Jointed body

Abstract

To provide a technology that improves durability against temperature changes in a jointed body.SOLUTION: A jointed body is formed by joining a first member and a second member via a joint, wherein: a difference in thermal expansion coefficients between a material forming the first member and a material forming the second member is 1.5 ppm / K or more; the joint has a plurality of columnar bodies mainly composed of a metal material arranged so that a direction of its own axis intersects with each of the first and second members; the plurality of columnar bodies includes a central columnar body arranged in a central part of the joint through which a central axis of the joint passes and an outer columnar body arranged in an outer part of the joint; a length of the outer columnar body in a direction of its own axis is 1.05 times or less than a length of the central columnar body in a direction of its own axis.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a conjugate. [Background technology]

[0002] 2. Description of the Related Art A bonded body in which two members having different thermal expansion coefficients are bonded together has been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-183637 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the prior art such as Patent Document 1, there is still room for improvement in terms of technology for improving the durability of a bonded body against temperature changes.

[0005] An object of the present invention is to provide a technique for improving the durability of a bonded structure against temperature changes. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, there is provided a bonded body, in which a first member and a second member are bonded together via a bonding part, the difference in thermal expansion coefficient between a material forming the first member and a material forming the second member is 1.5 ppm / K or more, the bonding part has a plurality of columns mainly made of a metal material arranged such that their axial directions are aligned in directions intersecting with each of the first member and the second member, the plurality of columns include a central column arranged in a central portion of the bonding part through which a central axis of the bonding part passes, and a peripheral column arranged on an outer periphery of the bonding part, and the axial length of the peripheral column is 1.05 times or less the axial length of the central column.

[0008] According to this configuration, the difference in thermal expansion coefficient between the material forming the first member and the material forming the second member is 1.5 ppm / K or more, so that the joint that joins the first member and the second member has a relatively large deformation amount at the outer peripheral part due to the temperature change of the joint. By making the axial length of the outer peripheral column arranged at the outer peripheral part of the joint, among the multiple columns that the joint has, 1.05 times or less the axial length of the central column arranged at the center part of the joint, the deformation of the columns made mainly of metal material is elastic even if the temperature of the joint changes, so that deterioration and breakage of the columns due to repeated deformation are suppressed. Therefore, the durability of the joint against temperature changes can be improved.

[0009] (2) In the joined body of the above embodiment, the axial length of the outer peripheral columnar body itself may be greater than 2 mm. According to this configuration, among the multiple columns of the joined body that joins the first member and the second member, the axial length of the outer peripheral columnar body arranged on the outer periphery of the joined body is greater than 2 mm. As a result, even if the temperature of the joined body changes, the deformation of the columnar body made mainly of a metal material is elastic, so that deterioration and breakage of the columnar body due to repeated deformation are suppressed. In other words, permanent deformation and metal fatigue due to plastic deformation occurring in the columnar body as the temperature of the joined body changes can be suppressed, so that deterioration and breakage of the columnar body due to repeated deformation are suppressed. Therefore, the durability of the joined body against temperature changes can be improved.

[0010] (3) According to another aspect of the present invention, a bonded body is provided. The bonded body is a bonded body in which a first member and a second member are bonded via a bonding part, the difference in thermal expansion coefficient between the material forming the first member and the material forming the second member is 1.5 ppm / K or more, the bonding part has a plurality of columns mainly made of a metal material arranged so that their axial directions are aligned along a direction intersecting with the first member and the second member, and among the plurality of columns, the axial length of the peripheral column arranged on the outer periphery of the bonding part is greater than 2 mm. According to this configuration, among the plurality of columns in the bonding part bonding the first member and the second member, the axial length of the peripheral column arranged on the outer periphery of the bonding part is greater than 2 mm. As a result, even if the temperature of the bonded body changes, the deformation of the columns mainly made of a metal material is elastic, so that deterioration or breakage of the columns due to repeated deformation is suppressed. Therefore, the durability of the bonded body against temperature changes can be improved.

[0011] (4) In the joined body of the above embodiment, the area of ​​the portion where the first member and the second member overlap is 5000 mm 2 According to this configuration, the area of ​​the overlapping portion between the first member and the second member is 5000 mm 2 For the above reasons, the peripheral columnar body joined to the first and second members undergoes a relatively large amount of deformation due to temperature changes in the bonded body. However, because the deformation of the columnar body is elastic, deterioration or breakage of the columnar body due to repeated deformation is suppressed. Therefore, the durability of the bonded body against temperature changes can be improved.

[0012] (5) In the joined body of the above embodiment, the first member may be made mainly of a metal material, and the plurality of columns may be a part of the first member. With this configuration, the plurality of columns are a part of the first member made mainly of a metal material. This makes it possible to manufacture a joined body by joining the plurality of columns of the first member to the second member. This makes it easier to manufacture the joined body.

[0013] The present invention can be realized in various forms, for example, in the form of an apparatus including a bonded body, a method for manufacturing a bonded body, a method for manufacturing a bonded portion, and the like. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a joint body according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional schematic view of a bonded body according to the first embodiment. [Diagram 3] FIG. 3 is an enlarged view of part A in FIG. 2. [Figure 4] FIG. 2 is a top view of the bonded body according to the first embodiment. [Diagram 5] 5A to 5C are schematic diagrams illustrating the effects of the bonded body according to the first embodiment. [Figure 6] FIG. 11 is a diagram showing the relationship between the temperature difference and the difference in size between a first member and a second member. [Figure 7] FIG. 13 is a diagram for explaining a method for calculating the deformation rate of the peripheral columnar body. [Figure 8] FIG. 1 is a first diagram showing the relationship between the length of a column and the deformation ratio of an outer peripheral column. [Figure 9] FIG. 2 is a second diagram showing the relationship between the length of the pillars and the deformation ratio of the peripheral pillars. [Figure 10] FIG. 11 is a schematic cross-sectional view of a bonded body according to a second embodiment. [Figure 11] FIG. 11 is a top view of a bonded body according to a second embodiment. [Figure 12] FIG. 13 is a diagram showing the relationship between the length of the pillars and the deformation ratio of the peripheral pillars. [Figure 13] FIG. 11 is a schematic cross-sectional view of a bonded body according to a third embodiment. [Figure 14] FIG. 13 is a cross-sectional schematic view of a bonded body according to a fourth embodiment. [Figure 15] FIG. 4 is a top view of a first modified example of the bonded body of the first embodiment. [Figure 16] FIG. 11 is a top view of a second modified example of the bonded body of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] First Embodiment FIG. 1 is a perspective view of the bonded body of the first embodiment. FIG. 2 is a schematic cross-sectional view of the bonded body of the first embodiment. The bonded body 1 of the first embodiment is, for example, an electrostatic chuck that holds a wafer W by electrostatic attraction, and is provided in an etching device that is a semiconductor manufacturing device. The bonded body 1 includes a first member 10, a second member 20, a bonding portion 30, and a plate-shaped portion 40. In the bonded body 1, as shown in FIG. 1, the second member 20, the bonding portion 30, the plate-shaped portion 40, and the first member 10 are laminated in this order from the positive side in the z-axis direction (stacking direction). In the bonded body 1, the first member 10 and the second member 20 are bonded via the bonding portion 30. In this embodiment, the bonded body 1 has a cylindrical shape with a cross-sectional shape perpendicular to the stacking direction being approximately circular. Note that each figure shows the arrangement of each part typically, and does not accurately show the ratio of the dimensions of each part.

[0016] The first member 10 is made of aluminum (Al) having a thermal expansion coefficient of 24 ppm / K. The first member 10 is a substantially circular flat plate member and has a pair of main surfaces 10a, 10b. The first member 10 functions as a cooling part in the electrostatic chuck. In this embodiment, a refrigerant flow passage (not shown) through which a refrigerant flows is formed inside the first member 10. In this embodiment, the diameter of the first member 10 is 360 mm. The diameter of the first member 10 is preferably within a range of 80 mm to 500 mm. The type of metal forming the first member 10 may be copper (Cu), stainless steel, an aluminum alloy, titanium (Ti), a titanium alloy, a magnesium alloy, or the like. In this application, the "thermal expansion coefficient" may also be called the "linear expansion coefficient" or the "linear expansion coefficient".

[0017] The second member 20 is made of alumina (Al 2 O 3). As a result, in the bonded body 1, the difference in thermal expansion coefficient between the material forming the first member 10 and the material forming the second member 20 is 1.5 ppm / K or more. The second member 20 is a substantially circular flat plate member with a diameter of 360 mm. When the bonded body 1 is viewed from the stacking direction (z-axis direction), the area of ​​the overlapping portion between the first member 10 and the second member 20, i.e., the bonding area, is 5000 mm2. 2 That's about 102,000 mm 2 The second member 20 functions as a holder for holding the wafer W in the electrostatic chuck. The second member 20 has a pair of main surfaces 20a, 20b. One of the pair of main surfaces 20a, 20b, the main surface 20a, forms a mounting surface on which the wafer W is placed. The wafer W placed on the mounting surface is attracted and fixed to the mounting surface by electrostatic attraction generated by an attraction electrode (not shown) arranged inside the second member 20. In this embodiment, a heater electrode (not shown) for heating the wafer W attracted and fixed to the mounting surface is built into the second member 20. The second member 20 is formed of a material such as aluminum nitride (AlN), zirconia (ZrO 2 ), silicon nitride (Si 3 N 4 ), silicon carbide (SiC), yttria (Y 2 O 3 ) etc.

[0018] The joint 30 is disposed between the first member 10 and the second member 20, and is joined to the first member 10 and the second member 20 via the plate-like portion 40 described later. The joint 30 has a plurality of columnar bodies 31 mainly made of a metal material arranged so that the axial direction of the joint 30 is aligned along a direction intersecting the first member 10 and the second member 20. Here, "mainly made of a metal material" does not necessarily mean that the joint 30 is made of only a metal material, but is preferably made of a material containing, for example, 90% or more of a metal component and has ductility that allows deformation by the thermal stress of the joint 1. Each of the columnar bodies 31 in this embodiment is made of aluminum, the same as the first member 10. Note that the material forming the columnar bodies 31 is not limited to aluminum. The material forming the columnar bodies 31 may be titanium (Ti), magnesium (Mg), or an alloy containing 90% or more of these metal components. The end of the joint 30 on the second member 20 side is joined to the second member 20 by various inorganic adhesives, brazing materials, metal nanopastes, solder materials, etc. As a material for joining the joint 30 and the second member 20, one that can join them at low temperatures and has excellent heat resistance is more preferable.

[0019] 3 is an enlarged view of a portion A in FIG. 2. FIG. 3 is a diagram illustrating the axial direction of each of the multiple columns 31 included in the bonded body 1. In the bonded body 1, each of the multiple columns 31 is disposed so that its axial direction is aligned along a direction intersecting with the first member 10 and the second member 20. That is, in a cross section including the central axis C1 of the bonded body 1 shown in FIG. 3, the column 31 is disposed so that its central axis C31 intersects with each of the cross sections of the first member 10 and the second member 20. The fact that each of the multiple columns 31 is disposed so that its axial direction is aligned along a direction intersecting with the first member 10 and the second member 20 can be confirmed by observing a cross section including the central axis C1 of the bonded body 1 as shown in FIG. 3.

[0020] 4 is a top view of the bonded body 1 of this embodiment, seen from the second member 20 side (the positive side of the z-axis). The multiple columns 31 shown in FIG. 4 indicate positions where they are bonded to the main surface 20b of the second member 20.

[0021] As shown in Fig. 4, each of the plurality of columns 31 is formed so that the cross section perpendicular to its own axial direction is substantially circular. In this embodiment, each of the plurality of columns 31 has a diameter of a cross section perpendicular to its own axial direction that is 0.1 mm or more and 1 mm or less, and is smaller than the length in its own axial direction. This makes the columns 31 easier to process and allows the columns 31 to deform flexibly, so that the columns 31 deform in accordance with the difference in contraction that occurs between the first member 10 and the second member 20 due to the difference in thermal expansion between the first member 10 and the second member 20, and can absorb thermal stress.

[0022] The distance between adjacent columns 31 (the distance between the side surfaces of adjacent columns 31 facing each other) is 0.5 mm or more and 10 mm or less. This allows each of the multiple columns 31 to be flexibly deformed, and therefore the multiple columns 31 can absorb thermal stress by deforming in accordance with the difference in contraction between the first member 10 and the second member 20. In addition, the multiple columns 31 can be reliably bonded to the second member 20. Furthermore, uniform and efficient heat conduction can be achieved between the first member 10 and the second member 20 via the multiple columns 31.

[0023] The multiple columns 31 include a central column 31a arranged in a central portion Pa1 of the joint 30 through which the central axis C1 of the joint 1 passes, and a peripheral column 31b arranged in a peripheral portion Pb1 of the joint 30. The central portion Pa1 of the joint 30 is a part of the joint 30 through which the central axis C1 of the joint 1 passes, and is, for example, a portion whose distance from the central axis C1 is within a range of 10% of the radius R1 of the joint 1. In FIG. 4, the central column 31a corresponds to a column 31 among the multiple columns 31 whose axial direction overlaps with the axial direction of the central axis C1. When the axial direction of the multiple columns 31 does not overlap with the axial direction of the central axis C1, the column 31 closest to the central axis C1 is defined as the central column 31a. Thus, the joint 30 may have multiple central columns 31a. When there are multiple central columns 31a, the length of the central column 31a in its own axial direction is the average value of the lengths of the multiple central columns 31a in their own axial direction.

[0024] The outer peripheral portion Pb1 of the joint 30 is a portion whose distance from the central axis C1 of the joined body 1 corresponds to a range of 90% or more of the radius R1 of the joined body 1. The outer peripheral portion Pb1 of the joint 30 is the portion of the joint 30 farthest from the central axis C1, and is also the portion that is most likely to expand and contract when the temperature of the joined body 1 changes. Therefore, it can be said that the outer peripheral column 31b is the column 31 that is most likely to expand and contract when the temperature of the joined body 1 changes, among the multiple columns 31. In this embodiment, the axial length of the outer peripheral column 31b disposed in the outer peripheral portion Pb1 of the joint 30 is greater than 2 mm. When the joint 30 has multiple outer peripheral columns 31b, the axial length of the outer peripheral column 31b is the average of the axial lengths of the multiple outer peripheral columns 31b.

[0025] The plate-shaped portion 40 is a substantially circular portion disposed between the first member 10 and the joint portion 30. The diameter of the plate-shaped portion 40 is the same as the diameter of the first member 10 (360 mm). The plate-shaped portion 40 contacts each end of the plurality of columns 31 and the first member 10. In this embodiment, the joint portion 30 and the plate-shaped portion 40 are one member, and the plate-shaped portion 40 is formed of the same aluminum as the columns 31. The end of the plate-shaped portion 40 on the first member 10 side is joined to the first member 10 by various inorganic adhesives, brazing materials, metal nanopastes, solder materials, and the like. As a material for joining the plate-shaped portion 40 and the first member 10, one that can be joined at low temperatures and has excellent heat resistance is more preferable.

[0026] Next, a method for manufacturing the joint body 1 will be described. First, the first member 10, the second member 20, and a disk-shaped member made of aluminum having the same size as the first member 10 and the second member 20 are prepared. Next, one of a pair of main surfaces of the disk-shaped member is partially cut or etched to form a plurality of columns 31. This forms a joint member having the other main surface side as the plate-shaped portion 40 and the one main surface side as the joint portion 30 on which the columns 31 are formed. Next, the other main surface of the joint member is joined to the first member 10, and the one main surface of the joint member on which the columns 31 are formed is joined to the second member 20, thereby manufacturing the joint body 1. Note that the manufacturing method of the joint portion 30 is not limited to this.

[0027] Next, the effects of the bonded body 1 of this embodiment will be described. In the bonded body 1, the axial length of the outer peripheral columnar body 31b is 1.05 times or less the axial length of the central columnar body 31a.

[0028] FIG. 5 is a schematic diagram for explaining the effect of the bonded body 1 of this embodiment. FIG. 5 shows the difference in cross-sectional shape of the bonded body 1 at different temperatures. FIG. 5 shows the shape of the bonded body 1 at a temperature of 425° C. when the first member 10 and the second member 20 are bonded via the bonding portion 30 as bonded body 1a, and shows the shape of the bonded body 1 at room temperature (25° C.) after the first member 10 and the second member 20 are bonded via the bonding portion 30 as bonded body 1b. For convenience of explanation, the plate-shaped portion 40 is omitted from the bonded body 1 shown in FIG. 5.

[0029] When the first member 10 and the second member 20, both of which have a substantially circular shape, are joined via the joint 30, in the joined body 1a, the sizes (radii) of the first member 10 and the second member 20 are substantially equal to each other. Therefore, each of the multiple columns 31 in the joint 30 is arranged such that its axial direction is substantially parallel to the central axis C1a of the joined body 1a in both the central portion Pa1 and the outer circumferential portion Pb1.

[0030] The degree of contraction of the first member 10 and the second member 20 differs due to the difference in thermal expansion coefficient between the material forming the first member 10 and the material forming the second member 20. When the temperature of the joined body 1a is returned to room temperature after joining, the shape becomes like the joined body 1b in FIG. 5. Specifically, the first member 10 contracts more than the second member 20, so the joint 30 joining the first member 10 and the second member 20 is deformed. In the deformation of the joint 30, the outer peripheral columnar body 31b arranged in the outer peripheral portion Pb1 has a larger deformation amount than the central columnar body 31a arranged in the central portion Pa1. In the joined body 1b, the shape of the joined body 1a before contraction is shown by a two-dot chain line.

[0031] FIG. 6 is a diagram showing the relationship between the temperature difference experienced by the bonded body 1 and the difference in size between the first member 10 and the second member 20. The horizontal axis of FIG. 6 shows the temperature difference between the maximum and minimum temperatures of the bonded body 1, and the vertical axis shows the difference in size (radius) between the first member 10 and the second member 20 relative to the temperature difference. In this embodiment, the maximum temperature is 425° C., which is the temperature when the first member 10 and the second member 20 are bonded, and the minimum temperature is 25° C., which is the temperature during use, so the temperature difference is 400° C. The first member 10 is made of aluminum (thermal expansion coefficient 24 ppm / K), and the second member 20 is made of alumina (thermal expansion coefficient 6 ppm / K). In the bonded body 1a shown in Fig. 5, if the size of the first member 10 and the size of the second member 20 are the same and the radius of the bonded body 1a is 180 mm, the difference in thermal expansion between the first member 10 and the second member 20 due to the temperature change described in Fig. 5 is 1.296 mm (see Fig. 6). Due to such a difference in thermal expansion between the first member 10 and the second member 20 due to temperature change, the peripheral columnar body 31b arranged in the peripheral portion Pb1 of the bonding part 30 deforms the most among the multiple columns 31. Therefore, the degree of deformation due to the temperature difference (hereinafter referred to as "deformation rate") of the peripheral columnar body 31b is the largest among the multiple columns 31.

[0032] FIG. 7 is a diagram for explaining a method for calculating the deformation rate of the peripheral columnar body. FIG. 7 is a diagram showing a schematic diagram of the change in length of the peripheral columnar body 31b arranged at the peripheral portion Pb1 of the joint 30. In this embodiment, the length of the peripheral columnar body 31b when the first member 10 and the second member 20 are joined is approximately the same as the length of the central columnar body 31a arranged at the central portion Pa1 of the joint 30. After the first member 10 and the second member 20 are joined, when the temperature of the joined body 1 becomes room temperature, as described in FIG. 6, the peripheral columnar body 31b joined to the first member 10 and the second member 20 will elongate due to the difference in thermal expansion occurring between the first member 10 and the second member 20. The length of the peripheral columnar body 31b at this time can be calculated using the so-called Pythagoras' theorem. Specifically, as shown in Fig. 7, if the length in the axial direction of the outer peripheral columnar body 31b itself when the first member 10 and the second member 20 are joined is taken as length Lbh, and the difference in thermal expansion (1.296 mm) occurring between the first member 10 and the second member 20 when the temperature of the joined body 1 becomes room temperature is taken as difference ΔR, then the length in the axial direction of the outer peripheral columnar body 31b itself when the temperature of the joined body 1 becomes room temperature can be calculated by the following formula (1). Note that the relationship between the lengths Lbh, Lbn, and the difference ΔR shown in Fig. 7 is different from the actual relationship for the sake of convenience of explanation.

number

[0033] In the bonded body 1, the central columnar body 31a is located in the central portion Pa1 of the joint 30, and is therefore hardly affected by the difference in thermal expansion between the first member 10 and the second member 20 due to temperature changes in the bonded body 1. For this reason, the length of the central columnar body 31a when the first member 10 and the second member 20 are bonded (temperature: 425°C) is approximately the same as the length when the bonded body 1 is used (temperature: 25°C). Therefore, if the axial length of the central columnar body 31a when the bonded body 1 is used is taken as length Lan, in the bonded body 1 during use, the ratio RL of the length Lbn of the peripheral columnar body 31b to the length Lan of the central columnar body 31a is expressed by the following formula (2):

number

[0034] Fig. 8 is a first diagram showing the relationship between the length of the peripheral column and the deformation ratio. Fig. 8 shows how much the peripheral column 31b is deformed relative to the length Lan of the central column 31a when the difference in thermal expansion between the first member 10 and the second member 20 is constant. The deformation ratio RD (unit: %) of the peripheral column is expressed by the following formula (3).

number

[0035] As shown in Fig. 8, as the length of the column 31 increases, the deformation ratio RD of the peripheral column 31b decreases. In this embodiment, the deformation ratio RD of the peripheral column 31b is within the range of elastic deformation of the column 31. For example, the deformation ratio RD shown in Fig. 8 is preferably within 5% (within the range indicated by the dotted arrow Rg1 in Fig. 8), and it is further preferable that the deformation ratio RD is within 2% (within the range indicated by the dotted arrow Rg2 in Fig. 8). When the deformation ratio RD is within 5%, the axial length of the peripheral column 31b itself is 4.0 mm or more, and when the deformation ratio RD is within 2%, the axial length of the peripheral column 31b itself is 6.4 mm or more.

[0036] Fig. 9 is a second diagram showing the relationship between the length of the columnar body and the deformation rate of the peripheral columnar body. Fig. 9 shows the relationship between the length of the columnar body and the deformation rate of the peripheral columnar body for multiple columnar bodies included in a joint. Here, Fig. 9 is used to explain the relationship between the length of the columnar body and the deformation rate of the peripheral columnar body for each of the joint area of ​​the joint body, the difference in the thermal expansion coefficient between the material forming the first member and the material forming the second member, and the temperature difference experienced by the joint body, for a joint body in which a first member and a second member having different thermal expansion coefficients are joined by a joint body.

[0037] When the bonding area of ​​the bonded body increases, the deformation rate of the peripheral columns increases, as shown by the open arrow A1 in Fig. 9, and the relationship between the length of the columns and the deformation rate of the peripheral columns becomes as shown by the two-dot chain line G1. When the bonding area decreases, the deformation rate of the peripheral columns decreases, as shown by the open arrow A2 in Fig. 9, and the relationship between the length of the columns and the deformation rate of the peripheral columns becomes as shown by the two-dot chain line G2. Thus, when the bonding area is large, the deformation of the peripheral columns can be made elastic by increasing the length of the columns.

[0038] When the difference in thermal expansion coefficient between the material forming the first member and the material forming the second member becomes large, the deformation rate of the peripheral column becomes large as shown by the white arrow A1 in Fig. 9, and the relationship between the length of the column and the deformation rate of the peripheral column becomes as shown by the two-dot chain line G1. When the difference in thermal expansion coefficient between the material forming the first member and the material forming the second member becomes small, the deformation rate of the peripheral column becomes small as shown by the white arrow A2 in Fig. 9, and the relationship between the length of the column and the deformation rate of the peripheral column becomes as shown by the two-dot chain line G2. As a result, when the difference in thermal expansion coefficient between the material forming the first member and the material forming the second member is large, the deformation of the peripheral column can be made elastic by increasing the length of the column.

[0039] When the temperature difference experienced by the joined body becomes larger, the deformation rate of the peripheral columns becomes larger, as shown by the open arrow A1 in Fig. 9, and the relationship between the length of the columns and the deformation rate of the peripheral columns becomes as shown by the two-dot chain line G1. When the temperature difference becomes smaller, the deformation rate of the peripheral columns becomes smaller, as shown by the open arrow A2 in Fig. 9, and the relationship between the length of the columns and the deformation rate of the peripheral columns becomes as shown by the two-dot chain line G2. Thus, when the temperature difference experienced by the joined body is large, the deformation of the peripheral columns can be made elastic by increasing the length of the columns.

[0040] According to the bonded body 1 of the present embodiment described above, the difference in thermal expansion coefficient between the material forming the first member 10 and the material forming the second member 20 is 1.5 ppm / K or more, so that the bonded portion 30 bonding the first member 10 and the second member 20 has a relatively large deformation amount in the outer peripheral portion Pb1 due to a temperature change of the bonded body 1. By making the axial length of the outer peripheral column 31b arranged in the outer peripheral portion Pb1 of the bonded portion 30, among the multiple columns 31 of the bonded portion 30, 1.05 times or less the axial length of the central column 31a arranged in the central portion Pa1 of the bonded portion 30, the deformation of the columnar body 31 made mainly of a metal material is elastic even if the temperature of the bonded body 1 changes, so that deterioration or breakage of the columnar body 31 due to repeated deformation is suppressed. Therefore, the durability of the bonded body 1 against temperature changes can be improved.

[0041] Moreover, according to the joined body 1 of the present embodiment, among the multiple columns 31 included in the joint 30, the axial length of the outer peripheral columns 31b arranged in the outer peripheral portion Pb1 of the joint 30 is greater than 2 mm. As a result, even if the temperature of the joined body 1 changes, the columns 31 made mainly of a metal material undergo elastic deformation, suppressing deterioration and breakage of the columns 31 due to repeated deformation. This improves the durability of the joined body 1 against temperature changes.

[0042] In addition, according to the joined body 1 of the present embodiment, the area of ​​the portion where the first member 10 and the second member 20 overlap is 5000 mm 2For the above reasons, the deformation amount of the outer peripheral columns 31b that are bonded to the first member 10 and the second member 20 in the bonded body 1 due to temperature changes becomes relatively large. However, because the deformation of the columns 31 is an elastic deformation, deterioration and breakage of the columns 31 due to repeated deformation is suppressed. Therefore, the durability of the bonded body 1 against temperature changes can be improved.

[0043] <Second embodiment> Fig. 10 is a schematic cross-sectional view of a bonded body according to the second embodiment. A bonded body 2 according to the second embodiment is different in shape from the bonded body 1 according to the first embodiment (Fig. 2).

[0044] The bonded body 2 of the second embodiment includes a first member 50, a second member 20, a joint 60, and a plate-shaped portion 40. The bonded body 2 of the second embodiment is a heat dissipation substrate, and constitutes a power semiconductor module together with a power semiconductor element. In the bonded body 2, as shown in FIG. 10, the second member 20, the joint 60, the plate-shaped portion 40, and the first member 50 are stacked in this order from the positive side in the z-axis direction (stacking direction). In the bonded body 2, the first member 50 and the second member 20 are joined via the joint 60. In this embodiment, the bonded body 2 has a square cross-sectional shape perpendicular to the stacking direction. Note that FIG. 10 shows the arrangement of each part in a schematic manner, and does not accurately show the ratio of the dimensions of each part.

[0045] The first member 50 is made of copper with a thermal expansion coefficient of 17.3 ppm / K. The first member 50 is a flat plate member having a square shape, and has a pair of main surfaces 50a, 50b. In this embodiment, the size of one side of the first member 50 is 200 mm. The first member 50 functions as a heat sink for the heat dissipation substrate in the power semiconductor module. The type of metal forming the first member 10 may be aluminum, stainless steel, an aluminum alloy, titanium (Ti), a titanium alloy, or the like.

[0046] The second member 20 is a square-shaped flat plate member made of alumina with a thermal expansion coefficient of 6 ppm / K. As a result, in the bonded body 2, the difference in thermal expansion coefficient between the material forming the first member 50 and the material forming the second member 20 is 1.5 ppm / K or more. The second member 20 functions as a wiring board on which a power semiconductor is mounted in a power semiconductor module. In this embodiment, the size of one side of the second member 20 is 200 mm. Therefore, when the bonded body 2 is viewed from the stacking direction (z-axis direction), the area of ​​the overlapping portion between the first member 50 and the second member 20, i.e., the bonding area, is 5000 mm 2 That's about 40,000 mm 2 It is.

[0047] The joint 60 is disposed between the first member 50 and the second member 20, and is joined to the first member 50 and the second member 20 via the plate-like portion 40. The joint 60 has a plurality of columns 61 made mainly of a metal material arranged such that the axial direction of the joint 60 is aligned in a direction intersecting with the first member 50 and the second member 20. Each of the columns 61 in this embodiment is made of aluminum. Note that the material forming the columns 61 is not limited to aluminum. The material forming the columns 61 may be titanium (Ti), magnesium (Mg), or an alloy containing 90% or more of these metal components.

[0048] 11 is a top view of the bonded body 2 of this embodiment, as viewed from the second member 20 side (the positive side of the z-axis). The multiple columns 61 shown in FIG. 11 indicate positions where they are bonded to the main surface 20b of the second member 20.

[0049] As shown in FIG. 11, among the multiple columns 61 included in the bonded body 2, the outer peripheral column 61b arranged in the outer peripheral portion Pb2 of the bonded part 60 has a length in its own axial direction that is greater than 2 mm. Here, the outer peripheral portion Pb2 of the bonded part 60 is a portion whose distance from the central axis C2 of the bonded body 2 corresponds to a range of 90% or more of the length L2 of the diagonal line D2 of the bonded body 2. The central axis C2 of the bonded body 2 in this embodiment is a virtual line that passes through the intersection of the two diagonal lines D2 and is parallel to the z-axis in the top view of the bonded body 2 shown in FIG. 11. The outer peripheral portion Pb2 of the bonded part 60 is the portion of the bonded part 60 that is farthest from the central axis C2, and is the portion that is most likely to expand and contract when there is a temperature change in the bonded body 2. Therefore, it can be said that the outer peripheral column 61b is the column 61 that is most likely to expand and contract when there is a temperature change in the bonded body 2 among the multiple columns 61. In this embodiment, the axial length of each peripheral column 61b located at peripheral portion Pb2 of joint 60 is greater than 2 mm. When joint 60 has multiple peripheral columns 61b, the axial length of each peripheral column 61b is defined as the average value of the axial lengths of each of the multiple peripheral columns 61b.

[0050] FIG. 12 is a diagram showing the relationship between the length of the columnar body and the deformation rate of the peripheral columnar body in this embodiment. FIG. 12 shows the degree to which the peripheral columnar body 61b is deformed relative to the length of the central columnar body 61a when the difference in thermal expansion between the first member 50 and the second member 20 is constant. As shown in FIG. 12, as the length of the columnar body 61 increases, the deformation rate of the peripheral columnar body 61b decreases. In this embodiment, the maximum temperature is 425°C, which is the temperature when the first member 10 and the second member 20 are joined, and the minimum temperature is 25°C, which is the temperature during use, so the temperature difference is 400°C. Even with such a temperature difference, the deformation rate of the peripheral columnar body 61b is within the range of elastic deformation of the columnar body 61. For example, the deformation rate shown in FIG. 12 is preferably within 5% (within the range indicated by the dotted arrow Rg1 shown in FIG. 12), and it is even more preferable that the deformation rate is within 2% (within the range indicated by the dotted arrow Rg2 shown in FIG. 12). In this embodiment, when the deformation rate is within 5%, the axial length of peripheral columnar body 61b itself is 2.0 mm or more, and when the deformation rate is within 2%, the axial length of peripheral columnar body 61b itself is 3.2 mm or more.

[0051] According to the joined body 2 of the present embodiment described above, among the multiple columns 61 included in the joint 60 joining the first member 50 and the second member 20, the axial length of the peripheral columns arranged on the outer periphery of the joint 30 is greater than 2 mm. As a result, even if the temperature of the joined body changes, the columns made mainly of a metal material are elastically deformed, so that deterioration or breakage of the columns due to repeated deformation is suppressed. Therefore, the durability of the joined body against temperature changes can be improved.

[0052] <Third embodiment> Fig. 13 is a schematic cross-sectional view of a bonded body of the third embodiment. The bonded body 3 of the third embodiment differs from the bonded body 1 of the first embodiment (Fig. 2) in that the multiple columns are part of the first member.

[0053] The joined body 3 of the third embodiment includes a first member 70 and a second member 20. The first member 70 is made of aluminum and includes a joint portion 70a consisting of a plurality of columnar bodies 71 and a base portion 70b connected to each of the plurality of columnar bodies 71. In the joined body 3, the first member 70 and the second member 20 are stacked in the order of the second member 20, the joint portion 70a of the first member 70, and the base portion 70b of the first member 70 from the positive side in the z-axis direction. In this embodiment, the joined body 3 is a columnar body having a cross-sectional shape perpendicular to the stacking direction that is substantially circular. Note that FIG. 13 shows the arrangement of each part in a schematic manner and does not accurately show the ratio of dimensions of each part.

[0054] The first member 70 is made of aluminum, so that the difference in thermal expansion coefficient between the material forming the first member 70 and the material forming the second member 20 is 1.5 ppm / K or more.

[0055] The joint 70a is disposed on the second member 20 side of the first member 70. The joint 70a has a plurality of columns 71 mainly made of a metal material disposed such that their axial directions intersect with the first member 70 and the second member 20. Each of the plurality of columns 71 has an end on the positive side in the z-axis direction bonded to the main surface 20b on the negative side in the z-axis direction of the second member 20, and an end on the negative side in the z-axis direction connected to the base portion 70b.

[0056] The base portion 70b serves as a platform for supporting the second member 20 in the bonded body 3. The size of the base portion 70b is the same as the size of the second member 20, as shown in Fig. 13. The base portion 70b functions as a cooling portion in the electrostatic chuck. A coolant flow passage (not shown) through which a coolant flows is formed inside the base portion 70b.

[0057] The multiple columns 71 included in joint 70a in this embodiment include a central column 71a arranged in a central portion Pa3 of joint 70a through which central axis C3 of joint 3 passes, and a peripheral column 71b arranged in a peripheral portion Pb3 of joint 70a. In joint 3, the axial length of each peripheral column 71b is 1.05 times or less the axial length of each central column 71a. In this embodiment, the axial length of each peripheral column 71b arranged in peripheral portion Pb3 of joint 70a is greater than 2 mm.

[0058] As described above, in the joined body 3 of this embodiment, the axial length of the outer peripheral columnar body 71b arranged in the outer peripheral portion Pb3 of the joined portion 70a is 1.05 times or less than the axial length of the central columnar body 71a arranged in the central portion Pa3 of the joined portion 70a. As a result, even if the temperature of the joined body 3 changes, the deformation of the columnar body 71 made mainly of a metal material is elastic, so that deterioration or breakage of the columnar body 71 due to repeated deformation is suppressed. Therefore, the durability of the joined body 2 against temperature changes can be improved.

[0059] Furthermore, in the joined body 3 of the present embodiment, the multiple columns 71 form a part of the first member 70 made mainly of a metal material. This allows the joined body 3 to be manufactured by joining the multiple columns 71 of the first member 70 to the second member 20. This makes it easier to manufacture the joined body 3.

[0060] <Fourth embodiment> Fig. 14 is a schematic cross-sectional view of a bonded body of the fourth embodiment. A bonded body 4 of the fourth embodiment differs from the bonded body 1 of the first embodiment (Fig. 2) in that a plurality of columns and a first member are directly bonded to each other.

[0061] The joined body 4 of the fourth embodiment includes a first member 10, a second member 20, and a joint 80. In the joined body 4, the second member 20, the joint 80, and the first member 10 are stacked in this order from the positive side in the z-axis direction. In the joined body 4, the first member 10 and the second member 20 are joined via the joint 80. In this embodiment, the joined body 4 is a columnar body having a substantially circular cross-sectional shape perpendicular to the stacking direction. Note that FIG. 14 shows the arrangement of each part in a schematic manner, and does not show the exact ratio of the dimensions of each part.

[0062] The joint 80 is disposed between the first member 10 and the second member 20, and is joined to the first member 10 and the second member 20. The joint 809 has a plurality of columnar bodies 81 made mainly of a metal material and arranged such that the axial direction of the columnar bodies 81 is aligned in a direction intersecting with the first member 10 and the second member 20. Each of the columnar bodies 81 in this embodiment is formed from aluminum.

[0063] The multiple columns 81 include a central column 81a arranged in a central portion Pa4 of the joint 80 through which the central axis C4 of the joint 4 passes, and a peripheral column 81b arranged in a peripheral portion Pb4 of the joint 80. In the joint 4, the axial length of each peripheral column 81b is 1.05 times or less the axial length of each central column 81a. In this embodiment, the axial length of each peripheral column 81b arranged in the peripheral portion Pb4 of the joint 80 is greater than 2 mm.

[0064] As described above, in the joined body 4 of this embodiment, the axial length of the outer peripheral columnar body 81b arranged in the outer peripheral portion Pb4 of the joined part 80 is 1.05 times or less the axial length of the central columnar body 81a arranged in the central portion Pa4 of the joined part 80. As a result, even if the temperature of the joined body 4 changes, the deformation of the columnar body 81 made mainly of a metal material is elastic, so that deterioration and breakage of the columnar body 81 due to repeated deformation is suppressed. This improves the durability of the joined body 3 against temperature changes.

[0065] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0066] [Variation 1] In the first embodiment, the bonded body is used as an electrostatic chuck provided in a semiconductor manufacturing device. In the second embodiment, the bonded body is a heat dissipation substrate constituting a power semiconductor module. However, the fields in which the bonded body is applied are not limited to these. The bonded body may be applied to a device including a bonded body in which two or more members having different thermal expansion coefficients are bonded via a joint, such as a wiring board.

[0067] [Variation 2] In the first embodiment, the first member is made of aluminum, the second member is made of alumina, and the columnar body is made of aluminum. In the second embodiment, the first member is made of copper. However, the materials forming the first member, the second member, and the columnar body are not limited to these. The first member may be aluminum, copper, stainless steel, an aluminum alloy, titanium, a titanium alloy, a magnesium alloy, or the like. The second member may be alumina, aluminum nitride, zirconia, silicon nitride, silicon carbide, yttria, or the like. The columnar body may be made of any material as long as it is mainly made of a metal material, and may be aluminum, titanium, magnesium, or an alloy containing 90% or more of these metal components.

[0068] [Variation 3] In the first embodiment, the axial length of the peripheral column is 1.05 times or less than the axial length of the central column and is greater than 2 mm. In the second embodiment, the axial length of the peripheral column is greater than 2 mm. The axial length of the peripheral column may be either 1.05 times or less than the axial length of the central column, or greater than 2 mm. By making the axial length of the peripheral column either 1.05 times or less than the axial length of the central column, or greater than 2 mm, the deformation of the peripheral column can be limited to elastic deformation, thereby suppressing breakage of the columns and improving the durability of the joined body against temperature changes.

[0069] [Variation 4] In the first, third and fourth embodiments, in a bonded body having a substantially circular cross section perpendicular to the stacking direction, the central portion where the central column is arranged is a portion whose distance from the central axis of the bonded body is within 10% of the radius of the bonded body, and the peripheral portion where the peripheral column is arranged is a portion whose distance from the central axis of the bonded body is within 90% of the radius of the bonded body or more. However, the central portion and peripheral portion of the bonded part are not limited to this.

[0070] FIG. 15 is a top view of a first modified example of the bonded body of the first embodiment. FIG. 15 shows a top view of the bonded body 1 having a cross section perpendicular to the stacking direction that is substantially elliptical. In the bonded body 1 shown in FIG. 15, the central portion Pa1 is a portion whose distance from the central axis C1 passing through the intersection of the major axis La and the minor axis Sa of the bonded body 1 is within 10% of the major axis Ld of the bonded body 1. In this case, the central columnar body 31a is a columnar body whose axial direction overlaps with the axial direction of the central axis C1, or the columnar body closest to the central axis C1 when the axial direction of the central axis C1 does not overlap with the axial direction of the central axis C1. The outer peripheral portion Pb1 is a portion whose distance from the central axis C1 of the bonded body 1 is within 90% of the major axis Ld of the bonded body 1. As shown in FIG. 15 , when peripheral portion Pb1 includes multiple columns 31, in the top view shown in FIG. 15 , among the multiple columns 31, a column 31 that overlaps with the long axis La of bonded body 1 or is closest to the long axis La is defined as peripheral column 31b.

[0071] FIG. 16 is a top view of a second modified example of the bonded body of the first embodiment. FIG. 16 shows a top view of a bonded body 1 having a substantially rectangular cross section perpendicular to the stacking direction. In the bonded body 1 shown in FIG. 16, the central portion Pa1 is a portion whose distance from the central axis C1 passing through the intersection of two diagonals D1 in the bonded body 1 is within 10% of the length Lda of the diagonal D1 of the bonded body 1. In this case, the central columnar body 31a is a columnar body whose axial direction overlaps with the axial direction of the central axis C1, or a columnar body whose axial direction does not overlap with the axial direction of the central axis C1 is the closest to the central axis C1. The peripheral portion Pb1 is a portion whose distance from the central axis C1 of the bonded body 1 is within 90% of the length Lda of the diagonal D1 of the bonded body 1. As shown in FIG. 16 , when peripheral portion Pb1 includes multiple columns 31, in the top view shown in FIG. 16 , among the multiple columns 31, a column 31 that overlaps with diagonal line D1 of bonded body 1 or a column 31 that is closest to diagonal line D1 is defined as peripheral column 31b.

[0072] [Variation 5] In the second embodiment, in a bonded body having a square cross section perpendicular to the stacking direction, the outer peripheral portion Pb2 of the bonded portion 60 where the outer peripheral columnar body 61b is arranged is a portion whose distance from the central axis C2 of the bonded body 2 corresponds to a range of 90% or more of the length L2 of the diagonal line D2 of the bonded body 2. However, the outer peripheral portion of the bonded portion is not limited to this. For example, when the cross section perpendicular to the stacking direction is circular as described in the first embodiment, the outer peripheral portion Pb2 may be a portion whose distance from the central axis of the bonded body corresponds to a range of 90% or more of the radius of the bonded body. Furthermore, when the cross section perpendicular to the stacking direction is elliptical as described in the fourth modification, the outer peripheral portion Pb2 may be a portion whose distance from the central axis of the bonded body corresponds to a range of 90% or more of the major axis of the bonded body.

[0073] [Variation 6] In the first embodiment, the joint area between the first member 10 and the second member 20 is 5000 mm 2 That's about 102,000 mm 2 In the second embodiment, the joint area between the first member 50 and the second member 20 is 5000 mm 2 That's about 40,000 mm 2 The joint area of ​​the joint is 5000mm 2 When the bonding area of ​​the bonded body is large, the amount of deformation of the peripheral columns due to temperature changes of the bonded body becomes relatively large, but since the deformation of the peripheral columns is an elastic deformation, deterioration or breakage of the columns due to repeated deformation is suppressed.

[0074] [Variation 7] In the first embodiment, each of the plurality of columns 31 is formed so that the cross-sectional shape perpendicular to its axial direction is substantially circular, and the diameter of the cross-sectional shape perpendicular to its axial direction is 0.1 mm or more and 1 mm or less, and is smaller than the length in the axial direction. However, the cross-sectional shape perpendicular to its axial direction and the size of the cross-sectional shape perpendicular to its axial direction of the columnar body are not limited to this. The cross-sectional shape perpendicular to its axial direction of the columnar body is not limited to a substantially circular shape, and may be a rectangular shape such as a square. When the cross-sectional shape perpendicular to its axial direction of the columnar body is substantially rectangular, it is preferable that the length of one side of the rectangular shape is 0.1 mm or more and 1 mm or less, and is smaller than the length in the axial direction of the columnar body. This makes it easier to process the columnar body 31, and the columnar body 31 can be flexibly deformed, so that the columnar body 31 can deform in accordance with the difference in contraction occurring between the first member 10 and the second member 20 due to the difference in thermal expansion between the first member 10 and the second member 20, and can absorb thermal stress.

[0075] [Variation 8] In the first embodiment, the distance between adjacent columns 31 is set to 0.5 mm or more and 10 mm or less. However, the distance between adjacent columns is not limited to this. By setting the distance between adjacent columns to an appropriate distance, each of the multiple columns 31 can be flexibly deformed, and therefore can absorb thermal stress. On the other hand, when the distance between adjacent columns is small, the number of columns increases, which may make it difficult to deform and absorb thermal stress. Furthermore, when the distance between adjacent columns is large, the number of columns decreases, which may not only make the joint between the first member and the second member unstable, but also may reduce the thermal conductivity between the first member and the second member. Furthermore, when the distance between adjacent columns is large, the temperature distribution in the surface of the second member may become non-uniform.

[0076] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0077] <Application example 1> A joint in which a first member and a second member are joined via a joint, a difference in thermal expansion coefficient between a material forming the first member and a material forming the second member is 1.5 ppm / K or more; the joint portion has a plurality of columnar bodies made mainly of a metal material and arranged such that their axial directions are aligned along a direction intersecting with each of the first member and the second member, the plurality of columns include a central columnarly disposed in a central portion of the joint through which a central axis of the joint body passes, and peripheral columnsarranged in a peripheral portion of the joint, The axial length of the peripheral column is 1.05 times or less than the axial length of the central column. A conjugate characterized in that <Application example 2> A joint in which a first member and a second member are joined via a joint, a difference in thermal expansion coefficient between a material forming the first member and a material forming the second member is 1.5 ppm / K or more; the joint portion has a plurality of columnar bodies made mainly of a metal material and arranged such that their axial directions are aligned along a direction intersecting with each of the first member and the second member, Among the plurality of columns, the axial length of the peripheral column arranged on the outer periphery of the joint is greater than 2 mm. A conjugate characterized in that <Application example 3> The bonded body according to Application Example 1 or Application Example 2, The axial length of the outer peripheral column is greater than 2 mm. A conjugate characterized in that <Application Example 4> The bonded structure according to any one of Application Examples 1 to 3, The area of ​​the overlapping portion between the first member and the second member is 5000 mm 2 That's all. A conjugate characterized in that <Application example 5> The bonded structure according to any one of Application Examples 1 to 4, The first member is mainly made of a metal material, The plurality of columns are part of the first member. A conjugate characterized in that [Explanation of symbols]

[0078] 1,2,3,4…zygote 10, 50, 70…First member 20…Second member 30,60,70a,80…Joint part 31,61,71,81…Column body C1,C2,C3,C4…Central axis Pa1,Pa3,Pa4…Central part 31a,61a,71a,81a...Central columnar body Pb1, Pb2, Pb3, Pb4...Outer periphery 31b,61b,71b,81b...Peripheral columnar body Lan: Length of the central column along its axis Lbn: Length of the outer column in the axial direction

Claims

1. A joint in which a first member and a second member are joined via a joint, a difference in thermal expansion coefficient between a material forming the first member and a material forming the second member is 1.5 ppm / K or more; the joint portion has a plurality of columnar bodies made mainly of a metal material and arranged such that their axial directions are aligned along a direction intersecting with each of the first member and the second member, the plurality of columns include a central columnarly disposed in a central portion of the joint through which a central axis of the joint body passes, and peripheral columnsarranged in a peripheral portion of the joint, The axial length of the peripheral column is 1.05 times or less than the axial length of the central column. A conjugate characterized in that

2. A joint in which a first member and a second member are joined via a joint, a difference in thermal expansion coefficient between a material forming the first member and a material forming the second member is 1.5 ppm / K or more; the joint portion has a plurality of columnar bodies made mainly of a metal material and arranged such that their axial directions are aligned along a direction intersecting with each of the first member and the second member, Among the plurality of columns, the axial length of the outer peripheral column arranged on the outer peripheral portion of the joint is greater than 2 mm. A conjugate characterized in that

3. The joint body according to claim 1 , The axial length of the outer peripheral column is greater than 2 mm. A conjugate characterized in that

4. The bonded body according to claim 1 or 2, The area of ​​the overlapping portion between the first member and the second member is 5000 mm 2 That's all. A conjugate characterized in that

5. The bonded body according to claim 1 or 2, The first member is mainly made of a metal material, The plurality of columns are part of the first member. A conjugate characterized in that

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