Method for manufacturing joined body

Abstract

Provided is a joined body having high joining reliability. This method for manufacturing a joined body includes a joining step for joining an anisotropic conductive member and a conductive part, the anisotropic conductive member having an insulating base material having electrical insulating properties, and a plurality of conductive paths that penetrate in the thickness direction of the insulating base material, that are provided in a state of being electrically insulated from each other, and that include protruding parts protruding from at least one surface of the insulating base material. The joining step includes a step for pressurizing the anisotropic conductive member in an atmosphere having a hydrogen gas partial pressure of 10 Pa or greater.

Description

Manufacturing method of the bonded body

[0001] The present invention relates to a method for manufacturing a bonded body that joins an anisotropically conductive member that has conductivity in the thickness direction of an insulating base material to a conductive part, and particularly to a method for manufacturing a bonded body in which the hydrogen gas partial pressure in the atmosphere during bonding is adjusted.

[0002] Currently, various joining methods are used to electrically connect electronic components such as semiconductor elements to each other and to connect electronic components to circuit boards. Various forms of connection have been proposed for connecting semiconductor elements to each other or between a semiconductor element and a substrate, such as wafer-on-wafer, chip-on-wafer, or chip-on-chip. An anisotropically conductive member having conductivity in the thickness direction of the insulating base material is used as an electronic connecting member for joining the above-mentioned electronic components to each other.

[0003] Patent Document 1 describes an anisotropically conductive member having a plurality of conductive paths made of a conductive material that penetrate an insulating substrate in the thickness direction and are insulated from one another, and an adhesive layer provided on the surface of the insulating substrate, wherein each conductive path has a protruding portion that protrudes from the surface of the insulating substrate, and the ends of the protruding portions of each conductive path are exposed or protrude from the surface of the adhesive layer. Patent Document 1 also describes a method of temporarily fixing the anisotropically conductive member to a wafer using the adhesive layer provided on the surface of the insulating substrate, and then thermocompressing the anisotropically conductive member using a wafer bonder.

[0004] International Publication No. 2016 / 006660

[0005] When joining the anisotropically conductive member of Patent Document 1 to a joining object, unless the joining conditions, such as suppressing oxidation during joining, are appropriate, there is a risk that a sufficient bond to the joining object will not be obtained. Furthermore, unless the joining conditions are appropriate, there is a risk that a sufficient bond strength will not be maintained after a predetermined time has passed since joining. This is related to the reliability of the joined body.

[0006] An object of the present invention is to provide a bonded body having high bonding reliability.

[0007] In order to achieve the above-mentioned object, invention [1] is a method for manufacturing a joined body, which includes a joining step of joining an electrically insulating base material and an anisotropically conductive member having a plurality of conductive paths that penetrate the insulating base material in the thickness direction, are provided in a state where they are electrically insulated from each other, and have protrusions that protrude from at least one surface of the insulating base material, and a conductive part, wherein the joining step includes a step of pressurizing the anisotropically conductive member in an atmosphere where the hydrogen gas partial pressure is 10 Pa or more.

[0008] Invention [2] is the method for producing a bonded body according to Invention [1], wherein the atmosphere in the bonding step has an oxygen gas partial pressure of 3 kPa or less. Invention [3] is the method for producing a bonded body according to Invention [1] or [2], wherein the bonding step has a bonding temperature of 150°C to 350°C. Invention [4] is the method for producing a bonded body according to any one of Inventions [1] to [4], wherein the bonding step has a bonding pressure of 5 MPa to 150 MPa.

[0009] Invention [5] is a method for producing a joined body according to any one of Inventions [1] to [4], in which the conductive part contains Au, Cu, or Sn. Invention [6] is a method for producing a joined body according to any one of Inventions [1] to [5], in which the conductive part is an electrode or a terminal provided on the joining object to which the anisotropically conductive member is joined.

[0010] According to the present invention, a bonded body with high bonding reliability can be provided.

[0011] FIG. 1 is a schematic diagram showing a first example of a bonded body produced by the method for producing a bonded body according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of an apparatus used in the first example of the method for producing a bonded body according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a second example of a bonded body produced by the method for producing a bonded body according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing a third example of a bonded body produced by the method for producing a bonded body according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of an anisotropically conductive member used in the method for producing a bonded body according to an embodiment of the present invention. FIG. 6 is a schematic plan view showing an example of an anisotropically conductive member used in the method for producing a bonded body according to an embodiment of the present invention. FIG. 7 is a schematic diagram for explaining an evaluation method.

[0012] The method for manufacturing a bonded body of the present invention will be described in detail below based on the preferred embodiment shown in the accompanying drawings. Note that the drawings described below are merely illustrative for explaining the present invention, and the present invention is not limited to the drawings shown below. Note that in the following, the term "to" indicating a range of values ​​includes the values ​​written on both sides. For example, when ε is a value ε α ~Number ε β That is, the range of ε is the number ε α and the number ε β The range includes ε α ≦ε≦ε β Unless otherwise specified, "parallel" includes a generally accepted error range in the relevant technical field. Unless otherwise specified, "same" and "the same" also include a generally accepted error range in the relevant technical field. Furthermore, unless otherwise specified, temperature, pressure, and partial pressure also include a generally accepted error range in the relevant technical field.

[0013] [First Example of Method for Manufacturing Bonded Body] Fig. 1 is a schematic diagram showing a first example of a bonded body produced by a method for manufacturing a bonded body according to an embodiment of the present invention. Fig. 2 is a schematic diagram showing an example of an apparatus used in the first example of the method for manufacturing a bonded body according to an embodiment of the present invention. In Fig. 2, the same components as those in the bonded body 10 shown in Fig. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. The bonded body 10 shown in Fig. 1 has one anisotropically conductive member 12 and one bonded member 14. The bonded member 14 has a conductive portion 15.

[0014] As will be described in detail later, the anisotropically conductive member 12 includes an electrically insulating substrate 30 and a plurality of conductive paths 32 that penetrate the insulating substrate 30 in the thickness direction Dt, are electrically insulated from one another, and have protrusions 32b that protrude from at least one surface of the insulating substrate 30. The conductive paths 32 are electrically conductive. The protrusions 32b are physically and electrically joined to the above-mentioned conductive portions 15. For this reason, the anisotropically conductive member 12 needs to have the protrusions 32b on the surface facing the conductive portions 15.

[0015] The members to be joined 14 are objects to be joined, and are, for example, electronic components such as semiconductor elements, printed wiring boards, and printed circuit boards. The members to be joined 14 will be described in detail later. The anisotropically conductive member 12 and the members to be joined 14 both have, for example, a rectangular outer shape in a plan view. A conductive portion 15 is provided on the surface 14a of the members to be joined 14. The conductive portion 15 is an electrode or a terminal. The conductive portion 15 enables the members to be joined 14 to input and output electrical signals from and to the outside.

[0016] The bonded body 10 includes, for example, an anisotropically conductive member 12 and a member to be bonded 14 stacked together, and the anisotropically conductive member 12 and the conductive portion 15 are physically and electrically bonded to each other. The direction in which the anisotropically conductive member 12 and the member to be bonded 14 are stacked is referred to as the stacking direction Ds. The thickness direction Dt of the insulating base material 30 and the stacking direction Ds are preferably substantially parallel to each other. Here, being physically and electrically bonded means that the anisotropically conductive member 12 and the member to be bonded 14 do not separate even when the bonded body 10 is transported for handling, and that there is electrical continuity between the anisotropically conductive member 12 and the member to be bonded 14, allowing input of an electrical signal to the member to be bonded 14 and output of an electrical signal from the member to be bonded 14 to the outside.

[0017] Next, a method for manufacturing the bonded body will be described. The bonded body 10 can be manufactured using bonding methods such as flip-chip bonding (FCB) and wafer bonding (WB). The bonded body 10 can be manufactured using, for example, an apparatus 20 shown in FIG. 2 , but is not limited thereto. The apparatus 20 shown in FIG. 2 includes a stage 22 disposed inside 21 a of a container 21. The stage 22 includes a heater (not shown) that can heat the anisotropically conductive member 12 and the bonded members 14. A pressure head 23 is disposed facing a surface 22 a of the stage 22. The pressure head 23 can move toward and away from the surface 22 a of the stage 22. The pressure head 23 can press the anisotropically conductive member 12 against the bonded members 14. The pressure head 23 also includes a heater (not shown) that can heat the anisotropically conductive member 12 and the bonded members 14.

[0018] The container 21 forms a closed space, and a bonding process is performed in the interior 21a thereof, as described below. The configuration of the container 21 is not particularly limited as long as it can maintain predetermined values ​​for the partial pressure of hydrogen gas and the partial pressure of oxygen gas, as described below. The container 21 is provided with a pump 25 via a valve 24. The pump 25 can reduce the pressure inside the container 21. The container 21 is also provided with a gas supply unit 27 via a valve 26. The gas supply unit 27 can supply a predetermined amount of a specific type of gas to the interior 21a of the container 21. The container 21 is also provided with a pressure gauge 28. The pressure gauge 28 is not particularly limited as long as it can measure negative pressure, and a known vacuum gauge or the like can be used as appropriate. The container 21 is also provided with a concentration meter 29. The concentration meter 29 is not particularly limited as long as it can measure the concentration of at least oxygen out of the hydrogen and oxygen inside the container 21, and known hydrogen and oxygen concentration meters can be used as appropriate. The hydrogen gas partial pressure can be obtained from the hydrogen concentration determined by the concentration meter 29. The oxygen gas partial pressure can also be obtained from the oxygen concentration. The hydrogen gas partial pressure can be determined, for example, by evacuating the gas inside the container 21a and then adjusting the amount of hydrogen gas (nitrogen mixed gas) before introducing it. The hydrogen gas partial pressure can be calculated using the pressure value inside the container 21a measured using the pressure meter 28 when introducing the hydrogen gas (nitrogen mixed gas). The hydrogen gas partial pressure can also be obtained using the hydrogen concentration measured using a commercially available hydrogen gas concentration measuring device. Furthermore, the hydrogen gas partial pressure can be quantified using gas chromatography. The hydrogen gas partial pressure can also be adjusted by adjusting the amount of hydrogen gas (nitrogen mixed gas) introduced into the container 21.

[0019] The bonding process is performed inside 21a of container 21 of apparatus 20. Specifically, the members to be bonded 14 are placed on surface 22a of stage 22, and the anisotropically conductive member 12 is placed on the conductive portion 15 of the members to be bonded 14. The bonding process is performed inside 21a of container 21 of apparatus 20 in this state. Prior to the bonding process, the anisotropically conductive member 12 may be temporarily bonded to the conductive portion 15 of the members to be bonded 14. This temporary bonding is preferable because it physically fixes the anisotropically conductive member 12 and the members to be bonded 14, thereby preventing separation of the anisotropically conductive member 12 and the members to be bonded 14. This allows the members to be transported, etc., in a state where the anisotropically conductive member 12 is placed on the conductive portion 15 of the members to be bonded 14.

[0020] The bonding process includes a process of pressurizing the anisotropically conductive member 12 in an atmosphere with a hydrogen gas partial pressure of 10 Pa or more. Specifically, for example, the valve 24 is opened, and the interior 21 a of the container 21 is depressurized by the pump 25. After the pressure is reduced, the valve 24 is closed. Thereafter, the valve 26 is opened, and a gas containing hydrogen gas, for example, a mixed gas of hydrogen gas and nitrogen gas, is supplied from the gas supply unit 27 to the interior 21 a of the container 21 to a predetermined pressure. The depressurization of the interior 21 a of the container 21 by the pump 25 and the supply of the gas containing hydrogen gas to the interior 21 a of the container 21 by the gas supply unit 27 are repeated multiple times to make the hydrogen gas partial pressure in the interior 21 a of the container 21 10 Pa or more. That is, an atmosphere with a hydrogen gas partial pressure of 10 Pa or more is created. In an atmosphere with a hydrogen gas partial pressure of 10 Pa or more, the anisotropically conductive member 12 is pressurized by the pressure head 23 to a preset bonding pressure. The heaters of the stage 22 and the pressure head 23 are then heated to heat the anisotropically conductive member 12 to the bonding temperature, and this temperature is maintained for a preset time. After the preset time has elapsed, the heaters of the stage 22 and the pressure head 23 are turned off. The anisotropically conductive member 12 is then cooled to room temperature while still pressurized, and the pressure of the pressure head 23 is released. This results in the bonded body 10 shown in FIG. 1 . The bonded body 10 is then removed from the container 21.

[0021] By setting the atmosphere in the bonding step, for example, the hydrogen gas partial pressure in the interior 21a of the container 21, to 10 Pa or more, the reducing effect of the hydrogen gas can improve the bondability, increasing the reliability of the bond, and providing a bonded body with high bonding reliability. Note that high bonding reliability means that the bond strength is maintained not only immediately after bonding but also over time.

[0022] The upper limit of the hydrogen gas partial pressure is 100,000 Pa (10 ５ From the viewpoint of the reduction effect of hydrogen, the hydrogen gas partial pressure is preferably 100 Pa to 100,000 Pa. The hydrogen gas partial pressure is more preferably 1,000 Pa to 6,000 Pa, and even more preferably 3,000 Pa to 6,000 Pa. If the hydrogen gas partial pressure exceeds 6,000 Pa, the above-mentioned effect can be obtained, but handling of the hydrogen gas tends to become difficult. For this reason, the upper limit of the hydrogen gas partial pressure is more preferably 6,000 Pa or less.

[0023] The atmosphere in the bonding process, for example, the oxygen gas partial pressure in the interior 21a of the container 21, is preferably 3 kPa or less in order to suppress oxidation of the conductive paths and the conductive portions 15 of the anisotropically conductive member 12. The lower limit of the oxygen gas partial pressure is ideally 0 Pa, but in consideration of the effort and cost required to control the oxygen gas partial pressure, it is realistically 0.05 Pa. The oxygen gas partial pressure is calculated using the oxygen concentration measured by the concentration meter 29, for example.

[0024] In the bonding process, the bonding temperature is preferably 150°C to 350°C. A bonding temperature of 150°C to 350°C is preferable because bonding can be more reliably achieved. The bonding temperature is the temperature of the heater of the stage 22 and the temperature of the heater of the pressure head 23. The temperatures of the heater of the stage 22 and the heater of the pressure head 23 are, for example, the set temperatures of the heaters. To achieve the set bonding temperature, for example, the set temperature of the heater of the stage 22 and the set temperature of the heater of the pressure head 23 are set to the same. In the bonding process, the bonding pressure is preferably 5 MPa to 150 MPa. A bonding pressure of 5 MPa to 150 MPa is preferable because bonding can be more reliably achieved. The bonding pressure is a value obtained by dividing the pressure load applied to the anisotropically conductive member 12 by the pressure head 23 by the area of ​​the anisotropically conductive member 12.

[0025] The conductive portion 15 includes, for example, Au, Cu, or Sn. The conductive portion 15 is an electrode or terminal made of, for example, gold (Au), copper (Cu), or tin (Sn). The outer shape of the conductive portion 15 is not particularly limited and may be, for example, circular or rectangular in plan view. In the bonded body 10 shown in FIG. 1 , the anisotropically conductive member 12 and the bonded member 14 are the same size and have the same outer edge when viewed from the conductive portion 15 side. However, this is not limited as long as the anisotropically conductive member 12 and the conductive portion 15 are bonded together. For example, when viewed from the conductive portion 15 side, the bonded member 14 may be larger than the anisotropically conductive member 12.

[0026] [Second Example of Method for Manufacturing a Bonded Body] Figure 3 is a schematic diagram showing a second example of a bonded body produced by the method for manufacturing a bonded body according to an embodiment of the present invention. Figure 4 is a schematic diagram showing an example of an apparatus used in the second example of the method for manufacturing a bonded body according to an embodiment of the present invention. In Figures 3 and 4, the same components as those in the bonded body 10 shown in Figure 1 and the apparatus 20 shown in Figure 2 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The bonded body 10a shown in Figure 3 differs from the bonded body 10 shown in Figure 1 in that one anisotropically conductive member 12 is disposed between two bonded members 14, and the conductive portions 15 of each bonded member 14 are bonded to the anisotropically conductive member 12. In the bonded body 10a, the anisotropically conductive member 12 is sandwiched between the bonded members 14 and has protrusions 32a and 32b on the surface facing the conductive portion 15.

[0027] Next, a method for manufacturing the bonded body will be described. For example, an apparatus 20a shown in FIG. 4 is used to manufacture the bonded body 10a. The apparatus 20a shown in FIG. 4 has the same configuration as the apparatus 20 shown in FIG. 2 , and therefore a detailed description thereof will be omitted. A bonding process is performed in the apparatus 20a. Specifically, members to be bonded 14 are placed on a surface 22a of a stage 22, an anisotropically conductive member 12 is placed on the conductive portion 15 of the members to be bonded 14, and the members to be bonded 14 are placed on the anisotropically conductive member 12. The bonding process is performed in an interior 21a of a container 21 of the apparatus 20a with the members to be bonded 14 on the anisotropically conductive member 12 in a state where the conductive portion 15 faces the anisotropically conductive member 12.

[0028] Prior to the bonding process, two bonded members 14, each with its conductive portion 15 facing the anisotropically conductive member 12, may be temporarily bonded to one anisotropically conductive member 12. Temporarily bonding is preferable because it allows one anisotropically conductive member 12 to be sandwiched between two bonded members 14 and be transported. In the bonding process, the hydrogen gas partial pressure in the interior 21a of the container 21 is set to 10 Pa or more as described above. That is, an atmosphere with a hydrogen gas partial pressure of 10 Pa or more is created. When an atmosphere with a hydrogen gas partial pressure of 10 Pa or more is created, the hydrogen gas partial pressure in a closed space, such as the interior 21a of the container 21 where the bonding process is performed, is set to 10 Pa or more. In an atmosphere with a hydrogen gas partial pressure of 10 Pa or more, the anisotropically conductive member 12 is pressurized by the pressure head 23 to a predetermined bonding pressure. The heaters of the stage 22 and the pressure head 23 are heated to heat the anisotropically conductive member 12 to a bonding temperature and maintained for a predetermined time. After a preset time has elapsed, the heaters of the stage 22 and the pressure head 23 are turned off. Then, the assembly is cooled to room temperature while still under pressure, and the pressure of the pressure head 23 is released. This results in the bonded body 10a shown in FIG. 3. The bonded body 10a is then removed from the container 21.

[0029] As described above, the atmosphere in the bonding step, for example, the oxygen gas partial pressure in the interior 21a of the container 21, is preferably 3 kPa or less. Furthermore, as described above, the bonding temperature in the bonding step is preferably 150°C to 350°C, and the bonding pressure is preferably 5 MPa to 150 MPa. The bonding pressure is a value obtained by dividing the pressure load on the bonded members 14 closest to the pressure head 23 by the area of ​​the bonded members 14 closest to the pressure head 23. Note that, prior to the bonding step, the anisotropically conductive member 12 and the bonded members 14 may be cleaned using a chemical solution or cleaned using an inert gas, such as in plasma treatment.

[0030] (Another Example of Bonded Body) The bonded body is not limited to the bonded body 10 shown in FIG. 1 and the bonded body 10a shown in FIG. 3. For example, as in the bonded body 11a shown in FIG. 5, a semiconductor substrate 16 having multiple element regions 17a, 17b, and 17c may have an anisotropically conductive member 12 bonded to each of the conductive portions 15 of the element regions 17a, 17b, and 17c. In this case, the semiconductor substrate 16 may be cut into individual pieces along cutting lines CL. In the bonded body 11a shown in FIG. 5, a bonded member 14 may be further bonded onto the anisotropically conductive member 12, as in the bonded body 10a shown in FIG. 3. In this case, the size of the bonded member 14 as viewed from the surface 16a of the semiconductor substrate 16 may be the same as, or larger than, the anisotropically conductive member 12. Furthermore, a configuration in which multiple anisotropically conductive members are bonded to one bonded member may be used. As in the bonded body 11b shown in Fig. 6, a conductive portion 15 is provided on the surface 18a of one bonded member 18, and two anisotropically conductive members 12 are bonded to the conductive portion 15. In the bonded body 11b shown in Fig. 6, a bonded member 14 can be further bonded to the anisotropically conductive member 12, as in the bonded body 10a shown in Fig. 3. In this case, the size of the bonded member 14 as viewed from the surface 18a of the bonded member 18 may be the same as, or may be smaller or larger than, the anisotropically conductive member 12.

[0031] Although the above-described conductive portions 15 are shown protruding from the surfaces, the configuration of the conductive portions 15 is not limited to protruding. The surfaces of the conductive portions 15 do not have to protrude from the surfaces of the members to be joined, and may be flush with the surfaces of the members to be joined.

[0032] Furthermore, the conductive portion 15 may be made of, other than the above-mentioned Au, Cu, or Sn, a conductive material such as tungsten, cobalt, aluminum, an alloy containing copper, a silicide, or a combination thereof. In addition, materials used for what are called terminals or electrode pads in the field of semiconductor devices may also be used as appropriate.

[0033] (Anisotropically Conductive Member) FIG. 7 is a schematic cross-sectional view showing an example of an anisotropically conductive member used in the manufacturing method of a bonded body according to an embodiment of the present invention. FIG. 8 is a schematic plan view showing an example of an anisotropically conductive member used in the manufacturing method of a bonded body according to an embodiment of the present invention. FIG. 8 is a plan view of FIG. 7 as seen from the surface side of the anodized film, showing a state without the resin layer 34. The anisotropically conductive member 12 shown in FIG. 7 is conductive in the stacking direction Ds (see FIG. 1) of the above-described bonded body 10. The anisotropically conductive member 12 includes an electrically insulating insulating substrate 30 and a plurality of conductive paths 32 that penetrate the insulating substrate 30 in the thickness direction Dt, are electrically insulated from one another, and have protrusions that protrude from at least one surface of the insulating substrate 30. The anisotropically conductive member 12 may also include a resin layer 34 covering at least one surface of the insulating substrate 30. The anisotropically conductive member 12 is disposed on the surface 14a of the bonded member 14 with the thickness direction Dt and the stacking direction Ds parallel to each other.

[0034] The multiple conductive paths 32 are spaced apart from one another and are provided in the insulating substrate 30 in a state where they are electrically insulated from one another. In this case, for example, the insulating substrate 30 has multiple pores 31 penetrating in the thickness direction Dt. The multiple pores 31 are provided with conductive paths 32. The conductive paths 32 protrude from the front surface 30a of the insulating substrate 30 and include protrusions 32a. The conductive paths 32 protrude from the back surface 30b of the insulating substrate 30 and include protrusions 32b. The conductive paths 32 protrude from one surface of the insulating substrate 30 in the thickness direction Dt. In this case, as described above, a resin layer 34 may be provided on the surface of the insulating substrate 30 from which the conductive paths 32 protrude. The resin layer 34 covers the protrusions 32a of the conductive paths 32, and the protrusions 32a are embedded in the resin layer 34. The resin layer 34 covers the protrusions 32b of the conductive paths 32, and the protrusions 32b are embedded in the resin layer 34. The insulating base material 30 is made of, for example, an anodized film. The front surface 30a and the back surface 30b of the insulating base material 30 are surfaces that face each other in the thickness direction Dt of the insulating base material 30.

[0035] The anisotropically conductive member 12 has anisotropic conductivity and is conductive in the thickness direction Dt, but has sufficiently low conductivity in a direction parallel to the surface 30a of the insulating base material 30. As shown in FIG. 8 , the anisotropically conductive member 12 has, for example, a rectangular outer shape. The outer shape and size of the anisotropically conductive member 12 are determined appropriately, for example, according to the outer shape and size of the joining region of the joined members 14. For example, the anisotropically conductive member 12 is joined without a resin layer 34, or with a resin layer 34 present but with nothing on the surface 34a of the resin layer 34.

[0036] The structure of the anisotropically conductive member will be described in more detail below. The anisotropically conductive member has a structure similar to that of the structure described in, for example, WO 2022 / 163260 and can be manufactured in a manner similar to that of the structure described above. <Insulating Substrate> The insulating substrate 30 electrically insulates a plurality of conductive paths 32, each made of a conductor, from one another. The insulating substrate 30 has electrical insulation properties. The insulating substrate 30 also has a plurality of pores 31 through which the conductive paths 32 are formed. The composition of the insulating substrate 30 will be described later. The length of the insulating substrate 30 in the thickness direction Dt, i.e., the thickness ht of the insulating substrate 30, is preferably within the range of 1 to 1000 μm, more preferably within the range of 5 to 500 μm, and even more preferably within the range of 10 to 300 μm. When the thickness ht of the insulating substrate 30 is within this range, the insulating substrate 30 is easy to handle. From the viewpoint of ease of winding, the thickness ht of the insulating substrate 30 is preferably 30 μm or less, and more preferably 5 to 20 μm.

[0037] The thickness of the insulating substrate is measured by cutting the insulating substrate in the thickness direction Dt using a focused ion beam (FIB), and then taking a surface photograph (magnification: 50,000 times) of the cross section using a scanning electron microscope (SEM) to obtain a photographed image. In the photographed image, 10 points corresponding to the thickness of the insulating substrate are measured, and the average value thereof can be calculated as the thickness of the insulating substrate.

[0038] <Average Diameter of Pores> The average diameter of the pores 31 is preferably 1 μm or less, more preferably 5 to 500 nm, even more preferably 20 to 400 nm, even more preferably 40 to 200 nm, and most preferably 50 to 100 nm. When the average diameter d of the pores 31 is 1 μm or less and within the above-mentioned range, conductive paths 32 having the above-mentioned average diameter can be obtained. The average diameter of the pores 31 is measured by photographing the surface of the insulating substrate 30 from directly above using a scanning electron microscope (SEM) at a magnification of 100 to 10,000 times. At least 20 pores with a circular periphery are extracted from the captured image, and their diameters are measured to determine the opening diameter. The average of the 20 opening diameters is calculated as the average diameter of the pores. The magnification can be appropriately selected within the above-mentioned range so as to obtain an image in which 20 or more pores can be extracted. The opening diameter is measured by measuring the maximum distance between the ends of the pore portions. In other words, since the shape of the opening of the pore is not limited to a substantially circular shape, when the opening shape is non-circular, the maximum value of the distance between the ends of the pore portion is taken as the opening diameter. Therefore, even when a pore has a shape in which two or more pores are integrated, this is considered to be a single pore, and the maximum value of the distance between the ends of the pore portion is taken as the opening diameter.

[0039] <Conductive Path> As described above, the multiple conductive paths 32 are provided in the insulating substrate 30, e.g., an anodized film, while being electrically insulated from one another. The multiple conductive paths 32 are electrically conductive. The conductive paths 32 are made of a conductive material. The conductive material is not particularly limited, and examples thereof include metals. Specific examples of metals include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), zinc (Zn), and cobalt (Co). From the viewpoint of electrical conductivity, copper, gold, aluminum, nickel, and cobalt are preferred, copper and gold are more preferred, and copper is most preferred. Metals have superior ductility and other properties compared to oxide conductors, making them more easily deformable, even when compressed during bonding. Therefore, the conductive paths 32 are preferably made of metal. The height of the conductive paths 32 in the thickness direction Dt is preferably 10 to 300 μm, and more preferably 20 to 30 μm.

[0040] <<Shape of Conductive Paths>> The average diameter d of the conductive paths 32 is preferably 1 μm or less, more preferably 5 to 500 nm, even more preferably 20 to 400 nm, still more preferably 40 to 200 nm, and most preferably 50 to 100 nm. The density of the conductive paths 32 is 20,000 / mm 2 It is preferable that the density is 2 million / mm or more. 2 More preferably, it is 10 million particles / mm or more. 2 More preferably, it is 50 million particles / mm or more. 2 It is particularly preferable that the number of particles is 100 million / mm or more. 2 Furthermore, the center-to-center distance p between adjacent conductive paths 32 is preferably 20 nm to 500 nm, more preferably 40 nm to 200 nm, and even more preferably 50 nm to 140 nm.

[0041] The average diameter of the conductive paths is determined by photographing the surface of the insulating substrate from directly above at a magnification of 100 to 10,000 times using a scanning electron microscope. At least 20 conductive paths with a circular periphery are extracted from the image, and their diameters are measured to determine the opening diameter. The average of the 20 opening diameters is calculated as the average diameter of the conductive paths. The magnification can be appropriately selected within the above-mentioned range so as to obtain an image that can extract 20 or more conductive paths. Furthermore, when the opening shape is non-circular, the maximum distance between the ends of the conductive path portion is used as the opening diameter. Therefore, for example, even when two or more conductive paths are integrated, this is considered as a single conductive path, and the maximum distance between the ends of the conductive path portion is used as the opening diameter. The average diameter d of the conductive paths 32 is the same as the average diameter of the protrusions. The center-to-center distance p of adjacent conductive paths 32 is further determined by identifying the center position (not shown) of the identified conductive path in the image of the insulating substrate 30 obtained as described above. The distance between the centers of adjacent conductive paths was measured at 10 locations. The average value of these 10 locations was used as the center-to-center distance p of adjacent conductive paths 32. The center positions were the center positions of the areas corresponding to conductive paths 32 in the captured image. Note that a known image analysis method was used to calculate the center positions of the areas in the captured image.

[0042] <<Protrusions>> The protrusions are part of the conductive paths and are columnar. The protrusions are preferably cylindrical because this increases the contact area with the object to be joined. The average protrusion length ha of the protrusions 32a and the average length hb of the protrusions 32b are preferably 10 nm to 1000 nm, more preferably 50 nm to 500 nm. When the average protrusion length ha and the average length hb are 10 nm to 1000 nm, the adhesion between the resin layer 34 and the insulating substrate 30 is improved. The average protrusion length ha of the protrusions 32a and the average length hb of the protrusions 32b are calculated by obtaining cross-sectional images of the protrusions using a scanning electron microscope as described above, and measuring the heights of the protrusions at 10 points on the cross-sectional images.

[0043] The distance between adjacent protrusions of the conductive paths 32 is preferably 20 nm to 200 nm, and more preferably 40 nm to 100 nm. When the distance between adjacent protrusions is within the above range, the distance between the conductive paths 32 can be maintained on the front surface 30a or the back surface 30b of the insulating substrate 30. This prevents short circuits of the conductive paths 32 when they are joined to the conductive part, further increasing reliability during joining.

[0044] <<Resin Layer>> As described above, the resin layer covers at least one of the front and back surfaces of the insulating substrate and protects the insulating substrate and the conductive paths. For example, if the conductive paths have protrusions, the resin layer buries the protrusions. That is, the resin layer covers the ends of the conductive paths protruding from the insulating substrate and protects the protrusions. To perform the above-described function, the resin layer preferably exhibits fluidity in a temperature range of 50°C to 200°C and hardens at 200°C or higher. The resin layer is a thermoplastic layer made of, for example, a thermoplastic resin, which will be described in detail later. The average thickness hm of the resin layer 34 is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. If the conductive paths have protrusions, the average thickness hm of the resin layer 34 is preferably equal to or greater than the average length of the protrusions of the conductive paths. If the average thickness hm of the resin layer 34 is 10 μm or less, the resin layer 34 can sufficiently protect the protruding portions of the conductive paths 32 and fill the periphery of the conductive portions when bonding to the conductive portions. The average thickness hm of the resin layer 34 is the average distance from the surface 30 a of the insulating substrate 30 or the average distance from the back surface 30 b of the insulating substrate 30. The average thickness hm of the resin layer 34 is obtained by cutting the resin layer in the thickness direction Dt of the anisotropically conductive member 12, observing the cut cross section using a scanning electron microscope, and measuring the distance from the surface 30 a of the insulating substrate 30 at 10 locations corresponding to the resin layer. The average thickness hm of the resin layer 34 is also obtained by measuring the distance from the back surface 30 b of the insulating substrate 30 at 10 locations corresponding to the resin layer.

[0045] The resin layer may have the following composition. The composition of the resin layer will be described below. For example, the resin layer contains a polymer material and may also contain an antioxidant material. Specific examples of the resin material constituting the resin layer include thermoplastic resins such as ethylene copolymers, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, acrylic resins, acrylonitrile resins, and cellulose resins. Polyacrylonitrile can also be used as the resin material constituting the resin layer 34. In addition to the above, the resin layer may contain, for example, a main composition containing an acrylic polymer, an acrylic monomer, and a maleimide compound, as described in International Publication No. 2022 / 163260.

[0046] [Bonding Object] The bonding object is not particularly limited as long as it has a conductive portion such as an electrode or a terminal as described above. The bonding object is, for example, an electronic component such as a semiconductor element, a printed wiring board, or a printed circuit board, and may be a TSV (Through Silicon Via) or a semiconductor device as described below. In a semiconductor element, the function of the semiconductor element is distinguished by the operation of the semiconductor element. Examples of the functions of a semiconductor include calculations such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), storage such as a memory, conversion such as a converter, filtering, and sensing. Furthermore, when these functions are integrated into a single chip or unit, the functions are identified in the integrated state. When the identified functions are different, the semiconductor elements are different.

[0047] The semiconductor element is not particularly limited as long as it has the above-described conductive portion. More specifically, examples of the semiconductor element include logic large-scale integration (LSI), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), and application-specific standard products (ASSP). Other examples include microprocessors such as CPUs and GPUs. Other examples include memories such as dynamic random access memory (DRAM), static random access memory (SRAM), hybrid memory cubes (HMC), magnetic random access memory (MRAM), phase-change memory (PCM), resistive random access memory (RRAM), ferroelectric random access memory (FeRAM), and flash memory. Other examples include light-emitting diodes (LEDs), power devices, analog integrated circuits (ICs), direct current (DC)-direct current (DC) converters, and insulated gate bipolar transistors (IGBTs).For example, examples include MEMS (Micro Electro Mechanical Systems) such as acceleration sensors, pressure sensors, vibrators, and gyro sensors, GPS (Global Positioning System), FM (Frequency Modulation), NFC (Nearfield communication), RFEM (RF Expansion Module), MMIC (Monolithic Microwave Integrated Circuit), WLAN (Wireless Local Area Network), discrete elements, BSI (Back Side Illumination), CIS (Contact Image Sensor), camera modules, passive devices, SAW (Surface Acoustic Wave) filters, RF (Radio Frequency) filters, RFIPD (Radio Frequency Integrated Passive Devices), and BB (Broadband).

[0048] The composition of the semiconductor constituting the semiconductor element is not particularly limited, and examples of the semiconductor composition include diamond, silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide, and silicon-on-insulator (SOI).

[0049] <Semiconductor Device> A semiconductor device is a device in which a plurality of semiconductor elements described above are stacked and electrically connected. A semiconductor device is a device in which a plurality of semiconductor elements are assembled to perform a specific function, but also includes devices that simply transmit electrical signals. A semiconductor device may be, for example, a logic device with a two-dimensional (2D), two-and-a-half-dimensional (2.5D), or three-dimensional (3D) architecture. Furthermore, a semiconductor device may be, for example, a DRAM stack in which a plurality of DRAMs are stacked, or a configuration in which a DRAM stack and a logic LSI are stacked.

[0050] The semiconductor device may also have a configuration including a printed wiring board, a heat sink, etc. The semiconductor device may have digital, analog, or mixed-signal peripheral circuits in addition to the semiconductor elements described above. More specifically, the semiconductor device may have a peripheral device layer including one or more of a page buffer, a row decoder, a column decoder, a sense amplifier, a driver, a charge pump, a transistor, a diode, a resistor, or a capacitor.

[0051] Furthermore, the semiconductor device may have an element region in addition to the semiconductor element described above. The element region is a region in which various element component circuits, etc., for functioning as electronic elements are formed. The element region may include, for example, a region in which a memory circuit such as a flash memory, a logic circuit such as a microprocessor and an FPGA (field-programmable gate array), etc., is formed, and a region in which a communication module such as a wireless tag and wiring are formed. In addition to the above, a MEMS may be formed in the element region. Examples of MEMS include sensors, actuators, and antennas. Examples of sensors include various sensors for acceleration, sound, light, etc.

[0052] The present invention is basically configured as described above. Although the method for manufacturing a bonded body of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various improvements and modifications may be made without departing from the spirit and scope of the present invention.

[0053] The features of the present invention will be described in more detail below with reference to examples. The materials, reagents, amounts and ratios of substances, and procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following examples. In these examples, bonded structures of Examples 1 to 17 and bonded structures of Comparative Examples 1 and 2 were produced. The strength of each of the bonded structures of Examples 1 to 17 and Comparative Examples 1 and 2 was evaluated. The strength evaluation results are shown in Table 1 below. The anisotropically conductive member of the bonded structure, as well as the bottom chip and top chip to be bonded to the anisotropically conductive member, will now be described.

[0054] [Anisotropically conductive member] <Preparation of aluminum substrate> A molten aluminum alloy containing 0.06% by mass of Si, 0.30% by mass of Fe, 0.005% by mass of Cu, 0.001% by mass of Mn, 0.001% by mass of Mg, 0.001% by mass of Zn, and 0.03% by mass of Ti, with the remainder being Al and inevitable impurities, was prepared. The molten aluminum alloy was treated and filtered, and an ingot 500 mm thick and 1200 mm wide was produced by DC (Direct Chill) casting. The surface was then scraped off to an average thickness of 10 mm using a facing mill, and the ingot was soaked at 550°C for about 5 hours. When the temperature was lowered to 400°C, it was rolled into a 2.7 mm thick plate using a hot rolling mill. Further, the aluminum substrate was subjected to heat treatment at 500°C using a continuous annealing machine, and then cold-rolled to a thickness of 1.0 mm to obtain an aluminum substrate conforming to JIS (Japanese Industrial Standards) 1050. This aluminum substrate was then cut to a width of 1030 mm and subjected to the following treatments.

[0055] <Electrolytic Polishing Treatment> The above-mentioned aluminum substrate was subjected to electrolytic polishing treatment using an electrolytic polishing solution having the following composition under conditions of a voltage of 25 V, a solution temperature of 65°C, and a solution flow rate of 3.0 m / min. A carbon electrode was used as the cathode, and a GP0110-30R (manufactured by Takasago Machinery Co., Ltd.) was used as the power source. The flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0056] (Electropolishing solution composition) 660 mL of 85% by mass phosphoric acid (reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 160 mL of pure water 150 mL of sulfuric acid 30 mL of ethylene glycol

[0057] <Anodizing Treatment Step> Next, the aluminum substrate after electrolytic polishing treatment was subjected to anodizing treatment by a self-ordering method according to the procedure described in JP 2007-204802 A. The aluminum substrate after electrolytic polishing treatment was subjected to a pre-anodizing treatment for 5 hours in a 0.50 mol / L oxalic acid electrolytic solution under conditions of a voltage of 40 V, a solution temperature of 16 ° C, and a solution flow rate of 3.0 m / min. Thereafter, the aluminum substrate after pre-anodizing treatment was subjected to a film removal treatment by immersing it in a mixed aqueous solution (liquid temperature: 50 ° C) of 0.2 mol / L chromic anhydride and 0.6 mol / L phosphoric acid for 12 hours. Thereafter, a re-anodizing treatment was performed for 3 hours and 45 minutes in a 0.50 mol / L oxalic acid electrolytic solution under conditions of a voltage of 40 V, a solution temperature of 16 ° C, and a solution flow rate of 3.0 m / min, to obtain an anodized film with a film thickness of 30 μm. In both the pre-anodizing treatment and the re-anodizing treatment, a stainless steel electrode was used as the cathode, and a GP0110-30R power supply (manufactured by Takasago Machinery Co., Ltd.) was used. A NeoCool BD36 (manufactured by Yamato Scientific Co., Ltd.) was used as the cooling device, and a Pair Stirrer PS-100 (manufactured by EYELA Tokyo Rikakikai Co., Ltd.) was used as the stirring / heating device. Furthermore, the flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0058] <Barrier Layer Removal Step> After the anodizing step, the aluminum substrate was subjected to an etching treatment by immersion in an alkaline aqueous solution prepared by dissolving zinc oxide in a sodium hydroxide aqueous solution (50 g / L) to a concentration of 2000 ppm at 30°C for 150 seconds, thereby removing the barrier layer at the bottom of the micropores of the anodized film and simultaneously depositing zinc on the exposed surface of the aluminum substrate. The average thickness of the anodized film after the barrier layer removal step was 30 µm.

[0059] <Metal Filling Step> Next, electrolytic plating was performed using the aluminum substrate as the cathode and platinum as the cathode. Specifically, a copper plating solution having the composition shown below was used, and constant-current electrolysis was performed to produce a metal-filled microstructure in which nickel was filled into the micropores. Constant-current electrolysis was performed using a plating device manufactured by Yamamoto Plating Tester Co., Ltd. and a power supply (HZ-3000) manufactured by Hokuto Denko Corporation. After confirming the deposition potential by performing cyclic voltammetry in the plating solution, the process was performed under the conditions shown below. (Copper Plating Solution Composition and Conditions) Copper sulfate 100 g / L Sulfuric acid 50 g / L Hydrochloric acid 15 g / L Temperature 25°C Current density 10 A / dm ２

[0060] The surface of the anodized film after filling the micropores with metal was observed using a field emission scanning electron microscope (FE-SEM), and the presence or absence of sealing with metal in 1,000 micropores was observed, and the sealing rate (number of sealed micropores / 1,000) was calculated to be 98%. Furthermore, the anodized film after filling the micropores with metal was cut in the thickness direction using a focused ion beam (FIB), and the surface of the cross section was photographed (magnification 50,000 times) using a field emission scanning electron microscope (FE-SEM) to confirm the interior of the micropores. It was found that the interior of the sealed micropores was completely filled with metal.

[0061] <Substrate Removal Step> The aluminum substrate was then dissolved and removed by immersion in a mixed solution of copper chloride and hydrochloric acid to produce a metal-filled microstructure with an average thickness of 30 μm. The diameter of the conductive paths in the produced metal-filled microstructure was 60 nm, the pitch between the conductive paths was 100 nm, and the density of the conductive paths was 57.7 million / mm. ２ It was.

[0062] <Protrusion process> The metal-filled microstructure after the substrate removal process was immersed in a potassium hydroxide (KOH) aqueous solution (concentration: 0.01 mol / L), and the immersion time was adjusted so that the protrusion height was 300 nm, selectively dissolving the surface of the aluminum anodized film. The structure was then washed with water and dried to protrude copper columns serving as conductive paths. Similarly, copper columns serving as conductive paths were protruded from the back surface of the aluminum anodized film so that the protrusion height was 300 nm. The metal-filled microstructure was then processed to a size of 4 mm × 10 mm to produce an anisotropic conductive member.

[0063] [Top Chip and Bottom Chip] A top chip measuring 2 mm x 3 mm was used. A bottom chip measuring 8 mm x 15 mm was used. The top chip had a layered structure formed in the following order on a 725 μm thick silicon substrate: a 50 nm thick titanium film, a 200 nm thick copper film, and a 200 nm thick gold film or a 200 nm thick tin film. In the top chip, the copper film, gold film, or tin film correspond to the conductive parts, and the copper film, gold film, or tin film is exposed. The bottom chip had a layered structure formed in the following order on a 725 μm thick silicon substrate: a 50 nm thick titanium film and a 200 nm thick copper film. In the bottom chip, the copper film corresponds to the conductive parts, and the copper film is exposed. The titanium film, copper film, gold film, and tin film were formed using a sputtering method.

[0064] A bonding method will be described. Prior to bonding, the anisotropically conductive members were immersed in a citric acid aqueous solution (concentration: 1% by mass) at a liquid temperature of 20°C for 1 minute, and then washed with running pure water for 5 minutes. Prior to bonding, the top chip and bottom chip having a copper film were immersed in a sulfuric acid aqueous solution (concentration: 10% by mass) at a liquid temperature of 40°C for 30 seconds. The immersion time was adjusted appropriately between 5 seconds and 1 minute depending on the state of formation of the surface oxide film of the copper film. Prior to bonding, the top chip having a gold film was washed with MEK (methyl ethyl ketone). Prior to bonding, the top chip having a tin film was washed with pure water.

[0065] With the conductive portion of the bottom chip facing the anisotropic conductive member and the conductive portion of the top chip facing the anisotropic conductive member, one bottom chip 50, one anisotropic conductive member 12, and two top chips 54 were stacked in this order and bonded together as shown in FIG. 9 to obtain a bonded body 10c. Two top chips were bonded simultaneously. Flip chip bonding (FCB) and wafer bonding (WB) were used as bonding methods. In Table 1 below, flip chip bonding is abbreviated as FCB, and wafer bonding is abbreviated as WB.

[0066] Example 1 Bonding was performed using a wafer bonding device (EVG540 (product name), manufactured by EVI Group Japan Co., Ltd.) as the bonding device, and wafer bonding as the bonding method. A top chip having a copper film was used, and a bottom chip having a copper film was used. The bottom chip was placed on a stage in a chamber of the bonding device. Next, an anisotropic conductive member was placed on the bottom chip. Next, two top chips were placed on the anisotropic conductive member. The stage was equipped with a heater. Next, in this state, a pressure head equipped with a heater was used to pressurize the top chip, the anisotropic conductive member, and the bottom chip from the top chip side. Next, the chamber was evacuated to a vacuum until the pressure in the chamber was 0.05 Pa. Next, a nitrogen-hydrogen mixed gas was introduced into the chamber until the pressure in the chamber was 100 kPa. Next, the chamber was evacuated to a vacuum until the pressure in the chamber was 0.05 Pa. This decompression and introduction of the nitrogen-hydrogen mixed gas were repeated five times, until the hydrogen gas partial pressure in the chamber was 5,000 Pa. At this time, the oxygen gas partial pressure was 0.05 Pa. The hydrogen gas partial pressure was calculated by measuring the pressure in the chamber, and the oxygen gas partial pressure was calculated by measuring the oxygen concentration with an oxygen concentration meter (manufactured by Toray Engineering D Solutions Co., Ltd.).

[0067] Next, the stage heater and the pressure head heater were heated with a bonding pressure of 30 MPa, and the top chip, anisotropically conductive member, and bottom chip were heated to a bonding temperature of 250°C and maintained at this temperature for 1,500 seconds. The stage heater and the pressure head heater were then stopped. The assembly was then cooled to room temperature while still under pressure, and the pressure on the top chip, anisotropically conductive member, and bottom chip was released, and the bonded assembly was removed. The bonded assembly was thus obtained. The bonding temperature was set to the set temperature of the stage heater and the set temperature of the pressure head heater. The set temperature of the stage heater and the set temperature of the pressure head heater were set to the same value, resulting in a set bonding temperature. The bonding temperature can be adjusted by changing the set temperature of the stage heater and the set temperature of the pressure head heater. The bonding pressure is the value obtained by dividing the pressure load on one top chip by the area of ​​one top chip. The bonding pressure can be adjusted by adjusting the pressure load on one top chip.

[0068] (Example 2) Example 2 differs from Example 1 in that the top chip has a gold film, and otherwise a bonded body was obtained in the same manner as Example 1. (Example 3) Example 3 differs from Example 1 in that the bonding pressure was 10 MPa, and otherwise a bonded body was obtained in the same manner as Example 1. (Example 4) Example 4 differs from Example 1 in that the bonding temperature was 160°C, and otherwise a bonded body was obtained in the same manner as Example 1. (Example 5) Example 5 differs from Example 1 in that the top chip has a tin film and the bonding temperature was 160°C, and otherwise a bonded body was obtained in the same manner as Example 1.

[0069] (Example 6) Example 6 differs from Example 1 in that the hydrogen gas partial pressure was 10 Pa, but a bonded body was obtained in the same manner as Example 1. The hydrogen gas partial pressure was adjusted to 10 Pa by adjusting the hydrogen concentration in the nitrogen-hydrogen mixed gas. (Example 7) Example 7 differs from Example 6 in that the top tip had a gold film, but a bonded body was obtained in the same manner as Example 6. (Example 8) Example 8 differs from Example 1 in that the hydrogen gas partial pressure was 100 Pa, but a bonded body was obtained in the same manner as Example 1. The hydrogen concentration in the nitrogen-hydrogen mixed gas was adjusted to 100 Pa. (Example 9) Example 9 differs from Example 1 in that the hydrogen gas partial pressure was 1000 Pa (1 kPa), but a bonded body was obtained in the same manner as Example 1. The hydrogen concentration in the nitrogen-hydrogen mixed gas was adjusted to 1000 Pa. Example 10 differs from Example 8 in that the oxygen gas partial pressure was set to 3000 Pa (3 kPa), and otherwise a bonded body was obtained in the same manner as Example 8. The hydrogen concentration in the nitrogen-hydrogen mixed gas was adjusted so that the hydrogen gas partial pressure was 100 Pa and the oxygen gas partial pressure was 3000 Pa.

[0070] Example 11 In Example 11, bonding was performed using a flip-chip bonding device (FC3000 (model) manufactured by Toray Engineering Co., Ltd.) as the bonding device, and flip-chip bonding as the bonding method. The top chip had a copper film, and the bottom chip had a copper film. The bottom chip was placed on a stage in a chamber of the bonding device. The stage was equipped with a heater. Next, an anisotropically conductive member was placed on the bottom chip. Next, two top chips were placed on the anisotropically conductive member. As a result, the bottom chip, the anisotropically conductive member, and the two top chips were arranged as shown in FIG. 9 above. Next, in this state, a pressure head equipped with a heater was lowered to pressurize the top chip, the anisotropically conductive member, and the bottom chip from the top chip side. In this state, the hydrogen gas partial pressure in the chamber was set to 10 Pa. At this time, the oxygen gas partial pressure was 0.05 Pa. The oxygen gas partial pressure was adjusted by supplying nitrogen gas to the stacked top chip, the anisotropically conductive member, and the bottom chip. The hydrogen gas partial pressure was obtained using the hydrogen concentration measured with a hydrogen gas concentration measuring device (UPX4 (product name) manufactured by UP Corporation). The oxygen gas partial pressure was obtained using the oxygen concentration measured with an oxygen concentration meter (manufactured by Toray Engineering D Solutions Co., Ltd.).

[0071] Next, the stage heater and the pressure head heater were heated with a bonding pressure of 30 MPa, and the top chip, anisotropically conductive member, and bottom chip were heated to a bonding temperature of 250°C and maintained at this temperature for 300 seconds. The stage heater and the pressure head heater were then stopped. The product was then cooled to room temperature while still under pressure, and the pressure on the top chip, anisotropically conductive member, and bottom chip was released, and the bonded product was removed. In this manner, a bonded product was obtained. The bonding temperature was set to the set temperature of the stage heater and the set temperature of the pressure head heater. The set temperature of the stage heater and the set temperature of the pressure head heater were set to the same value, resulting in a set bonding temperature. The bonding temperature can be adjusted by changing the set temperature of the stage heater and the set temperature of the pressure head heater. The bonding pressure is the value obtained by dividing the pressure load on one top chip by the area of ​​one top chip. The bonding pressure can be adjusted by adjusting the pressure load on one top chip.

[0072] (Example 12) Example 12 differs from Example 11 in that the top chip has a gold film, and otherwise a bonded body was obtained in the same manner as Example 11. (Example 13) Example 13 differs from Example 11 in that the oxygen gas partial pressure was 3000 Pa (3 kPa), and otherwise a bonded body was obtained in the same manner as Example 11. The oxygen gas partial pressure was adjusted by reducing the amount of nitrogen gas supplied to the stacked top chip, anisotropically conductive member, and bottom chip, as described above. (Example 14) Example 14 differs from Example 13 in that the top chip has a gold film, and otherwise a bonded body was obtained in the same manner as Example 13.

[0073] (Example 15) Example 15 differs from Example 11 in that the bonding temperature was set to 350°C, and otherwise a bonded body was obtained in the same manner as Example 11. (Example 16) Example 16 differs from Example 11 in that the bonding pressure was set to 100 MPa, and otherwise a bonded body was obtained in the same manner as Example 11. (Example 17) Example 17 differs from Example 11 in that the bonding pressure was set to 150 MPa, and otherwise a bonded body was obtained in the same manner as Example 11.

[0074] (Comparative Example 1) Comparative Example 1 differs from Example 11 in that the hydrogen gas partial pressure was 0.05 Pa and the oxygen gas partial pressure was 20,000 Pa (20 kPa), and otherwise a bonded body was obtained in the same manner as Example 11. The hydrogen gas partial pressure and oxygen gas partial pressure in Comparative Example 1 correspond to the hydrogen gas partial pressure and oxygen gas partial pressure in the atmosphere. Comparative Example 1 is similar to the bonding performed in the atmosphere. In Comparative Example 1, the atmosphere was not adjusted during bonding, and nitrogen gas was not supplied. (Comparative Example 2) Comparative Example 2 differs from Comparative Example 1 in that the top chip had a gold film, and otherwise a bonded body was obtained in the same manner as Comparative Example 1.

[0075] The strength test and strength evaluation performed on the bonded structure are described below. (Strength Test) A die shear device (Dage 4000 (device name) manufactured by Nordson Advanced Technologies, Inc.) was used for the strength test. As shown in FIG. 10 , the bonded structure 10c has an anisotropically conductive member 12 bonded to a bottom chip 50, and a top chip 54 bonded to the anisotropically conductive member 12. The bottom chip 50 has a titanium film (not shown) formed on a silicon substrate 52, and a copper film formed on the titanium film as a conductive portion 53. The top chip 54 has a titanium film (not shown) formed on a silicon substrate 55, and a copper film, gold film, or tin film formed on the titanium film as a conductive portion 56. FIG. 10 shows a cross section taken along line A-A in FIG. 9. Note that in FIG. 10 , components identical to those in the bonded structure 10 shown in FIG. 1 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0076] Although only one top chip 54 is shown in FIG. 10 , two top chips 54 were bonded as shown in FIG. 9 . In this state, a shear tool 60 was used to apply a load to one of the two top chips 54 so as to displace the top chip 54 in a direction parallel to the surface of the anisotropically conductive member 12, thereby applying shear stress and measuring the bonding strength of the bonded structure. The shear tool 60 was moved at a speed of 0.05 mm / sec, and the load was applied by the shear tool 60 until delamination occurred in the bonded structure 10c or the top chip 54 broke. The bonding strength per area of ​​the top chip was calculated from the load at which delamination occurred in the bonded structure or the load at which the top chip broke. A bonding strength of 20 MPa corresponds to the stress at which a silicon substrate breaks. In other words, a bonding strength of 20 MPa or higher leads to fracture of the top chip. Therefore, in the evaluation criteria below, "no delamination occurred in the bonded structure and the top chip broke" is equivalent to a bonding strength of 20 MPa or higher. Furthermore, "peeling occurred in the bonded body without breaking the top chip" is the same as a bonding strength of less than 20 MPa. The above-mentioned strength test was performed on one of the two top chips 54 immediately after bonding. Then, three months after bonding, the above-mentioned strength test was performed on the remaining top chip 54 of the two top chips 54. Note that "immediately after bonding" means within six hours after bonding.

[0077] The results of two strength tests, one immediately after bonding and one three months after bonding, were evaluated based on the following evaluation criteria. (Evaluation criteria) A: In both strength tests, no peeling occurred in the bonded body and the top tip broke. B: In both strength tests, in the strength test immediately after bonding, no peeling occurred in the bonded body and the top tip broke, and in the strength test three months later, the top tip did not break and peeling occurred in the bonded body. C: In both strength tests, peeling occurred in the bonded body.

[0078]

[0079] As shown in Table 1, Examples 1 to 17, in which the hydrogen gas partial pressure was 10 Pa or more, had high strength and high bonding reliability of the bonded bodies. On the other hand, Comparative Examples 1 and 2, in which the hydrogen gas partial pressure was less than 10 Pa, had low strength and low bonding reliability of the bonded bodies. From Examples 1 to 9, it was found that if the hydrogen gas partial pressure was 1000 Pa or more, the strength was further increased and the bonding reliability of the bonded bodies was also further increased. From Examples 8 and 10, and Examples 11 to 13, it was found that if the oxygen gas partial pressure was 3000 Pa (3 kPa) or less, the strength was high and high bonding reliability of the bonded bodies was obtained.

[0080] 10, 10a, 10c, 11a, 11b Bonded body 12 Anisotropically conductive member 14, 18 Bonded members 14a, 16a, 18a Surface 15 Conductive portion 16 Semiconductor substrate 17a, 17b, 17c Element region 20, 20a Apparatus 21 Container 21a Interior 22 Stage 22a Surface 23 Pressure head 24, 26 Valve 25 Pump 27 Gas supply unit 28 Pressure gauge 29 Concentration meter 30 Insulating base material 30a Surface 30b Back surface 31 Pore 32 Conductive path 32a Protrusion 32b Protrusion 34 Resin layer 34a Surface 50 Bottom chip 52, 55 Silicon substrate 53 Conductive portion 54 Top chip 56 Conductive portion 60 Shear tool CL Cutting line Ds Layer direction Dt Thickness direction d Average diameter hm Average thickness ht Thickness p Center distance

Claims

1. A method for manufacturing a joined body, comprising: a joining step for joining an anisotropically conductive member having an electrically insulating base material and a plurality of conductive paths penetrating the insulating base material in the thickness direction, being electrically insulated from one another, and having protrusions protruding from at least one surface of the insulating base material, to a conductive part, wherein the joining step includes a step of pressurizing the anisotropically conductive member in an atmosphere having a hydrogen gas partial pressure of 10 Pa or more.

2. The method for producing a bonded body according to claim 1, wherein the atmosphere in the bonding step has an oxygen gas partial pressure of 3 kPa or less.

3. The method for manufacturing a bonded body according to claim 1 or 2, wherein the bonding temperature in the bonding step is 150°C to 350°C.

4. The method for producing a bonded body according to claim 1 or 2, wherein the bonding pressure in the bonding step is 5 MPa to 150 MPa.

5. The method for producing a joint body according to claim 1 or 2, wherein the conductive portion contains Au, Cu or Sn.

6. The method for manufacturing a joined body according to claim 1 or 2, wherein the conductive portion is an electrode or a terminal provided on an object to be joined to which the anisotropically conductive member is joined.

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