Anisotropic conductive member and joined body

Abstract

Provided are an anisotropic conductive member and a joined body in which buckling of a conductive path is suppressed. The anisotropic conductive member includes: an insulating base material having electrical insulation properties; and a plurality of conductive paths that pass through in the thickness direction of the insulating base material, are electrically insulated from each other, and each have a protruding part protruding from at least one surface of the insulating base material. In a cross section in the thickness direction of the insulating base material, the surface of the insulating base material from which the protruding parts of the conductive paths protrude has a plurality of top sections and contact sections at which the plurality of protruding parts are in contact with the insulating base material, respectively. The arithmetic average distance between the plurality of contact sections and the plurality of top sections in the thickness direction is 2-200 nm.

Description

Anisotropically conductive member and joint body

[0001] The present invention relates to an anisotropically conductive member and a bonded body having a plurality of conductive paths that penetrate an insulating substrate in the thickness direction and have protrusions that protrude from at least one surface of the insulating substrate, and in particular to an anisotropically conductive member and a bonded body in which the surface of the insulating substrate from which the protrusions protrude has a plurality of apexes and a plurality of contact portions where the protrusions come into contact with the insulating substrate.

[0002] An anisotropically conductive member has conductive paths formed by filling a plurality of through-holes in an insulating substrate with a conductive material such as metal. An anisotropically conductive member can be inserted between an electronic component such as a semiconductor element and a circuit board and electrically connected therebetween simply by applying pressure. Therefore, the anisotropically conductive member is widely used as an electrical connection member for electronic components such as semiconductor elements, and as an inspection connector for functional testing. Electronic components such as semiconductor elements are particularly prone to downsizing. Conventional methods for directly connecting wiring boards, such as wire bonding, flip-chip bonding, and thermocompression bonding, may not be able to fully ensure the stability of the electrical connection of electronic components. Therefore, anisotropically conductive members are attracting attention as electronic connection members.

[0003] As an anisotropically conductive member, for example, Patent Document 1 describes an anisotropically conductive joining member including an insulating substrate made of an inorganic material, a plurality of conductive paths made of a conductive member, and a resin layer provided on the entire surface of the insulating substrate. The conductive paths are insulated from each other and penetrate the insulating substrate in the thickness direction. The conductive paths are parallel to each other and have protruding portions protruding from the surface of the insulating substrate, with the ends of the protruding portions embedded in the resin layer.

[0004] Japanese Patent Application Laid-Open No. 2018-037509

[0005] When the anisotropically conductive bonding member of Patent Document 1 is used in an electronic connection member, the conductive paths of the anisotropically conductive bonding member are bonded to electrodes of a semiconductor element, etc., to be connected. During bonding, the protruding portions of the conductive paths that protrude from the surface of the insulating substrate may buckle. If the protruding portions of the conductive paths buckle during bonding, the bonding between the conductive paths and electrodes of the semiconductor element, etc., may be insufficient, and sufficient bonding strength may not be obtained. Therefore, it is desirable to prevent the conductive paths from buckling. An object of the present invention is to provide an anisotropically conductive member and a bonded body in which buckling of the conductive paths is suppressed.

[0006] In order to achieve the above-mentioned object, invention [1] is an anisotropically conductive member having an electrically insulating substrate and a plurality of conductive paths that penetrate the insulating substrate 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 substrate, wherein, in a cross section in the thickness direction of the insulating substrate, the surface of the insulating substrate from which the protrusions of the conductive paths protrude has a plurality of apexes, and each of the plurality of protrusions has a contact portion in contact with the insulating substrate, and the arithmetic mean distance in the thickness direction between the plurality of contact portions and the plurality of apexes is 2 nm to 200 nm.

[0007] Invention [2] is the anisotropically conductive member according to Invention [1], in which the conductive paths are composed of Cu, Au, or Al. Invention [3] is the anisotropically conductive member according to Invention [1] or [2], in which, when the diameter of the protrusion is d and the length of the protrusion in the thickness direction of the insulating substrate is h, d / h is 0.1 to 20. Invention [4] is the anisotropically conductive member according to any one of Inventions [1] to [3], in which the length of the protrusion in the thickness direction of the insulating substrate is 6 to 6,000 nm.

[0008] Invention [5] is a joined body in which an anisotropically conductive member and a member to be joined are joined, wherein a resin is filled between the anisotropically conductive member and the member to be joined, the anisotropically conductive member has an electrically insulating insulating base material and a plurality of conductive paths that penetrate the insulating base material in a thickness direction and 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, the surface of the insulating base material from which the protrusions of the conductive paths protrude in a cross section in the thickness direction of the insulating base material has a plurality of apexes, and each of the plurality of protrusions has a contact portion in contact with the insulating base material, and the arithmetic mean distance in the thickness direction between the plurality of contact portions and the plurality of apexes is 2 nm to 200 nm. Invention [6] is the joined body according to Invention [5], in which the member to be joined has a metal layer and a resin layer, and the metal layer is exposed from the resin layer. Invention [7] is the joined body according to Invention [5], in which the joined members have a plurality of metal layers, at least one of the plurality of metal layers having a different height. Invention [8] is the joined body according to Invention [6], in which the joined members have a joining surface on which a plurality of metal layers are provided, and the area of ​​the joining surface is larger than the area of ​​the surface from which the protruding portion of the anisotropically conductive member protrudes.

[0009] According to the present invention, it is possible to provide an anisotropically conductive member and a bonded body in which buckling of the conductive paths is suppressed.

[0010] FIG. 1 is a schematic cross-sectional view showing an example of an anisotropically conductive member according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of an anisotropically conductive member according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an enlarged portion of the example of an anisotropically conductive member according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a first example of a joined body according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an enlarged portion of the first example of a joined body according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing an enlarged portion of a second example of a joined body according to an embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing one step of an example of a method for manufacturing an anisotropically conductive member according to an embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing one step of an example of a method for manufacturing an anisotropically conductive member according to an embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing one step of an example of a method for manufacturing an anisotropically conductive member according to an embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing one step of an example of a method for manufacturing an anisotropically conductive member according to an embodiment of the present invention.

[0011] The anisotropically conductive member and bonded body of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. Note that the drawings described below are illustrative for explaining the present invention, and are simplified and exaggerated for the purpose of explaining the present invention. Therefore, 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 α The range includes ε α ≦ε≦ε αUnless otherwise specified, the parallel and perpendicular directions include the tolerance ranges generally accepted in the relevant technical field. Unless otherwise specified, the temperature, time, and pressure include the tolerance ranges generally accepted in the relevant technical field. Furthermore, the term "same" includes the tolerance ranges generally accepted in the relevant technical field. Furthermore, terms such as "entire surface" include the tolerance ranges generally accepted in the relevant technical field. Anisotropically conductive members and bonded bodies will be specifically described below.

[0012] [Example of Anisotropically Conductive Member] FIG. 1 is a schematic cross-sectional view showing an example of an anisotropically conductive member according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of an anisotropically conductive member according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an enlarged portion of an example of an anisotropically conductive member according to an embodiment of the present invention. FIGS. 1 and 3 show a cross-section of an insulating substrate 20 in the thickness direction Dt. FIG. 2 is a plan view of the insulating substrate 20 of FIG. 1 as viewed from the surface 20a side, showing a state without the resin layer 24. The anisotropically conductive member 10 shown in FIG. 1 includes an electrically insulating insulating substrate 20 and a plurality of conductive paths 22 that penetrate the insulating substrate 20 in the thickness direction Dt, are electrically insulated from one another, and have protrusions protruding from at least one surface. The anisotropically conductive member 10 also includes a resin layer 24 covering at least one surface of the insulating substrate 20. The anisotropically conductive member 10 is conductive in the thickness direction Dt of the insulating substrate 20. In the anisotropically conductive member 10, the resin layer 24 is not necessarily required, and the anisotropically conductive member 10 may have a configuration without the resin layer 24.

[0013] The plurality of conductive paths 22 are provided in the insulating substrate 20 in a state where they are electrically insulated from one another. In this case, for example, the insulating substrate 20 has a plurality of pores 21 penetrating in the thickness direction Dt. The conductive paths 22 are provided in the plurality of pores 21. The conductive paths 22 protrude from the front surface 20a of the insulating substrate 20. The conductive paths 22 also protrude from the back surface 20b of the insulating substrate 20. The conductive paths 22 may protrude from one surface of the insulating substrate 20 in the thickness direction Dt. For example, a resin layer 24 is provided on the surface of the insulating substrate 20 from which the conductive paths 22 protrude. The resin layer 24 covers the protruding portions 22a of the conductive paths 22, and the protruding portions 22a are embedded in the resin layer 24. The resin layer 24 also covers the protruding portions 22b of the conductive paths 22, and the protruding portions 22b are embedded in the resin layer 24. The insulating substrate 20 is formed, for example, of an anodized film. The anodized film is formed by, for example, anodizing a valve metal. The front surface 20a and the back surface 20b of the insulating substrate 20 are surfaces that face each other in the thickness direction Dt of the insulating substrate 20.

[0014] The anisotropically conductive member 10 has anisotropic conductivity and is conductive in the thickness direction Dt as described above, but has sufficiently low conductivity in the direction x parallel to the surface 20a of the insulating substrate 20. The direction x is a direction perpendicular to the thickness direction Dt. As shown in FIG. 2 , the anisotropically conductive member 10 has, for example, a circular outer shape. The outer shape and size of the anisotropically conductive member 10 are determined appropriately depending on the application, etc., and the outer shape may be, for example, a square. For example, the anisotropically conductive member 10 is bonded without the resin layer 24, or with the resin layer 24 present but with nothing on the surface 24a.

[0015] As shown in Fig. 3, the surface 20a of the insulating substrate 20 is not flat but has an uneven structure. There are multiple recesses 20d on the surface 20a of the insulating substrate 20. A recess 20d is provided for each conductive path 22. The recesses 20d are arranged so as to surround the conductive path 22, with the conductive path 22 at the center. In the cross section of the insulating substrate 20 in the thickness direction Dt shown in Fig. 3, the surface of the insulating substrate 20 from which the protrusions 22a protrude, i.e., the surface 20a in Fig. 3, has multiple apexes Pc and multiple contact portions Vc.

[0016] The apex Pc is a high portion of the surface of the insulating substrate 20 on the side of the protrusion 22a in a cross section of the insulating substrate 20 in the thickness direction Dt. The apex Pc is, for example, a boundary portion between adjacent recesses 20d. The contact portion Vc is a portion where each of the multiple protrusions 22a contacts the insulating substrate 20 in a cross section of the insulating substrate 20 in the thickness direction Dt. The contact portion Vc is located at the end of the protrusion 22a on the insulating substrate 20 side. More specifically, the contact portion Vc is located at the bottom of the recess 20d on the back surface 20b side of the insulating substrate 20. In the anisotropically conductive member 10, the arithmetic mean distance in the thickness direction Dt between the multiple contact portions Vc and the multiple apexes Pc is 2 nm to 200 nm, preferably 2 nm to 150 nm, more preferably 20 nm to 100 nm, and even more preferably 20 nm to 60 nm.

[0017] In the anisotropically conductive member 10, the surface 20a of the insulating substrate 20 from which the protrusions 22a protrude is configured such that the arithmetic mean distance δ in the thickness direction Dt between the multiple contact points Vc and the multiple peaks Pc is 2 nm to 200 nm. This allows the protrusions 22a to bend more in the direction x when a force acts on the protrusions 22a in a direction parallel to the thickness direction Dt than when the surface 20a of the insulating substrate 20 is a flat surface with an arithmetic mean distance of less than 2 nm. That is, within the recess 20d, the side surfaces 22c of the protrusions 22a are allowed to displace more in the direction x than when the surface is flat. This suppresses buckling of the protrusions 22a, thereby achieving sufficient bonding strength to the connection object and ensuring sufficient conductivity with the connection object. Furthermore, there is no contact between adjacent protrusions, and the occurrence of short circuits is also suppressed. Furthermore, when a force acts on the protrusion 22a in a direction parallel to the thickness direction Dt, if the protrusion 22a deforms so that its diameter increases in the direction x, the protrusion 22a is allowed to deform so that its diameter increases in the direction x compared to when the surface 20a of the insulating substrate 20 is a flat surface. In this case, the diameter of the protrusion 22a is allowed to increase in the direction x within the recess 20d. Therefore, buckling of the protrusion 22a is suppressed. Even in this case, sufficient bonding strength to the connection object can be obtained, sufficient conductivity with the connection object can be ensured, and further, there is no contact between adjacent protrusions, suppressing the occurrence of short circuits.

[0018] If the arithmetic mean distance δ is less than 2 nm, when a force acts on the protrusion 22a in a direction parallel to the thickness direction Dt, the amount of displacement of the protrusion 22a in the direction x is small, and the protrusion 22a buckles. As a result, sufficient bonding strength to the connection object is not obtained. If the protrusion 22a buckles, it may come into contact with adjacent protrusions, and sufficient conductivity with the connection object cannot be ensured. If the arithmetic mean distance δ is greater than 200 nm, the end on the insulating substrate 20 side becomes closer to the center in the thickness direction Dt of the insulating substrate 20, the recess 20d becomes deeper, and the protrusion 22a becomes substantially longer. As a result, the protrusion is prone to buckling. If a force acts on the protrusion 22a in a direction parallel to the thickness direction Dt, the protrusion buckles and comes into contact with adjacent protrusions, and sufficient conductivity with the connection object cannot be ensured.

[0019] The arithmetic mean distance δ can be determined, for example, as follows. First, the anisotropically conductive member 10 is cut using a focused ion beam (FIB) to expose a cross section of the insulating substrate 20 in the thickness direction Dt. A field emission scanning electron microscope (FE-SEM) is used to obtain a photographed image of the cross section of the insulating substrate 20 in the thickness direction Dt at a magnification of 150k. In the photographed image, a reference point Pb is set at an arbitrary position on the back surface 20b of the insulating substrate 20, opposite the front surface 20a. A reference line Ls is set parallel to the direction x passing through the reference point Pb. In the photographed image, from the points corresponding to the apexes Pc, ten apexes Pc are selected in descending order of their distance from the reference line Ls. Furthermore, from the points corresponding to the contact portions Vc, ten contact portions Vc are selected in descending order of their distance from the reference line Ls. In the photographed image, the distance from the reference line Ls to each of the selected ten points corresponding to the apexes Pc is determined. The average of ten distances between the points corresponding to the ten apexes Pc and the reference line Ls is calculated using the least squares method. The average value calculated using the least squares method is displayed as a point on the captured image. A line Lc parallel to the direction x passing through the point indicating the average value of the apexes Pc is calculated. A plane including this parallel line Lc is the average plane of the surface 20a of the insulating substrate 20. The average plane of the surface 20a of the insulating substrate 20 serves as the reference for the length of the protrusions 22a. In the captured image, the distance from the reference line Ls to each of the points corresponding to the selected ten contact portions Vc is calculated. The average of ten distances between the points corresponding to the ten contact portions Vc and the reference line Ls is calculated using the least squares method. The average value calculated using the least squares method is displayed as a point on the captured image. A line Lb parallel to the direction x passing through the point indicating the average value of the contact portions Vc is calculated. A plane including this parallel line Lb is the average plane of the contact portions Vc. The arithmetic mean distance δ is the absolute value of the difference between the average value of the apex Pc calculated using the least squares method and the average value of the contact Vc calculated using the least squares method. That is, the arithmetic mean distance δ is the distance between the parallel line Lc and the parallel line Lb in the thickness direction Dt. Therefore, the arithmetic mean distance δ is obtained by calculating the distance between the parallel line Lc and the parallel line Lb in the thickness direction Dt. Although not shown in detail, the back surface 20b of the insulating substrate 20 also has a configuration similar to that of the front surface 20a of the insulating substrate 20 shown in FIG. 3 .The arithmetic mean distance δ is also determined for the rear surface 20b of the insulating substrate 20 in the same manner as for the front surface 20a of the insulating substrate 20 described above.

[0020] [First Example of Bonded Body] FIG. 4 is a schematic cross-sectional view showing a first example of a bonded body according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an enlarged portion of the first example of a bonded body according to an embodiment of the present invention. In FIGS. 4 and 5, components identical to those of the anisotropically conductive member 10 shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The bonded body 12 shown in FIG. 4 is formed by bonding the anisotropically conductive member 10 to semiconductor elements 30 and 31 as bonded members. The bonded members are the connection targets. In the bonded body 12, a resin is filled between the anisotropically conductive member 10 and the bonded members. The semiconductor element 30 includes, for example, three electrodes 34 on the surface 32a of the element substrate 32 and an insulating layer 36 that prevents electrical continuity between the three electrodes 34. The three electrodes 34 are at the same height from the surface 32a of the element substrate 32. Furthermore, the semiconductor element 31 includes, for example, three electrodes 38 on the surface 37a of the element substrate 37, and an insulating layer 39 that prevents conduction between the three electrodes 38. The three electrodes 38 are at the same height from the surface 37a of the element substrate 37. The electrodes 34 and 38 are bonded to the conductive paths 22 of the anisotropically conductive member 10. For example, as shown in FIG. 5 , the surface 34a of the electrode 34 and the protruding portion 22a of the conductive paths 22 are bonded in contact with each other. At this time, the surface 34a of the electrode 34 presses the protruding portion 22a of the conductive paths 22, deforming the protruding portion 22a, but buckling of the protruding portion 22a is suppressed as described above. Therefore, the bonded body 12 can obtain sufficient bonding strength between the semiconductor elements 30 and 31. Furthermore, suppressing buckling of the protruding portion 22a ensures sufficient conductivity with the connection target, and further prevents contact with adjacent protruding portions, thereby suppressing the occurrence of short circuits.

[0021] The electrodes 34 and 38 are used to exchange signals with the outside, or to transfer voltage or current, and are made of, for example, copper or solder. Electrodes made of solder are also called solder bumps. The insulating layer 39 is not particularly limited in its configuration as long as it can prevent electrical conduction between the electrodes, and can be made of a known insulating layer used in semiconductor elements. The insulating layer 39 can be made of, for example, a silicon oxide film (SiO ２ ), silicon nitride film (Si ３ N ４ ), a PSG (Phospho Silicate Glass) film, a BPSG (Boron Phospho Silicate Glass) film, and an SOG (Spin On Glass) film.

[0022] The resin layer 33 is formed, for example, by the resin layer 24 of the anisotropically conductive member 10. In this case, the anisotropically conductive member 10 having the resin layer 24 is used for bonding. The resin layer 33 can also be formed by a resin layer (not shown) provided on the surface 34a of the electrode 34 of the semiconductor element 30 and a resin layer (not shown) provided on the surface 38a of the electrode 38 of the semiconductor element 31. After bonding the conductive path 22 of the anisotropically conductive member 10 to the electrodes 34, 38, the resin layer 33 can also be formed by supplying a resin agent between the conductive path 22 and the electrode 34 and between the conductive path 22 and the electrode 38.

[0023] (First Example of Manufacturing Method of Bonded Body) The bonded body 12 shown in FIG. 4 is bonded, for example, as shown in FIG. 6. FIG. 6 is a schematic cross-sectional view showing a first example of a manufacturing method of a bonded body according to an embodiment of the present invention. Note that in FIG. 6, components identical to those of the bonded body 12 shown in FIGS. 4 and 5 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. As shown in FIG. 6, semiconductor elements 30 and 31 are arranged with the anisotropically conductive member 10 sandwiched therebetween. At this time, alignment is performed, for example, using alignment marks (not shown) provided on the semiconductor elements 30 and 31 and the anisotropically conductive member 10. Note that the alignment using the alignment marks is not particularly limited, as long as, for example, an image or a reflected image of the alignment mark can be acquired and positional information of the alignment mark can be obtained, and any known alignment method can be used as appropriate. As shown in FIG. 6, a resin layer 24 is provided on the anisotropically conductive member 10, and the resin layer 24 forms the resin layer 33 of the bonded body 12 shown in FIG. 4.

[0024] Next, the semiconductor element 30 and the anisotropically conductive member 10, and the semiconductor element 31 and the anisotropically conductive member 10 are bonded together. This allows the bonded body 12 shown in FIG. 4 to be manufactured. Note that bonding the semiconductor element 30 and the anisotropically conductive member 10, and the semiconductor element 31 and the anisotropically conductive member 10 together is the bonding process. In the bonding process, for example, bonding may be performed under predetermined conditions in a temporarily bonded state, but the temporary bonding may be omitted. Note that the bonding in the bonding process is also referred to as actual bonding.

[0025] Temporary bonding refers to fixing the semiconductor elements 30, 31 and the anisotropically conductive member 10 in an aligned state. The temperature conditions in the temporary bonding process are not particularly limited, but are preferably 0°C to 300°C, more preferably 10°C to 200°C, and particularly preferably room temperature (23°C) to 100°C. Similarly, the pressure conditions in the temporary bonding process are not particularly limited, but are preferably 10 MPa or less, more preferably 5 MPa or less, and particularly preferably 1 MPa or less.

[0026] The temperature conditions for the main bonding are not particularly limited, but are preferably higher than the temperature for the temporary bonding. Specifically, 120°C to 350°C is more preferred, and 200°C to 300°C is particularly preferred. The pressure conditions for the main bonding are not particularly limited, but are preferably 30 MPa or less, and more preferably 0.1 MPa to 20 MPa. The time for the main bonding is not particularly limited, but is preferably 1 second to 60 minutes, and more preferably 5 seconds to 10 minutes. By performing the main bonding under the above conditions, the protrusion 22a of the conductive path 22 is bonded to the surface 34a of the electrode 34, and the protrusion 22b of the conductive path 22 is bonded to the surface 38a of the electrode 38. At this time, as described above, buckling of both the protrusions 22a and 22b of the conductive path 22 is suppressed, and for example, the protrusions 22a, 22b are also suppressed from collapsing and coming into contact with the adjacent protrusions 22a, 22b. This ensures sufficient bonding strength to the connection object, ensures sufficient conductivity with the connection object, and also prevents short circuits from occurring.

[0027] [Second Example of Bonded Body] Figure 7 is a schematic cross-sectional view showing an enlarged portion of a second example of a bonded body according to an embodiment of the present invention. In Figure 7, components identical to those in the bonded body 12 shown in Figures 4 and 5 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The bonded body 13 shown in Figure 7 differs from the bonded body 12 shown in Figures 4 and 5 in that the semiconductor element 30 has electrodes 35 of different heights. The other components are similar to the bonded body 12 shown in Figures 4 and 5. The electrode 35 is taller than the electrode 34. In the bonded body 13, the electrode 34 and the taller electrode 35 are bonded to the anisotropically conductive member 10. In the bonded body 13, the electrode 35 is closer to the anisotropically conductive member 10 than the electrode 34, causing greater deformation of the protruding portion 22a of the conductive path 22. Even in this case, buckling of the protruding portion 22a is suppressed as described above. Even if the semiconductor element 30 has a relatively high electrode 35 in this manner, sufficient bonding strength can be obtained between the semiconductor element 30 and the semiconductor element 31. Furthermore, since buckling of the protrusion 22a is suppressed, sufficient conductivity is ensured and the occurrence of short circuits is also suppressed.

[0028] In the bonded bodies 12 and 13, the bonded members have bonding surfaces on which multiple metal layers are provided, and the area of ​​the bonding surface is preferably larger than the area of ​​the surface from which the protrusions of the anisotropically conductive member protrude. Here, the semiconductor elements 30 and 31 described above have multiple electrodes provided on the surface of an element substrate, and the surface of the element substrate corresponds to the bonding surface. The area of ​​the surface of the element substrate is preferably larger than the area of ​​the front surface 20a and the back surface 20b of the insulating base material 20 from which the protrusions 22a and 22b of the anisotropically conductive member 10 protrude.

[0029] The configuration of the anisotropically conductive member will be described in more detail below.

[0030] (Insulating Substrate) The insulating substrate 20 has electrical insulation properties and keeps the plurality of conductive paths 22, which are made of a conductive material, electrically insulated from one another. The insulating substrate 20 has a plurality of pores 21 in which the conductive paths 22 are formed. The composition of the insulating substrate will be described later. The length of the insulating substrate 20 in the thickness direction Dt, i.e., the thickness ht of the insulating substrate 20, is preferably in the range of 1 to 1000 μm, more preferably in the range of 5 to 500 μm, even more preferably in the range of 10 to 300 μm, and particularly preferably 10 μm or more and 30 μm or less. When the thickness of the insulating substrate 20 is in this range, the insulating substrate 20 is easy to handle.

[0031] The thickness of the insulating base material is determined by measuring the line Lc on both the front surface 20a side and the back surface 20b side of the insulating base material 20. The distance in the thickness direction Dt between the line Lc on the front surface 20a side and the line Lc on the back surface 20b side is defined as the thickness of the insulating base material.

[0032] The insulating substrate 20 is made of, for example, an inorganic material and has an electrical resistivity (10 14 The term "made of an inorganic material" is intended to distinguish it from the polymer material that constitutes the resin layer described below, and is not intended to limit the insulating base material to an insulating base material that is made of only inorganic materials, but rather to a base material that is mainly composed of inorganic materials (50% by mass or more).

[0033] Examples of insulating substrates include metal oxide substrates, metal nitride substrates, glass substrates, ceramic substrates such as silicon carbide and silicon nitride, carbon substrates such as diamond-like carbon, polyimide substrates, composite materials thereof, etc. In addition to these, the insulating substrate may be, for example, a substrate in which a film of an inorganic material containing 50 mass % or more of a ceramic material or a carbon material is formed on an organic material having through holes.

[0034] The insulating substrate has micropores with a desired average opening diameter formed as through-holes. The insulating substrate is preferably a metal oxide substrate, more preferably an anodized film of a valve metal, because it is easy to form conductive paths. Specific examples of valve metals include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among these, an anodized film of aluminum (substrate) is preferred because it has good dimensional stability and is relatively inexpensive. Therefore, it is preferable to use an aluminum substrate to form an anodized film, which is an insulating substrate, and produce an anisotropically conductive member. The thickness of the anodized film is the thickness of the insulating substrate 20 described above.

[0035] <Aluminum Substrate> The aluminum substrate for forming an anodized film, which is an insulating base material, is not particularly limited, and specific examples thereof include a pure aluminum plate; an alloy plate containing aluminum as the main component and trace amounts of other elements; a substrate in which high-purity aluminum is vapor-deposited onto low-purity aluminum (e.g., recycled material); a substrate in which the surface of a silicon wafer, quartz, glass, or the like is coated with high-purity aluminum by a method such as vapor deposition or sputtering; and a resin substrate laminated with aluminum.

[0036] Of the aluminum substrates, the surface on which an anodized film is formed by an anodizing treatment process preferably has an aluminum purity of 99.5% by mass or more, more preferably 99.9% by mass or more, and even more preferably 99.99% by mass or more. When the aluminum purity is within the above range, the through-hole arrangement is sufficiently regular. Micropores become fine pores. The aluminum substrate is not particularly limited as long as it can form an anodized film, and for example, JIS (Japanese Industrial Standards) 1050 material is used.

[0037] In addition, it is preferable that the surface of one side of the aluminum substrate to be subjected to the anodizing treatment process is previously subjected to heat treatment, degreasing treatment, and mirror finish treatment. Here, the heat treatment, degreasing treatment, and mirror finish treatment can be the same treatments as those described in paragraphs

[0044] to

[0054] of JP 2008-270158 A. The mirror finish treatment before the anodizing treatment is, for example, electrolytic polishing, and for electrolytic polishing, an electrolytic polishing solution containing, for example, phosphoric acid is used.

[0038] <Average Diameter of Pores> The average diameter of the pores 21 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 21 is 1 μm or less and within the above-mentioned range, conductive paths 22 having the above-mentioned average diameter can be obtained. The average diameter of the pores 21 can be determined, for example, as follows. First, a scanning electron microscope (SEM) is used to photograph the surface of the insulating substrate 20 from directly above at a magnification of 100 to 10,000 times to obtain a captured image. 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 these 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 determined 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 plurality of conductive paths 22 are provided in the insulating substrate 20, e.g., an anodized film, while being electrically insulated from one another. Each of the plurality of conductive paths 22 is a columnar conductor having electrical conductivity and is 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 viewpoints of electrical conductivity and formation by a plating method, copper (Cu), gold (Au), aluminum (Al), nickel (Ni), and cobalt (Co) are preferred as conductive materials, copper (Cu), gold (Au), and aluminum (Al) are more preferred, and copper (Cu) is even more preferred. Metals have superior ductility and are more easily deformed than oxide conductors, and are also easily deformed by compression during bonding. Therefore, it is preferable to make the conductive paths out of metal.

[0040] The average diameter d of the conductive paths 22 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. 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. 2or more is most preferable. Furthermore, the center-to-center distance p between adjacent conductive paths 22 is preferably 20 nm to 500 nm, more preferably 40 nm to 200 nm, and even more preferably 50 nm to 140 nm. With respect to the conductive paths 22, the distance w (see FIG. 1) between adjacent protrusions is 20 nm to 200 nm, and preferably 40 nm to 100 nm. When the distance between adjacent protrusions is within the above range, the distance between the conductive paths 22 can be maintained even on the front surface 20a or the back surface 20b of the insulating substrate 20 of the conductive paths 22. This suppresses short-circuiting of the conductive paths 22 during bonding, improving reliability during bonding.

[0041] The average diameter of the conductive paths can be determined, for example, as follows. First, a scanning electron microscope is used to photograph the surface of the insulating substrate from directly above at a magnification of 100 to 10,000 times to obtain a photographed image. At least 20 conductive paths with a circular periphery are extracted from the photographed image, and their diameters are measured to determine the opening diameter. The average of these 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 a photographed image from which 20 or more conductive paths can be extracted. Furthermore, when the opening shape is non-circular, the maximum value of the distance between the ends of the conductive path portion is taken as the opening diameter. Therefore, for example, even when a conductive path has a shape in which two or more conductive paths are integrated, this is considered as a single conductive path, and the maximum value of the distance between the ends of the conductive path portion is taken as the opening diameter. The average diameter d of the conductive paths 22 is the same as the average diameter of the protrusions. When the shape of the conductive paths 22 on the surface 20a side of the insulating substrate 20 is not circular, the average diameter on the surface 20a side of the insulating substrate 20 is taken as the average diameter of the circle-equivalent diameter. Furthermore, when the shape of the conductive paths 22 on the back surface 20b of the insulating substrate 20 is not circular, the average diameter on the back surface 20b of the insulating substrate 20 is the average diameter of the circle-equivalent diameter. Furthermore, the average diameter d of the conductive paths 22 on the front surface 20a of the insulating substrate 20 can be measured from a surface image of the front surface 20a of the insulating substrate 20 obtained by a scanning electron microscope. The average diameter d of the conductive paths 22 on the back surface 20b of the insulating substrate 20 can be measured from a back surface image of the back surface 20b of the insulating substrate 20 obtained by a scanning electron microscope.

[0042] When using the front and back images as described above, if protrusions make it difficult to measure the average diameter, the protrusions are removed by dissolution or the like. This causes pores to appear. The opening diameters of multiple pores in this front image can be measured, and the average opening diameter of the pores on the front surface can be used instead of the average diameter on the front surface. Similarly, the opening diameters of multiple pores in this back image can be measured, and the average opening diameter of the pores on the back surface can be used instead of the average diameter on the back surface. The average opening diameter of the pores can be measured, for example, as follows: First, 20 pores corresponding to pores are selected in the front image, and the diameters of the locations corresponding to the pore openings of the selected 20 pores are measured. The average value of the diameters of the locations corresponding to the measured pore openings is calculated, and this average value is used as the average opening diameter of the pores on the front surface. Furthermore, 20 pores corresponding to pores are selected in the back image, and the diameters of the locations corresponding to the pore openings of the selected 20 pores are measured. The average value of the diameters of the locations corresponding to the measured pore openings is calculated, and this average value is used as the average opening diameter of the pores on the back surface.

[0043] The center-to-center distance p between adjacent conductive paths 22 is determined by further identifying the identified center positions (not shown) of the conductive paths in the photographed image of the insulating substrate 20 obtained as described above. The distance between the center positions of adjacent conductive paths was determined at 10 locations. The average value of these distances was used as the center distance p between adjacent conductive paths 22. The center positions are the center positions of the areas corresponding to the conductive paths 22 in the photographed image. Note that a known image analysis method is used to calculate the center positions of the areas in the photographed image.

[0044] <<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 bonded members. The length h of the protrusions 22a in the thickness direction Dt of the insulating base material 20 and the length h of the protrusions 22b in the thickness direction Dt of the insulating base material 20 are preferably 2 nm to 6000 nm, more preferably 5 nm to 3000 nm. A length h of 10 nm to 1000 nm ensures good bonding to the bonded members. The length h of the protrusions 22a and the length h of the protrusions 22b are based on the average plane of the surface 20a of the insulating base material 20. If the length h of the protrusions 22a and 22b in the thickness direction Dt of the insulating base material 20 is 2 nm to 6000 nm, the protrusions can follow the bump height distribution of the bumps on the bonded member side well, and high height accuracy of the bump surface on the bonded member side is not required.

[0045] To determine the length h of the protrusion 22a and the length h of the protrusion 22b, a field emission scanning electron microscope (FE-SEM) is used to capture a 100,000x magnification image of a cross section of the insulating substrate 20 in the thickness direction Dt. In the captured image, the line Lc on the front surface side of the insulating substrate and the line Lc on the back surface side of the insulating substrate are determined as described above. Next, ten protrusions 22a are selected in the captured image. Points corresponding to the apexes of the selected ten protrusions 22a are identified. The distance between the identified point corresponding to the apex of the protrusion 22a and the line Lc on the front surface side of the insulating substrate in the thickness direction Dt of the insulating substrate 20 is determined for each of the ten protrusions 22a. The average value of the above-mentioned distances for the points corresponding to the apexes of the ten protrusions 22a is calculated. This average value is set to the length h of the protrusion 22a. Furthermore, ten protrusions 22b are selected in the captured image. Points corresponding to the apexes of the selected ten protrusions 22b are identified. The distance in the thickness direction Dt of the insulating substrate 20 between the point corresponding to the apex of the identified protrusion 22b and the line Lc on the back surface side of the insulating substrate is determined for each of the 10 protrusions 22b. The average of the distances for the points corresponding to the apexes of the 10 protrusions 22b is determined. This average is the length h of the protrusion 22b. When the diameter of the protrusion is d and the length of the protrusion in the thickness direction of the insulating substrate is h, it is preferable that d / h, which represents the aspect ratio, is 0.1 to 20. If the aspect ratio d / h is 0.1 to 20, stable production is possible and the bonding strength is excellent.

[0046] [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 functions, 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, for example, a thermoplastic layer made of a thermoplastic resin, which will be described in detail later. The average thickness hm of the resin layer 24 is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. When the average thickness hm of the resin layer 24 is 10 μm or less, it can fully protect the protrusions of the conductive paths 22 and fill the periphery of the electrodes when bonding to a connection target such as a semiconductor device. The average thickness hm of the resin layer 24 is the average distance from the surface 20a of the insulating substrate 20 or the average distance from the back surface 20b of the insulating substrate 20. The average thickness hm of the resin layer 24 described above is determined by cutting the resin layer in the thickness direction Dt of the anisotropically conductive member 10 and capturing an image of the cross section using a scanning electron microscope. In the captured image, the line Lc on the surface 20a side of the insulating substrate 20 and the line Lc on the back surface side of the insulating substrate 20 are determined as described above. Next, ten locations corresponding to the surface 24a of the resin layer 24 are selected in the captured image. The distance between the selected locations and the line Lc on the surface 20a side of the insulating substrate 20 is determined for each of the ten locations. The average distance of the ten locations is calculated. This average value is used as the average thickness hm of the resin layer 24 on the surface 20a side of the insulating substrate 20. Similarly, for the resin layer on the back surface 20b side of the insulating substrate 20, ten locations corresponding to the surface 24a of the resin layer 24 are selected in the captured image. The distance between the selected location and the line Lc on the back surface 20b of the insulating substrate 20 is measured at each of 10 locations. The average value of the distances at the 10 locations is calculated. This average value is set as the average thickness hm of the resin layer 24 on the back surface 20b of the insulating substrate 20.

[0047] 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 contain an antioxidant material. Specific examples of resin materials 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. Examples of resin materials constituting the resin layer include epoxy resins, phenolic resins, polyimide resins, melamine resins, isocyanate resins, and the like. Among these, polyimide resins and / or epoxy resins are preferred because of their improved insulation reliability and excellent chemical resistance. In addition to the above-mentioned resin layers, resins containing a main composition including an acrylic polymer, an acrylic monomer, and a maleimide compound, as described in International Publication No. 2022 / 163260, can be used as the resin layer.

[0048] ((Bonded Member of Anisotropically Conductive Member)) When an anisotropically conductive member is used as an electronic connecting member, the joined member to be connected is, for example, one having a semiconductor element, an electrode, or an element region. Examples of elements having electrodes include semiconductor elements that perform a specific function by themselves, but also include elements that perform a specific function when multiple elements are combined together. Furthermore, elements that simply transmit electrical signals, such as wiring members, are also included, and printed wiring boards and the like are also included as elements having electrodes. The element region is a region in which various element configuration circuits and the like that function as electronic elements are formed. The element region includes, 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), or a communication module such as a wireless tag and wiring are formed. In addition to the above, a MEMS (Micro Electro Mechanical System) 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, and the like. The optical sensor is not particularly limited as long as it can detect light, and for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor may be used. As described above, the element region has an element configuration circuit and the like formed therein, and electrodes (not shown) are provided to electrically connect the semiconductor chip to the outside. The element region has an electrode region in which electrodes are formed. Note that the electrodes in the element region are, for example, Cu posts. The electrode region basically refers to a region including all the formed electrodes. However, if the electrodes are provided discretely, the region in which each electrode is provided also refers to the electrode region. The form of the connection object may be an individualized object such as a semiconductor chip, a semiconductor wafer, or a wiring layer.Furthermore, the anisotropic conductive member is joined to a connection object, but the connection object is not particularly limited to the above-mentioned semiconductor elements, etc., and can be, for example, a semiconductor element in wafer form, a semiconductor element in chip form, a printed wiring board, a heat sink, etc.

[0049] ((Semiconductor Element)) In addition to the above, the semiconductor element may be, for example, a logic LSI (Large Scale Integration) (for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), an ASSP (Application Specific Standard Product), etc.), a microprocessor (for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc.), a memory (for example, a DRAM (Dynamic Random Access Memory), an HMC (Hybrid Memory Cube), an MRAM (Magnetic RAM), a PCM (Phase-Change Memory), a ReRAM (Resistive RAM), an FeRAM (Ferroelectric RAM), a flash memory (NAND (Not AND) flash), etc.), an LED (Light Emitting Diode), (for example, a microflash for a mobile terminal, an in-vehicle device, a projector light source, an LCD backlight, a general lighting, etc.), a power device, an analog IC (Integrated Circuit), (for example, a DC (Direct Current Current-DC (Direct Current) converters, insulated gate bipolar transistors (IGBTs), etc.), MEMS (Micro Electro Mechanical Systems), (for example, acceleration sensors, pressure sensors, vibrators, gyro sensors, etc.), wireless (for example, GPS (Global Positioning System), FM (Frequency Modulation), NFC (Nearfield communication), RFEM (RF Expansion Module), MMIC (Monolithic Microwave Integrated Circuit), WLAN (Wireless Local Area Network), etc.), discrete elements, BSI (Back Side Illumination), CIS (Contact Isolation System),Examples of semiconductor devices include a semiconductor device (e.g., a CMOS (Complementary Metal Oxide Semiconductor), a passive device, a SAW (Surface Acoustic Wave) filter, an RF (Radio Frequency) filter, an RFIPD (Radio Frequency Integrated Passive Devices), and a BB (Broadband). A semiconductor device is, for example, a self-contained device that performs a specific function such as a circuit or a sensor. The semiconductor device may have an interposer function. Furthermore, for example, it is also possible to stack multiple devices, such as a logic chip having a logic circuit and a memory chip, on a device having an interposer function. In this case, bonding is possible even if the electrode sizes of each device are different.

[0050] (Example of a Manufacturing Method of an Anisotropically Conductive Member) Next, a manufacturing method of an anisotropically conductive member will be described. FIGS. 8 to 14 are schematic cross-sectional views showing the steps of an example of a manufacturing method of an anisotropically conductive member according to an embodiment of the present invention. In FIGS. 8 to 14, components identical to those of the anisotropically conductive member 10 shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted. In this example of a manufacturing method of an anisotropically conductive member, an anisotropically conductive member 10 shown in FIG. 1 will be described in which the insulating substrate 20 is formed of an anodized aluminum film. An aluminum substrate is used to form the anodized aluminum film. Therefore, in this example of a manufacturing method of an anisotropically conductive member, an aluminum substrate 40 is first prepared, as shown in FIG. 8. The size and thickness of the aluminum substrate 40 are appropriately determined depending on the thickness of the insulating substrate 20 (see FIG. 1) of the final anisotropically conductive member 10 (see FIG. 1), the processing equipment, and the like. The aluminum substrate 40 is, for example, a plate material having a circular outer shape. The aluminum substrate 40 is not limited to an aluminum substrate; any metal substrate capable of forming an electrically insulating insulating film can be used. Valve metals that can form an anodic oxide film by anodization can be used.

[0051] Next, one surface 40a (see FIG. 8) of the aluminum substrate 40 is anodized. As a result, the one surface 40a (see FIG. 8) of the aluminum substrate 40 is anodized, forming an anodized film 44 having a plurality of pores 21 extending in the thickness direction Dt of the aluminum substrate 40, as shown in FIG. 9. The anodized film 44 is the insulating base material 20 (see FIG. 1) described above. As shown in FIG. 9, a barrier layer 43 is present at the bottom of each pore 21. The above-described anodizing process is referred to as an anodizing process. The anodized film 44 having a plurality of pores 21 has a barrier layer 43 at the bottom of each pore 21, as described above. However, the barrier layer 43 is removed. This results in an anodized film 44 having a plurality of pores 21 without the barrier layer 43 (see FIG. 10). The process of removing the barrier layer 43 described above is referred to as a barrier layer removal process.

[0052] In the barrier layer removal step, an alkaline aqueous solution containing ions of a metal M1 having a higher hydrogen overvoltage than aluminum is used to remove the barrier layer 43 of the anodic oxide film 44, while simultaneously forming a metal layer 45a (see FIG. 10) made of a metal (metal M1) on the surface 42d (see FIG. 10) of the bottom 42c (see FIG. 10) of the pore 21. As a result, the aluminum substrate 40 exposed in the pore 21 is covered with the metal layer 45a. This facilitates the progress of plating when filling the pore 21 with metal, suppresses insufficient filling of the pore with metal, prevents the pore 21 from being left unfilled, and suppresses poor formation of the conductive path 22 (see FIG. 1). The alkaline aqueous solution containing ions of the metal M1 may further contain an aluminum ion-containing compound (sodium aluminate, aluminum hydroxide, aluminum oxide, etc.). The content of the aluminum ion-containing compound is preferably 0.1 to 20 g / L, more preferably 0.3 to 12 g / L, and even more preferably 0.5 to 6 g / L, converted into the amount of aluminum ions.

[0053] Next, plating is performed on the surface 44a of the anodic oxide film 44, which has multiple pores 21 extending in the thickness direction Dt. In this case, the metal layer 45a can be used as an electrode for electrolytic plating. The plating uses a metal 45b, and the plating begins at the metal layer 45a formed on the surface 42d (see FIG. 10) of the bottom 42c (see FIG. 10) of the pore 21. As a result, as shown in FIG. 11 , the pores 21 of the anodic oxide film 44 are filled with the metal 45b as a conductive material that forms the conductive paths 22. Filling the pores 21 with the metal 45b forms the conductive paths 22. The metal layer 45a and the metal 45b together are referred to as the filled metal 45. The process of filling the multiple pores 21 of the anodic oxide film 44 with the metal 45b to form the multiple conductive paths 22 is referred to as the metal filling process. As described above, the conductive paths 22 are made of a conductive material and are not limited to being filled with a metal. The metal filling step uses electrolytic plating and will be described in detail later. Note that the surface 44a of the anodic oxide film 44 corresponds to one surface of the insulating base material 20. The step of filling the pores 21 of the anodic oxide film 44 with a conductive material, including metals and non-metals, to form the conductive paths 22 is simply referred to as the filling step.

[0054] After the metal filling step, a polishing step is performed to polish and smooth the surface 44a of the anodic oxide film 44 shown in FIG. 11 . For example, CMP (Chemical Mechanical Polishing) is used for polishing. Next, after the polishing step, as shown in FIG. 12 , the surface 44a of the anodic oxide film 44 on the side where the aluminum substrate 40 is not provided is partially removed in the thickness direction Dt, causing the metal 45 filled in the metal filling step to protrude beyond the surface 44a of the anodic oxide film 44. That is, the conductive paths 22 protrude beyond the surface 44a of the anodic oxide film 44. This results in the protrusions 22a. The step of causing the conductive paths 22 to protrude beyond the surface 44a of the anodic oxide film 44 is referred to as a surface protrusion step. In the surface protrusion step, the surface 44a of the anodic oxide film 44 is dissolved using, for example, a solution that dissolves the anodic oxide film 44 without dissolving the metal that constitutes the conductive paths 22. In this step, a spray etching method is used in which the dissolving solution is formed into droplets and sprayed onto the surface 44a of the anodic oxide film 44. As a result, the surface 20a of the insulating substrate 20 shown in FIG. 3 is obtained.

[0055] After the surface protruding step, the aluminum substrate 40 is removed as shown in Fig. 13. The step of removing the aluminum substrate 40 is called a substrate removing step. In the case of a configuration with only one protruding portion, the state shown in Fig. 13 can be used as the anisotropically conductive member 10. In this case, in the state shown in Fig. 13, a resin layer 24 (see Fig. 1) is formed to cover the entire surface 44a of the anodic oxide film 44 from which the protruding portion 22a protrudes, thereby forming the anisotropically conductive member 10.

[0056] Next, as shown in FIG. 13 , after the substrate removal step, a polishing step is performed to polish and smooth the surface of the anodic oxide film 44 on the side where the aluminum substrate 40 was provided, i.e., the back surface 44b of the anodic oxide film 44. For example, CMP processing is used for polishing. Next, after the polishing step of the back surface 44b of the anodic oxide film 44, as shown in FIG. 14 , the back surface 44b of the anodic oxide film 44 is partially removed in the thickness direction Dt, causing the metal 45 filled in the metal filling step, i.e., the conductive path 22, to protrude beyond the back surface 44b of the anodic oxide film 44. This results in the protrusion 22b. The step of causing the conductive path 22 to protrude beyond the back surface 44b of the anodic oxide film 44 is called a back surface protrusion step. Note that the back surface protrusion step is not necessarily performed. If the back surface protrusion step is not performed, the above-mentioned protrusion 22b will not be formed. In the back surface protruding step, similarly to the front surface protruding step, the back surface 44b of the anodic oxide film 44 is dissolved using, for example, a solution that dissolves the anodic oxide film 44 without dissolving the metal that constitutes the conductive paths 22. At this time, a spray etching method is used in which the dissolving solution is formed into droplets and sprayed onto the back surface 44b of the anodic oxide film 44. This results in a back surface 20b that is similar to the front surface 20a of the insulating substrate 20 shown in FIG.

[0057] The above-described front surface protruding step and back surface protruding step may be both steps, or one of the front surface protruding step and back surface protruding step may be included. The front surface protruding step and back surface protruding step are both included in the "protruding step." The protruding step is also called a trimming step. When the protruding step is performed, the thickness of the anodized film 44 after the protruding step is the thickness of the insulating base material.

[0058] Next, as shown in Fig. 14, a resin layer 24 (see Fig. 1) is formed to cover the entire surface 44a of the anodic oxide film 44 from which the protruding portions 22a protrude. Also, a resin layer 24 (see Fig. 1) is formed to cover the entire back surface 44b of the anodic oxide film 44 from which the protruding portions 22b protrude. In this way, the anisotropically conductive member 10 shown in Fig. 1 is manufactured.

[0059] [Anodizing Treatment Step] Conventional methods can be used for the anodizing treatment, but from the viewpoint of increasing the regularity of the micropore arrangement and ensuring the anisotropic conductivity of the structure, it is preferable to use a self-ordering method or constant voltage treatment. This results in, for example, a hexagonal arrangement of the pores and conductors. Here, the self-ordering method and constant voltage treatment of the anodizing treatment can be the same as the respective treatments described in paragraphs

[0056] to

[0108] and [Figure 8] of JP 2008-270158 A.

[0060] [Holding Step] When manufacturing an anisotropically conductive member, a holding step may be included. The holding step is a step of holding the anisotropically conductive member for a total of 5 minutes or more at a voltage of 95% to 105% of a holding voltage selected from the range of 1 V or more and less than 30% of the voltage used in the anodizing step, after the anodizing step. In other words, the holding step is a step of performing electrolysis for a total of 5 minutes or more at a voltage of 95% to 105% of a holding voltage selected from the range of 1 V or more and less than 30% of the voltage used in the anodizing step, after the anodizing step. Here, the "voltage used in anodizing" refers to the voltage applied between the aluminum substrate and the counter electrode. For example, if the electrolysis time for anodizing is 30 minutes, the holding step refers to the average voltage maintained over 30 minutes.

[0061] From the viewpoint of controlling the thickness of the sidewall of the anodic oxide film, i.e., the thickness of the barrier layer to an appropriate thickness relative to the depth of the pores, the voltage in the holding step is preferably 5% to 25% of the voltage in the anodizing treatment, and more preferably 5% to 20%.

[0062] In addition, for the reason that in-plane uniformity is further improved, the total holding time in the holding step is preferably 5 minutes or more and 20 minutes or less, more preferably 5 minutes or more and 15 minutes or less, and even more preferably 5 minutes or more and 10 minutes or less. Furthermore, the holding time in the holding step may be 5 minutes or more in total, but is preferably 5 minutes or more continuously.

[0063] Furthermore, the voltage in the holding step may be set by decreasing continuously or stepwise from the voltage in the anodizing treatment step to the voltage in the holding step, but it is preferable to set the voltage to a voltage of 95% to 105% of the above-mentioned holding voltage within 1 second after the end of the anodizing treatment step, in order to further improve the in-plane uniformity.

[0064] The above-mentioned holding step can also be carried out consecutively with the above-mentioned anodizing treatment step, for example, by lowering the electrolytic potential at the end of the above-mentioned anodizing treatment step. The above-mentioned holding step can employ the same electrolytic solution and treatment conditions as those of the above-mentioned conventionally known anodizing treatment, except for the electrolytic potential. In particular, when the holding step and the anodizing treatment step are carried out consecutively, it is preferable to use the same electrolytic solution.

[0065] As described above, an anodic oxide film having a plurality of micropores has a barrier layer (not shown) at the bottom of the micropores, and a barrier layer removal step is included to remove this barrier layer.

[0066] [Barrier Layer Removal Step] The barrier layer removal step is a step of removing the barrier layer of the anodized film using, for example, an alkaline aqueous solution containing ions of a metal M1 having a higher hydrogen overvoltage than aluminum. The above-described barrier layer removal step removes the barrier layer, and a conductive layer made of the metal M1 is formed at the bottom of the pores. Here, hydrogen overvoltage refers to the voltage required to generate hydrogen; for example, the hydrogen overvoltage of aluminum (Al) is −1.66 V (Journal of the Chemical Society of Japan, 1982, (8), pp. 1305-1313). Examples of metals M1 with a higher hydrogen overvoltage than aluminum and their hydrogen overvoltage values ​​are listed below. <Metal M1 and hydrogen (1N H2SO4) overvoltage> Platinum (Pt): 0.00 V Gold (Au): 0.02 V Silver (Ag): 0.08 V Nickel (Ni): 0.21 V Copper (Cu): 0.23 V Tin (Sn): 0.53 V Zinc (Zn): 0.70 V

[0067] In the above-described barrier layer removal process, removing the barrier layer using an alkaline aqueous solution containing ions of metal M1, which has a higher hydrogen overvoltage than aluminum, not only removes the barrier layer 43 but also forms a metal layer 45a of metal M1, which is less likely to generate hydrogen gas than aluminum, on the exposed bottom of the pore 21. As a result, the in-plane uniformity of the metal filling is improved. This is thought to be due to the suppression of hydrogen gas generation by the plating solution, facilitating the progress of metal filling by electrolytic plating. Furthermore, it has been found that the barrier layer removal process includes a holding step in which a voltage (holding voltage) selected from a range of less than 30% of the voltage used in the anodizing process is held at 95% to 105% inclusive for a total of 5 minutes or more, and this voltage is significantly improved by applying an alkaline aqueous solution containing ions of metal M1. For this reason, the holding step is preferable. Although the detailed mechanism is unknown, it is thought that in the barrier layer removal process, an alkaline aqueous solution containing ions of metal M1 is used, which forms a layer of metal M1 below the barrier layer, thereby preventing damage to the interface between the aluminum substrate and the anodized film and improving the uniformity of the dissolution of the barrier layer.

[0068] In the barrier layer removal step, metal layer 45a made of a metal (metal M1) is formed at the bottom of pore 21, but the present invention is not limited to this, and only barrier layer 43 is removed to expose aluminum substrate 40 at the bottom of pore 21. In the exposed state, aluminum substrate 40 may be used as an electrode for electrolytic plating.

[0069] The pores 21 can also be formed by enlarging the diameter of the micropores and removing the barrier layer. In this case, a pore-widening treatment is used to enlarge the diameter of the micropores. The pore-widening treatment involves immersing the anodized film in an acidic or alkaline aqueous solution to dissolve the anodized film and enlarge the pore diameter of the micropores. For the pore-widening treatment, an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, or hydrochloric acid, or a mixture thereof, or an aqueous solution of sodium hydroxide, potassium hydroxide, or lithium hydroxide can be used. Note that the pore-widening treatment can also remove the barrier layer at the bottom of the micropores. By using a sodium hydroxide aqueous solution in the pore-widening treatment, the micropores are enlarged and the barrier layer is removed.

[0070] [Filling Step] The filling step is a step of forming a plurality of conductive paths by filling a conductive material into the pores of an anodized film having a plurality of pores extending in the thickness direction, i.e., an insulating base material. The conductive paths are, for example, columnar conductors. When a metal is filled in the filling step, it is called a metal filling step. <Metal Used in the Filling Step> In the filling step, the metal filled as a conductive material inside the pores 21 of the above-mentioned anodized film 44 to form the conductive paths is a metal having an electrical resistivity of 10 3 Preferably, the material has a resistivity of Ω cm or less. Specific examples of the above-mentioned metals include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), zinc (Zn), and cobalt (Co). From the viewpoints of electrical conductivity and formation by plating, the conductive material is preferably copper (Cu), gold (Au), aluminum (Al), nickel (Ni), and cobalt (Co), more preferably copper (Cu) and gold (Au), and even more preferably copper (Cu).

[0071] <Plating Method> For an anodic oxide film 44 having a plurality of pores 21 extending in the thickness direction Dt, a plating method for filling the pores 21 with metal can be, for example, electrolytic plating or electroless plating. Here, conventional electrolytic plating methods used for coloring and the like have difficulty selectively depositing (growing) metal in the pores with a high aspect ratio. This is thought to be because the deposited metal is consumed within the pores, and plating does not grow even if electrolysis is performed for a certain period of time or longer. Therefore, when filling metal using electrolytic plating, a rest period must be provided between pulse electrolysis or constant-potential electrolysis. The rest period must be at least 10 seconds, preferably 30 to 60 seconds. It is also desirable to apply ultrasound to promote stirring of the electrolyte.

[0072] Furthermore, the electrolysis voltage is usually 20 V or less, preferably 10 V or less, but it is preferable to measure the deposition potential of the target metal in the electrolyte solution to be used in advance and perform constant-potential electrolysis at a potential within +1 V of that potential. When performing constant-potential electrolysis, it is desirable to use a device that can also be used with cyclic voltammetry, and potentiostat devices such as those manufactured by Solartron, BAS Corporation, Hokuto Denko Corporation, and IVIUM can be used.

[0073] (Plating Solution) A conventionally known plating solution can be used as the plating solution. Specifically, when depositing copper, an aqueous copper sulfate solution is generally used, and the copper sulfate concentration is preferably 1 to 300 g / L, and more preferably 100 to 200 g / L. Furthermore, the addition of hydrochloric acid to the electrolytic solution can promote deposition. In this case, the hydrochloric acid concentration is preferably 10 to 20 g / L. Furthermore, when depositing gold, it is desirable to use a sulfuric acid solution of tetrachloroauric acid and perform plating by AC electrolysis.

[0074] The plating solution preferably contains a surfactant. Known surfactants can be used. Sodium lauryl sulfate, which is a surfactant conventionally added to plating solutions, can also be used as is. While surfactants with ionic (cationic, anionic, or zwitterionic) or nonionic (nonionic) hydrophilic moieties can both be used, cationic surfactants are preferred in order to avoid the generation of bubbles on the surface of the object to be plated. The concentration of surfactant in the plating solution composition is preferably 1% by mass or less. Since electroless plating requires a long time to completely fill metal into pores with high aspect ratios, it is preferable to fill the pores with metal using electroplating.

[0075] [Substrate Removal Step] The substrate removal step is a step of removing the aluminum substrate described above after the filling step. The method for removing the aluminum substrate is not particularly limited, and a suitable example is a method of removing it by dissolution.

[0076] <Dissolution of Aluminum Substrate> The dissolution of the aluminum substrate described above is preferably carried out using a treatment liquid that is less likely to dissolve an anodized oxide film but is more likely to dissolve aluminum. The dissolution rate of such a treatment liquid for aluminum is preferably 1 μm / min or more, more preferably 3 μm / min or more, and even more preferably 5 μm / min or more. Similarly, the dissolution rate for anodized oxide film is preferably 0.1 nm / min or less, more preferably 0.05 nm / min or less, and even more preferably 0.01 nm / min or less. Specifically, the treatment liquid preferably contains at least one metal compound having a lower ionization tendency than aluminum and has a pH of 4 or less or 8 or more, more preferably 3 or less or 9 or more, and even more preferably 2 or less or 10 or more.

[0077] The treatment solution for dissolving aluminum is preferably based on an acid or alkaline aqueous solution and blended with, for example, compounds of manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, copper, mercury, silver, palladium, platinum, or gold (e.g., chloroplatinic acid), their fluorides, or their chlorides. Among these, an acid aqueous solution base is preferred, and blending of chlorides is preferable. In particular, a treatment solution blended with mercury chloride in a hydrochloric acid aqueous solution (hydrochloric acid / mercury chloride) or a treatment solution blended with copper chloride in a hydrochloric acid aqueous solution (hydrochloric acid / copper chloride) is preferred from the viewpoint of treatment latitude. The composition of the treatment solution for dissolving aluminum is not particularly limited, and examples that can be used include a bromine / methanol mixture, a bromine / ethanol mixture, and aqua regia.

[0078] The acid or alkali concentration of the treatment solution for dissolving aluminum is preferably 0.01 to 10 mol / L, more preferably 0.05 to 5 mol / L. Furthermore, the treatment temperature using the treatment solution for dissolving aluminum is preferably −10° C. to 80° C., more preferably 0° C. to 60° C.

[0079] The aluminum substrate is dissolved by contacting the aluminum substrate after the plating step with the treatment solution. The contacting method is not particularly limited, and examples thereof include immersion and spraying. Of these, the immersion method is preferred. The contact time is preferably 10 seconds to 5 hours, more preferably 1 minute to 3 hours.

[0080] When forming the anisotropically conductive member, for example, a support substrate may be provided on the anodic oxide film 44. The support substrate preferably has the same outer shape as the anodic oxide film 44. By attaching the support substrate, the anodic oxide film 44 becomes easier to handle when forming the anisotropically conductive member.

[0081] [Protruding Step] The protruding step is a step of making the conductive paths protrude from at least one of the one surface and the other surface of the insulating base material after the polishing step. Specific examples include removing a portion of the anodic oxide film 44. The removal of the portion of the anodic oxide film 44 may be performed, for example, by dissolving the anodic oxide film 44, i.e., aluminum oxide (Al), without dissolving the metal that constitutes the conductive paths 22. ２ O ３ An acidic aqueous solution or an alkaline aqueous solution that dissolves the metal ions is used. The acidic aqueous solution or alkaline aqueous solution is formed into droplets and brought into contact with the anodized film 44 having the pores 21 filled with metal, thereby partially removing the anodized film 44. As a method for bringing the acidic aqueous solution or alkaline aqueous solution into droplets and bringing it into contact with the anodized film 44, a spray etching method is used in which the dissolving solution is formed into droplets and sprayed onto the insulating base material, i.e., the anodized film 44, as described above.

[0082] When an acid aqueous solution is used, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, or hydrochloric acid, or a mixture thereof. Among these, an aqueous solution free of chromic acid is preferable due to its excellent safety. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 60°C. Furthermore, when an alkaline aqueous solution is used, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35°C. Specifically, for example, a 50 g / L phosphoric acid aqueous solution at 40°C, a 0.5 g / L sodium hydroxide aqueous solution at 30°C, or a 0.5 g / L potassium hydroxide aqueous solution at 30°C are preferably used.

[0083] The immersion time in the acid or alkali aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and even more preferably 15 to 60 minutes. Here, when short-term immersion treatments are repeated, the immersion time refers to the total immersion time. Note that a washing treatment may be performed between each immersion treatment.

[0084] Furthermore, the metal 45, i.e., the conductive path 22, is caused to protrude from the front surface 44a or the back surface 44b of the anodized film 44, but as described above, it is preferable that the conductive path 22 protrude by 10 nm to 1000 nm from the front surface 44a or the back surface 44b of the anodized film 44. That is, the length h of the protrusion 22a in the thickness direction Dt is preferably 10 nm to 1000 nm, more preferably 50 nm to 500 nm, in order to improve the bondability with the bonded members.

[0085] To precisely control the length h of the protruding portion of the conductive path 22 in the thickness direction Dt, it is preferable to fill the inside of the pore 21 with a conductive material such as metal, then process the anodized film 44 and the end of the conductive material such as metal so that they are flush with each other, and then selectively remove the insulating base material such as the anodized film. Furthermore, after the above-described metal filling or protruding process, a heat treatment can be performed to reduce distortion in the conductive path 22 caused by the metal filling. The heat treatment is preferably performed in a reducing atmosphere to suppress metal oxidation. Specifically, the heat treatment is preferably performed at an oxygen concentration of 20 Pa or less, and more preferably in a vacuum. Here, a vacuum refers to a space state in which at least one of the gas density and the air pressure is lower than that of the atmosphere. The heat treatment is preferably performed while applying stress to the anodized film 44 for the purpose of straightening.

[0086] [Resin Layer Forming Process] The resin layer 18 can be formed by, for example, an inkjet method, a transfer method, a spray method, or a screen printing method. The inkjet method is preferred because it simplifies the resin layer 18 formation process by forming the resin layer 18 directly on the insulating substrate 20. The resin layer 18 can be formed using, for example, a conventionally known surface protection tape application device and laminator. In the resin layer forming process, the resin layer is formed on the entire surface of the insulating substrate. The resin material constituting the resin layer 18 is as described above.

[0087] In addition to the above-described methods, other methods for forming the resin layer 18 include, for example, applying a resin composition containing an antioxidant, a polymeric material, a solvent (e.g., methyl ethyl ketone), etc., to the entire surface of the insulating substrate, drying, and optionally baking. The method for applying the resin composition is not particularly limited, and conventionally known coating methods such as gravure coating, reverse coating, die coating, blade coating, roll coating, air knife coating, screen coating, bar coating, and curtain coating can be used. Furthermore, the drying method after application is not particularly limited, and examples include a heating treatment in the atmosphere at a temperature of 0°C to 100°C for several seconds to several tens of minutes, or a heating treatment under reduced pressure at a temperature of 0°C to 80°C for several minutes to several tens of minutes. The baking method after drying is not particularly limited as it differs depending on the polymer material used. When a polyimide resin is used, for example, a treatment of heating at a temperature of 160°C to 240°C for 2 minutes to 60 minutes can be mentioned, and when an epoxy resin is used, for example, a treatment of heating at a temperature of 30°C to 80°C for 2 minutes to 60 minutes can be mentioned.

[0088] The present invention is basically configured as described above. While the anisotropically conductive member and joined body of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the spirit and scope of the present invention.

[0089] 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, conjugated structures of Examples 1 to 12 and conjugated structures of Comparative Examples 1 and 2 were produced. The sizes of the conjugated structures of Examples 1 to 12 and Comparative Examples 1 and 2 are shown in Table 1 below. The bond strength and the state of the protrusions after bonding were evaluated for the conjugated structures of Examples 1 to 12 and Comparative Examples 1 and 2. The evaluation results of the bond strength and the state of the protrusions after bonding are shown in Table 2 below. Next, the bond strength and the state of the protrusions after bonding will be described.

[0090] (Evaluation of Bonding Strength) The bonding strength was evaluated by measuring the shear strength of the bonded assembly of the TEG chip, anisotropically conductive member, and interposer in each example and comparative example using a Stellar 4000 bond tester (manufactured by Nordson Advanced Technologies Co., Ltd.). The bonding strength was calculated as the bonding strength value (MPa) per area of ​​the TEG chip from the obtained breaking load. The bonding strength value was evaluated according to the following evaluation criteria. The evaluation results are shown in the bonding strength column in Table 2 below. Evaluation criteria A: 10 MPa≦bonding strength value B: 3 MPa≦bonding strength value<10 MPa C:bonding strength value<3 MPa

[0091] <Preparation of Bonded Structure for Evaluation> A TEG chip (Test Element Group chip) having Cu pads and an interposer were prepared. The insulating layer was SiN. The step between the insulating layer and the Cu pad surface was 1 μm. The TEG chip had a chip size of 8 mm square, and the ratio of electrode area (copper post) to chip area was 25%. The interposer had a chip size of 10 mm square because it included lead wiring around the periphery. The anisotropically conductive member used was 10 mm square. For bonding, the TEG chip, the anisotropically conductive member, and the interposer were stacked in this order, and temporarily bonded using a room-temperature bonding apparatus (WP-100 (model), manufactured by PMT Co., Ltd.) under temporary bonding process conditions of a heating temperature of 80°C, a time of 1 minute, and a pressure of 10 MPa. Next, the temporarily bonded samples were pressed at a pressure of 10 MPa using a room temperature bonding machine (model, manufactured by PMT Co., Ltd.), and then permanently bonded at a heating temperature of 140°C for 10 seconds. Next, the resin layer of the permanently bonded samples was cured under resin curing process conditions of a heating temperature of 250°C, 180 seconds, and a pressure of 10 MPa, to produce a bonded body for evaluation. The TEG chip, an anisotropic conductive member, and an interposer stacked in this order constituted the Type 1 stack configuration.

[0092] In addition, a TEG chip, an anisotropic conductive member, a TEG chip, an anisotropic conductive member, and an interposer were stacked in this order, and temporarily bonded using a room temperature bonding apparatus (WP-100 (model), manufactured by PMT Co., Ltd.) as described above under temporary bonding process conditions of a heating temperature of 80 ° C, a time of 1 minute, and a pressure of 10 MPa. Next, the temporarily bonded sample was pressurized using a room temperature bonding apparatus ((model), manufactured by PMT Co., Ltd.) under pressure conditions of 10 MPa, and then permanently bonded under conditions of a heating temperature of 140 ° C, a time of 10 seconds. Next, the resin layer of the permanently bonded sample was cured under resin curing process conditions of a heating temperature of 250 ° C, 180 seconds, and a pressure of 10 MPa, to produce a bonded body for evaluation. A TEG chip, an anisotropic conductive member, a TEG chip, an anisotropic conductive member, and an interposer stacked in this order is called a Type 2 stack configuration.

[0093] (State of protrusions after bonding) The state of the protrusions after bonding will be described. For the bonded structures of the TEG chip, anisotropically conductive member, and interposer of each example and comparative example, the anodic oxide film was cut in the thickness direction using a focused ion beam (FIB). Next, a field emission scanning electron microscope (S-4800 (model number) manufactured by Hitachi High-Technologies Corporation) was used to acquire images at a magnification of 100,000 times. 100 protrusions were identified in the acquired images. For the identified 100 protrusions, the presence or absence of contact with adjacent protrusions was determined. For the identified 100 protrusions, the state of the protrusions after bonding was evaluated according to the evaluation criteria shown below based on the presence or absence of contact with adjacent protrusions. The evaluation results are shown in the column for the state of the protrusions after bonding in Table 1 below. The state of the protrusions after bonding is an index for evaluating the degree of buckling of the protrusions. Evaluation criteria A: Of 100 protrusions, the number of protrusions that contact adjacent protrusions is 0 B: Of 100 protrusions, the number of protrusions that contact adjacent protrusions is 1 to 10 C: Of 100 protrusions, the number of protrusions that contact adjacent protrusions is 11 or more Regarding contact with adjacent protrusions, if there is even partial contact with the adjacent protrusion, it is determined that there is contact.

[0094] Examples 1 to 12 and Comparative Examples 1 and 2 are described below. Example 1 The bonded body of Example 1 is described. In Example 1, an anodized aluminum film was used as the insulating substrate. [Structure] <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 unavoidable impurities, was prepared. The molten aluminum alloy was subjected to molten metal treatment and filtration, and an ingot measuring 500 mm thick and 1200 mm wide was produced by DC (Direct Chill) casting. Next, the surface was ground to an average thickness of 10 mm using a facing mill, and the substrate was soaked at 550°C for approximately 5 hours. When the temperature dropped 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 finished to a thickness of 1.0 mm by cold rolling to obtain an aluminum substrate of JIS 1050. The aluminum substrate was formed into a wafer having a diameter of 200 mm (8 inches), and then subjected to the following treatments.

[0095] <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 electrolytic solution was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0096] (Electrolytic polishing solution composition) 85 mass % phosphoric acid (reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 660 mL, purified water 160 mL, sulfuric acid 150 mL, ethylene glycol 30 mL

[0097] <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 an electrolytic solution of 0.50 mol / L oxalic acid under the conditions of a voltage of 40 V, a liquid temperature of 16 ° C, and a liquid 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 of 0.2 mol / L chromic anhydride and 0.6 mol / L phosphoric acid (liquid temperature: 50 ° C) for 12 hours. Thereafter, a re-anodizing treatment was performed for 10 hours in an electrolytic solution of 0.50 mol / L oxalic acid under the conditions of a voltage of 40 V, a liquid temperature of 16 ° C, and a liquid flow rate of 3.0 m / min, to obtain an anodized film with a film thickness of 80 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).

[0098] <Barrier Layer Removal Step> Next, using the same treatment solution and treatment conditions as those used in the above-mentioned anodizing treatment, an electrolytic treatment (electrolytic removal treatment) was performed while continuously decreasing the voltage from 40 V to 0 V at a voltage decrease rate of 0.2 V / sec. Thereafter, an etching treatment (etching removal treatment) was performed by immersing the sample in 5 mass % phosphoric acid at 30°C for 30 minutes, thereby removing the barrier layer at the bottom of the micropores of the anodized film and exposing the aluminum through the micropores.

[0099] The average opening diameter of the micropores present in the anodized film after the barrier layer removal process was 60 nm. The average opening diameter was determined by obtaining a surface image at 50,000x magnification using a field emission scanning electron microscope (FE-SEM), selecting 50 micropores from the surface image, and measuring the diameter of the openings for each of the 50 selected micropores. The average diameter of the measured micropores was calculated. This average value was used as the average opening diameter. The average thickness of the anodized film after the barrier layer removal process was 80 μm. The average thickness was determined by cutting the anodized film in the thickness direction using a focused ion beam (FIB), and then obtaining a cross-sectional image of the cross-section at 50,000x magnification using a field emission scanning electron microscope (FE-SEM). The length of 10 locations corresponding to the thickness of the anodized film in the cross-sectional image was measured, and the average length of the 10 measured locations was calculated. This average value was used as the average thickness of the anodized film after the barrier layer removal process. The density of micropores in the anodic oxide film is approximately 100 million / mm 2 The micropore density was measured and calculated by the method described in paragraphs

[0168] and

[0169] of JP 2008-270158 A. The degree of ordering of the micropores present in the anodic oxide film was 92%. The degree of ordering was measured and calculated by obtaining a surface image at a magnification of 20,000 times using a field emission scanning electron microscope (FE-SEM) and using the method described in paragraphs

[0024] to

[0027] of JP 2008-270158 A.

[0100] <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 copper was filled into the pores (micropores) to form conductive paths. 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

[0101] <Polishing Step> Next, the surface of the metal-filled microstructure in which the conductive paths had been formed by filling with metal was subjected to CMP treatment, and the surface was smoothed by polishing 5 μm from the surface. PNANERLITE-7000 manufactured by Fujimi Incorporated was used as the CMP slurry. The surface of the anodized film after filling the pores (micropores) with metal was observed with a field emission scanning electron microscope (FE-SEM). The presence or absence of metal sealing in 1000 micropores was observed, and the sealing rate (number of sealed micropores / 1000) was calculated to be 96%. In addition, after the pores (micropores) were filled with metal, the anodic oxide film was cut in the thickness direction using an FIB, and a cross-sectional image was taken of the cross-section at a magnification of 50,000 times using a field emission scanning electron microscope (FE-SEM).When the inside of the pores (micropores) was confirmed, it was found that the inside of the sealed pores (micropores) was completely filled with metal.

[0102] <Trimming Process> A spray etching method was used on the metal-filled microstructure after the polishing process, spraying droplets of sodium hydroxide aqueous solution (concentration: 5% by mass, liquid temperature: 20°C) onto the surface of the anodized film. The amount of sodium oxide aqueous solution sprayed was adjusted so that the arithmetic mean distance δ in the thickness direction (see Figure 3) was 100 nm, selectively dissolving the surface of the aluminum anodized film. The sample was then washed with water and dried, resulting in protruding copper columns serving as conductive paths. As a result, the length h of the protrusions (see Figure 1) was 1000 nm. An ADE-3000S (product name) manufactured by Actes Kyosan Co., Ltd. was used for the spray etching method. The arithmetic mean distance δ in the thickness direction on the surface side of the anodized film (see Figure 3) was measured using the photographed image as described above.

[0103] <Substrate Removal Step> Next, the aluminum substrate was dissolved and removed by immersion in a 20% by mass aqueous solution of mercury chloride (mercury chloride) at 20° C. for 3 hours, thereby producing a structure.

[0104] <Polishing Step> Next, the rear surface of the anodized film formed after the aluminum substrate of the structure was removed was subjected to CMP treatment to smooth the metal-filled microstructure. PNANERLITE-7000 manufactured by Fujimi Inc. was used as the CMP slurry.

[0105] <Trimming Process> After the polishing process, droplets of a sodium hydroxide aqueous solution (concentration: 5% by mass, liquid temperature: 20°C) were sprayed onto the rear surface of the anodized oxide film of the structure using a spray etching method. The amount of sodium hydroxide aqueous solution sprayed was adjusted so that the arithmetic mean distance δ (see Figure 3) in the thickness direction was 100 nm, selectively dissolving the surface of the aluminum anodized oxide film. The structure was then washed with water and dried, resulting in protruding copper columns serving as conductive paths. As a result, the length h (see Figure 1) of the protrusions was 1000 nm. An ADE-3000S (product name) manufactured by Actes Kyosan Co., Ltd. was used for the spray etching method. The arithmetic mean distance δ in the thickness direction on the rear surface of the anodized oxide film was measured using the photographed images as described above.

[0106] <Resin Layer Formation Process> Resin layers were formed on the front and back surfaces of the anodized film of the structure after the trimming process using the method described below to produce an anisotropic conductive bonding member. The resin layer was formed using a resin composition containing a non-conductive epoxy thermosetting resin (BST001A, curing temperature 150°C, manufactured by Namics Corporation) and diethylene glycol diethyl ether as a dilution solvent, and the rotation speed of a spin coater was adjusted to achieve a thickness of 1.5 μm. Next, the produced anisotropic conductive bonding member was cut into a 10 mm square. A DAD3230 (product name) manufactured by Disco Corporation was used to cut the anisotropic conductive member.

[0107] The arithmetic mean distance δ was determined as follows. The fabricated anisotropically conductive member was machined using a focused ion beam (FIB) to expose a cross section in the thickness direction of the anodic oxide film, which is the insulating substrate. Next, a field emission scanning electron microscope (FE-SEM) was used to capture an image of the cross section in the thickness direction of the anodic oxide film at a magnification of 150k. In the captured image, a reference point Pb (see FIG. 3) was set at an arbitrary position on the back surface 20b of the insulating substrate 20, opposite the front surface 20a. A reference line Ls (see FIG. 3) was set parallel to the direction x passing through the reference point Pb. Next, from the points corresponding to the apexes Pc (see FIG. 3), 10 apexes Pc were selected in descending order of their distance from the reference line Ls. Furthermore, from the points corresponding to the contact portions Vc (see FIG. 3), 10 contact portions Vc were selected in descending order of their distance from the reference line Ls. In the captured image, the distance from the reference line Ls to each of the points corresponding to the selected 10 apexes Pc was calculated. The average of the 10 distances between the points corresponding to the selected 10 apexes Pc and the reference line Ls was calculated using the least squares method. The average value calculated using the least squares method is shown as a point on the captured image. A line Lc (see Figure 3) parallel to the direction x passing through the point indicating the average value of the apexes Pc was calculated. In the captured image, the distance from the reference line Ls to each of the points corresponding to the selected 10 contact areas Vc was calculated. The average of the 10 distances between the points corresponding to the selected 10 contact areas Vc and the reference line Ls was calculated using the least squares method. The average value calculated using the least squares method is shown as a point on the captured image. A line Lb (see Figure 3) parallel to the direction x passing through the point indicating the average value of the contact areas Vc was calculated. Next, the distance between the parallel line Lc and the parallel line Lb in the thickness direction Dt was calculated to obtain the arithmetic mean distance δ.

[0108] Example 2 Example 2 differs from Example 1 in that the spray amount of the sodium oxide aqueous solution was adjusted to selectively dissolve the front and back surfaces of the aluminum anodized oxide film so that the arithmetic mean distance δ (see FIG. 3 ) in the thickness direction on both the front and back surfaces of the anodized oxide film was 20 nm. Other than that, Example 1 was the same. Example 3 Example 3 differs from Example 1 in that the spray amount of the sodium oxide aqueous solution was adjusted to selectively dissolve the front and back surfaces of the aluminum anodized oxide film so that the arithmetic mean distance δ (see FIG. 3 ) in the thickness direction on both the front and back surfaces of the anodized oxide film was 60 nm. Other than that, Example 1 was the same. Example 4 Example 4 differs from Example 1 in that the spray amount of the sodium oxide aqueous solution was adjusted to selectively dissolve the front and back surfaces of the aluminum anodized oxide film so that the arithmetic mean distance δ (see FIG. 3 ) in the thickness direction on both the front and back surfaces of the anodized oxide film was 5 nm. Other than that, Example 1 was the same. (Example 5) Example 5 differs from Example 3 in that the resin is on the CNP surface, but is otherwise the same as Example 2. Note that "resin on the CNP surface" refers to a state in which epoxy resin is applied to the protruding portion of the anisotropic conductive member. (Example 6) Example 6 differs from Example 3 in that the resin is on the electrode surface, but is otherwise the same as Example 2. Note that "resin on the electrode surface" refers to a state in which epoxy resin is applied to the Cu pad surface of the TEG chip.

[0109] Example 7 Example 7 differs from Example 2 in that the conductive paths are made of Ni, but otherwise is the same as Example 2. The conductive paths were formed by electrolytic plating using a mixed solution of nickel sulfate / nickel chloride / boric acid = 300 / 60 / 40 (g / L) as the electrolyte, a nickel electrode as the cathode, and a platinum electrode as the positive electrode. In the electrolytic plating, the electrolyte was kept at a temperature of 50°C and constant current electrolysis (5 A / dm ２) was performed. (Example 8) Example 8 differs from Example 2 in that the length h (see FIG. 1) of the protrusions described above was set to 10,000 nm, and was otherwise the same as Example 2. (Example 9) Example 9 differs from Example 2 in that the length h (see FIG. 1) of the protrusions described above was set to 3 nm, and was otherwise the same as Example 2. (Example 10) Example 10 differs from Example 3 in that the size of the TEG chip was set to 4 mm square, and was otherwise the same as Example 3. (Example 11) Example 11 differs from Example 3 in that the size of the anisotropically conductive member was set to 8 mm square, and was otherwise the same as Example 3. (Example 12) Example 12 differs from Example 3 in that it uses a Type 2 stacking configuration in which a TEG chip, an anisotropic conductive material, a TEG chip, an anisotropic conductive material, and an interposer are stacked in this order, and the size of the anisotropic conductive material is 8 mm square; otherwise, it is the same as Example 3.

[0110] (Comparative Example 1) Comparative Example 1 differs from Example 1 in that all of the trimming processes described above were performed using a dipping method rather than a spray etching method. Furthermore, Comparative Example 1 differs in that the temporarily bonded samples were pressurized at a pressure of 10 MPa using a room-temperature bonding machine ((model), manufactured by PMT Co., Ltd.), and then permanently bonded at a heating temperature of 120°C for 10 seconds. Other than these, Comparative Example 1 was the same as Example 1. In Comparative Example 1, the arithmetic mean distance δ in the thickness direction (see FIG. 3) described above was 1 nm.

[0111] Comparative Example 2 differs from Example 1 in that the amount of sodium oxide solution sprayed was adjusted to selectively dissolve the front and back surfaces of the anodized aluminum film so that the arithmetic mean distance δ (see FIG. 3 ) in the thickness direction on both the front and back surfaces of the anodized aluminum film was 250 nm.

[0112]

[0113]

[0114] As shown in Table 2, Examples 1 to 12 had better bonding strength and post-bonding protrusion state than Comparative Examples 1 and 2. Comparative Example 1 had a short arithmetic mean distance δ, low bonding strength, and many protrusions in contact with adjacent protrusions. Comparative Example 2 had a long arithmetic mean distance δ, and many protrusions in contact with adjacent protrusions. Among Examples 1 to 12, Examples 2, 3, 5, 6, 10, and 11 had better bonding strength and post-bonding protrusion state. Among Examples 1 to 4, when the arithmetic mean distance δ was 20 to 100 nm, the bonding strength and post-bonding protrusion state were better, and when it was 20 to 60 nm, the bonding strength and post-bonding protrusion state were even better. Among Examples 2 and 7, Cu conductive paths were better than Ni conductive paths in bonding strength and post-bonding protrusion state. Among Examples 2, 8, and 9, Example 2, with a protrusion length of 300 nm, had better bonding strength and post-bonding protrusion state.

[0115] REFERENCE SIGNS LIST 10 Anisotropically conductive member 12, 13 Bonded body 18 Resin layer 20 Insulating substrate 20a, 24a, 40a, 32a, 34a, 37a, 44a Surface 20b, 44b Back surface 20d Recess 21 Pore 22 Conductive path 22a, 22b Protrusion 22c Side surface 24 Resin layer 30, 31 Semiconductor element 32, 37 Element substrate 33 Resin layer 34, 35, 38 Electrode 36, 39 Insulating layer 40 Aluminum substrate 42c Bottom 42d Surface 43 Barrier layer 44 Anodic oxide film 45, 45b Metal 45a Metal layer Dt Thickness direction Ls Reference line Pb Reference point Pc Top Vc Contact portion d Average diameter hm Average thickness ht Thickness p Center-to-center distance x direction δ Arithmetic mean distance w Spacing

Claims

1. An anisotropically conductive member comprising: an insulating base material having electrical insulation properties; 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; in a cross section of the insulating base material in the thickness direction, the surface of the insulating base material from which the protrusions of the conductive paths protrude has a plurality of apexes, and each of the plurality of protrusions has a contact portion in contact with the insulating base material; and the arithmetic mean distance in the thickness direction between the plurality of contact portions and the plurality of apexes is 2 nm to 200 nm.

2. The anisotropically conductive member according to claim 1, wherein the conductive paths are made of Cu, Au or Al.

3. The anisotropically conductive member according to claim 1, wherein d / h is 0.1 to 20, where d is the diameter of the protrusion and h is the length of the protrusion in the thickness direction of the insulating substrate.

4. The anisotropically conductive member according to any one of claims 1 to 3, wherein the length of the protrusion in the thickness direction of the insulating substrate is 6 to 6000 nm.

5. A bonded body in which an anisotropically conductive member and a member to be bonded are bonded, wherein a resin is filled between the anisotropically conductive member and the member to be bonded, the 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, wherein in a cross section of the insulating base material in the thickness direction, the surface of the insulating base material from which the protrusions of the conductive paths protrude has a plurality of apexes, and each of the plurality of protrusions has a contact portion in contact with the insulating base material, and the arithmetic mean distance in the thickness direction between the plurality of contact portions and the plurality of apexes is 2 nm to 200 nm.

6. The joined body according to claim 5, wherein the members to be joined have a metal layer and a resin layer, and the metal layer is exposed from the resin layer.

7. The joined body according to claim 5, wherein the members to be joined have a plurality of the metal layers, and at least one of the plurality of metal layers has a different height.

8. The joined body according to claim 6, wherein the members to be joined have a joining surface on which a plurality of metal layers are provided, and the area of ​​the joining surface is larger than the area of ​​the surface from which the protruding portion of the anisotropically conductive member protrudes.

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