Anisotropically conductive member and joint

Abstract

To provide an anisotropically conductive member and a joint that suppress buckling of a conductive path.SOLUTION: An anisotropically conductive member includes an electrically insulating substrate and a plurality of conductive paths that penetrate the insulating substrate in the thickness direction, are electrically insulated from one another, and have protrusions that protrude from at least one surface of the insulating substrate. In a cross section of the insulating substrate in the thickness direction, the surface of the insulating substrate from which the protrusions of the conductive paths protrude has a plurality of peaks, and the plurality of peaks each have a contact portion in contact with the insulating substrate. The arithmetic mean distance in the thickness direction between the plurality of contact portions and the plurality of peaks is 2 nm to 200 nm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[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. [Background technology]

[0002] 2. Description of the Related Art There is an anisotropic conductive member having conductive paths formed by filling a plurality of through holes formed in an insulating substrate with a conductive material such as metal. Anisotropically conductive materials can be inserted between an electronic component such as a semiconductor element and a circuit board and electrically connected to the electronic component by simply applying pressure between the electronic component and the circuit board. Therefore, they are widely used as electrical connecting members for electronic components such as semiconductor elements, and as testing connectors for functional testing. In particular, downsizing of electronic components such as semiconductor elements is remarkable. 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 electrical connections of electronic components, and therefore anisotropically conductive materials have attracted attention as electronic connecting materials.

[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 that protrude from the surface of the insulating substrate, and the ends of the protruding portions are embedded in the resin layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-037509 Summary of the Invention [Problem to be solved by the invention]

[0005] When the anisotropic conductive bonding member of Patent Document 1 is used as an electronic connecting member, the conductive paths of the anisotropic conductive bonding member are bonded to the electrodes of the semiconductor element to be connected. During bonding, the protruding portions of the conductive paths that protrude from the surface of the insulating base material may buckle. If the protruding portion of the conductive path buckles during bonding, the bonding between the conductive path and the electrode of the semiconductor element may become insufficient, and sufficient bonding strength may not be obtained. For this reason, it is desirable to prevent the conductive path 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. [Means for solving the problem]

[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 the plurality of protrusions each have 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 made of Cu, Au or Al. Invention [3] is an anisotropically conductive member according to invention [1] or [2], in which 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. Invention [4] is the anisotropically conductive member according to any one of inventions [1] to [3], wherein the length of the protrusion in the thickness direction of the insulating substrate is 6 to 6000 nm.

[0008] Invention [5] is a bonded body in which an anisotropically conductive member and a member to be bonded are bonded, and a resin is filled between the anisotropically conductive member and the member to be bonded. The anisotropically conductive member has an electrically insulating base material and a plurality of conductive paths that penetrate the insulating base material in the 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. In a cross section in the thickness direction of the insulating base material, the surface of the insulating base material from which the protrusions of the conductive paths protrude has a plurality of apexes, and the plurality of protrusions each have contact portions 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 joined members have 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, and at least one of the plurality of metal layers has a different height. Invention [8] is a 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. [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing an example of an anisotropically conductive member according to an embodiment of the present invention. [Figure 2] 1 is a schematic plan view illustrating an example of an anisotropically conductive member according to an embodiment of the present invention. [Figure 3]1 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. [Figure 4] FIG. 1 is a schematic cross-sectional view showing a first example of a bonded body according to an embodiment of the present invention. [Figure 5] 1 is a schematic cross-sectional view showing an enlarged portion of a first example of a bonded body according to an embodiment of the present invention. [Figure 6] 1A to 1C are schematic cross-sectional views showing a first example of a method for producing a bonded body according to an embodiment of the present invention. [Figure 7] FIG. 3 is a schematic cross-sectional view showing an enlarged view of a part of a second example of a bonded body according to an embodiment of the present invention. [Figure 8] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 9] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 10] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 11] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 12] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 13] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. [Figure 14] 1 is a schematic cross-sectional view showing one step of an example of a method for producing an anisotropically conductive member according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The anisotropically conductive member and the bonded body of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. It should be noted that the drawings described below are merely illustrative of the present invention and are simplified or exaggerated for the purpose of explaining the present invention, and therefore the present invention is not limited to the drawings shown below. In the following, the range of values ​​indicated by "~" includes the values ​​written on both sides. For example, when ε is the 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 α is. Unless otherwise specified, the parallel and perpendicular directions include error ranges generally accepted in the relevant technical field. Unless otherwise specified, the temperature, time, and pressure include error ranges generally accepted in the relevant technical field. Furthermore, the term "same" includes a generally acceptable margin of error in the relevant technical field. Furthermore, terms such as "over the entire surface" include a generally acceptable margin of error in the relevant technical field. The anisotropically conductive member and the bonded body will be specifically described below.

[0012] [Example of anisotropic conductive material] 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. 1 and 3 show a cross section in the thickness direction Dt of the insulating base material 20. Also, Fig. 2 is a plan view of the insulating base material 20 in Fig. 1 as seen from the surface 20a side, showing a state in which the resin layer 24 is not present. 1 includes an electrically 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 that protrude from at least one surface. The anisotropically conductive member 10 also includes a resin layer 24 that covers 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 base material 20 in a state in which they are electrically insulated from one another. In this case, for example, the insulating base material 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 base material 20. The conductive paths 22 also protrude from the back surface 20b of the insulating base material 20. The conductive paths 22 may protrude from one surface of the insulating base material 20 in the thickness direction Dt. For example, a resin layer 24 is provided on the surface of the insulating base material 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 base material 20 is made of, for example, an anodic oxide film, which is formed by anodizing a valve metal, for example. The front surface 20a of the insulating base material 20 and the back surface 20b of the insulating base material 20 are surfaces that face each other in the thickness direction Dt of the insulating base material 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. The anisotropically conductive member 10 has, for example, a circular outer shape as shown in Fig. 2. 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 in a state where there is no resin layer 24, or in a state where there is a resin layer 24 but nothing is present on the surface 24a.

[0015] 3, the surface 20a of the insulating substrate 20 is not flat but has an uneven structure. There are a plurality of 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 insulating substrate 20 in the thickness direction Dt shown in Figure 3, the surface of insulating substrate 20 from which protrusion 22a protrudes, i.e., surface 20a in Figure 3, has multiple apexes Pc and multiple contact portions Vc.

[0016] The apex Pc is a high portion of the surface of the insulating base material 20 on the protruding portion 22a side in a cross section in the thickness direction Dt of the insulating base material 20. The apex Pc is, for example, a boundary portion between adjacent recesses 20d. The contact portions Vc are portions where the multiple protrusions 22a each contact the insulating substrate 20 in a cross section in the thickness direction Dt of the insulating substrate 20. The contact portions Vc are located at the ends of the protrusions 22a on the insulating substrate 20 side. More specifically, the contact portions Vc are located at the bottoms of the recesses 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 target and ensuring sufficient conductivity with the connection target. Furthermore, contact between adjacent protrusions is prevented, thereby suppressing the occurrence of short circuits. Furthermore, when a force acts on the protrusion 22a in a direction parallel to the thickness direction Dt, if the protrusion 22a deforms to increase in diameter in the direction x, the protrusion 22a is allowed to deform to increase in diameter 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. This prevents buckling of the protrusion 22a. 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, preventing 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 cannot be obtained. If the protrusion 22a buckles, it may come into contact with an adjacent protrusion, and sufficient conductivity with the connection object cannot be ensured. If the arithmetic mean distance δ exceeds 200 nm, the end portion 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. Therefore, 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 an adjacent protrusion, preventing sufficient electrical conductivity from being secured with the connection target.

[0019] The above-mentioned arithmetic mean distance δ can be calculated, 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 base material 20 in the thickness direction Dt. A photographic image of a cross section of the insulating base material 20 in the thickness direction Dt is obtained at a magnification of 150k using a field emission scanning electron microscope (FE-SEM). In the captured image, a reference point Pb is set at an arbitrary position on the back surface 20b opposite to the front surface 20a of the insulating substrate 20. A reference line Ls is set that passes through the reference point Pb and is parallel to the direction x. In the captured image, from among the points corresponding to the apexes Pc, 10 apexes Pc are selected in descending order of their height relative to the reference line Ls. Also, from among the points corresponding to the contact points Vc, 10 contact points Vc are selected in descending order of their height relative to 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 vertices Pc is calculated. The average of the 10 distances between the reference line Ls and the points corresponding to the 10 vertices Pc calculated 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 vertices Pc is calculated. The plane containing 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 protrusion 22a. In the captured image, the distance from the reference line Ls is calculated for each of the points corresponding to the 10 selected contact areas Vc. The average of the 10 distances between the reference line Ls and the points corresponding to the 10 contact areas Vc 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 is calculated that is parallel to the direction x and passes through the point that indicates the average value of the contact areas Vc. The plane containing this parallel line Lb is the average plane of the contact areas Vc. The arithmetic mean distance δ is the absolute value of the difference between the average value of the peaks Pc calculated using the least squares method and the average value of the contact points Vc calculated using the least squares method. In other words, the arithmetic mean distance δ is the distance between the parallel lines Lc and Lb in the thickness direction Dt. Therefore, the arithmetic mean distance δ is obtained by calculating the distance between the parallel lines Lc and Lb in the thickness direction Dt. Although not shown in detail, the rear surface 20b of the insulating substrate 20 also has the same configuration as the front surface 20a of the insulating substrate 20 shown in Fig. 3. The arithmetic mean distance δ for the rear surface 20b of the insulating substrate 20 is also determined in the same manner as for the front surface 20a of the insulating substrate 20 described above.

[0020] [First example of a zygote] 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. 4 and 5, the same components as those in the anisotropically conductive member 10 shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. 4 is obtained by bonding an 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 49 is filled between the anisotropically conductive member 10 and the bonded member. In the semiconductor element 30, for example, three electrodes 34 and an insulating layer 36 that prevents conduction between the three electrodes 34 are provided on the surface 32a of the element substrate 32. The three electrodes 34 are at the same height from the surface 32a of the element substrate 32. Furthermore, in the semiconductor element 31, for example, three electrodes 38 and an insulating layer 39 that prevents conduction between the three electrodes 38 are provided on the surface 37a of the element substrate 37. The three electrodes 38 are at the same height from the surface 37a of the element substrate 37. The electrodes 34 and 38 are joined to the conductive paths 22 of the anisotropically conductive member 10. For example, as shown in FIG. 5 , the electrodes are joined in a state in which the surface 34a of the electrode 34 and the protruding portion 22a of the conductive paths 22 are 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, causing the protruding portion 22a to deform, but as described above, buckling of the protruding portion 22a is suppressed. Therefore, the bonded body 12 can obtain sufficient bonding strength between the semiconductor elements 30 and 31. Furthermore, because buckling of the protruding portion 22a is suppressed, sufficient conductivity with the connection target can be ensured, and further, contact with adjacent protruding portions does not occur, 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 configuration as long as it can prevent conduction between electrodes, and can be configured with any known insulating layer used in semiconductor elements. The insulating layer 39 can be configured with, for example, a silicon oxide film (SiO2), a silicon nitride film (Si3N4), a PSG (Phospho Silicate Glass) film, a BPSG (Boron Phospho Silicate Glass) film, or 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. In addition, 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. In addition, after joining the conductive path 22 of the anisotropically conductive member 10 to the electrodes 34 and 38, a resin agent can be supplied between the conductive path 22 and the electrode 34 and between the conductive path 22 and the electrode 38 to form a resin layer 33.

[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. FIG. 6 is a schematic cross-sectional view showing a first example of a method for producing a bonded body according to an embodiment of the present invention. In FIG. 6, the same components as those of the bonded body 12 shown in FIGS. 4 and 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. 6, semiconductor elements 30 and 31 are arranged with anisotropically conductive member 10 sandwiched therebetween. At this time, alignment is performed using alignment marks (not shown) provided on semiconductor elements 30 and 31 and anisotropically conductive member 10, for example. Note that alignment using alignment marks is not particularly limited, and any known alignment method can be used as appropriate, as long as it is possible to obtain an image or a reflected image of the alignment mark and determine the position information of the alignment mark. As shown in FIG. 6, the anisotropically conductive member 10 is provided with a resin layer 24, which forms the resin layer 33 of the bonded body 12 shown in FIG.

[0024] Next, the semiconductor element 30 is bonded to the anisotropically conductive member 10, and the semiconductor element 31 is bonded to the anisotropically conductive member 10. In this way, the bonded body 12 shown in FIG. 4 can be manufactured. Note that the joining step is to join the semiconductor element 30 and the anisotropically conductive member 10, and the semiconductor element 31 and the anisotropically conductive member 10. In the joining step, for example, joining may be performed under predetermined conditions in a temporarily joined state, but the temporary joining may be omitted. Note that the joining in the joining step is also referred to as actual joining.

[0025] Temporary bonding refers to fixing the semiconductor elements 30 and 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 it is preferable that the temperature be higher than the temperature for the temporary bonding, specifically, 120°C to 350°C is more preferable, and 200°C to 300°C is particularly preferable. The pressure conditions for this 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 this bonding under the above conditions, protrusion 22a of conductive path 22 is bonded to surface 34a of electrode 34, and protrusion 22b of conductive path 22 is bonded to surface 38a of electrode 38. At this time, as described above, buckling of both protrusions 22a and 22b of conductive path 22 is suppressed, and for example, protrusions 22a, 22b are suppressed from collapsing and coming into contact with adjacent protrusions 22a, 22b. This ensures sufficient bonding strength to the connection objects, sufficient conductivity with the connection objects, and suppresses the occurrence of short circuits.

[0027] [Second example of a zygote] FIG. 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 FIG. 7, the same components as those in the bonded body 12 shown in FIGS. 4 and 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. The bonded body 13 shown in Fig. 7 differs from the bonded body 12 shown in Fig. 4 and Fig. 5 in that the semiconductor element 30 has electrodes 35 with different heights, but otherwise has the same configuration as the bonded body 12 shown in Fig. 4 and Fig. 5. The electrodes 35 are taller than the electrodes 34. In the bonded body 13, the electrode 34 and the tall 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 more 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 in this configuration in which the semiconductor element 30 has a relatively tall electrode 35, sufficient bonding strength can be obtained between the semiconductor element 30 and the semiconductor element 31. Furthermore, because buckling of the protruding portion 22a is suppressed, sufficient conductivity is ensured and the occurrence of short circuits is suppressed.

[0028] In the bonded bodies 12 and 13, the bonded members have bonding surfaces on which a plurality of metal layers are provided, and it is preferable that the area of ​​the bonding surface is larger than the area of ​​the surface from which the protruding portion of the anisotropically conductive member protrudes. Here, the above-mentioned semiconductor elements 30 and 31 have a plurality of 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 protruding portions 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 a plurality of conductive paths 22, each 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 becomes easy to handle.

[0031] The thickness of the insulating base material is determined by measuring the above-mentioned 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 There are no particular limitations as long as the material has a resistivity of about Ω·cm. Note that "made of inorganic material" is a definition to distinguish it from the polymeric material that makes up the resin layer described below, and is not a definition that is limited to insulating substrates made up of inorganic materials only, but rather a definition that has inorganic materials as the main component (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% by 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 through-holes formed therein that have micropores with a desired average opening diameter. The insulating substrate is preferably a metal oxide substrate, and more preferably an anodized film of a valve metal, because this facilitates the formation of conductive paths. Specific examples of valve metals include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among these, an anodized aluminum film (substrate) is preferred because it has good dimensional stability and is relatively inexpensive. For this reason, it is preferred to use an aluminum substrate to form an anodized aluminum film, which is an insulating substrate, and then manufacture an anisotropically conductive member. The thickness of the anodized film is the same as 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 high-purity aluminum is coated on the surface of a silicon wafer, quartz, glass, or the like by a method such as vapor deposition or sputtering; and a resin substrate laminated with aluminum.

[0036] The surface of the aluminum substrate on which the anodized film is formed by the anodizing treatment 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-holes are arranged with sufficient regularity. The 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] It is also preferable that the surface of the aluminum substrate on one side to be subjected to the anodizing treatment step is previously subjected to heat treatment, degreasing treatment and mirror finishing treatment. Here, the heat treatment, degreasing treatment, and mirror finish treatment can be the same as the treatments described in paragraphs

[0044] to

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

[0038] <Average pore diameter> The average diameter of 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 pores 21 is 1 μm or less and within the above range, conductive paths 22 having the above 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 photographed image. In the photographed image, at least 20 pores that are connected in a ring shape are extracted, 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 a photographed image from which 20 or more pores can be extracted. The opening diameter is measured as the maximum distance between the ends of the pore portion. That is, the shape of the opening of the pore is not limited to a substantially circular shape, so 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, for example, even in the case of a pore having 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] <Conduction Path> As described above, the plurality of conductive paths 22 are provided in the insulating substrate 20, for example, in the anodized film, in a state in which they are 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 plating, the conductive material is preferably copper (Cu), gold (Au), aluminum (Al), nickel (Ni), or cobalt (Co), more preferably copper (Cu), gold (Au), or aluminum (Al), and even more preferably copper (Cu). Metals have superior ductility and are more easily deformed than oxide conductors, and are also more easily deformed by compression during bonding, so it is preferable to form the conductive paths from 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. The density of the conductive paths 22 is 20,000 pieces / mm 2 It is preferable that the density is 2 million / mm or more. 2 More preferably, it is 10 million particles / mm 2More preferably, it is 50 million particles / mm or more. 2 It is particularly preferable that the number is 100 million / mm or more. 2 More preferably, it is equal to or greater than this. 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. Regarding 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 on the front surface 20a or the back surface 20b of the insulating substrate 20 of the conductive paths 22. This prevents short circuits in 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 that are connected in a circular shape are extracted from the photographed image, and their diameters are measured to determine the opening diameter. The average of these opening diameters is then calculated as the average diameter of the conductive paths. The magnification can be appropriately selected within the above range so as to obtain a captured image from which 20 or more conductive paths can be extracted. Furthermore, if the opening has a non-circular shape, the maximum distance between the ends of the conductive path portion is taken as the opening diameter. Therefore, for example, even if a conductive path has a shape in which two or more conductive paths are integrated, this is considered to be a single conductive path, and the maximum 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 conductive paths 22 on the front surface 20a of the insulating substrate 20 are not circular, the average diameter of the conductive paths 22 on the front surface 20a of the insulating substrate 20 is the average diameter of the circle-equivalent diameter. When the conductive paths 22 on the back surface 20b of the insulating substrate 20 are not circular, the average diameter of the conductive paths 22 on the back surface 20b of the insulating substrate 20 is the average diameter of the circle-equivalent diameter. The average diameter d of the conductive paths 22 on the front surface 20a side 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 the front image in this state can be measured, and the average opening diameter of the pores on the front side can be used instead of the average diameter on the front side. Similarly, the opening diameters of multiple pores in the back image in this state can be measured, and the average opening diameter of the pores on the back side can be used instead of the average diameter on the back side. The average opening diameter of the pores can be measured, for example, as follows. First, 20 pores are selected from the surface image, and the diameters of the pores at the openings are measured for the 20 pores. The average value of the diameters at the openings of the measured pores is calculated, and this average value is used as the average opening diameter of the pores on the surface side. In addition, 20 pores are selected from the backside image, and the diameters of the pore openings are measured for the 20 pores. The average value of the diameters of the pore openings is calculated, and this average value is used as the average opening diameter of the pores on the backside.

[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 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 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] <<Protrusion>> The protrusion is a part of the conductive path and is columnar, and is preferably cylindrical in shape because it can increase the contact area with the workpiece. The length h of the protrusion 22a in the thickness direction Dt of the insulating base material 20 and the length h of the protrusion 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. If the length h is 10 nm to 1000 nm, good bonding to the bonded member can be achieved. The length h of the protrusion 22a and the length h of the protrusion 22b are determined based on the average plane of the surface 20a of the insulating substrate 20 described above. If the length h of the above-mentioned protrusions 22a and 22b in the thickness direction Dt of the insulating base material 20 is 2 nm to 6000 nm, the bump height distribution tracking ability of the bumps on the bonded object side is good, and height accuracy of the bump surface on the bonded object 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 an image at a magnification of 100,000 times of a cross section in the thickness direction Dt of the insulating base material 20. In the captured image, the line Lc on the front surface side of the insulating base material and the line Lc on the back surface side of the insulating base material are determined as described above. Next, ten protrusions 22a are selected in the captured image. The points corresponding to the tops of the selected ten protrusions 22a are identified. The distance in the thickness direction Dt of the insulating substrate 20 between the point corresponding to the top of the identified protrusion 22a and the line Lc on the front surface side of the insulating substrate is calculated for each of the ten protrusions 22a. The average value of the above-mentioned distances for the points corresponding to the tops of the ten protrusions 22a is calculated. This average value is set to the length h of the protrusion 22a. Further, ten protrusions 22b are selected in the captured image. The points corresponding to the tops of the selected ten protrusions 22b are identified. The distance in the thickness direction Dt of the insulating substrate 20 between the identified point corresponding to the top of the protrusion 22b and the line Lc on the back surface side of the insulating substrate is calculated for each of the ten protrusions 22b. The average value of the above-mentioned distances for the points corresponding to the tops of the ten protrusions 22b is calculated. This average value is set to 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 base material is h, the aspect ratio d / h is preferably 0.1 to 20. When 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, protecting 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, protecting the protrusions. In order to exert the above-mentioned functions, the resin layer preferably exhibits fluidity in a temperature range of, for example, 50° C. to 200° C. and hardens at temperatures equal to or higher than 200° C. The resin layer is, for example, a thermoplastic layer made of a thermoplastic resin, and the resin layer 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. If the average thickness hm of the resin layer 24 is 10 μm or less, the resin layer 24 can sufficiently protect the protruding portions 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 front 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 is determined by cutting the resin layer in the thickness direction Dt of the anisotropically conductive member 10 and obtaining a photographic image of the cut cross section using a scanning electron microscope. In the photographic 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 locations corresponding to the surface of the resin layer are selected in the captured image. The distance between the selected location and the line Lc on the surface side of the insulating base material is calculated for each of the ten locations. The average value of the distances at 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 base material 20. Furthermore, for the resin layer on the back surface 20b of the insulating substrate 20, ten locations corresponding to the surface of the resin layer are similarly selected in the captured image. The distance between the selected location and the line Lc on the back surface of the insulating substrate is calculated for each of the ten locations. The average value of the distances at the ten locations is calculated. This average value is defined 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 also 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 a resin material constituting the resin layer. Examples of resin materials constituting the resin layer include epoxy resins, phenolic resins, polyimide resins, melamine resins, and isocyanate resins. 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, the resin layer may contain, for example, a main composition containing an acrylic polymer described in WO 2022 / 163260, an acrylic monomer, and a maleimide compound.

[0048] ((Anisotropically conductive material to be joined)) When an anisotropically conductive member is used as an electronic connecting member, the member to be connected is, for example, a member having a semiconductor element, an electrode, or an element region. Examples of members having electrodes include semiconductor elements that perform a specific function by themselves, but also include members that perform a specific function when multiple elements are combined. Furthermore, members that simply transmit electrical signals, such as wiring members, are also included, and printed wiring boards are also included in members having electrodes. The element region is a region in which various element component 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), and a region in which a communication module such as a wireless tag and wiring are formed. In addition to the above, the element region may also include MEMS (Micro Electro Mechanical Systems). Examples of MEMS include sensors, actuators, and antennas. Examples of sensors include various sensors for acceleration, sound, and light. The optical sensor is not particularly limited as long as it can detect light; 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 component 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. The electrodes in the element region are, for example, Cu posts. The electrode region basically refers to a region that includes all the formed electrodes. However, if the electrodes are provided discretely, the region in which each electrode is provided is also referred to as the electrode region. The structure may be in the form of an individual semiconductor chip, a semiconductor wafer, or a wiring layer. Furthermore, the structure is joined to a connection object, but the connection object is not particularly limited to the above-mentioned semiconductor elements, etc., and examples of the connection object include semiconductor elements in wafer state, semiconductor elements in chip state, printed wiring boards, and heat sinks, etc.

[0049] ((Semiconductor element)) In addition to the above, the semiconductor elements include, for example, logic LSIs (Large Scale Integration) (e.g., ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), ASSPs (Application Specific Standard Products), etc.), microprocessors (e.g., CPUs (Central Processing Units), GPUs (Graphics Processing Units), etc.), memories (e.g., DRAMs (Dynamic Random Access Memory), HMCs (Hybrid Memory Cubes), MRAMs (Magnetic RAMs), PCMs (Phase-Change Memory), ReRAMs (Resistive RAMs), FeRAMs (Ferroelectric RAMs), flash memories (NAND (Not AND) flash), etc.), LEDs (Light Emitting Diodes) (e.g., microflash for mobile terminals, in-vehicle devices, projector light sources, LCD backlights, general lighting, etc.), power devices, analog ICs (Integrated Circuits), (e.g., DC (Direct Current) Current-DC (Direct Current) converters, insulated gate bipolar transistors (IGBTs), etc.), MEMS (Micro Electro Mechanical Systems) (e.g., acceleration sensors, pressure sensors, vibrators, gyro sensors, etc.), wireless (e.g., GPS (Global Positioning System), FM (Frequency Modulation), NFC (Near Field Communication), RFEM (RF Expansion Module), MMIC (Monolithic Microwave Integrated Circuit), WLAN (Wireless Local Area Network), etc.), discrete elements, BSI (Back Side Illumination), CIS (Contact Image Sensor)Sensors), camera modules, CMOS (Complementary Metal Oxide Semiconductors), passive devices, SAW (Surface Acoustic Wave) filters, RF (Radio Frequency) filters, RFIPDs (Radio Frequency Integrated Passive Devices), and BB (Broadband). A semiconductor element is, for example, a self-contained device that performs a specific function such as a circuit or a sensor. The semiconductor element may also have an interposer function. It is also possible to stack multiple devices, such as a logic chip having a logic circuit and a memory chip, on a device with an interposer function. In this case, the electrodes of each device can be bonded even if they have different sizes.

[0050] (One example of a method for manufacturing an anisotropically conductive member) Next, a method for manufacturing an anisotropically conductive member will be described. Figures 8 to 14 are schematic cross-sectional views showing an example of a method for manufacturing an anisotropically conductive member according to an embodiment of the present invention in the order of steps. In Figures 8 to 14, the same components as those in the anisotropically conductive member 10 shown in Figures 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted. In one example of a method for manufacturing an anisotropically conductive member, an anisotropically conductive member 10 shown in FIG. 1 will be described in which the insulating base material 20 is made of an anodized aluminum film. To form the anodized aluminum film, an aluminum substrate is used. Therefore, in this example of a method for manufacturing an anisotropically conductive member, an aluminum substrate 40 is first prepared as shown in FIG. The size and thickness of the aluminum substrate 40 are determined appropriately depending on the thickness of the insulating base material 20 (see FIG. 1) of the anisotropically conductive member 10 (see FIG. 1) to be finally obtained, the processing equipment, etc. The aluminum substrate 40 is, for example, a plate material having a circular outer shape. However, it is not limited to an aluminum substrate, and any metal substrate on which an electrically insulating insulating film can be formed can be used. Valve metals on which an anodized film can be formed by anodization can be used.

[0051] Next, one surface 40a (see FIG. 8) of the aluminum substrate 40 is anodized. As a result, one surface 40a (see FIG. 8) of the aluminum substrate 40 is anodized, and an anodized film 44 having a plurality of pores 21 extending in the thickness direction Dt of the aluminum substrate 40 is formed, as shown in FIG. The anodic oxide film 44 is the insulating substrate 20 (see FIG. 1) described above. As shown in FIG. 9, a barrier layer 43 exists at the bottom of each pore 21. The above-described anodizing step is called an anodizing treatment step. As described above, the anodic oxide film 44 having the plurality of pores 21 has a barrier layer 43 at the bottom of each pore 21, but the barrier layer 43 is removed. As a result, an anodic oxide film 44 having the plurality of pores 21 and no barrier layer 43 (see FIG. 10) is obtained. The step of removing the barrier layer 43 is referred to as a barrier layer removal step.

[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, and at the same time, a metal layer 45a (see FIG. 10) made of a metal (metal M1) is formed 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 the pore 21 is filled with metal, suppressing insufficient filling of the metal into the pore, suppressing incomplete filling of the metal into the pore 21, and suppressing defective 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, converted into the amount of aluminum ions, 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.

[0053] Next, plating is performed on the surface 44a of the anodic oxide film 44, which has a plurality of pores 21 extending in the thickness direction Dt. In this case, the metal layer 45a can be used as an electrode for electrolytic plating. Metal 45b is used for plating, and plating proceeds starting from 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 metal 45b is filled inside the pores 21 of the anodic oxide film 44 as a conductive material that forms the conductive paths 22. By filling the inside of the pores 21 with the metal 45b, the conductive conductive paths 22 are formed. The metal layer 45a and the metal 45b are collectively referred to as the filled metal 45. The process of filling the pores 21 of the anodic oxide film 44 with metal 45b to form the 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 filling with metal is not limited to this. Electrolytic plating is used in the metal filling process, and the metal filling process 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 process of filling the pores 21 of the anodic oxide film 44 with a conductive material, including metal and non-metal materials, to form the conductive paths 22 is simply referred to as the filling process.

[0054] After the metal filling step, a polishing step is carried out to polish and smooth the surface 44a of the anodic oxide film 44 shown in Fig. 11. For polishing, for example, a chemical mechanical polishing (CMP) process is used. Next, after the polishing step, as shown in Fig. 12, the surface 20a of the anodized film 44 on the side where the aluminum substrate 40 is not provided is partially removed in the thickness direction Dt, and the metal 45 filled in the metal filling step is made to protrude from the surface 44a of the anodized film 44. In other words, the conductive paths 22 are made to protrude from the surface 44a of the anodized film 44. This results in protruding portions 22a. The step of making the conductive paths 22 protrude from the surface 44a of the anodized film 44 is called a surface protrusion step. In the surface protruding 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. At this time, 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. This results in the surface 20a of the insulating base material 20 shown in FIG.

[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 anisotropically conductive member 10 can be in the state shown in Fig. 13. 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] 14, after the substrate removal step, a polishing step is carried out 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 polishing, for example, CMP processing is used. Next, after the polishing process of the back surface 44b of the anodic oxide film 44, the back surface 44b of the anodic oxide film 44 is partially removed in the thickness direction Dt as shown in FIG. 14, and the metal 45 filled in the metal filling process, i.e., the conductive path 22, is made to protrude beyond the back surface 44b of the anodic oxide film 44. This results in a protruding portion 22b. The process of making the conductive path 22 protrude beyond the back surface 44b of the anodic oxide film 44 is called a back surface protruding process. Note that the back surface protruding process does not necessarily have to be performed. If the back surface protruding process is not performed, the above-mentioned protruding portion 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. As a result, a back surface 20b similar to the front surface 20a of the insulating base material 20 shown in FIG. 3 is obtained.

[0057] The above-mentioned front surface protruding step and back surface protruding step may be both steps, or may be one of the front surface protruding step and the back surface protruding step. The front surface protruding step and the back surface protruding step correspond to the "protruding step", and both the front surface protruding step and the back surface protruding step are protruding steps. The protruding step is also called a trimming step. When the protruding step is performed, the thickness of the anodic oxide 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 Process] Although a conventionally known method can be used for the anodization treatment, it is preferable to use a self-ordering method or constant voltage treatment from the viewpoint of increasing the regularity of the micropore arrangement and ensuring the anisotropic conductivity of the structure, which results in, for example, a hexagonal arrangement of the pores and conductors. Here, the self-ordering method of anodizing treatment and constant voltage treatment can be the same as the treatments described in paragraphs

[0056] to

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

[0060] [Holding process] 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 in anodizing treatment" refers to the voltage applied between the aluminum substrate and the counter electrode. For example, if the electrolysis time in anodizing treatment is 30 minutes, the voltage refers to the average value of the voltage maintained over that 30 minutes.

[0061] From the viewpoint of controlling the thickness of the sidewall of the anodized 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] Furthermore, in order to further improve in-plane uniformity, 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. The holding time in the holding step may be a total of 5 minutes or more, 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 95% or more and 105% or less 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 step, for example, by lowering the electrolytic potential at the end of the above-mentioned anodizing step. In the above-mentioned holding step, the same electrolytic solution and treatment conditions as those in the above-mentioned conventionally known anodizing treatment can be used, except for the electrolytic potential. In particular, when the holding step and the anodizing step are carried out successively, it is preferable to carry out the treatment using the same electrolyte.

[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 anodic oxide film using, for example, an alkaline aqueous solution containing ions of a metal M1 having a higher hydrogen overvoltage than aluminum. By the above-mentioned barrier layer removal step, the barrier layer is removed, and a conductive layer made of metal M1 is formed at the bottom of the pore. Here, hydrogen overvoltage refers to the voltage required to generate hydrogen, and 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 shown below. <Metal M1 and hydrogen (1N H2SO4) overvoltage> ·Platinum (Pt): 0.00V ·Gold (Au): 0.02V ·Silver (Ag): 0.08V Nickel (Ni): 0.21V ·Copper (Cu): 0.23V ·Tin (Sn): 0.53V Zinc (Zn): 0.70V

[0067] In the above-described barrier layer removal process, the barrier layer is removed using an alkaline aqueous solution containing ions of metal M1, which has a higher hydrogen overvoltage than aluminum. This 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 aluminum substrate 40 at the bottom of the pores 21. As a result, the in-plane uniformity of the metal filling is improved. This is thought to be because hydrogen gas generation by the plating solution is suppressed, facilitating the progress of metal filling by electrolytic plating. Furthermore, it has been found that the uniformity of metal filling during plating can be significantly improved by providing a holding step in the barrier layer removal step, in which a voltage (holding voltage) selected from a range of less than 30% of the voltage used in the anodizing treatment step is maintained at 95% to 105% for a total of 5 minutes or more, and by combining this with the application of an alkaline aqueous solution containing ions of metal M1. For this reason, it is preferable to provide a holding step. 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 beneath 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. With aluminum substrate 40 exposed, it 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 size 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. The pore widening treatment can also remove the barrier layer at the bottom of the micropores. By using an aqueous sodium hydroxide solution in the pore widening treatment, the micropores are enlarged and the barrier layer is removed.

[0070] [Filling process] 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. <Metals used in the filling process> In the filling step, the metal filled as a conductive material into the pores 21 of the anodic oxide film 44 to form the conductive paths has an electrical resistivity of 10 3 It is preferable that 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) or cobalt (Co), more preferably copper (Cu) or gold (Au), and even more preferably copper (Cu).

[0071] <Plating method> For the anodic oxide film 44 having a plurality of pores 21 extending in the thickness direction Dt, the plating method for filling the interior of the pores 21 with metal may be, for example, electrolytic plating or electroless plating. However, it is difficult to selectively deposit (grow) metal in pores with a high aspect ratio using conventional electroplating methods used for coloring, etc. This is thought to be because the deposited metal is consumed in the pores and the plating does not grow even if electrolysis is performed for a certain period of time. Therefore, when filling metal by electroplating, it is necessary to provide a rest period between pulse electrolysis or constant potential electrolysis. The rest period must be 10 seconds or more, and preferably 30 to 60 seconds. It is also desirable to apply ultrasonic waves 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) As the plating solution, a conventionally known plating solution can be used. Specifically, when depositing copper, an aqueous solution of copper sulfate is generally used, and the concentration of copper sulfate is preferably 1 to 300 g / L, more preferably 100 to 200 g / L. Furthermore, the addition of hydrochloric acid to the electrolytic solution can promote the deposition. In this case, the concentration of hydrochloric acid is preferably 10 to 20 g / L. When gold is to be deposited, it is desirable to use a sulfuric acid solution of gold tetrachloride and carry out 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. Both ionic (cationic, anionic, zwitterionic) and nonionic surfactants with hydrophilic moieties can be used, but cationic surfactants are preferred to avoid the generation of bubbles on the surface of the object to be plated. The concentration of surfactant in the plating solution composition should preferably be 1% by mass or less. In electroless plating, it takes a long time to completely fill the pores with metal, which are pores with high aspect ratios, so it is preferable to use electrolytic plating to fill the pores with metal.

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

[0076] <Dissolving aluminum substrate> The aluminum substrate is preferably dissolved using a treatment liquid that does not easily dissolve the anodized film but easily dissolves aluminum. Such a treatment solution preferably has a dissolution rate for aluminum of 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 films 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 an acid or alkaline aqueous solution based on which compounds of, for example, manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, copper, mercury, silver, palladium, platinum, or gold (e.g., chloroplatinic acid), or fluorides or chlorides thereof are blended. Among these, an acid aqueous solution base is preferred, and it is preferable to blend a chloride. In particular, a treatment solution in which mercury chloride is blended into an aqueous hydrochloric acid solution (hydrochloric acid / mercury chloride) and a treatment solution in which copper chloride is blended into an aqueous hydrochloric acid solution (hydrochloric acid / copper chloride) are preferred from the viewpoint of treatment latitude. The composition of the treatment liquid for dissolving aluminum is not particularly limited, and for example, a bromine / methanol mixture, a bromine / ethanol mixture, aqua regia, etc. can be used.

[0078] The acid or alkali concentration of the treatment liquid for dissolving aluminum is preferably 0.01 to 10 mol / L, more preferably 0.05 to 5 mol / L. Furthermore, the treatment temperature using a treatment liquid that dissolves aluminum is preferably from -10°C to 80°C, and more preferably from 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] [Protrusion process] 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 substrate after the polishing step. As a specific example, a portion of the anodic oxide film 44 is removed. To remove the portion of the anodic oxide film 44, for example, an acidic or alkaline aqueous solution is used that dissolves the anodic oxide film 44, i.e., aluminum oxide (Al2O3), but does not dissolve the metal that constitutes the conductive paths 22. The anodic oxide film 44 is partially removed by forming the acidic or alkaline aqueous solution into droplets and bringing them into contact with the anodic oxide film 44 having the pores 21 filled with metal. As a method for bringing the acidic or alkaline aqueous solution into droplets and into contact with the anodic oxide 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 anodic oxide film 44.

[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 that does not contain chromic acid is preferable from the viewpoint of excellent safety. The concentration of the acid aqueous solution is preferably 1 to 10 mass %. The temperature of the acid aqueous solution is preferably 25 to 60°C. 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 mass %. The temperature of the alkaline aqueous solution is preferably 20 to 35°C. Specifically, for example, a 50 g / L, 40° C. aqueous solution of phosphoric acid, a 0.5 g / L, 30° C. aqueous solution of sodium hydroxide, or a 0.5 g / L, 30° C. aqueous solution of potassium hydroxide is 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 paths 22, are allowed to protrude from the front surface 44a or the back surface 44b of the anodized film 44, and as described above, it is preferable that the conductive paths 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 protrusions 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 to the bonded members.

[0085] When the length h of the protruding portion of the conductive path 22 in the thickness direction Dt is to be strictly controlled, it is preferable to fill the inside of the pore 21 with a conductive material such as a metal, process the anodized film 44 and the end of the conductive material such as the metal so that they are flush with each other, and then selectively remove the insulating base material such as the anodized film. After the above-described metal filling or protruding step, a heat treatment can be carried out in order to reduce distortion in the conductive path 22 that occurs due to the metal filling. The heat treatment is preferably carried out in a reducing atmosphere from the viewpoint of suppressing oxidation of the metal, and more preferably in an atmosphere with an oxygen concentration of 20 Pa or less, more preferably in a vacuum. Here, vacuum refers to a state of space in which at least one of the gas density and the atmospheric pressure is lower than that of the atmosphere. Furthermore, the heat treatment is preferably carried out while applying stress to the anodic oxide film 44 for the purpose of correction.

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

[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. [Example]

[0089] The features of the present invention will be explained in more detail below with reference to examples. The materials, reagents, amounts and proportions of substances, and procedures shown in the following examples can be changed 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 this example, bonded bodies were produced in Examples 1 to 12 and Comparative Examples 1 and 2. The sizes and other details of the bonded bodies in 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 bonded bodies of Examples 1 to 12 and the bonded bodies of 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 bonding strength and the state of the protrusion after bonding will be described.

[0090] (Evaluation of bonding strength) The bond 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 (MPa) per area of ​​the TEG chip was calculated from the fracture load. The bonding strength was evaluated according to the following criteria. The evaluation results are shown in the bonding strength column in Table 2 below. Evaluation criteria A: 10 MPa or less bonding strength value B: 3MPa≦bonding strength value<10MPa C: Bond strength value < 3MPa

[0091] <Preparation of junction for evaluation> A TEG (Test Element Group) chip with 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 was 8 mm square, with an electrode area (copper post) to chip area ratio of 25%. The interposer was prepared with a chip size of 10 mm square, as it included extraction wiring around the periphery. An anisotropic conductive member measuring 10 mm square was used. During bonding, the TEG chip, anisotropic conductive material, and interposer were stacked in this order, and temporary bonding was performed using a room temperature bonding device (WP-100 (model), manufactured by PMT Co., Ltd.) under the 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 bonded sample was cured under the conditions of a resin curing process at a heating temperature of 250°C for 180 seconds and a pressure of 10 MPa, to prepare a bonded body for evaluation. A type 1 laminate structure is one in which a TEG chip, an anisotropic conductive material, and an interposer are laminated in this order.

[0092] In addition, the TEG chip, anisotropically conductive material, TEG chip, anisotropically conductive material, and 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 the 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 subjected to pressure application at 10 MPa using a room temperature bonding machine (model: manufactured by PMT Corporation), followed by permanent bonding 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. A type 2 laminate structure is one in which a TEG chip, an anisotropic conductive material, a TEG chip, an anisotropic conductive material, and an interposer are laminated in this order.

[0093] (Protrusion condition after joining) The state of the protrusions after bonding will be described. For each of the bonded structures of the TEG chip, the anisotropic conductive member, and the interposer in each of the examples and comparative examples, 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 obtain photographed images at a magnification of 100,000 times. In the acquired photographed images, 100 protrusions were identified. The 100 identified protrusions were judged for contact with adjacent protrusions. The state of the 100 identified protrusions after bonding was evaluated based on whether or not they were in contact with adjacent protrusions, using the evaluation criteria shown below. 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 come into contact with adjacent protrusions is 0 B: Of 100 protrusions, the number of protrusions that contact adjacent protrusions is 1 or more but less than 10 C: Of 100 protrusions, the number of protrusions that contact adjacent protrusions is 11 or more Regarding whether or not there was contact with an adjacent protrusion, even partial contact with the adjacent protrusion was determined to be in contact.

[0094] Examples 1 to 12 and Comparative Examples 1 and 2 will be explained below. Example 1 A description will be given of the bonded body of Example 1. In Example 1, an anodized aluminum film was used for the insulating substrate. [Structure] <Preparation of aluminum substrate> A molten metal was prepared using an aluminum alloy containing 0.06 mass% Si, 0.30 mass% Fe, 0.005 mass% Cu, 0.001 mass% Mn, 0.001 mass% Mg, 0.001 mass% Zn, 0.001 mass% Ti, and the remainder being Al and unavoidable impurities. After molten metal treatment and filtration, an ingot measuring 500 mm in thickness and 1200 mm in width was produced using a DC (Direct Chill) casting method. Next, the surface was scraped off to an average thickness of 10 mm using a facing mill, and then the material 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 sheet was heat-treated at 500°C using a continuous annealing machine, and then cold-rolled to a thickness of 1.0 mm to obtain an aluminum substrate of JIS 1050 material. 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 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. The cathode was a carbon electrode, and the power supply was GP0110-30R (manufactured by Takasago Manufacturing Co., Ltd.) The flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0096] (Electrolytic polishing liquid composition) 85% by weight phosphoric acid (reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 660 mL ·Pure water 160mL ·Sulfuric acid 150mL 30mL of ethylene glycol

[0097] <Anodizing process> Next, the aluminum substrate after the electrolytic polishing treatment was subjected to anodizing treatment by a self-ordering method in accordance with the procedure described in JP-A-2007-204802. The aluminum substrate after electrolytic polishing was subjected to a pre-anodizing treatment for 5 hours using an electrolytic solution of 0.50 mol / L oxalic acid under conditions of a voltage of 40 V, a solution temperature of 16°C, and a solution flow rate of 3.0 m / min. Thereafter, the aluminum substrate after the 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, the plate was subjected to re-anodization treatment for 10 hours in an electrolyte solution of 0.50 mol / L oxalic acid under 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 anodic oxide film with a thickness of 80 μm. In both the pre-anodizing and re-anodizing treatments, a stainless steel cathode was used, and a GP0110-30R power supply (manufactured by Takasago Machinery Co., Ltd.) was used. The cooling device was a NeoCool BD36 (manufactured by Yamato Scientific Co., Ltd.), and the stirring and heating device was a Pair Stirrer PS-100 (manufactured by EYELA Tokyo Rikakikai Co., Ltd.). The flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0098] <Barrier layer removal process> Next, using the same treatment solution and treatment conditions as those used in the above-mentioned anodizing treatment, electrolysis treatment (electrolytic removal treatment) was carried out 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% by mass phosphoric acid at 30°C for 30 minutes, thereby removing the barrier layer at the bottom of the micropores in 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 capturing 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 opening 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 anodic oxide film after the barrier layer removal process was 80 μm. The average thickness was determined by cutting the anodic oxide film in the thickness direction using a focused ion beam (FIB), and then capturing a cross-sectional image of the cut surface at 50,000x magnification using a field emission scanning electron microscope (FE-SEM). The length of 10 locations on the cross-sectional image, corresponding to the thickness of the anodic oxide film, was measured, and the average of the 10 measured lengths was calculated. This average was used as the average thickness of the anodic oxide film after the barrier layer removal process. The density of micropores in the anodic oxide film is approximately 100 million / mm 2The micropore density was measured and calculated by the method described in paragraphs

[0168] and

[0169] of JP-A No. 2008-270158. The degree of ordering of the micropores present in the anodic oxide film was 92%. The degree of ordering was measured and calculated by taking a surface image at a magnification of 20,000 times using a field emission scanning electron microscope (FE-SEM) and measuring it using the method described in paragraphs

[0024] to

[0027] of JP 2008-270158 A.

[0100] <Metal filling process> Next, electrolytic plating was carried out using the aluminum substrate as the cathode and platinum as the anode. 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 inside of the pores (micropores) to form conductive paths. Here, 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 treatment was carried out under the conditions shown below. (Copper plating solution composition and conditions) ·Copper sulfate 100g / L ·Sulfuric acid 50g / L Hydrochloric acid 15g / L ·Temperature 25℃ ·Current density 10A / dm 2

[0101] <Polishing process> The surface of the metal-filled microstructure, in which the conductive paths were formed by filling the metal, was then polished by 5 μm from the surface to smooth the surface, using CMP slurry PNANERLITE-7000 manufactured by Fujimi Inc. The surface of the anodized film after filling the pores (micropores) with metal was observed using a field emission scanning electron microscope (FE-SEM). The presence or absence of metal sealing in 1,000 micropores was observed, and the sealing rate (number of sealed micropores / 1,000) was calculated to be 96%. In addition, after filling the pores (micropores) with metal, the anodized 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 examined, it was found that the inside of the sealed pores (micropores) was completely filled with metal.

[0102] <Trimming process> The metal-filled microstructures after the polishing process were subjected to spray etching, spraying droplets of sodium hydroxide solution (concentration: 5% by mass, liquid temperature: 20°C) onto the surface of the anodized film. The amount of sodium hydroxide 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 structure was then washed with water and dried, leaving protruding copper columns as conductive paths. As a result, the length h of the protrusions (see Figure 1) was 1000 nm. For the spray etching method, ADE-3000S (product name) manufactured by Actes Kyosan Co., Ltd. was used. The arithmetic mean distance δ (see FIG. 3) in the thickness direction on the surface side of the anodic oxide film was measured using the captured image as described above.

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

[0104] <Polishing process> 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 sodium hydroxide solution (concentration: 5% by mass, liquid temperature: 20°C) were sprayed onto the back surface of the anodized film of the structure using a spray etching method. The amount of sodium hydroxide solution sprayed was adjusted so that the arithmetic mean distance δ in the thickness direction (see Figure 3) was 100 nm, and the surface of the aluminum anodized film was selectively dissolved. The structure was then washed with water and dried, leaving protruding copper columns as conductive paths. As a result, the length h of the protrusions (see Figure 1) was 1000 nm. For the spray etching method, ADE-3000S (product name) manufactured by Actes Kyosan Co., Ltd. was used. The arithmetic mean distance δ in the thickness direction on the rear surface side of the anodic oxide film was measured using the photographed image as described above.

[0106] <Resin layer formation process> After the trimming step, resin layers were formed on the front and back surfaces of the anodized film of the structure by the method described below, thereby producing 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, by adjusting the rotation speed of a spin coater so that the thickness was 1.5 μm. Next, the anisotropically conductive bonding member thus produced was cut into pieces of 10 mm square using a cutting tool, DAD3230 (product name) manufactured by Disco Corporation.

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

[0108] Example 2 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 20 nm. Example 3 Example 3 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 60 nm. Example 4 Example 4 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 5 nm. Example 5 Example 5 differs from Example 3 in that the resin is on the CNP surface, but otherwise is the same as Example 2. Note that "having the resin on the CNP surface" refers to a state in which epoxy resin is applied onto the protruding portion of the anisotropically conductive member. Example 6 Example 6 differs from Example 3 in that resin is present on the electrode surface, but otherwise is the same as Example 2. Note that "resin is present 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, and boric acid (300 / 60 / 40 g / L) as the electrolyte, with the nickel electrode as the cathode and platinum as the anode. The electrolytic plating was performed by constant current electrolysis (5 A / dm 2 ) was carried out. Example 8 Example 8 differs from Example 2 in that the length h of the protrusions (see FIG. 1) was set to 10,000 nm, but otherwise was the same as Example 2. Example 9 Example 9 differs from Example 2 in that the length h of the protrusion (see FIG. 1) was set to 3 nm, but otherwise was the same as Example 2. Example 10 Example 10 was the same as Example 3 except that the size of the TEG chip was 4 mm square. Example 11 Example 11 was the same as Example 3 except that the size of the anisotropically conductive member was 8 mm square. 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 that 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, the example was the same as Example 1. In Comparative Example 1, the arithmetic mean distance δ in the thickness direction (see FIG. 3) was 1 nm.

[0111] (Comparative Example 2) Comparative Example 2 differs from Example 1 in that the spray amount of the sodium oxide aqueous solution was adjusted so that the arithmetic mean distance δ (see FIG. 3) in the thickness direction on both the front and back sides of the anodized aluminum film was 250 nm, and the other aspects were the same as Example 1.

[0112] [Table 1]

[0113] [Table 2]

[0114] As shown in Table 2, Examples 1 to 12 were superior to Comparative Examples 1 and 2 in terms of bonding strength and the state of the protrusions after bonding. In Comparative Example 1, the arithmetic mean distance δ was short, the bonding strength was low, and many protrusions were in contact with adjacent protrusions. In Comparative Example 2, the arithmetic mean distance δ was long, and many protrusions were in contact with adjacent protrusions. Among Examples 1 to 12, Examples 2, 3, 5, 6, 10 and 11 were superior in bonding strength and in the state of the protrusions after bonding. From Examples 1 to 4, when the arithmetic mean distance δ was 20 to 100 nm, the bonding strength and the state of the protrusions after bonding were better, and when it was 20 to 60 nm, the bonding strength and the state of the protrusions after bonding were even better. From Examples 2 and 7, it was found that Cu conductive paths were superior to Ni in bonding strength and state of the protrusions after bonding. From Example 2, Example 8, and Example 9, Example 2, in which the protrusions were 300 nm, had better bonding strength and the state of the protrusions after bonding. [Explanation of symbols]

[0115] 10 Anisotropic conductive material 12, 13 zygote 18 Resin layer 20 Insulating substrate 20a, 24a, 40a, 32a, 34a, 37a, 44a surface 20b, 44b back side 20d recess 21 pores 22 Conduction Path 22a, 22b protrusion 22c side 24 Resin layer 30, 31 Semiconductor elements 32, 37 Element substrate 33 Resin layer 34, 35, 38 electrodes 36 Insulating layer 39 Insulating layer 40 Aluminum substrate 42c bottom 42d side 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 part d average diameter hm average thickness ht Thickness p Center distance x direction δ arithmetic mean distance w interval

Claims

1. an insulating substrate having electrical insulation properties; a plurality of conductive paths that penetrate the insulating base material in a thickness direction, are provided in a state of being electrically insulated from one another, and have protrusions that protrude 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 protruding portions of the conductive paths protrude has a plurality of apexes, and each of the plurality of protruding portions has a contact portion in contact with the insulating base material; An anisotropically conductive member, wherein the arithmetic mean distance between the plurality of contact portions and the plurality of apexes in the thickness direction 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. 2. 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. 2. The anisotropically conductive member according to claim 1, 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, a resin is filled between the anisotropically conductive member and the member to be joined; The anisotropically conductive member includes an insulating substrate having electrical insulation properties; a plurality of conductive paths that penetrate the insulating base material in a thickness direction, are provided in a state of being electrically insulated from one another, and have protrusions that protrude 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 protruding portions of the conductive paths protrude has a plurality of apexes, and each of the plurality of protruding portions has a contact portion in contact with the insulating base material; a bonded structure in which the arithmetic mean distance between the plurality of contact portions and the plurality of apexes in the thickness direction 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 bonded body according to claim 5 , wherein the bonded members have a plurality of the metal layers, and at least one of the plurality of metal layers has a different height.

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

Images