time of 1 msec / spot, the Vickers hardness Hv1 of the welded part can be 60 or more.

[0195] As can be seen from these embodiments and comparative examples, by increasing the area ratio with a GAM value of 0.5° or higher and less than 2.0°, the hardness of the welded part can be controlled to be 60 or higher. Furthermore, when the hardness slope between the welded part and the non-welded part is 0.2 / μm or lower, the resistance to deformation is stronger, and therefore there are no practical problems. Therefore, according to the present invention, in electrical and electronic equipment components with welded parts, such as heat spreaders and busbars, by controlling the hardness of the welded and non-welded parts, it is possible to obtain electrical and electronic equipment components with rigidity and strong resistance to local deformation of the welded parts.

[0196] Explanation of reference numerals in the attached figures

[0197] 1, 2 boards

[0198] 3. Welding sections 3A, 3B, and 3C

[0199] 10, 10A, 10B, 10C junction

[0200] 10D Cu parts

[0201] 101 and 102 Cu plates

[0202] 20 Laser welding equipment

[0203] 21 Laser Control Department

[0204] 24 processing tables

[0205] 25 glass fiber

[0206] 26 Condensing Lens

[0207] 28 Converging Lens

[0208] 29 Laser Heads

[0209] 30 Gas supply nozzle

[0210] 221, 222 Laser Oscillators

[0211] 231 First Laser

[0212] 232 Second laser

[0213] 261 First Condensing Lens

[0214] 262 Second Condenser Lens

[0215] 271 First Mirror

[0216] 272 Second Mirror

Claims

1. A component for electrical and electronic equipment, comprising multiple plates containing 90% or more Cu by mass. The component for electrical and electronic equipment has a welded part that integrates the plurality of plates by welding them together in a linear or dotted manner, in a mutually opposing or overlapping state. The welded portion extends throughout the thickness of the plate. In the cross-section when the weld portion is cut in the direction in which the plurality of joined plates extend, The Vickers hardness of the weld, measured at a position corresponding to half the thickness of the plate at the center of the weld width (i.e., the weld width) on the plate surface, is defined as HV1. When the Vickers hardness of the non-welded portion, measured at a distance equivalent to only 1.5 times the half-width of the weld, is taken from the center of the welded portion along the direction of the weld width, and defined as HV2, The Vickers hardness HV1 at the welded part is above 60. The Vickers hardness HV2 of the non-welded portion is above 75. The hardness slope (HV2-HV1) / X when the difference between the Vickers hardness HV2 at the non-welded part and the Vickers hardness HV1 at the welded part is divided by the indentation spacing X μm between the locations where the Vickers hardness HV1 and HV2 are measured is less than 0.2 / μm.

2. The component for electrical and electronic equipment as claimed in claim 1, wherein, In the cross section, when measuring the GAM value obtained from crystal orientation analysis data by SEM-EBSD method in a rectangular area divided by the weld width of the welded part and the thickness of the plate, the area ratio of grains with a GAM value of 0.5° or higher and less than 2.0° relative to all grains present in the measurement area is 25% or higher.

3. The component for electrical and electronic equipment as described in claim 1 or 2, wherein, The plate contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P.

4. The component for electrical or electronic equipment as claimed in claim 1 or 2, wherein, The plate material contains 99.96% Cu or more by mass, and unavoidable impurities.

5. The component for electrical or electronic equipment as claimed in claim 1 or 2, wherein, The component used in the electrical and electronic equipment is a heat spreader.

6. The component for electrical or electronic equipment as claimed in claim 1 or 2, wherein, The component used in the electrical and electronic equipment is a busbar.

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