Component joining device and component joining method

Abstract

To improve productivity of a joining work while securing a good joining state of an electronic component to a joined body.SOLUTION: The bonding apparatus includes a head part for pressurizing and heating a bonding work in which a plurality of electronic components are bonded to a body to be bonded, and a metal fiber sheet attached to the head part and pressed against the plurality of electronic components by the head part when pressurizing the bonding work.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a component joining apparatus and a component joining method that joins a plurality of electronic components to an object to be joined by applying pressure and heat to the joining workpiece with a head portion. [Background technology]

[0002] A component joining device that performs joining processing of joining workpieces in which electronic components are joined to objects to be joined includes a head unit that is movable in directions toward and away from a stage on which the joining workpieces are placed and has a heating device, and joins the objects to be joined and the electronic components by applying pressure and heat to the joining workpieces with the head unit while the electronic components are placed on the objects to be joined.

[0003] Incidentally, a plurality of electronic components are often bonded to a bonded object, and when a plurality of electronic components are bonded, the heights of the respective electronic components may differ.

[0004] One method for joining electronic components of different heights to a workpiece is to apply pressure and heat to each electronic component using a separate head unit. However, since a head unit is required for each electronic component, this method has the disadvantage of complicating the structure of the component joining device, which can easily increase manufacturing costs, and also requires a lot of time and effort for the joining process, resulting in low productivity.

[0005] On the other hand, there is a method for simultaneously joining electronic components of different heights using a single head. Known methods include attaching components pre-fabricated to the head to match the height of each electronic component, or using a stage that matches the height of each electronic component. However, this method requires the components and stages to be remade depending on the type of workpiece to be joined, which also reduces productivity.

[0006] In contrast to this, there is a component joining device in which a film made of a resin material is attached to the head portion, and the joining workpieces are pressurized and heated via the film (see, for example, Patent Document 1). In the component joining device described in Patent Document 1, the film is elastically deformed to absorb differences in height between electronic components, so multiple electronic components can be joined at once regardless of the type of joining workpiece. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-092176 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the method using a film formed from the above-mentioned resin material, the film is crushed by pressure, so it is necessary to replace the film after each bonding process, and a process is also required to separate the film melted by heating from the bonded workpiece, which again may result in a decrease in productivity. In addition, since it is necessary to use a film with high thermal conductivity and heat resistance, the film tends to be expensive, which is another problem that can easily lead to an increase in costs.

[0009] Therefore, an object of the present invention is to improve the productivity of joined works. [Means for solving the problem]

[0010] The component joining device of the present invention comprises a head unit that applies pressure and heat to a joining workpiece in which a plurality of electronic components are joined to a workpiece, and a metal fiber sheet that is attached to the head unit and is pressed against the plurality of electronic components by the head unit when pressure is applied to the joining workpiece.

[0011] This allows the metal fiber sheet to absorb the height difference between the electronic components when pressure is applied to the workpiece to be joined.

[0012] The component mounting method according to the present invention is a component joining method in a component joining device that repeatedly performs joining processes on a joining workpiece in which a plurality of electronic components are joined to a workpiece, the component joining device comprising: a head unit that applies pressure and heat to the joining workpiece; and a metal fiber sheet that is attached to the head unit and is pressed against the plurality of electronic components by the head unit when pressure is applied to the joining workpiece, the surface of the metal fiber sheet facing the joining workpiece is formed as a work-facing surface, the portion of the work-facing surface that is pressed against the electronic components is formed as a pressing portion, and the portion other than the pressing portion is formed as a non-contact portion, and the component joining method is such that during a first joining process, the metal fiber sheet is pressed against the electronic components, so that the pressing portion is displaced toward the head unit from the non-contact portion, and during a second or subsequent joining process, the metal fiber sheet is pressed against the electronic components with the pressing portion displaced toward the head unit from the non-contact portion.

[0013] This allows the metal fiber sheet to absorb differences in height between electronic components when pressure is applied to the workpieces to be joined, and makes it possible to repeat the joining process without replacing the metal fiber sheet. [Effects of the Invention]

[0014] According to the present invention, the metal fiber sheet absorbs the height differences between electronic components when pressure is applied to the workpiece to be joined, making it possible to join multiple electronic components to the workpiece at once regardless of the height differences of the electronic components, thereby improving the productivity of the joined workpiece. [Brief explanation of the drawings]

[0015] [Figure 1] 2 to 4, this figure shows an embodiment of the present invention, and is a schematic cross-sectional view of a component joining apparatus. [Figure 2]FIG. 2 is a schematic cross-sectional view showing a state in which the workpieces to be joined are pressurized and heated. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a state in which recesses are formed in a metal fiber sheet. [Figure 4] 5 to 18 show various tests carried out using a metal fiber sheet, and this figure is a schematic cross-sectional view for explaining the test method of test (1). [Figure 5] FIG. 10 is a plan view for explaining the verification method of verification (1). [Figure 6] FIG. 10 is a diagram showing the measurement results of verification (1). [Figure 7] FIG. 10 is a diagram showing the measurement results of verification (1). [Figure 8] 10 is a graph showing the measurement results of verification (2). [Figure 9] FIG. 10 is a diagram showing the measurement results of verification (3)-1. [Figure 10] FIG. 10 is a cross-sectional view for explaining the verification methods of verifications (3)-2 and (3)-3. [Figure 11] FIG. 10 is a plan view for explaining the verification methods of verifications (3)-2 and (3)-3. [Figure 12] FIG. 10 is a diagram showing the measurement results of verification (3)-2. [Figure 13] FIG. 10 is a diagram showing the measurement results of verification (3)-3. [Figure 14] FIG. 10 is a schematic cross-sectional view for explaining the verification method of verification (4). [Figure 15] 10 is a graph showing the measurement results of verification (4). [Figure 16] 10 is a graph showing the measurement results of Verification (5)-1. [Figure 17] FIG. 10 is a diagram showing the measurement results of verification (5)-2. [Figure 18] FIG. 10 is a diagram showing the measurement results of verification (5)-3. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] <Configuration of part joining equipment> First, the configuration of a component bonding apparatus 1 according to the present invention will be described (see FIG. 1).

[0018] The component bonding device 1 has a stage 2 , a head unit 3 , and a metal fiber sheet 4 .

[0019] The stage 2 is supported, for example, on a base (not shown), and has a flat upper surface formed as a placement surface 2a. A joining workpiece (described later) is placed on the placement surface 2a. A heating device (not shown) is provided on the stage 2, and the heating state of the stage 2 is controlled by heat transferred from the heating device.

[0020] The head unit 3 is positioned, for example, directly above the stage 2, and is movable by a drive mechanism (not shown) in a direction to approach and separate from the stage 2, for example, up and down. The head unit 3 has a flat lower surface formed as a pressing surface 3a. The head unit 3 has a plurality of suction holes 3b opened in the pressing surface 3a. A heating device (not shown) is also provided on the head unit 3, and the heating state of the head unit 3 is controlled by heat transferred from the heating device in the same way as the stage 2.

[0021] A metal fiber sheet 4 is detachably attached to the pressing surface 3a.

[0022] The metal fiber sheet 4 is a porous sheet formed by intertwining non-oriented metal fibers, and has elasticity. For example, copper is used as the metal fibers that make up the metal fiber sheet 4. The hardness of the metal fibers that make up the metal fiber sheet 4 is set to be equal to or smaller than the hardness of the main body of the electronic component described below.

[0023] A thin metal plate 5 made of, for example, copper is adhered to the upper surface of the metal fiber sheet 4. The metal fiber sheet 4 is attached to the underside of the head unit 3 by vacuum adsorption of the metal plate 5 to the head unit 3, and is moved up and down integrally with the head unit 3.

[0024] The metal fiber sheet 4 may be attached to the head portion 3 by a method other than vacuum suction. In that case, the metal plate 5 may not be provided, and the metal fiber sheet 4 may be attached directly to the head portion 3.

[0025] The lower surface of the metal fiber sheet 4 is formed as a work-facing surface 6 that faces the workpieces to be joined, which will be described later, during the joining process. The part of the work-facing surface 6 that is pressed against the workpieces to be joined is formed as a pressing portion 7, and the part other than the pressing portion 7 is formed as a non-contact portion 8.

[0026] <Component mounting method> Next, the operation of the component bonding apparatus 1 and the bonding process executed by the component bonding apparatus 1 will be described (see FIGS. 1 to 3).

[0027] Before the joining process is performed, the metal fiber sheet 4 is attached to the head unit 3. After the metal fiber sheet 4 is attached to the head unit 3 and before the first pressure is applied, the work-facing surface 6 of the metal fiber sheet 4 is made substantially flat, and the pressing portion 7 and the non-contact portion 8 are positioned on substantially the same plane.

[0028] In the component bonding apparatus 1, a workpiece 100 to be bonded is placed at a predetermined position on the placement surface 2a of the stage 2 (see FIG. 1). The number of workpieces 100 to be bonded placed on the placement surface 2a is arbitrary, and may be one or more.

[0029] The joining work 100 has a workpiece 101 and a plurality of electronic components 102. The workpiece 100 is placed on the placement surface 2a in a state where the workpieces 101 and the electronic components 102 are positioned with a joining material 103 sandwiched between them, and before the workpieces 101 and the electronic components 102 are joined. At least two of the electronic components 102 are formed to have different heights.

[0030] The object to be bonded 101 is, for example, a substrate or a heat sink, and the electronic component 102 is, for example, a semiconductor element or a substrate. The bonding material 103 is, for example, a thermally conductive adhesive or solder that melts when heated and solidifies when cooled.

[0031] The electronic component 102 is configured such that, for example, an electrode 102b is provided on the lower surface side of a main body 102a, and the electrode 102b is connected to a circuit pattern (not shown) formed on the bonded body 101 by a bonding material 103. The main body 102a is formed of, for example, copper, SiC (silicon carbide), GaN (gallium nitride), or the like.

[0032] When the workpiece 100 to be joined is placed on the placement surface 2a, the head part 3 is moved downward so that the pressing part 7 of the metal fiber sheet 4 is pressed against the electronic component 102 (see FIG. 2). At this time, the stage 2 and the head part 3 are each heated to a predetermined temperature by a heating device.

[0033] The metal fiber sheet 4 is pressed against the workpiece 100 to be joined, and the heat of the head portion 3 is transmitted to the workpiece 100 to be joined via the metal fiber sheet 4 .

[0034] When the head portion 3 presses the metal fiber sheet 4 against the electronic components 102, the metal fiber sheet 4 is elastically deformed, and the work-facing surface 6 is deformed so that the pressing portion 7 is displaced toward the head portion from the non-contact portion 8 according to the height of the workpieces 100 to be joined. This brings the pressing portion 7 of the metal fiber sheet 4 into close contact with each electronic component 102, and applies an appropriate pressure to each workpiece 100 to be joined.

[0035] When the application of pressure and heat to the workpiece 100 to be joined is completed, the head part 3 is moved upward (see FIG. 3). The metal fiber sheet 4 has a sufficiently high heat resistance against the joining temperature, so it is not joined to the electronic component 102 during joining and is moved upward together with the head part 3.

[0036] The metal fiber sheet 4 pressed against the electronic component 102 by the head portion 3 remains in a state in which the pressing portion 7 is displaced toward the head portion 3 from the non-contact portion 8 even when the pressure on the joining workpiece 100 is released due to plastic deformation.

[0037] When the head portion 3 and the metal fiber sheet 4 are moved to a predetermined position, the workpiece 100 in which the electronic component 102 is joined to the object 101 is removed from the placement surface 2a, and the joining process of the workpiece 100 is completed.

[0038] After the joining work 100 is removed from the placement surface 2a, another joining work 100 is placed on the placement surface 2a in a state before the joining object 101 and the electronic component 102 are joined, and pressure and heat are applied to the other joining work 100.

[0039] In the second and subsequent joining processes, the metal fiber sheet 4, with the pressing portion 7 displaced toward the head portion 3 from the non-contact portion 8, moves downward along with the head portion 3. However, as the head portion 3 presses the metal fiber sheet 4 against the joining work 100, the elastic force of the metal fiber sheet 4 brings the pressing portion 7 and the electronic component 102 into close contact, and appropriate pressure is applied to each joining work 100.

[0040] In the component bonding apparatus 1, the bonding process is repeatedly carried out as described above without replacing the metal fiber sheet 4.

[0041] It is desirable to replace the metal fiber sheet 4 when a predetermined number of joining processes have been completed.

[0042] In the component joining device 1, the metal fiber sheet 4 is attached to the head unit 3 by vacuum suction. This makes it possible to easily remove the metal fiber sheet 4 from the head unit 3 by controlling the state of suction of the metal fiber sheet 4 to the head unit 3, and therefore makes it possible to easily replace the metal fiber sheet 4 while ensuring a stable attachment state of the metal fiber sheet 4 to the head unit 3.

[0043] Furthermore, when joining different types of joining workpieces 100 using the component joining device 1, it is only necessary to replace the metal fiber sheet 4 with a new one, and the stage 2 and head portion 3 can be reused as they are, making it possible to handle the joining process of various types of joining workpieces without requiring major modification work on the component joining device 1.

[0044] As described above, the component joining device 1 is equipped with the metal fiber sheet 4 that is pressed against the plurality of electronic components 102 by the head unit 3 when pressure and heat are applied to the workpiece 100 to be joined. As a result, the metal fiber sheet 4 absorbs differences in height between the electronic components 102 when pressure is applied to the workpiece 100 to be joined, making it possible to join the plurality of electronic components 102 to the workpiece 101 at once regardless of the height of the electronic components 102. Furthermore, the metal fiber sheet 4 and the electronic components 102 are not joined to each other, and are automatically separated as the head unit 3 moves, so no dedicated process is required to separate the metal fiber sheet 4 from the workpiece 100 to be joined, thereby simplifying the joining process.

[0045] Furthermore, in the component joining device 1, during the first joining process, the metal fiber sheet 4 is pressed against the electronic component 102, displacing the pressing portion 7 toward the head portion 3 from the non-contact portion 8, and during the second or subsequent joining process, the metal fiber sheet 4 is pressed against the electronic component 102 with the pressing portion 7 displaced toward the head portion 3 from the non-contact portion 8.

[0046] As a result, even in the second and subsequent joining processes, the head portion 3 applies appropriate pressure to each joining work 100 via the metal fiber sheet 4, making it possible to perform repeated joining processes without replacing the metal fiber sheet 4.

[0047] Therefore, it is possible to improve the productivity of the workpiece 100 to be joined while ensuring a good joining state of the electronic component 102 to the object to be joined 101.

[0048] Furthermore, in the component joining apparatus 1, the hardness of the metal fibers that make up the metal fiber sheet 4 is set to be the same as or smaller than the hardness of the main body 102a of the electronic component 102 to be joined. This makes it difficult for the metal fiber sheet 4 to damage the main body 102a when the metal fiber sheet 4 is pressed against the electronic component 102, thereby preventing breakage or damage to the workpiece 100 to be joined.

[0049] Furthermore, copper is used as the metal fibers that make up the metal fiber sheet 4. This gives the metal fiber sheet 4 high thermal conductivity, allowing the heat from the head portion 3 to be efficiently transferred to the workpiece 100 to be joined. Furthermore, because copper is a metal with a relatively low hardness, there is a wider range of materials to choose from for forming the main body 102a of the electronic component 102, which increases the degree of freedom in designing the workpiece 100 to be joined. In addition, the metal fiber sheet 4 can be manufactured relatively inexpensively, allowing for cost reductions.

[0050] Metals other than copper, such as stainless steel, may be used as the metal fibers constituting the metal fiber sheet 4. However, when a metal fiber sheet made of stainless steel is used, it is desirable that the main body 102a of the electronic component 102 be made of a hard material, such as SiC or GaN.

[0051] Furthermore, it is also possible to use metal fiber sheets with different lengths, fiber diameters, porosities, etc. of the constituent metal fibers depending on the workpiece 100 to be joined.

[0052] <Verification using metal fiber sheets> The results of various tests that were actually conducted using metal fiber sheets are shown below (see Figures 4 to 18). Five types of tests were conducted, from Test (1) to Test (5). All of the metal fiber sheets used in the tests were made of copper fibers with a fiber diameter of 20 μm, and metal fiber sheets with a porosity of 68% were used in Tests (1) to (4). The porosity of the metal fiber sheet used in Test (5) will be described later.

[0053] <Verification (1)> First, verification was carried out to confirm that repeated joining processes were possible without replacing the metal fiber sheet (see FIGS. 4 to 7).

[0054] The verification method involved placing four identical chips (electronic components) 60 on pressure-sensitive paper 50, placing shim plates 70 made of a metal material on two of the chips 60, and simultaneously applying pressure to the four chips 60 via the metal fiber sheet 4 (see Figures 4 and 5). The thickness (height) of the shim plate 70 was 10 μm, and the thickness of the metal fiber sheet 4 was 100 μm.

[0055] In the following verifications, the chip 60 on which the shim plate 70 is placed may be referred to as chip 60A, and the chip 60 on which the shim plate 70 is not placed may be referred to as chip 60B.

[0056] The applied pressure was 10 MPa, which is the normal range, and 50 MPa, which is the maximum load that can be applied, and pressure was applied 10 times at each pressure.

[0057] Figure 6 shows the pressure-sensitive paper 50 and metal fiber sheet 4 after being pressurized at 10 MPa, and Figure 7 shows the pressure-sensitive paper 50 and metal fiber sheet 4 after being pressurized at 50 MPa. In each figure, the dark colored parts of the pressure-sensitive paper 50 are the colored parts of the pressure-sensitive paper 50, i.e., the parts where pressure was applied. The white parts of the metal fiber sheet 4 are the pressing parts 7.

[0058] 6 and 7, there was almost no difference in the color development of the pressure-sensitive paper 50 between the first and tenth times at either pressure, and it was confirmed that the same pressure was applied at the tenth time as at the first time. Therefore, it can be said that the joining process can be repeated multiple times without replacing the metal fiber sheet 4.

[0059] <Verification (2)> Next, the durability of the metal fiber sheet 4 was verified (see FIG. 8).

[0060] The verification method involved applying pressure to the chip 60 on which the shim plate 70 was placed, and measuring the coordinates (height) of the head part 3 when pressure was applied, based on the position before the head part 3 was moved. The thicknesses of the shim plate 70 and metal fiber sheet 4 used were 10 μm and 100 μm, respectively, as in verification (1). The applied pressures were also 10 MPa and 50 MPa, as in verification (1), but in this verification, pressure was applied 50 times at each pressure.

[0061] FIG. 8 is a graph showing the coordinates of the head portion 3 and the number of times pressure is applied when pressures of 10 MPa and 50 MPa are applied.

[0062] The change in coordinates of the head part 3 shows that the amount of crushing of the metal fiber sheet 4 gradually increases with the application of pressure, but it can be seen that the change in the amount of crushing with the application of pressure from the third time onwards is almost the same for 10 MPa and 50 MPa. Also, it is possible to estimate that it takes about 200 pressurizations for the metal fiber sheet 4 to be crushed to 10 μm, which is the thickness of the shim plate 70 used in this study, and it can be said that the metal fiber sheet 4 has sufficient durability to withstand repeated joining processes.

[0063] <Verification (3)> Next, three tests were carried out to determine the height that can be absorbed by the metal fiber sheet (see FIGS. 9 to 12).

[0064] <Verification (3)-1> In the first test, the same pressure-sensitive paper 50 and four chips 60 as in Test (1) were used, and pressure was applied at 10 MPa and 50 MPa for different thicknesses of the shim plate 70. The shim plates 70 used were of four thicknesses: 5 μm, 10 μm, 15 μm, and 20 μm.

[0065] Figure 9 shows the pressure-sensitive paper 50 and metal fiber sheet 4 after each pressure application. The two areas surrounded by dashed lines are the pressure marks on chip 60A. When pressure was applied at 10 MPa and the shim plate 70 had a thickness of 15 μm or 20 μm, it can be seen that the pressure marks on chip 60B were rubbed. This indicates that sufficient pressure was not being applied to chip 60B.

[0066] <Verification (3)-2> Second, an SAT test (ultrasonic flaw detection test) was performed using a joined workpiece 200 in which chips 60 were bonded to a copper plate 80. The joined workpiece 200 was formed by bonding four chips 60 to a copper plate 80 using silver paste as the bonding material, and the bonding process was performed with shim plates 70 placed on two of the chips 60 (see FIGS. 10 and 11). The SAT test was performed on four types of joined workpieces 200 in which the thickness of the shim plates 70 was changed. The thicknesses of the shim plates 70 used during bonding were 0 (no shim plate 70), 5 μm, 10 μm, and 20 μm. In all cases, the thickness of the metal fiber sheet 4 used in the bonding process was 100 μm, the applied pressure was 15 MPa, and the heating temperature was 300°C.

[0067] Figure 12 shows the results of the SAT test. The two boxes enclosed by dashed lines represent the chip 60A. A white area is visible under the chip 60 only when the shim plate 70 used during bonding is 20 μm thick. This indicates that a space has formed between the copper plate 80 and the chip 60, and the bonding between the two is insufficient.

[0068] <Verification (3)-3> Thirdly, a shear test was carried out in which a load was applied to the tip 60 from the side using the same joined workpiece 200 as in the verification (3)-2.

[0069] 13 shows the results of the shear test on chip 60A. The chip was destroyed in all three cases where the thickness of the shim plate 70 used during bonding was other than 20 μm, whereas the chip 60 peeled off from the copper plate 80 when the thickness of the shim plate 70 was 20 μm. This shows that when the thickness of the shim plate 70 was 20 μm, the bonding between the copper plate 80 and the chip 60 was insufficient.

[0070] From the above results, it can be said that when pressure is applied at 10 MPa, which is the normal range, if the difference in height of the tip 60 is 10% or less of the thickness of the metal fiber sheet 4, the difference in height can be absorbed.

[0071] <Verification (4)> Next, the heat transfer properties of the metal fiber sheet were verified (see FIGS. 14 and 15).

[0072] The verification method involved sandwiching a thermocouple 90 between two chips 60 in the height direction (see FIG. 14), applying pressure and heat while changing the thickness of the metal fiber sheet 4, and collecting the temperature of the thermocouple 90 in each case. The heating temperatures were 100°C for the stage 2 and 250°C for the head part 3, and the values ​​were collected after applying pressure and heating and the temperature of the thermocouple 90 stabilized in each case. The thicknesses of the metal fiber sheet 4 used were four types: 0 mm (no sheet), 0.1 mm, 0.3 mm, and 0.5 mm.

[0073] Figure 15 is a graph showing the collected temperatures. This graph shows that the thicker the metal fiber sheet 4, the lower the temperature transmitted to the tip. Therefore, it is essential to measure the temperature in advance and adjust the temperature of the stage 2 and head unit 3 appropriately according to the thickness of the metal fiber sheet 4 used in the joining process.

[0074] On the other hand, even when a 0.5 mm metal fiber sheet 4 was used, the temperature difference compared to when no metal fiber sheet 4 was used was about 10 degrees, which can be said to demonstrate the high heat conductivity of the metal fiber sheet 4.

[0075] <Verification (5)> Next, three tests were carried out using three types of metal fiber sheets with different porosities (see Figs. 16 to 18).

[0076] The metal fiber sheets used in verification (5) were of three types with porosities of 58%, 68%, and 78%. In the following explanation, the metal fiber sheet with a porosity of 58% will be referred to as metal fiber sheet A, the metal fiber sheet with a porosity of 68% as metal fiber sheet B, and the metal fiber sheet with a porosity of 78% as metal fiber sheet C. Note that metal fiber sheet B is the same as metal fiber sheet 4 used in the above-mentioned verifications (1) to (4).

[0077] <Verification (5)-1> First, similar to the verification (2), the durability of the metal fiber sheet was verified by measuring the coordinates of the head part 3 when pressure was applied. The thickness of the shim plate 70 used in this verification was 10 μm, the thickness of each metal fiber sheet was 100 μm, and the applied pressure was 10 MPa.

[0078] 16 is a graph showing the coordinates of the head part 3 and the number of times of pressure application when using metal fiber sheet A and metal fiber sheet C. The graph for metal fiber sheet B is as shown in FIG.

[0079] From these results, it can be seen that the smaller the porosity of the metal fiber sheet, the smaller the change in the amount of crushing due to pressure and the higher the durability against repeated joining processes. On the other hand, even when metal fiber sheet C was used, it was possible to withstand more than 50 pressurizations before it was crushed by 10 μm, which is the thickness of the shim plate 70, and it can be said that the joining process can be repeated without replacing the metal fiber sheet.

[0080] <Verification (5)-2> Second, SAT testing was performed on the joined workpieces that had been joined using each metal fiber sheet. For this verification, five types of shim plates 70 with thicknesses of 5 μm, 10 μm, 15 μm, 20 μm, and 25 μm were prepared, and verification was performed using four types of shim plates 70 excluding the 25 μm thickness for metal fiber sheets A and B, and four types of shim plates 70 excluding the 5 μm thickness for metal fiber sheet C. The other conditions were the same as in verification (3)-2.

[0081] Figure 17 shows the results of the SAT test. The two boxes surrounded by dashed lines indicate chip 60A. When metal fiber sheet A was used, a white area was observed under chip 60 (60B) when the thickness of shim plate 70 was 10 μm or more. When metal fiber sheet B was used, a white area was observed under chip 60 (60B) when the thickness of shim plate 70 was 15 μm or more. When metal fiber sheet C was used, a white area was observed under chip 60 (60B) when the thickness of shim plate 70 was 15 μm or more.

[0082] <Verification (5)-3> Third, a shear test was conducted using the same joint workpiece as in Verification (5)-2.

[0083] Figure 18 summarizes the results of the shear test. When metal fiber sheet A was used, the chip broke only when the shim plate 70 was 5 μm thick, and the chip 60 peeled off from the copper plate 80 when the shim plate 70 was 10 μm or thicker. When metal fiber sheet B was used, the chip broke when the shim plate 70 was 10 μm or thicker, and the chip 60 peeled off from the copper plate 80 when the shim plate 70 was 15 μm or thicker. When metal fiber sheet C was used, the chip broke when the shim plate 70 was 15 μm or thicker, and the chip 60 peeled off from the copper plate 80 when the shim plate 70 was 20 μm or thicker. Therefore, it can be seen that the chip 60 and the copper plate 80 were sufficiently bonded in the combinations enclosed by the thick lines.

[0084] From the results of verifications (5)-2 and (5)-3, it was found that when a 100 μm thick metal fiber sheet is used and pressurized at 10 MPa, metal fiber sheet A (porosity 58%) can absorb height differences of 5% or less of the sheet thickness, metal fiber sheet B (porosity 68%) can absorb height differences of 10% or less of the sheet thickness, and metal fiber sheet C (porosity 78%) can absorb height differences of 15% or less of the sheet thickness.

[0085] Therefore, for example, when performing a bonding process in which the difference in height between electronic components is about 5 to 15 μm, it is desirable to use a metal fiber sheet with a porosity of about 55% to 80%. In particular, using a metal fiber sheet with a porosity of 58% to 78% ensures good bonding of the chip (electronic component) to the copper plate (joined object). Furthermore, when performing a bonding process in which the difference in height between electronic components is about 10 μm, it is desirable to use a metal fiber sheet with a porosity of 63% to 73%. [Explanation of symbols]

[0086] 1. Component mounting equipment 2 Stage 3 Pressure head 4 Metal fiber sheet 6 Workpiece facing surface 7 Pressing part 8 Non-contact part 100 Joined Work 101 Object to be joined 102 Electronic Components 102a Main body 102b electrode

Claims

1. a head unit that applies pressure and heat to a workpiece to be joined, the workpiece being a workpiece to be joined, and a plurality of electronic components; a metal fiber sheet attached to the head portion and pressed against the plurality of electronic components by the head portion when pressure is applied to the joining workpieces; Part joining equipment.

2. The metal fiber sheet is attached to the head portion by vacuum suction. The component joining apparatus according to claim 1 .

3. the electronic component has a main body against which the metal fiber sheet is pressed and an electrode connected to the object to be joined, The hardness of the metal fibers constituting the metal fiber sheet is the same as or smaller than the hardness of the main body. The component joining device according to claim 1 or 2.

4. Copper was used as the metal fiber constituting the metal fiber sheet. The component joining device according to claim 1 or 2.

5. The porosity of the metal fiber sheet was increased from 58% to 78%. The component joining device according to claim 1 or 2.

6. A component joining method in a component joining apparatus that repeatedly performs a joining process on a joining workpiece in which a plurality of electronic components are joined to a workpiece, comprising: The component joining device includes: a head portion that applies pressure and heat to the workpieces to be joined; a metal fiber sheet attached to the head portion and pressed against the plurality of electronic components by the head portion when pressure is applied to the joining workpiece, The metal fiber sheet has a surface facing the workpieces to be joined, and a portion of the workpiece facing surface that is pressed against the electronic component is formed as a pressing portion, and a portion other than the pressing portion is formed as a non-contact portion, The component joining method includes: During the first joining process, the metal fiber sheet is pressed against the electronic component, and the pressing portion is displaced toward the head portion from the non-contact portion, During the second or subsequent joining process, the metal fiber sheet is pressed against the electronic component with the pressing portion displaced toward the head portion from the non-contact portion. Part joining method.

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