JP2021186868A - Component for electric and electronic equipment - Google Patents

Abstract

To provide a component for electric/electronic equipment configured to have rigidity and has excellent performance in unbending a welded part by controlling inclinations of hardness of the welded part and hardness of the whole of plate materials.SOLUTION: The component for electric/electronic equipment comprises a weld part, constituted of a plurality of plate materials containing Cu of 90 mass% or more, in which the plurality of plate materials are joined to each other in a linear shape or in a point shape while butting the plate materials to each other or while overlapping the materials with each other to be integrated with each other. When each Vickers hardness HV1 and HV2 of the welded part are measured from a center of a welding width of the welded part and a distance corresponding to 1.5 times of the welding width along a width direction of the welding width from the center of the welded part, the Vickers hardness HV2 in a non-welded part is 75 or more, and a numerical value ((HV2-HV1)/X) determined by dividing a difference between the Vickers hardness HV2 in the non-welded part and the Vickers hardness HV1 in the welded part by a direct distance X(μm) between the positions where the Vickers hardness HV1 and HV2 are measured is 0.2/μm or less.SELECTED DRAWING: Figure 3

Description

The present invention relates to parts for electrical and electronic devices.

In recent years, the amount of heat generated tends to increase due to higher functionality and higher performance of electric and electronic devices. In addition, as the miniaturization of electric and electronic devices progresses, the heat generation density increases, so it is becoming important to cool the generated heat. Examples of the member for cooling the generated heat include a vapor chamber which is a planar heat pipe. As the material of the vapor chamber, it is desirable to use a copper-based material (copper, copper alloy) having high thermal conductivity.

Here, the vapor chamber has a closed structure in which the working liquid is put into an internal space formed by joining the outer peripheral portions in a state where two plates are stacked, and then sealed under reduced pressure. Examples of such a joining method include laser welding, resistance welding, diffusion welding, and TIG welding.
When joined by these welds, the welded part is formed by melting once by heating to a high temperature and then re-solidifying, so that the plate is softened and the plate itself is softened as in the case of annealing. There is a problem that it becomes softer than the strength and the strength becomes low. The lower the strength, the easier it is to deform.

To deal with such problems, Patent Document 1 describes a method of manufacturing a vapor chamber by joining a plurality of parts by diffusion joining or brazing, using a precipitation hardening copper alloy as a material of a housing and aging treatment. Then, a technique for improving the strength of the housing and the like by precipitation hardening is disclosed.
However, in the technique of Patent Document 1, it is necessary to use a precipitation hardening type copper alloy, and there is a problem that it cannot be applied to a non-precipitation type copper alloy or pure copper. Further, in the technique of Patent Document 1, it is necessary to perform aging treatment, and there is a problem that productivity is lowered due to an increase in the number of steps.
Therefore, it is desired to increase the strength of the welded portion by a method other than the method of precipitation hardening using a precipitation hardening type copper alloy by aging treatment.

The above-mentioned problem of low strength of the welded portion exists not only in the vapor chamber but also in other electric / electronic devices such as a bus bar.

Note that Patent Document 2 discloses a technique for improving the bonding strength by irradiating a laser with a specific trajectory, but the technique of Patent Document 2 is a technique relating to bonding between aluminum and copper. It is difficult to apply to joining copper-based materials. More specifically, the copper-based material has a high thermal conductivity, so that heat easily escapes, and the laser beam is easily reflected. Therefore, the copper-based material is a material that is difficult to join by laser welding. Therefore, as in Patent Document 2, simple welding using a laser beam has low bonding strength and cannot be sufficiently bonded.

International Publication No. 2018/199219 Japanese Unexamined Patent Publication No. 2017-168340

Conventionally, various types of welding have been performed. For example, in resistance welding, the hardness inclination of the welded portion and the non-welded portion is large, and in diffusion joining, the entire member is softened, so that the hardness inclination disappears. .. On the contrary, when the inclination of the hardness is large, stress concentration is generated in the low-strength welded portion and the weld is easily deformed. When the deformation is corrected, there is a problem that cracks are likely to occur due to processing such as bending back, and the parts are damaged. On the other hand, when the whole is softened, there is a problem that the member is easily deformed because the member loses its hardness and its rigidity.

Therefore, the present invention has been made in view of the above problems, and in an electric / electronic device component having a welded portion such as a vapor chamber or a bus bar, the hardness of the welded portion and the entire plate material and the hardness of the entire plate material are obtained. It is an object of the present invention to provide a component for electric / electronic equipment having rigidity and strong bending back workability of a welded portion by controlling the inclination of the welded portion.

The present inventions have found that by controlling an appropriate hardness from a welded portion to a non-welded portion and an inclination of the hardness, the present invention is rigid and resistant to bending back of the welded portion. We have completed the parts for electrical and electronic equipment.

(1) Welding that is composed of a plurality of plate materials containing 90% by mass or more of Cu, and the plurality of plate materials are joined to each other in a linear or dot shape in a state of being abutted against each other or in a state of being overlapped with each other to be integrated. In the welded portion and the non-welded portion located adjacent to the welded portion, as seen in the cross section when the plurality of integrated plate materials are cut in a direction having a portion and crossing the welded portion. The weld width is the width of the weld mark on the surface of the plate, and the center of the weld width and the non-welded portion are the weld width along the width direction of the weld width from the center of the weld portion. When the Vickers hardness HV1 and HV2 were measured at a distance of 5 times, the Vickers hardness HV2 in the non-welded portion was 75 or more, and the Vickers hardness HV2 in the non-welded portion was , The numerical value ((HV2-HV1) / X) when the difference from the Vickers hardness HV1 at the welded portion is divided by the linear distance X (μm) between the measured positions of the Vickers hardness HV1 and HV2 is Parts for electrical and electronic equipment that are 0.2 / μm or less.
(2) The plate material contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P, and
The component for electrical / electronic equipment according to (1), wherein the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 240.
(3) The plate material contains 99.96% by mass or more of Cu and unavoidable impurities, and
The component for electrical / electronic equipment according to (1), wherein the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 120.
(4) The parts for electric / electronic equipment according to (1) to (3), wherein the parts for electric / electronic equipment are vapor chambers.
(5) The parts for electric / electronic equipment according to (1) to (3), wherein the parts for electric / electronic equipment are bus bars.

The parts for electrical and electronic equipment of the present invention are rigid and rigid by controlling the inclination of hardness between the welded portion and the non-welded portion while obtaining appropriate hardness at the welded portion. It is possible to provide parts for electrical and electronic equipment that are resistant to bending back of welded parts.

(A) is a schematic perspective view when two Cu plates are joined in a linearly abutted state, and (b) is a schematic perspective view when two Cu plates are joined in a linearly overlapped state. It is a schematic perspective view of. It is an optical micrograph when observing the surface state of the Cu member which joined the butted Cu plate material. It is an optical micrograph when observing the cross-sectional state of the bonded Cu plate material. It is a figure which shows the schematic structure of the laser welding apparatus. It is a figure which shows the magnitude of the laser beam of a laser welding apparatus.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. It should be noted that it is easy for a person skilled in the art to modify or amend the present invention within the scope of the claims to form another embodiment, and these changes or amendments are included in the scope of the claims. , The following description is an example of the best form of the present invention and does not limit the scope of the claims.

(Parts for electrical and electronic equipment)
A component for an electric / electronic device according to an embodiment of the present invention is composed of a plurality of plate materials (hereinafter, referred to as “Cu plate material”) containing 90% by mass or more of Cu, and the plurality of plate materials are connected to each other. A cross section when a plurality of integrated plates are cut in a direction crossing the welded portion, which has a welded portion that is joined and integrated in a linear or dot shape in a state of being abutted against each other or in a state of being overlapped with each other. In the welded portion and the non-welded portion located adjacent to the welded portion, the welded portion has the width of the weld mark on the surface of the plate as the weld width, and the center of the welded width and the non-welded portion have. When the Vickers hardness HV1 and HV2 are measured at a distance of 1.5 times the welding width from the center of the welded portion along the width direction of the weld width, the Vickers hardness HV2 at the heat-affected portion is 75. The difference between the Vickers hardness HV2 at the heat-affected portion and the Vickers hardness HV1 at the welded portion is divided by the linear distance X (μm) between the positions where the Vickers hardness HV1 and HV2 are measured. (Hereinafter, it may be referred to as “hardness inclination rate”) ((HV2-HV1) / X) is 0.2 / μm or less.

(Linear welding)
As shown in FIG. 1 (a) (only the description of FIG. 1 is numbered), the Cu member 10 is arranged so that the two Cu plates 101 and 102 are butted against each other. By irradiating the center of the abutted state with a laser beam and sweeping it, the two Cu plates 101 and 102 are linearly welded, and the two Cu plates 101 and 102 are abutted and joined at the center 121 of the welded portion 12. Here, the laser beam is swept to form a linear joint. Melted liquid Cu is formed in the portion irradiated with the strong laser beam. After that, after the laser beam passes through the Cu, the liquid Cu rapidly cools and changes to a solid Cu due to its high thermal conductivity. When this progresses continuously, a welded portion 12 having a wavy bead is formed. Since it is once melted and solidified, it is clearly in a state different from that of the base material 11 of the Cu plate materials 101 and 102. Further, around the welded portion 12, a portion affected by heat and affected by heat is formed in a state different from the surface of the base material 11 of the Cu plate materials 101 and 102. The heat-affected portion is also affected by the heat, and the characteristics of the base material 11 of the Cu plate materials 101 and 102 are also altered. The heat to the heat-affected zone includes both the heat generated by the irradiation of the laser beam and the heat generated from the welded portion 12. As shown in FIG. 1 (b), the Cu member 10 is a Cu member 10 in which the surface of the Cu plate material is linearly welded by irradiating and sweeping the two Cu plate materials 101 and 102 in a state of being overlapped with each other and irradiating with a laser beam. .. In order to obtain sufficient bonding strength, the overlapped Cu plates are welded so that the width in the Y-axis direction joined by welding is ½ or more of the welding width of the surface.

(Dot-shaped welding)
A point-shaped joint can be formed by irradiating and joining the centers of two Cu plates in a state where they are butted together without sweeping the laser beam. The shape of the laser beam may be any of a circular shape, an elliptical shape, a barrel shape, and a rectangular shape. Further, the point shape may be a broken line shape as long as the welded portions are present separately from each other. In the point-shaped welding, in the case of joining in the case of butt welding, the Cu plate material may be penetrated in the plate thickness direction, or the melting of the metal Cu may be stopped in the middle. Further, the two Cu plates may be overlapped with each other and irradiated with a laser beam to join them in a dot shape. Also in this case, in order to obtain sufficient bonding strength, the overlapped Cu plates are welded so that the width in the Y-axis direction joined by welding is ½ or more of the welding width of the surface.

(Surface condition of Cu member)
FIG. 2 is a photograph showing the surface state of a Cu member formed by laser welding and joining butt Cu plates, and shows that the X-axis direction is the laser sweep direction. In addition, it can be seen that there is a portion where the processing traces of rolling of the Cu plate material have disappeared due to the irradiation of the laser beam. Further, it can be clearly seen that the Cu plate material has a melted and solidified portion, which is a welded portion. The width of the welded portion of the laser welding mark shown in the figure is defined as the welding width in the present invention, and the cut is cut at the dotted line cross-sectional observation position to observe the cross-sectional structure.

(Position of measuring Vickers hardness of linear joint)
FIG. 3 is an optical micrograph showing a cross-sectional state of a Cu member formed by laser welding a Cu plate material. As shown in FIG. 3, the welded portion joined by irradiating a laser beam to melt and then solidifying is represented as a weld width. Even when viewed from the cross-sectional view from FIG. 3, the width of the welding mark on the surface of the Cu plate material on the side irradiated with the laser beam can be clearly recognized. A point advanced along the direction of the weld width by a distance 1.5 times the length of half the weld width (half-width of the weld) from the center of the weld is called a non-weld part, and in the plate thickness direction at these two points. As shown by the arrows in FIG. 3, the depth in the plate thickness direction at the center of the weld width is the Vickers hardness HV1 and HV2 of the welded portion and the non-welded portion at the position of 1/2 of the plate thickness, respectively. Measure.
When the welding width is smaller than the plate thickness, the depth in the plate thickness direction is measured at a position halved of the welding width.

(Vickers hardness)
Vickers hardness is a measurement method standardized by "JIS Z 2244". The Vickers hardness HV is a numerical value indicating whether a rigid body (indenter) made of diamond is pressed against a test object and the area of a dent (indentation) formed at that time is large or small, and whether it is hard or soft. The indentation is ideally square because the indenter has a quadrangular pyramid shape that resembles an inverted pyramid. The test force is variable, and the JIS standard specifies 10 gf to 100 kgf.
Here, if there are welding marks on the front and back of the plate material, the one with the wider welding mark is the laser irradiation surface side. In the case of superposition joining, the material on the laser irradiation surface side is measured. Here, the depth in the plate thickness direction is 1/2 of the plate thickness when the welding width is larger than the plate thickness.
If the welding width is smaller than the plate thickness, it is halved of the welding width.
The observation is performed at a position relatively close to the laser irradiation surface because the laser irradiation surface side is affected by the heat of the laser irradiation.

(Inclination rate of hardness)
In the case of the butting shown in FIG. 1A, the measurement of the non-welded portion is performed by measuring the points on both sides perpendicular to the traveling direction of the laser beam from the center of the welded portion and measuring the average value of the non-welded portion. Vickers hardness is HV2. Further, in the case of superposition shown in FIG. 1 (b), the Vickers hardness HV2 of the non-welded portion is measured from the center of the welded portion at a right angle to the direction in which the laser beam travels and at a point opposite to the near end portion. ..
The Cu plate material at this time measures the Vickers hardness HV1 and HV2 at two points, the center of the welded portion and the non-welded portion. The value when the difference between the Vickers hardness HV2 at the non-welded portion and the Vickers hardness HV1 at the center of the welded portion is divided by the linear distance X μm between the measured positions of the Vickers hardness HV1 and HV2. ((HV2-HV1) / X) is defined as the hardness inclination rate.

(Measurement position of Vickers hardness of point joint)
In dot-shaped welding, the welding width is defined as the widest portion of the dotted welded portion as the welding width and the surface on which the cross section of that portion is measured. Therefore, the non-welded portion is a portion adjacent to the dotted welded portion and at a distance of 1.5 times the weld width from the center of the welded portion along the width direction of the weld width.
Therefore, the hardness is measured at the center point of the widest part of the point shape and the point of the non-welded part at a certain distance from the center point. Thereby, the Vickers hardness HV1 and HV2 can be measured, and the hardness inclination rate can be obtained.

(Hardness distribution)
The hardness represents the difficulty of deforming the object and the resistance of the object to be scratched, especially when the surface of the Cu plate is about to be deformed or scratched. In particular, in a bonded body in which two Cu plates are welded and joined, if the hardness is distributed, cracks are likely to occur and the joints are easily cracked. This is because when stress is applied to a plate material in which a hard portion having a high hardness and a soft portion having a low hardness coexist, deformation stress is concentrated, so that a crack may occur in the low hardness portion. Therefore, the Cu plate material, which has a large difference in the effect of heat between the part affected by heat due to the rapid heating and quenching of the laser welding process and the welded part that has melted and solidified, becomes brittle to stress and cracks occur. Tends to enter easily. Therefore, if the hardness inclination ratio is large, cracks may occur and damage may occur due to bending or unbending during the manufacture of parts for electrical and electronic equipment.

Therefore, it is desirable that the hardness inclination rate indicating the change in hardness in the base material, the non-welded portion, and the welded portion of the Cu plate material is small. The larger the hardness inclination ratio, the larger the difference in hardness between the base material, the non-welded part, and the welded part of the Cu plate material. It will be easier. Therefore, the difference between the Vickers hardness HV1 at the welded portion and the Vickers hardness HV2 at the non-welded portion located adjacent to the welded portion is the linear distance X between the positions where the Vickers hardness HV1 and HV2 are measured ( The hardness inclination rate ((HV2-HV1) / X), which is a numerical value when divided by μm), is 0.2 / μm or less, and more preferably 0.1 / μm or less.

Further, in order to put it into practical use as a component for electrical and electronic equipment, there is a practical problem if it is easily deformed, and rigidity due to the hardness of the base material of the Cu plate material itself is required. Therefore, in the present invention, the welded portion. It is necessary to set the Vickers hardness HV2 of the Cu plate material portion other than the above, particularly the non-welded portion located adjacent to the welded portion to 75 or more.

(Cu alloy plate material)
A plate material having a Cu content of 90% by mass or more may be used, and may be pure Cu or any Cu alloy, and is not particularly limited.
When the Cu plate material used as a component for electrical and electronic equipment is a Cu alloy, one to two or more types selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P as alloy components. It is preferable to have a component composition containing an element and having a residual Cu of 90% by mass or more. The Cu alloy may be a precipitation hardening type Cu alloy or a non-precipitation hardening type Cu alloy. When the plate material is a Cu alloy, the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 240.

By using a Cu alloy as the Cu plate material, the hardness inclination ratio is set to 0.2 / μm or less to suppress the occurrence of cracks. Further, it is preferable that not only the hardness inclination rate but also the base material of the Cu plate material, the non-welded portion, and the welded portion are hard, and in particular, the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 240. Is preferable. If the Vickers hardness HV2 at the non-welded portion is less than 75, the Cu alloy plate material is likely to be deformed during processing. When the Vickers hardness HV2 in the non-welded portion exceeds 240, cracks are likely to occur at the boundary between the non-welded portion, the base metal, and the welded portion when the bending back processing is applied.

(Pure Cu plate material)
Further, when the Cu plate material used as a component for electric / electronic equipment is pure Cu containing 99.96% by mass or more of Cu and unavoidable impurities, the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 120. Is preferable. It is preferable that the hardness inclination of the base material, the welded portion, and the non-welded portion of the Cu plate material is small. By using the pure Cu plate material, the hardness inclination ratio can be reduced to 0.1 / μm or less, and the bending back can be achieved. The properties can be better. In particular, in a pure Cu plate material, if the Vickers hardness HV2 in the non-welded portion is less than 75, it is likely to be deformed during processing. When the Vickers hardness HV2 in the non-welded portion exceeds 120, cracks are likely to occur at the boundary between the non-welded portion and the base metal and the welded portion and the non-welded portion when the bending back processing is applied. Examples of so-called pure Cu include electrolytic copper, oxygen-free copper (OFC), and TPC.

(Shape of Cu plate material)
Further, the Cu plate material is a material processed into a predetermined shape, for example, a plate, a strip, a foil, a rod, a wire, etc., and has a predetermined thickness, and is a strip material in a broad sense. It means to include. In the present invention, the thickness of the plate material is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.8 mm.

(Component composition of Cu alloy)
The reason for limiting the component composition in the case where the Cu plate material is a Cu alloy having both mechanical properties and electrical properties will be described.
(1) When the plate material is a Cu alloy The Cu alloy preferably contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P. ..

(Ag: 0.05 to 5.00% by mass)
Ag (silver) is a component having an action of improving mechanical properties without impairing electrical properties, and in order to exert such actions, the Ag content is preferably 0.05% by mass or more. .. Further, it is not necessary to set an upper limit of the Ag content in particular, but since Ag is expensive, it is preferable to set the upper limit of the Ag content to 5.0% by mass from the viewpoint of material cost.

(Fe: 0.05 to 0.50% by mass)
Fe (iron) is a component having an action of improving mechanical properties. In order to exert such an effect, the Fe content is preferably 0.05% by mass or more. However, even if Fe is contained in an amount of more than 0.50% by mass, no further improvement effect can be expected, and there is a concern about corrosion resistance. Therefore, the Fe content is preferably 0.05 to 0.50% by mass.

(Ni: 0.05 to 5.00% by mass)
Ni (nickel) is finely precipitated in the matrix of Cu as a precipitate of second-phase particles composed of a simple substance or a compound with Si, for example, in a size of about 50 to 500 nm, and this precipitate is formed. It is a component having an action of precipitation hardening by suppressing dislocation movement, further suppressing grain growth, and increasing material strength by refining crystal grains. In order to exert such an effect, the Ni content is preferably 0.05% by mass or more. On the other hand, when the Ni content exceeds 5.00% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the upper limit of the Ni content is preferably 5.00% by mass.

(Co: 0.05 to 2.00% by mass)
Co (cobalt) is finely precipitated in the matrix of Cu as a precipitate of second-phase particles composed of a simple substance or a compound with Si, for example, in a size of about 50 to 500 nm, and this precipitate is formed. It is a component having an action of precipitation hardening by suppressing dislocation movement, further suppressing grain growth, and increasing material strength by refining crystal grains. In order to exert such an effect, the Co content is preferably 0.05% by mass or more. On the other hand, when the Co content exceeds 2.00% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the upper limit of the Co content is preferably 2.00% by mass.

(Si: 0.05 to 1.10% by mass)
Si (silicon) is finely precipitated in the matrix of Cu as a precipitate of second-phase particles composed of compounds together with Ni and Co, and this precipitate is precipitated and hardened by suppressing dislocation movement. Furthermore, it is an important component having an action of suppressing grain growth and increasing the material strength by refining the crystal grains. In order to exert such an effect, the Si content is preferably 0.05% by mass or more. On the other hand, when the Si content exceeds 1.10% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the upper limit of the Si content is preferably 1.10% by mass.

(Cr: 0.05 to 0.50% by mass)
Cr (chromium) is finely precipitated in the matrix of Cu as a compound or a single substance in the form of a precipitate having a size of, for example, about 10 to 500 nm, and this precipitate suppresses dislocation movement. It is a component that has the effect of precipitating and hardening, further suppressing grain growth, and increasing the material strength by refining the crystal grains. In order to exert this effect, the Cr content is preferably 0.05% by mass or more. Further, when the Cr content exceeds 0.50% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the Cr content is preferably 0.05 to 0.50% by mass.

(Sn: 0.05 to 9.50% by mass)
Sn (tin) is a component that is solid-solved in the matrix of Cu and contributes to the improvement of the strength of the Cu alloy, and the Sn content is preferably 0.05% by mass or more. On the other hand, when the Sn content exceeds 9.50%, embrittlement is likely to occur. Therefore, the Sn content is preferably 0.05 to 9.50% by mass. Further, since the Sn content tends to decrease the conductivity and the thermal conductivity, the Sn content is set to 0.05 to 0.50% by mass in the case of suppressing the decrease in the conductivity and the thermal conductivity. Is more preferable.

(Zn: 0.05 to 0.50% by mass)
Zn (zinc) is a component having an effect of improving the adhesion and migration characteristics of Sn plating and solder plating. In order to exert such an effect, the Zn content is preferably 0.05% by mass or more. On the other hand, if the Zn content exceeds 0.50% by mass, the amount of zinc vapor increases during welding, which may cause defects in the welded portion. Therefore, the Zn content is preferably 0.05 to 0.50% by mass.

(Mg: 0.01 to 0.50% by mass)
Mg (magnesium) is a component having an action of improving stress relaxation resistance. In order to exert such an effect, the Mg content is preferably 0.01% by mass or more. On the other hand, when the Mg content exceeds 0.50% by mass, the conductivity and the thermal conductivity tend to decrease. Therefore, the Mg content is preferably 0.01 to 0.50% by mass.

(P: 0.01 to 0.50% by mass)
P (phosphorus) not only contributes as a deoxidizing material for Cu alloys, but also finely precipitates as a compound in the form of precipitates having a size of about 20 to 500 nm, and these precipitates suppress dislocation migration to cause precipitation hardening. Further, the grain growth is suppressed and the material strength can be increased by refining the crystal grains. In order to exert such an effect, the P content is preferably 0.01% by mass or more. On the other hand, when the P content exceeds 0.50% by mass, cracks tend to easily occur in hot working during plate material molding. Therefore, the P content is set to 0.01 to 0.50% by mass.

(Component composition of pure Cu)
(2) When the plate material is pure Cu with excellent conductivity and heat dissipation Pure Cu is 99.96% or more Cu and, as unavoidable impurities, for example, Cd, Mg, Pb, Sn, Cr, Bi, Se, It is preferable to have a component composition in which Te is 5 ppm or less in total and Ag and O are 400 ppm or less, respectively.

(Manufacturing method of parts for electrical and electronic equipment)
In the method for manufacturing a component for an electric / electronic device according to an embodiment of the present invention, a plurality of plate materials containing 90% by mass or more of Cu are set in a state of being abutted against each other or in a state of being overlapped with each other, and then the plurality of plates are set. After irradiating the first laser beam having a wavelength of 400 to 500 nm with a spot diameter of 100 to 500 μm along the welded line between the plates, the second laser beam having a wavelength of 800 to 1200 nm is applied to 10 to 300 μm. In the welding step, the tip of the spot diameter in the irradiation scanning direction of the first laser beam is the line to be joined. The passing time difference from passing through the first position, which is an arbitrary position above, to passing the tip of the spot diameter in the irradiation scanning direction of the second laser beam passes through the first position is 50 to 1500 μsec.
As described above, the laser beam 1 having a wavelength of 400 nm or more and 500 nm or less is irradiated with a spot diameter of 100 to 500 μm, and the second laser beam having a wavelength of 800 nm or more and 1200 nm or less is irradiated with a spot of 10 to 300 μm. By irradiating with a diameter, welding of Cu plate material, which was difficult in the past, is facilitated, and lasers with different wavelengths and spot diameters are used, and the spot tip and the second laser in the traveling direction of the first laser beam are used. By setting the passing time difference of the spot tip in the traveling direction of light to 50 μsec or more and 1500 μsec or less, changes in hardness in the base material, non-welded portion, and welded portion of the Cu plate material of the Cu plate material are suppressed, and further, the non-welded portion of the Cu plate material is not welded. It is possible to manufacture parts for electrical and electronic equipment that keep the inclination of the hardness of parts and welds low.
In the embodiment of the present invention, in order to obtain sufficient bonding strength, in the case of superimposition, the width in the Y-axis direction in which the overlapped plates are joined by welding is 1/2 or more of the welding width of the surface. Manufactured in.

(Laser welding method)
The laser welding method is a welding method in which light having a wavelength with good directivity and concentration is collected by a lens and laser light having an extremely high energy density is used as a heat source. By adjusting the output of the laser beam, penetration welding with a narrow width with respect to the depth is also possible. In addition, the laser beam can be narrowed down to a very small size as compared with the arc of arc welding. With the energy densified by the condenser lens, the laser welding device can perform local welding and joining materials with different melting points. It is suitable for fine welding because it has little heat effect due to welding, the welding pattern is fine, and no processing reaction force is generated.

(Laser welding equipment)
FIG. 4 is a diagram showing an example of a schematic configuration of a laser welding apparatus. The laser welding apparatus 20 includes a control unit 21, a laser oscillator 221 and 222, a laser head 29, a processing table 24, and a gas supply nozzle 30. Cu plate materials 111 and 112, which are the materials to be processed, are arranged on the processing table 14 in a state of being unwound or overlapped. The control unit 21 controls laser oscillators 221 and 222 that oscillate laser light, a scanner (not shown), a laser head 29, a processing table, and the like. The control unit 21 controls the course directions of the Cu plate members 111 and 112, which are the workpieces, by controlling the rotation of the X-axis motor and the Y-axis motor (not shown), for example. Further, the control unit 21 may move and control the laser beams 231 and 232. This can be appropriately selected depending on the size of the work material. The control unit 21 oscillates a plurality of first and second laser beams 231 and 232 oscillated from the laser oscillators 221 and 222. The oscillated first and second laser beams 231 and 232 are collected in parallel light by the first and second condenser lenses 261 and 262 in the laser head 29 through the glass fiber 25. The first and second laser beams 231 and 232 are changed in the direction of the processing table by the first and second mirrors 271 and 272, and the first and second laser beams 231 and 232 are joined to the Cu plate material by the focusing lens 28. Welding is performed by focusing on the part and irradiating it. At this time, an inert gas is supplied from the gas supply nozzle 30 in order to prevent oxidation caused by overheating by the laser beam. The inert gas can be appropriately selected from argon, helium and the like.

The laser can be appropriately selected from those known as welding lasers. Examples of _{lasers include CO 2} lasers, Nd: YAG lasers, semiconductor lasers, fiber lasers and the like. It is preferable to use a fiber laser from the viewpoint of output and condensing property of laser light. Other configurations of the total laser machining apparatus can be selected from any conventionally known configuration.

(Laser welding)
FIG. 5 is a diagram showing the spot diameter of the laser beam of the laser welding apparatus. As shown in FIG. 5, the first laser beam 231 having a wavelength of 400 nm or more and 500 nm or less is irradiated with a spot diameter of 100 to 500 μm. Then, the second laser beam 232 having a wavelength of 800 nm or more and 1200 nm or less is irradiated with a spot diameter of 10 to 300 μm. By irradiating a plurality of laser beams at the same time, it has become possible to easily weld a Cu plate material, which has been difficult in the past. Moreover, using a plurality of laser beams having different wavelengths and different spot diameters, the passing time difference between the tip of the spot diameter in the traveling direction of the first laser beam 231 and the tip of the spot diameter in the traveling direction of the second laser beam 232 is 50 μsec. It should be 1500 μsec or less. This makes it possible to prevent the occurrence of cracks when manufacturing parts for electric / electronic devices by performing bending or unbending.

Further, in the welding process in the method for manufacturing parts for electrical and electronic equipment, as shown in FIG. 5, after the tip of the spot diameter in the irradiation scanning direction of the first laser beam 231 passes through the joint portion, the second laser beam is emitted. The passage time difference until the tip of the spot diameter of 232 in the irradiation scanning direction passes through the same position as the junction where the first laser beam 231 has passed is 50 to 1500 μsec, which is a method for manufacturing parts for electrical and electronic equipment. The passing time difference means that, as shown in FIG. 5 (a), after the tip of the first laser beam 231 passes through a certain point P1 of the Cu member, the second laser beam 232 is shown in FIG. 5 (b). It shows the time difference between traveling in the same direction and passing the previous point P1. Therefore, this transit time difference does not represent the distance between P1-P2, but merely represents the time difference until the second laser beam 232 passes the point P1.

In the parts for electrical and electronic equipment of the present invention, after setting a plurality of plate materials in a state of being butted or overlapped with each other, the joints between the plurality of plate materials are irradiated with the first and second laser beams 231 and 232. Then, a plurality of plate materials are joined to each other in a linear or dot shape to be integrated. The first laser beam 231 that efficiently penetrates only the surface of the Cu plate material preheats the Cu plate material in a wider range than the second laser beam 232, and the second laser beam 232 that penetrates deeply into the Cu plate material is irradiated before the preheating cools down. , It is possible to perform welding processing that causes almost no defects such as blow holes and internal defects.

If the wavelengths and spot diameters of the first and second laser beams 231 and 232 are out of the range, the surface quality is deteriorated and welding cannot be performed, which is inappropriate. Further, controlling the preheating by the first laser beam 231 affects the cooling rate when the plate material is melted and solidified by the second laser beam 232, and as a result of diligent examination, the passing time difference is 50 μsec or more and 1500 μsec or less. By doing so, it is possible to suppress changes in the hardness of the Cu plate base material, the non-welded portion, and the welded portion of the Cu plate material, and further suppress the inclination of the hardness of the non-welded portion and the welded portion of the Cu plate material to be low. understood. If the passing time difference is less than 50 μsec, the preheating is insufficient, and if it is 1500 μsec or more, the preheat is removed. Since the hardness of the welded portion changes significantly, the desired hardness and the inclination ratio of the hardness cannot be obtained. If the wavelengths and spot diameters of the first and second laser beams 231 and 232 are out of the range, defects such as blow holes occur on the surface, which is inappropriate.

(Effect of welding)
In this way, by controlling the base material, non-welded portion, and welded portion of the Cu plate material having a predetermined composition, the electricity is hard and rigid, and the welded portion is resistant to bending back workability. Parts for electronic devices can be obtained.

(Application to electrical and electronic equipment)
The parts for electrical and electronic devices of the present invention can be considered to be used in semiconductor devices, LSIs, or many electronic devices using these, and further, for example, homes that need to be particularly miniaturized and highly integrated. Use for electrical and electronic equipment such as game consoles, medical equipment, workstations, servers, personal computers, car navigation systems, mobile phones, robot connectors, battery terminals, jacks, relays, switches, autofocus camera modules, lead frames, etc. Is possible.

(Vapor chamber)
In particular, it is preferably applied to heat pipes and vapor chambers because it has excellent bend-back workability with less cracking. In particular, since cracks are less likely to occur as a structural material for vapor chamber products, leakage and corrosion during use due to cracks are improved, which suppresses deterioration of thermal conductivity and deteriorates vapor chamber products. It can contribute to suppression and extension of life.

(Busbar)
Further, since the bus bar has excellent bend-back workability, it can be applied as an electric path for electrically connecting and a transport path for heat dissipation. In particular, it can also be applied as a cooling device by connecting a bus bar from a heat generating portion and providing a path to a heat radiating portion or the outside.

(Examples 1 to 10 and Comparative Examples 1 to 11: Joining of two same plates with a Cu alloy by butt-butting)
In Examples 1 to 10 and Comparative Examples 1 to 11, two Cu alloy plates were cut into t = 0.15 mm, a width of 20 mm, and a length of 1000 mm, and placed so as to be in contact with each other so that the respective lengths of 1000 mm were in contact with each other. A laser beam having a width of 20 mm and a laser beam having a wavelength of 400 nm or more and 500 nm or less is irradiated with a spot diameter of 100 to 500 μm, and a laser beam having a wavelength of 800 nm or more and 1200 nm or less is emitted from 100 with a spot diameter of 10 to 300 μm. It was swept at 400 mm / sec and welded.
The welded Cu plate material was cut in the width direction. After embedding the plate material in resin, cross-section polisher processing (model number: SM-09010, manufacturer: JEOL Ltd.) was performed to obtain a material cross section with a smooth surface. The hardness of this smooth surface was measured.

(Hardness, distance, hardness inclination rate)
The hardness was measured with a Vickers hardness tester (model number: HM-215, manufacturer: Mitutoyo Co., Ltd.) according to the method specified in JIS Z2244 (2009). At this time, the indenter is moved to the center of the weld width, and the indenter made of regular quadrangular pyramid diamond is pushed into the material surface. At that time, the load (test force) was 100 gf, and the test was selected and tested within a range in which the diagonal length of the indentation did not exceed 0.03 mm. The pressing time (pushing time) of the indenter is 15 sec. Then, the indenter was moved from the center of the welding width of the Cu plate material by a distance of 1.5 times the welding width, and the hardness was measured again. At this time, the distance traveled and the hardness are recorded. From this, the hardness, the moving distance, and the hardness inclination rate were obtained.
When the plate materials having the same composition were used, two points at the measurement points were measured and the average value was obtained. When plate materials having different compositions were used, two points were measured, and the hardness and the hardness inclination ratio of each were determined. In addition, the song return test evaluated whether cracks would occur on each side.
In the case of joining in a superposed state, the hardness of the material on the laser irradiation surface side was evaluated by measuring the non-welded portion on the opposite side to the near end from the center of the welded portion.

(Bending back test)
In the bending back test, a 90 ° bending test was performed with the apex removed by 0.1 mm from the center of the welded portion, then returned to a flat surface, and the bending test was performed again five times. Observe the cross section at the position of the center of width 10 mm, and mark "◎" if there is no crack on the surface or welded part up to the 5th time, and crack on the surface or welded part up to the 3rd time, but crack at the 4th or 5th time. Those in which the occurrence of cracks occurred were evaluated as "○", and those in which cracks occurred the third time or less were evaluated as "x".
In the examples in which Cu alloy plates and pure Cu plates having different composition compositions were butted and welded, the bending back test was completed when a crack was formed on only one side, and the evaluation was performed based on the number of times at that time.

Tables 1 to 7 show the component composition, plate thickness, laser welding conditions, and the hardness of the welded portion, the hardness of the non-welded portion, the weld width, the measurement distance, and the hardness as measurement data regarding the welded portion and the non-welded portion. The tilt ratio and the result of the bending back test as a performance evaluation are shown.

In Examples 1 to 10, by irradiating between 80 and 1390 μsec, the hardness HV2 of the non-welded portion in the cross section is 75 or more, and the hardness inclination ratio is 0.2 / μm or less. The results of the bending back test are all "○" or higher. On the other hand, in Comparative Examples 1 to 6, the hardness of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio exceeds 0.2 / μm. The results of the bending back test are all "x". Further, in Comparative Example 7, the hardness of the non-welded portion in the cross section is less than 75. In Comparative Examples 8 and 9, the hardness of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio exceeds 0.2 / μm. In Comparative Example 10, welding was not possible and the joint was not joined. In Comparative Example 11, the hardness of the non-welded portion is 75 or more, but the hardness inclination ratio exceeds 0.2 / μm. The results of the bending back test are all "x". Therefore, it can be seen that it is difficult to apply Comparative Examples 1 to 11 as electrical / electronic device parts.

(Examples 11 to 20, Comparative Examples 12 to 21: Joining by superimposing two same plates with Cu alloy)
In Examples 11 to 20 and Comparative Examples 12 to 21, the conditions are the same as those in Example 1 except that the two Cu alloy plates are overlapped and welded.

From the results in Table 2, in Examples 11 to 20, the hardness HV2 of the non-welded portion in the cross section is 75 or more, and the hardness inclination ratio is 0.2 / μm or less. The results of the bending back test are all "○" or higher.
On the other hand, in Comparative Examples 12 to 21, the hardness HV2 of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio is more than 0.2 / μm. The results of the bending back test are all "x".

(Examples 21 to 23, Comparative Examples 22 to 24: Joining of two same plates with pure Cu by butt-butting)
In Examples 21 to 23 and Comparative Examples 22 to 24, the conditions are the same as those in Example 1 except that the two plates of pure Cu alloy are butt-welded and welded.

In Examples 21 to 23, the hardness of the non-welded portion in the cross section is 75 or more, the hardness inclination ratio is 0.1 / μm or less, and the results of the bending back test are all “◎”. ing.
On the other hand, in Comparative Example 22, the hardness of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio exceeds 0.2 / μm. The result of the bending back test is "x". Further, in Comparative Examples 23 and 24, the bending test could not be evaluated because they could not be welded and were not joined.

(Examples 24 and 25, Comparative Examples 25 and 26: Joining by superimposing two same plates with pure Cu)
In Examples 24 and 25 and Comparative Examples 25 and 26, the conditions are the same as those in Example 1 except that the two pure Cu plates are overlapped and welded. As described above, the measurement of the Cu member by superposition is the Vickers hardness HV2 measured at a point opposite to the end portion at a right angle to the direction in which the laser beam travels from the center of the welded portion.

In Examples 24 and 25, the hardness of the non-welded portion in the cross section is 75 or more, the hardness inclination ratio is 0.1 / μm or less, and the result of the bending back test is “◎”. It has become.
On the other hand, in Comparative Example 25, the hardness HV2 of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio exceeds 0.2 / μm. In Comparative Example 26, the hardness HV2 of the non-welded portion in the cross section is less than 75. The results of the bending back test are all "x".

(Examples 26 to 28, Comparative Examples 27 to 29: Joining of two plates having different compositions with a Cu alloy by butt-butting)
In Examples 26 to 28 and Comparative Examples 27 to 29, two Cu plate materials having different component compositions, which are Cu alloy plates, were arranged in a butted state and welded under the same conditions as in Example 1.

In Examples 26 to 28, the hardness HV2 of the non-welded portion in the cross section is 75 or more, and the hardness inclination ratio is 0.2 / μm or less. The results of the bending back test are all "○".
In Comparative Examples 27 to 29, the non-welded portions on both sides of the center of the welded portion are measured. In Comparative Example 27, the hardness inclination ratios were "0.19" and "0.25", respectively. In the bending back test, cracks occur independently on both sides, so cracks occur on only one side. Therefore, in Comparative Example 27, when the hardness inclination ratio on one side exceeds 0.2 / μm, cracks occur and the result of the bending back test is “x”. In Comparative Examples 28 and 29, the hardness of the non-welded portion in the cross section is 75 or more, but the hardness inclination ratio on both sides exceeds 0.2 / μm. The results of the bending back test are all "x".

(Examples 29 and 30, Comparative Examples 30 and 31: Joining of two sheets of the same plate material having different compositions with pure Cu by butting)
In Examples 29 and 30, and Comparative Examples 30 and 31, two Cu plates having different component compositions, which were pure Cu plates, were arranged in a butted state and welded under the same conditions as in Example 1.

In Examples 29 and 30, the hardness HV2 of the non-welded portion in the cross section is 75 or more, the hardness inclination ratio is 0.1 / μm or less, and the result of the bending back test is “◎”. It has become.
On the other hand, in Comparative Examples 30 and 31, the hardness HV2 of the non-welded portion in the cross section is 75 or more. However, the hardness inclination ratio of each Cu plate material on both sides from the center of the welded portion exceeds 0.2 / μm. The result of the bending back test is "x".

(Example 31, Comparative Example 32: Bonding of Cu alloy and pure Cu plate material by butt)
In Example 31 and Comparative Example 32, two Cu plates having different Cu alloy and pure Cu plates were arranged in a butted state and welded under the same conditions as in Example 1.

In Example 31, the hardness HV2 of the non-welded portion in the cross section is 75 or more, and the hardness inclination ratio is 0.2 / μm or less for all the plate materials. The result of the bending back test is "○".
On the other hand, in Comparative Example 32, the hardness HV2 of the non-welded portion in the cross section is 75 or more, but in particular, the hardness inclination ratio on the Cu alloy side is more than 0.2 / μm. The result of the bending back test is "x".

As described above, according to these Examples and Comparative Examples, if the Vickers hardness of the non-welded portion is 75 or more and the hardness inclination ratio is 0.2 / μm or less, there is a practical problem in the bending back test. It turns out that there is no. Therefore, according to the present invention, in an electric / electronic device component having a welded portion such as a vapor chamber or a bus bar, by controlling the hardness of the welded portion / non-welded portion, it is rigid and bent at the welded portion. It can be seen that parts for electrical and electronic equipment that are resistant to return can be obtained.

10 Cu member 101, 102 Cu plate material 111, 112 Cu plate material 11 Base material 12 Welded part 121 Center of welded part 13 Heat-affected part 20 Laser welding device 21 Control unit 22 Controller 22 1 First oscillator 222 Second oscillator 23 Laser Light 231 1st laser light 232 2nd laser light 24 Processing table 25 Glass fiber 26 Condensing lens 261 1st condensing lens 262 2nd condensing lens 27 Mirror 271 1st mirror 272 2nd mirror 28 Focusing lens 29 Laser head 30 Gas supply nozzle

Claims (5)

It is composed of a plurality of plate materials containing 90% by mass or more of Cu.
It has a welded portion that joins and integrates the plurality of plate materials in a linear or dot shape in a state of being abutted against each other or in a state of being overlapped with each other.
In the cross section when the plurality of integrated plate materials are cut in a direction crossing the welded portion, in the welded portion and the non-welded portion located adjacent to the welded portion,
The welded portion has the width of the weld mark on the surface of the plate as the weld width, and the center of the weld width and the center of the weld width.
The non-welded portion is at a distance of 1.5 times the weld width from the center of the weld portion along the width direction of the weld width.
When the Vickers hardness HV1 and HV2 are measured, the Vickers hardness HV2 in the non-welded portion is 75 or more, and the Vickers hardness HV2 in the non-welded portion and the Vickers in the welded portion. The numerical value ((HV2-HV1) / X) when the difference from the hardness HV1 is divided by the linear distance X (μm) between the positions where the Vickers hardness HV1 and HV2 are measured is 0.2 / μm or less. be,
Parts for electrical and electronic equipment that are characterized by this. The plate material contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P, and
The component for electrical / electronic equipment according to claim 1, wherein the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 240. The plate material is 99.96% by mass or more of Cu and unavoidable impurities, and
The component for electrical / electronic equipment according to claim 1, wherein the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 120. The component for electrical / electronic equipment according to any one of claims 1 to 3, wherein the component for electrical / electronic equipment is a vapor chamber. The component for electrical / electronic equipment according to any one of claims 1 to 3, wherein the component for electrical / electronic equipment is a bus bar.

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