Plating solution and method for manufacturing metal-filled structure

Abstract

The present invention addresses the problem of providing: a plating solution able to suppress variations in the filling height of a metal filled in through holes; and a method for producing a metal-filled structure using the plating solution. This plating solution is used when filling a metal in through holes in a structure having a plurality of through holes, and contains a salt of the metal to be filled in the through holes and a compound having a mercapto group. The content of the compound having a mercapto group is more than 0.01 mg / L and less than 2000 mg / L.

Description

[Technical Field]

[0001] The present invention relates to a plating solution and a method for producing a metal-filled structure. [Background technology]

[0002] Metal-filled microstructures (devices), which are formed by filling micropores in an insulating substrate with metal, are one of the fields that have attracted attention in recent years in nanotechnology, and are expected to be used, for example, as anisotropically conductive materials. 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, and are therefore widely used as electrical connecting members for electronic components such as semiconductor elements, and as testing connectors for functional testing.

[0003] For example, Patent Document 1 describes a method for manufacturing such metal-filled microstructures as follows: "A method for manufacturing metal-filled microstructures, comprising: an anodizing step of anodizing one surface of an aluminum substrate to form an anodized film on the surface of the aluminum substrate, the anodized film having micropores present in the thickness direction and a barrier layer present at the bottom of the micropores; a barrier layer removal step of removing the barrier layer of the anodized film using an alkaline aqueous solution containing a metal M1 having a higher hydrogen overvoltage than aluminum; a metal filling step of filling the micropores with a metal M2 by electroplating after the barrier layer removal step; and a substrate removal step of removing the aluminum substrate after the metal filling step to obtain a metal-filled microstructure" ([Claim 1]). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 057150 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have examined known methods for manufacturing metal-filled microstructures, such as those described in Patent Document 1, and have found that, depending on the plating conditions, variations can occur in the height of the metal filled inside through holes such as micropores (hereinafter referred to as "filling height"), and that there is room for improvement in the plating conditions.

[0006] Therefore, an object of the present invention is to provide a plating solution that can suppress variations in the filling height of the metal filled into through holes, and a method for manufacturing a metal-filled structure using the same. [Means for solving the problem]

[0007] As a result of intensive research conducted by the inventors to achieve the above object, it was discovered that the use of a plating solution containing a salt of the metal to be filled into the through-holes and a compound having a mercapto group can suppress variation in the filling height of the metal filled into the through-holes, and this led to the completion of the present invention. That is, it has been found that the above object can be achieved by the following configuration.

[0008] [1] A plating solution used to fill metal into through holes of a structure having a plurality of through holes, The composition contains a metal salt to be filled into the through-holes and a compound having a mercapto group, A plating solution having a content of a compound having a mercapto group of more than 0.01 mg / L and less than 2000 mg / L. [2] The plating solution according to [1], wherein the compound having a mercapto group includes sulfonic acid or a salt thereof. [3] The plating solution according to [1] or [2], wherein the content of the compound having a mercapto group is 0.1 to 1000 mg / L. [4] The plating solution according to any one of [1] to [3], wherein the compound having a mercapto group includes sodium 3-mercapto-1-propanesulfonate. [5] The plating solution according to any one of [1] to [4], wherein the ratio of the depth to the opening diameter of the plurality of through holes is 10 or more. [6] A method for manufacturing a metal-filled structure produced by filling a structure having a plurality of through holes with a metal, comprising: A method for producing a metal-filled structure, wherein the plating solution according to any one of [1] to [5] is used when filling through-holes in the structure with metal. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a plating solution that can suppress variations in the filling height of metal that is filled into through holes, and a method for manufacturing a metal-filled structure using the same. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a metal-filled structure. [Figure 2] FIG. 2 is a schematic plan view showing an example of a metal-filled structure. [Figure 3] 1 is a schematic cross-sectional view showing one step of an example of a method for manufacturing a metal-filled structure according to an embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing one step of an example of a method for manufacturing a metal-filled structure according to an embodiment of the present invention. [Figure 5] 1 is a schematic cross-sectional view showing one step of an example of a method for manufacturing a metal-filled structure according to an embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional view showing one step of an example of a method for manufacturing a metal-filled structure according to an embodiment of the present invention. [Figure 7] 1 is a schematic cross-sectional view showing one step of an example of a method for manufacturing a metal-filled structure 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 manufacturing a metal-filled structure 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 manufacturing a metal-filled structure according to an embodiment of the present invention. [Figure 10]1 is a schematic diagram illustrating an example of a bonded body according to an embodiment of the present invention. [Figure 11] FIG. 10 is a schematic diagram showing another example of a bonded body 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 a bonded body 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 a bonded body according to an embodiment of the present invention. [Figure 14] 1A to 1C are schematic diagrams illustrating a step in an example of a method for manufacturing a stacked device using the structure according to an embodiment of the present invention. [Figure 15] 1A to 1C are schematic diagrams illustrating a step in an example of a method for manufacturing a stacked device using the structure according to an embodiment of the present invention. [Figure 16] 1A to 1C are schematic diagrams illustrating a step in an example of a method for manufacturing a stacked device using the structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. The following description of the components may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0012] [Plating solution] The plating solution of the present invention is a plating solution used when filling a metal into through holes of a structure having a plurality of through holes, and contains a salt of the metal to be filled into the through holes and a compound having a mercapto group, wherein the content of the compound having a mercapto group is more than 0.01 mg / L and less than 2000 mg / L.

[0013] In the present invention, as described above, by using a plating solution containing a salt of the metal to be filled into the through holes and a compound having a mercapto group, it is possible to suppress variation in the filling height of the metal filled into the through holes. Although the details are not clear, it is assumed that the reason is roughly as follows. In other words, when a compound having a mercapto group is used, the metal salt (metal ion) contained in the plating solution precipitates as fine crystals when it precipitates as metal during plating processing, so that initially it precipitates uniformly in the in-plane direction of the bottom surface of the through-hole.Furthermore, the crystal growth rate thereafter tends to become uniform, which is thought to have suppressed variation in the filling height of the metal filled into the through-hole.

[0014] [Metal salts] The metal salt contained in the plating solution of the present invention is the metal salt to be filled into the through-holes. The metals mentioned above include, for example, metals having an electrical resistivity of 10 3 Examples of materials with a resistivity of Ω·cm or less include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), and zinc (Zn). Furthermore, examples of salts of the above metals include oxoacid salts of the above metals, and specific examples thereof include carboxylates (e.g., formate, acetate, benzoate, etc.), phosphates, phosphonates, sulfonates, sulfates, etc.

[0015] In the present invention, the salt of the above metal is preferably copper sulfate (CuSO4), nickel sulfate, or silver nitrate, and more preferably copper sulfate, because of its good solubility.

[0016] The concentration of the metal salt contained in the plating solution is not particularly limited, but is preferably 1 to 300 g / L, and more preferably 100 to 200 g / L.

[0017] [Compounds having a mercapto group] The compound having a mercapto group contained in the plating solution of the present invention is not particularly limited as long as it has one or more mercapto groups in the molecule. From the viewpoint of ease of handling, however, it is preferable that the compound has one or two mercapto groups and a molecular weight of 50 to 1000.

[0018] Specific examples of the compound having a mercapto group include sodium 3-mercapto-1-propanesulfonate (hereinafter also abbreviated as "MPS"), 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-thiazoline-2-thiol, 2-mercaptoimidazole, 3-mercapto-4-methyl-4H-1,2,4-triazole, sodium 5-mercapto-1H-tetrazolemethanesulfonate, thiosalicylic acid, sodium 2-mercaptobenzthiazole, sodium 2-mercapto-5-benzimidazolesulfonate, sodium-3-(5-mercapto-1H-tetrazol-1-yl)benzenesulfonate monohydrate, and 3-mercapto-1,2-propanediol.

[0019] In the present invention, the compound having a mercapto group preferably includes sulfonic acid or a salt thereof, and more preferably includes sodium 3-mercapto-1-propanesulfonate, because this can further suppress variations in filling height.

[0020] Furthermore, in the present invention, the content of the compound having a mercapto group is preferably 0.1 to 1000 mg / L, more preferably 1 to 500 mg / L, even more preferably 10 to 400 mg / L, and most preferably 20 to 300 mg / L, because this can further suppress variations in filling height. Furthermore, with regard to the content of the compound having a mercapto group, the molar ratio to the salt of the metal is preferably 0.0001 to 0.01, and more preferably 0.001 to 0.005.

[0021] The through holes to be filled with metal using the plating solution of the present invention preferably have a ratio of depth to opening diameter (hereinafter also abbreviated as "aspect ratio") of 10 or more, more preferably 500 to 5000, for the reason that the effect of using the plating solution of the present invention becomes apparent. Here, the aspect ratio is calculated as the ratio of the average depth of the through holes to the average opening diameter of the through holes. The average opening diameter of the through-holes can be calculated as the average value of 50 measurements taken at 50 points on a surface photograph (for example, at a magnification of 50,000 times) using a field emission scanning electron microscope (FE-SEM). The average depth of the through holes is the average thickness of the structure, and can be calculated as the average value of 10 measurements taken by cutting the structure in the thickness direction with a focused ion beam (FIB), taking a surface photograph of the cross section (for example, at a magnification of 50,000 times) with a field emission scanning electron microscope (FE-SEM).

[0022] 〔acid〕 The plating solution of the present invention preferably contains an acid, and more preferably is an aqueous solution containing an acid. Specific examples of such acids include hydrochloric acid, sulfuric acid, and phosphoric acid. Of these, hydrochloric acid or sulfuric acid is preferred, and a combination of hydrochloric acid and sulfuric acid is more preferred.

[0023] [Additives] The plating solution of the present invention may contain additives such as sulfur-based saturated organic compounds other than the above-mentioned compounds having a mercapto group, polymer components, surfactants, and the like, in addition to the above-mentioned components.

[0024] Specific examples of the sulfur-based saturated organic compounds include 3,3'-dithiobis(sodium propanesulfonate). In the present invention, when 3,3'-dithiobis(sodium propanesulfonate) is contained, the content is preferably 15 to 500 parts by mass per 100 parts by mass of the compound having a mercapto group described above, because this can further suppress variations in filling height.

[0025] Specific examples of the polymer component include polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer.

[0026] The surfactants mentioned above can be either ionic (cationic, anionic, zwitterionic) or nonionic (nonionic) in the hydrophilic portion, but cationic surfactants are preferred in order to avoid the generation of bubbles on the surface of the object to be plated.

[0027] [Metal Filled Structure Manufacturing Method] The method for manufacturing a metal-filled structure of the present invention is a method for manufacturing a metal-filled structure that is produced by filling the through holes of a structure having a plurality of through holes with metal, and is a manufacturing method that uses the above-mentioned plating solution of the present invention when filling the through holes of the structure with metal. Here, the method for manufacturing the metal-filled structure of the present invention can use a conventionally known method, except that the plating solution of the present invention described above is used when filling the through holes of the structure with metal (metal filling process).For example, the method described in JP 2008-270157 A, the method described in WO 2017 / 057150 A, the method described in WO 2018 / 155273 A, the method described in JP 2019-153415 A, etc. can be used.

[0028] The configuration of the metal-filled structure (hereinafter also simply referred to as "structure") produced by the method for producing a metal-filled structure of the present invention will be described in more detail below. 1 includes an electrically insulating insulating film 12 and a plurality of conductors 14 that penetrate the insulating film 12 in a thickness direction Dt and are electrically insulated from one another. The conductors 14 protrude from at least one surface of the insulating film 12 in the thickness direction Dt. When the conductors 14 protrude from at least one surface of the insulating film 12 in the thickness direction Dt, in a configuration in which the conductors 14 protrude from one surface, it is preferable that the conductors protrude from the front surface 12a or the back surface 12b. The structure 10 has a resin layer 20 that partially covers the surface of the insulating film 12 from which the conductors 14 protrude. That is, the resin layer 20 is not provided on the entire surface 12a or the entire back surface 12b of the insulating film 12, but is provided partially on the surface 12a of the insulating film 12 and partially on the back surface 12b of the insulating film 12. The insulating film 12 is formed of, for example, an anodic oxide film 15.

[0029] The plurality of conductors 14 are arranged in the insulating film 12 while being electrically insulated from one another. In this case, for example, the insulating film 12 has a plurality of pores 13 penetrating in the thickness direction Dt. The conductors 14 are provided in the plurality of pores 13. The conductors 14 protrude from a surface 12a of the insulating film 12 in the thickness direction Dt. The conductor 14 protrudes from the rear surface 12b in the thickness direction Dt of the insulating film 12. A resin layer 20 is provided to partially cover the surface of the insulating film 12 from which the conductor 14 protrudes. The resin layer 20 has a resin layer portion 20a and a space 20b. The resin layer 20 has the resin layer portion 20a partially disposed on the surface 12a of the insulating film 12 with a space 20b therebetween, and the resin layer portion 20a covers the protruding portion 14a of the conductor 14. The protruding portion 14a is embedded in the resin layer portion 20a. Furthermore, a resin layer portion 20a is partially disposed on the back surface 12b of the insulating film 12 with a space 20b therebetween, and the resin layer portion 20a covers the protruding portion 14b of the conductor 14. The protruding portion 14b is embedded in the resin layer portion 20a. The structure 10 has anisotropic conductivity and is conductive in the thickness direction Dt, but its conductivity in a direction parallel to the surface 12a of the insulating film 12 is sufficiently low.

[0030] As shown in Fig. 2, the structure 10 has, for example, a rectangular outer shape. Note that the outer shape of the structure 10 is not limited to a rectangle and may be, for example, a circle. The outer shape of the structure 10 can be a shape that depends on the application, ease of fabrication, etc.

[0031] By configuring structure 10 to have resin layer 20 that partially covers the surface of insulating film 12 from which conductors 14 protrude as described above, generated static electricity can be released and charging is suppressed due to the presence of spaces 20b in resin layer 20. This suppresses charging when structure 10 is transported, making it easier to handle. Furthermore, since the resin layer 20 is partially provided on the surface of the insulating film 12, when the structure 10 is inserted between an electronic component such as a semiconductor element and a circuit board and bonded by applying pressure, less resin layer 20 needs to be removed, and therefore no large pressure is required, reducing the force required for bonding. This makes it possible to prevent the bonding device from becoming too large, for example.

[0032] The structure of the structure will be described in more detail below. [Insulating film] The insulating film 12 electrically insulates the plurality of conductors 14, which are made of a conductive material, from one another. The insulating film has electrical insulating properties. The insulating film 12 also has a plurality of pores 13 in which the conductors 14 are formed. The insulating film is made of, for example, an inorganic material. 14 A material having an electrical resistivity of about Ω·cm can be used. The term "made of inorganic material" is used to distinguish it from polymeric materials, and does not limit the insulating substrate to one made of only inorganic materials, but refers to an insulating substrate whose main component is inorganic material (50% by mass or more). As described above, the insulating film is made of, for example, an anodic oxide film. The insulating film may also be made of, for example, ceramics such as metal oxides, metal nitrides, glass, silicon carbide, silicon nitride, etc., carbon substrates such as diamond-like carbon, polyimides, composite materials thereof, etc. In addition to these, the insulating film may be, for example, a film formed on an organic material having through holes from an inorganic material containing 50 mass % or more of a ceramic material or a carbon material.

[0033] The length of the insulating film 12 in the thickness direction Dt, i.e., the thickness of the insulating film 12, is preferably in the range of 1 to 1000 μm, more preferably in the range of 5 to 500 μm, and even more preferably in the range of 10 to 300 μm. When the thickness of the insulating film 12 is in this range, the insulating film 12 becomes easy to handle. From the viewpoint of ease of winding, the thickness ht of the insulating film 12 is preferably 30 μm or less, and more preferably 5 to 20 μm. The thickness of the anodic oxide film was calculated as the average value of 10 measurements taken at 10 points after cutting the anodic oxide film in the thickness direction Dt with a focused ion beam (FIB) and taking surface photographs (magnification: 50,000 times) of the cross section with a field emission scanning electron microscope (FE-SEM). The spacing between the conductors 14 in the insulating film 12 is preferably 5 nm to 800 nm, more preferably 10 nm to 200 nm, and even more preferably 20 nm to 60 nm. When the spacing between the conductors 14 in the insulating film 12 is within the above range, the insulating film 12 functions satisfactorily as an electrically insulating partition wall for the conductors 14. Here, the spacing between each conductor refers to the width between adjacent conductors, and is the average value of the width between adjacent conductors measured at 10 points when the cross section of the structure 10 is observed at a magnification of 200,000 times using a field emission scanning electron microscope.

[0034] <Average pore diameter> The average diameter of the pores is preferably 1 μm or less, more preferably 5 to 500 nm, even more preferably 20 to 400 nm, even more preferably 40 to 200 nm, and most preferably 50 to 100 nm. When the average diameter d of the pores 13 is 1 μm or less and within the above range, a conductor 14 having the above average diameter can be obtained. The average diameter of the pores 13 is determined by photographing the surface of the insulating film 12 from directly above at a magnification of 100 to 10,000 times using a scanning electron microscope. At least 20 pores with a circular periphery are extracted from the photographed image, and their diameters are measured to determine the opening diameter. The average of these opening diameters is calculated as the average diameter of the 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.

[0035] 〔conductor〕 As described above, the plurality of conductors 14 are provided in a state where they are electrically insulated from one another by the anodic oxide film. The plurality of conductors 14 are electrically conductive. The conductors are made of a conductive material. The conductive material is not particularly limited, and examples thereof include metals. Specific examples of metals include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), and nickel (Ni). From the viewpoint of electrical conductivity, copper, gold, aluminum, and nickel are preferred, copper and gold are more preferred, and copper is most preferred. In addition to metals, oxide conductive materials can be used. Examples of oxide conductive materials include indium-doped tin oxide (ITO). However, 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 use metal. Furthermore, the conductor can also be made of a conductive resin containing nanoparticles of Cu, Ag, or the like. The height H of the conductor 14 in the thickness direction Dt is preferably 10 to 300 μm, and more preferably 20 to 30 μm.

[0036] <Conductor shape> The average diameter d of the conductor 14 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 conductor 14 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 2 More 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 conductors 14 is preferably 20 nm to 500 nm, more preferably 40 nm to 200 nm, and even more preferably 50 nm to 140 nm. The average diameter of the conductors is measured by photographing the surface of the anodized film from directly above using a scanning electron microscope at a magnification of 100 to 10,000 times. At least 20 conductors with a ring-shaped periphery 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 conductors. The magnification can be appropriately selected within the above-mentioned range so as to obtain a captured image from which 20 or more conductors can be extracted. The aperture diameter is measured as the maximum distance between the ends of the conductor portions. That is, the shape of the conductor opening is not limited to a substantially circular shape. Therefore, if the opening shape is non-circular, the maximum distance between the ends of the conductor portions is taken as the aperture diameter. Therefore, for example, even if a conductor has a shape in which two or more conductors are integrated, it is considered to be a single conductor, and the maximum distance between the ends of the conductor portions is taken as the aperture diameter.

[0037] [Example of manufacturing method for structure] 3 to 9 are schematic cross-sectional views showing an example of a method for manufacturing a structure according to an embodiment of the present invention in the order of steps. In Fig. 3 to Fig. 9, the same components as those shown in Fig. 1 and Fig. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. In one example of a method for manufacturing a structure, a structure 10 shown in Fig. 1 will be described in which the insulating film 12 is composed 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 a structure, an aluminum substrate 30 is first prepared as shown in Fig. 3. The size and thickness of the aluminum substrate 30 are determined appropriately depending on the thickness of the insulating film 12 of the final structure 10 (see FIG. 1), the processing equipment, etc. The aluminum substrate 30 is, for example, a rectangular plate material. However, it is not limited to an aluminum substrate, and any metal substrate on which an electrically insulating insulating film 12 can be formed can be used.

[0038] Next, one surface 30a (see FIG. 3) of the aluminum substrate 30 is anodized. As a result, one surface 30a (see FIG. 3) of the aluminum substrate 30 is anodized, and an insulating film 12 having a plurality of pores 13 extending in the thickness direction Dt of the aluminum substrate 30, i.e., an anodized film 15, is formed as shown in FIG. 4. A barrier layer 31 exists at the bottom of each pore 13. The above-mentioned anodization process is called an anodization process. As described above, the insulating film 12 having the plurality of pores 13 has a barrier layer 31 at the bottom of each pore 13, but the barrier layer 31 shown in Fig. 4 is removed. As a result, an insulating film 12 having the plurality of pores 13 without the barrier layer 31 (see Fig. 5) is obtained. The step of removing the barrier layer 31 described above is called a barrier layer removal step. 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 31 of the insulating film 12, and at the same time, a metal layer 35a (see FIG. 5) made of a metal (metal M1) is formed on the surface 32d (see FIG. 5) of the bottom 32c (see FIG. 5) of the pore 13. As a result, the aluminum substrate 30 exposed in the pore 13 is covered with the metal layer 35a. This facilitates the progress of plating when filling the pore 13 with metal, suppressing insufficient filling of the metal into the pore, suppressing incomplete filling of the metal into the pore, and suppressing defective formation of the conductor 14. 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.

[0039] Next, plating is performed on the surface 12a of the insulating film 12, which has a plurality of pores 13 extending in the thickness direction Dt. In this case, the metal layer 35a can be used as an electrode for electrolytic plating. Metal 35b is used for plating, and plating proceeds starting from the metal layer 35a formed on the surface 32d (see FIG. 5) of the bottom 32c (see FIG. 5) of the pore 13. As a result, as shown in FIG. 6, the metal 35b constituting the conductor 14 is filled inside the pore 13 of the insulating film 12. By filling the inside of the pore 13 with the metal 35b, the conductor 14 having conductivity is formed. The metal layer 35a and the metal 35b are collectively referred to as the filled metal 35. The process of filling the pores 13 of the insulating film 12 with metal 35b is called the metal filling process. As mentioned above, the conductor 14 is not limited to being made of metal, and any conductive material can be used. Electrolytic plating is used in the metal filling process, and the metal filling process will be described in detail later. Note that the surface 12a of the insulating film 12 corresponds to one side of the insulating film 12. After the metal filling step, as shown in FIG. 7, the surface 12a of the insulating film 12 on the side where the aluminum substrate 30 is not provided is partially removed in the thickness direction Dt, and the metal 35 filled in the metal filling step is made to protrude from the surface 12a of the insulating film 12. That is, the conductor 14 is made to protrude from the surface 12a of the insulating film 12. This results in a protruding portion 14a. The step of making the conductor 14 protrude from the surface 12a of the insulating film 12 is called a surface metal protrusion step. After the surface metal protrusion step, the aluminum substrate 30 is removed as shown in Fig. 8. The step of removing the aluminum substrate 30 is called a substrate removal step.

[0040] 9, after the substrate removal step, the surface of the insulating film 12 on which the aluminum substrate 30 was provided, i.e., the back surface 12b, is partially removed in the thickness direction Dt, and the metal 35 filled in the metal filling step, i.e., the conductor 14, is made to protrude beyond the back surface 12b of the insulating film 12. This results in a protruding portion 14b. The above-mentioned front surface metal protruding step and back surface metal protruding step may be both steps, or may be either one of the front surface metal protruding step and the back surface metal protruding step. The front surface metal protruding step and the back surface metal protruding step correspond to the "protruding step", and both the front surface metal protruding step and the back surface metal protruding step are protruding steps. As shown in FIG. 9, the conductor 14 protrudes from the front surface 12a and the back surface 12b of the insulating film 12, and has a protruding portion 14a and a protruding portion 14b. Next, a resin layer 20 (see FIG. 1) is formed partially on the front surface 12a and back surface 12b of the insulating film 12 from which the conductor 14 protrudes. This allows the structure 10 shown in FIG. 1 to be obtained. The resin layer 20 may have, for example, the pattern shown in FIG. 3 or 4 above. The process of forming the resin layer 20 will be described later. In the case where the conductor 14 does not protrude from the rear surface 12b of the insulating film 12, the structure 10 is obtained by forming the resin layer 20 on the front surface 12a of the insulating film 12 in the state shown in FIG.

[0041] 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 31, but also forms a metal layer 35a of metal M1, which is less likely to generate hydrogen gas than aluminum, on the aluminum substrate 30 exposed at the bottom of the pores 13. 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.

[0042] In the barrier layer removal step, metal layer 35a made of a metal (metal M1) is formed at the bottom of pore 13, but the present invention is not limited to this, and only barrier layer 31 is removed to expose aluminum substrate 30 at the bottom of pore 13. In the exposed state, aluminum substrate 30 may be used as an electrode for electrolytic plating.

[0043] [Anodic oxide film] As described above, an anodized film made of aluminum is used because it allows pores with a desired average diameter to be formed and makes it easy to form a conductor. However, the anodized film is not limited to an aluminum anodized film, and an anodized film made of a valve metal can also be used. Therefore, a valve metal is used as the metal substrate. Here, specific examples of valve metals include the above-mentioned aluminum, as well as tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among these, an anodized aluminum film is preferred because it has good dimensional stability and is relatively inexpensive. For this reason, it is preferable to manufacture a structure using an aluminum substrate. The thickness of the anodic oxide film is the same as the thickness ht of the insulating film 12 described above.

[0044] [Metal substrate] The metal substrate is used in the manufacture of a structure, and is a substrate on which an anodized film is formed. As the metal substrate, for example, as described above, a metal substrate on which an anodized film can be formed is used, and a substrate made of the above-mentioned valve metal can be used. For example, as described above, an aluminum substrate is used as the metal substrate because it is easy to form an anodized film as an anodized film.

[0045] [Aluminum substrate] The aluminum substrate used to form the insulating film 12 is not particularly limited, and specific examples 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, etc. by a method such as vapor deposition or sputtering; a resin substrate laminated with aluminum; and the like.

[0046] The surface of the aluminum substrate on which the anodized film is formed by 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 micropore arrangement becomes sufficiently regular. The aluminum substrate is not particularly limited as long as it can form an anodic oxide film, and for example, JIS (Japanese Industrial Standards) 1050 material is used.

[0047] It is preferable that the surface of one side of the aluminum substrate to be anodized has been 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 those 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.

[0048] [Anodizing Treatment Process] The anodization treatment can be carried out by a conventionally known method, but from the viewpoint of increasing the regularity of the micropore arrangement and ensuring the anisotropic conductivity of the structure, it is preferable to use a self-ordering method or constant voltage treatment. 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. 3] of JP-A-2008-270158.

[0049] [Holding process] The method for manufacturing a structure may include a holding step, which is a step of holding, after the anodizing treatment step, 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 treatment step for a total of 5 minutes or more. In other words, the holding step is a step of performing electrolysis, after the anodizing treatment step, 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 treatment step for a total of 5 minutes or more. Here, "voltage in anodizing treatment" refers to the voltage applied between the aluminum and the counter electrode. For example, if the electrolysis time in anodizing treatment is 30 minutes, this refers to the average voltage maintained over that 30 minutes.

[0050] 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%.

[0051] 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.

[0052] 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.

[0053] 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 used 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.

[0054] 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 the method includes a barrier layer removal step for removing this barrier layer.

[0055] [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 micropores. 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

[0056] The pores 13 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 of these, 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.

[0057] [Metal filling process] <Metals used in the metal filling process> In the metal filling step, in order to form a conductor, the metal filled as a conductor inside the pores 13 and the metal constituting the metal layer have 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), and zinc (Zn). From the viewpoint of electrical conductivity and formation by plating, the conductor is preferably copper (Cu), gold (Au), aluminum (Al), or nickel (Ni), more preferably copper (Cu) or gold (Au), and even more preferably copper (Cu).

[0058] <Plating method> The plating method for filling the inside of the pores with a metal is not particularly limited as long as it is a method that uses the plating solution of the present invention described above, and for example, electrolytic plating or electroless plating can be used. 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 electrolytic plating, 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.

[0059] 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.

[0060] [Substrate removal process] The substrate removal step is a step of removing the aluminum substrate after the metal 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.

[0061] <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 that has a lower ionization tendency than aluminum and has a pH (hydrogen ion exponent) of 4 or less or 8 or more, more preferably a pH of 3 or less or 9 or more, and even more preferably a pH of 2 or less or 10 or more.

[0062] 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.

[0063] The acid or alkali concentration of the treatment solution for dissolving aluminum is preferably 0.01 to 10 mol / L, more preferably 0.05 to 5 mol / L. Furthermore, the treatment temperature using a treatment liquid that dissolves aluminum is preferably from -10°C to 80°C, and more preferably from 0°C to 60°C.

[0064] 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.

[0065] Incidentally, for example, a support may be provided on the insulating film 12. The support preferably has the same outer shape as the insulating film 12. By attaching a support, handling becomes easier.

[0066] [Protrusion process] To partially remove the insulating film 12, for example, an acidic or alkaline aqueous solution is used that dissolves the insulating film 12, i.e., aluminum oxide (Al2O3), but not the metal that constitutes the conductor 14. The insulating film 12 having the pores 13 filled with the metal is brought into contact with the acidic or alkaline aqueous solution to partially remove the insulating film 12. The method for bringing the acidic or alkaline aqueous solution into contact with the insulating film 12 is not particularly limited, and examples include a dipping method and a spraying method. Of these, the dipping method is preferred.

[0067] 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 because of its 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.

[0068] 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.

[0069] Furthermore, the metal 35, i.e., the conductor 14, is caused to protrude from the front surface 12a or the back surface 12b of the insulating film 12, preferably by 10 nm to 1000 nm, more preferably by 50 nm to 500 nm, from the front surface 12a or the back surface 12b of the insulating film 12. That is, the protrusion amount of the protrusion 14a from the front surface 12a and the protrusion amount of the conductor 14 from the back surface 12b of the protrusion 14b are each preferably 10 nm to 1000 nm, more preferably 50 nm to 500 nm. The height of the protrusions 14a and 14b of the conductor 14 is the average value of the heights of the conductor protrusions measured at 10 points when the cross section of the structure 10 is observed at 20,000 magnifications using a field emission scanning electron microscope.

[0070] When the height of the protruding portion of the conductor 14 needs to be strictly controlled, it is preferable to fill the inside of the pore 13 with a conductive material such as a metal, process the insulating film 12 and the end of the conductive material such as a metal so that they are flush with each other, and then selectively remove the anodic oxide film. After the above-mentioned metal filling or protruding step, a heat treatment can be carried out in order to reduce distortion in the conductor 14 caused by 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 insulating film 12 for the purpose of correction.

[0071] [Method of manufacturing the bonded body] Another aspect of the present invention provides a method for manufacturing a bonded body, which includes a bonding step of bonding a conductive member having a conductive portion with the above-mentioned structure by contacting the conductor of the structure with the conductive portion. As a method for manufacturing a bonded body, a method for manufacturing a laminated device 40 having an anisotropically conductive member 45 shown in FIG. 10 will be described. 12 and 13 are schematic cross-sectional views showing an example of a method for manufacturing a bonded body according to an embodiment of the present invention in the order of steps. In Fig. 12 and Fig. 13, the same components as those in the stacked device 40 and semiconductor elements 42, 44 shown in Fig. 10 and Fig. 11 are designated by the same reference numerals, and detailed description thereof will be omitted. The manufacturing method of the stacked device 40 shown in FIGS. 12 and 13 relates to chip-on-chip.

[0072] When manufacturing the laminated device 40 having the anisotropically conductive member 45, first, the semiconductor element 42, the semiconductor element 44, and the anisotropically conductive member 45 shown in FIG. 12 are prepared. The semiconductor element 42 has, for example, a semiconductor element portion 50 provided with a plurality of electrodes 52 for exchanging signals with the outside or for transmitting and receiving voltage or current. The electrodes 52 are electrically insulated by an insulating layer 54. The electrodes 52 protrude, for example, from a surface 54a of the insulating layer 54.

[0073] The semiconductor element 44 has the same configuration as the semiconductor element 42. The semiconductor element 44 is, for example, an interposer substrate 51 provided with a plurality of electrodes 53 for transmitting and receiving signals or voltages or currents to and from the outside. The electrodes 53 are electrically insulated by an insulating layer 55. The electrodes 53 protrude, for example, from a surface 55a of the insulating layer 55. The interposer substrate 51 has, for example, a lead wiring layer, and the electrodes 53 electrically connect the laminated device 40 to the outside.

[0074] The anisotropically conductive member 45 includes a plurality of conductors 14, each having a protruding portion 14a protruding from the front surface 12a of the insulating film 12 and a protruding portion 14b protruding from the back surface 12b. Furthermore, a resin layer 20 is partially provided on each of the front surface 12a and the back surface 12b of the insulating film 12. Note that the anisotropically conductive member 45 has the same configuration as the above-described structure 10, and therefore a detailed description thereof will be omitted.

[0075] As shown in FIG. 12, the semiconductor element 42 and the semiconductor element 44 are arranged with the anisotropically conductive member 45 sandwiched therebetween, with the electrodes 53 and 52 facing each other. At this time, the semiconductor elements 42 and 44 and the anisotropically conductive member 45 are aligned using alignment marks (not shown) provided thereon. 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.

[0076] Next, the semiconductor element 42, the anisotropically conductive member 45, and the semiconductor element 44 are brought close to each other, and stacked as shown in Fig. 13, and with the semiconductor element 42, the anisotropically conductive member 45, and the semiconductor element 44 aligned, the semiconductor element 42, the anisotropically conductive member 45, and the semiconductor element 44 are bonded together. In this way, the semiconductor element 42, the anisotropically conductive member 45, and the semiconductor element 44 are bonded together, and the stacked device 40 can be obtained. In this way, a bonded body can be obtained by a bonding step in which a conductive member having a conductive portion with conductivity and a structure are bonded by bringing the conductor of the structure into contact with the conductive portion. In the anisotropically conductive member 45, the resin layer 20 is partially provided on each of the front surface 12a and the back surface 12b of the insulating film 12. This prevents charging when the anisotropically conductive member 45 is transported, facilitating handling, and allows the anisotropically conductive member 45 to be easily disposed between the semiconductor element 42 and the semiconductor element 44. Furthermore, since the resin layer 20 is partially provided during bonding, the force required for bonding can be reduced.

[0077] [An example of a manufacturing method for a stacked device] Next, an example of a method for manufacturing a device using the structure will be described using the stacked device 40 shown in FIG. 10 as an example. An example of a method for manufacturing a stacked device using a structure relates to a chip-on-wafer. 14 to 16 are schematic diagrams showing an example of a method for manufacturing a multilayer device using the structure according to the embodiment of the present invention in the order of steps. In one example of a method for manufacturing a stacked device using a structure, a first semiconductor wafer 60 has a plurality of element regions (not shown) on a surface 60a thereof, and an anisotropically conductive member 45 is provided for each element region. Next, the semiconductor element 44 is placed facing c on the first semiconductor wafer 60. The semiconductor element 44 has electrodes (not shown). Next, the alignment marks of the semiconductor element 44 and the alignment marks of the first semiconductor wafer 60 are used to align the semiconductor element 44 with the first semiconductor wafer 60 . Regarding alignment, the configuration is not particularly limited as long as digital image data can be obtained for the image or reflected image of the alignment mark on the first semiconductor wafer 60 and the image or reflected image of the alignment mark on the semiconductor element 44, and any known imaging device can be used as appropriate.

[0078] Next, the semiconductor elements 44 are placed on the anisotropically conductive member 45 provided in the element region of the first semiconductor wafer 60, and temporarily bonded by, for example, applying a predetermined pressure, heating to a predetermined temperature, and maintaining the temperature for a predetermined time. This is performed for all of the semiconductor elements 44, and all of the semiconductor elements 44 are temporarily bonded to the element region of the first semiconductor wafer 60, as shown in FIG. For the temporary bonding, for example, a resin layer 20 (see FIG. 1) provided partially is used. However, the use of the resin layer 20 (see FIG. 1) is not limited to this. For example, a sealing resin or the like may be supplied onto the anisotropic conductive member 45 of the first semiconductor wafer 60 using a dispenser or the like to temporarily bond the semiconductor element 44 to the element region of the first semiconductor wafer 60, or an insulating resin film (NCF (Non-conductive Film)) previously supplied onto the first semiconductor wafer 60 may be used to temporarily bond the semiconductor element 44 to the element region.

[0079] Next, with all of the semiconductor elements 44 temporarily bonded to the element regions of the first semiconductor wafer 60, a predetermined pressure is applied to the semiconductor elements 44, the semiconductor elements 44 are heated to a predetermined temperature, and held for a predetermined time, thereby bonding all of the semiconductor elements 44 together to the element regions of the first semiconductor wafer 60 via the anisotropically conductive member 45. This bonding is called "full bonding." As a result, the terminals (not shown) of the semiconductor elements 44 are bonded to the anisotropically conductive member 45 of the first semiconductor wafer 60. During the full bonding, the resin layer 20 (see FIG. 1) is partially provided, so the force required for bonding can be reduced. This full bonding corresponds to a bonding process in which the electrodes of the semiconductor elements 44 are bonded to the anisotropically conductive member 45, i.e., the structure 10, by contacting the conductors of the structure with the electrodes of the semiconductor elements 44. 16, the first semiconductor wafer 60 to which the semiconductor elements 44 are bonded is divided into individual element regions by dicing, laser scribing, or the like. This makes it possible to obtain a stacked device 40 in which the semiconductor elements 42 and the semiconductor elements 44 are bonded together.

[0080] In addition, if the temporary bonding strength is weak, misalignment will occur during the transport process and the process leading up to bonding, and therefore the temporary bonding strength is important. The temperature conditions and pressure conditions in the temporary bonding step are not particularly limited, and examples thereof include the temperature conditions and pressure conditions described below.

[0081] The temperature and pressure conditions for the main bonding are not particularly limited. By performing the main bonding under appropriate conditions, the resin layer flows between the electrodes of the semiconductor element 44 and is less likely to remain in the bonded portion. As described above, in the main bonding, by bonding multiple semiconductor elements 44 at once, the takt time can be reduced and productivity can be increased. The stacked device 40 having the configuration shown in Fig. 11 can also be manufactured as described above. In addition, the stacked devices 40 shown in Fig. 10 and Fig. 11 can also be manufactured by a wafer-on-wafer manufacturing method.

[0082] The semiconductor elements 42, 44, and 46 each have an element region (not shown). The element region is as described above. As described above, the element region has an element configuration circuit and the like formed therein, and the semiconductor elements are provided with, for example, a rewiring layer (not shown). The stacked device may be, for example, a combination of semiconductor elements having logic circuits and semiconductor elements having memory circuits. Furthermore, all of the semiconductor elements may have memory circuits, or all of the semiconductor elements may have logic circuits. The combination of semiconductor elements in the stacked device 40 may be a combination of a sensor, an actuator, an antenna, or the like, with a memory circuit and a logic circuit, and is determined appropriately depending on the application of the stacked device 40.

[0083] [Objects to be joined in the structure] As mentioned above, the object to be bonded to the structure is exemplified by a semiconductor element, but it can also be, for example, an object having an electrode or an element region. An example of an object having an electrode is a semiconductor element that performs a specific function by itself, but it can also include an object in which a plurality of elements are assembled to perform a specific function. Furthermore, it also includes an object that simply transmits an electrical signal, such as a wiring member, and a printed wiring board or the like is also included in the object having an electrode. 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, MEMS (Micro Electro Mechanical Systems) may also be formed in the element region. Examples of MEMS include sensors, actuators, and antennas. Examples of sensors include various sensors for acceleration, sound, light, and the like. 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 bonded to an object to be bonded, but the object to be bonded is not particularly limited to the above-mentioned semiconductor elements, etc., and examples of the object to be bonded include semiconductor elements in wafer state, semiconductor elements in chip state, printed wiring boards, and heat sinks.

[0084] [Semiconductor element] The semiconductor elements 42, 44, and 46 may be, in addition to those mentioned above, 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 Memorys), ReRAMs (Resistive RAMs), FeRAMs (Ferroelectric RAMs), flash memories (NAND (Not AND) flash), etc.), LEDs (Light Emitting Diodes) (e.g., micro flash for mobile terminals, in-vehicle devices, projector light sources, LCD backlights, general lighting, etc.), power devices, analog ICs (Integrated Circuits), etc. Circuit), (e.g., DC (Direct Current)-DC (Direct Current) converters, insulated gate bipolar transistors (IGBT), 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 Array)Examples include semiconductor devices such as semiconductor integrated circuits (ICs), contact image sensors (CISs), camera modules, complementary metal oxide semiconductors (CMOSs), passive devices, surface acoustic wave (SAW) filters, radio frequency (RF) filters, RFIPDs (Radio Frequency Integrated Passive Devices), and broadband (BB). 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, bonding is possible even if the electrode sizes of each device are different. Note that the stacked device is not limited to a one-to-multiple configuration in which multiple semiconductor elements are bonded to one semiconductor element, but may also be a multiple-to-multiple configuration in which multiple semiconductor elements are bonded to multiple semiconductor elements.

[0085] The present invention is basically configured as described above. While the plating solution, the structure, the method for manufacturing the structure, the method for manufacturing the bonded body, and the method for manufacturing the device 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]

[0086] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0087] [Example 1] <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 thick and 1200 mm wide 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. This aluminum substrate was cut to a width of 1030 mm and then subjected to the following treatments.

[0088] <Electrolytic polishing treatment> The 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). (Electrolytic polishing liquid composition) 85% by weight phosphoric acid (reagent manufactured by Wako Pure Chemical Industries, Ltd.) 660 mL ·Pure water 160mL ·Sulfuric acid 150mL 30mL of ethylene glycol

[0089] <Anodizing process> Next, the aluminum substrate after the electrolytic polishing treatment was subjected to anodizing treatment by a self-ordering method according to 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 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 30 μm. In both pre-anodizing and re-anodizing treatments, a stainless steel cathode was used, and a GP0110-30R power supply (manufactured by Takasago Manufacturing 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 electrolyte flow rate was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE Corporation).

[0090] <Barrier layer removal process> Next, after the anodizing treatment step, an etching treatment was performed by immersing the substrate in an alkaline aqueous solution of sodium hydroxide (50 g / l) with zinc oxide dissolved to a concentration of 2000 ppm at 30°C for 150 seconds, thereby removing the barrier layer at the bottom of the micropores in the anodized film and simultaneously depositing zinc on the surface of the exposed aluminum substrate. The average thickness of the anodized film after the barrier layer removal step (i.e., the average depth of the micropores) was 30 μm. Since the average opening diameter of the micropores was 60 nm, the aspect ratio (average depth / average opening diameter) was 500.

[0091] <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 carried out to produce a metal-filled structure in which copper was filled into the inside of the micropores. 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 Sodium 3-mercapto-1-propanesulfonate (MPS) 50mg / L ·Temperature 25℃ ·Current density 10A / dm 2

[0092] [Example 2] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 10 mg / L.

[0093] [Example 3] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 3 mg / L.

[0094] [Example 4] A metal-filled structure was produced in the same manner as in Example 1, except that in the metal filling step, MPS in the copper plating solution composition was changed to sodium 2-mercapto-5-benzimidazole sulfonate.

[0095] [Example 5] A metal-filled structure was produced in the same manner as in Example 1, except that in the metal filling step, MPS in the copper plating solution composition was changed to 3-mercapto-1,2-propanediol.

[0096] [Example 6] A metal-filled structure was produced in the same manner as in Example 1, except that 50 mg / L of 3,3'-dithiobis(sodium propanesulfonate) was added to the copper plating solution composition in the metal filling step.

[0097] [Example 7] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 300 mg / L.

[0098] [Example 8] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 500 mg / L.

[0099] [Example 9] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution composition in the metal filling step was set to 1000 mg / L.

[0100] [Example 10] A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 0.1 mg / L.

[0101] [Examples 11 to 14] A metal-filled structure was produced in the same manner as in Example 1, except that in the metal filling step, the contents of MPS and 3,3'-dithiobis(sodium propanesulfonate) in the copper plating solution composition were set to the values ​​shown in Table 1 below.

[0102] [Example 15] A metal-filled structure was produced in the same manner as in Example 1, except that the re-anodizing treatment time was shortened and an anodized film with a thickness of 10 μm was formed in the anodizing treatment step. As in Example 1, the average opening diameter of the micropores was 60 nm, and therefore the aspect ratio (average depth / average opening diameter) was 167.

[0103] [Example 16] A metal-filled structure was produced in the same manner as in Example 1, except that the plating solution used in the metal filling step was changed to the following composition and conditions. (Nickel plating solution composition and conditions) Nickel sulfate 300g / L Nickel chloride 60g / L ·Boric acid 40g / L Sodium 3-mercapto-1-propanesulfonate (MPS) 50mg / L ·Temperature 50℃ ·Current density 10A / dm 2

[0104] [Comparative Example 1] A metal-filled structure was produced in the same manner as in Example 1, except that MPS was not added to the copper plating solution composition in the metal filling step.

[0105] Comparative Example 2 A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 2000 mg / L.

[0106] Comparative Example 3 A metal-filled structure was produced in the same manner as in Example 1, except that the content of MPS in the copper plating solution in the metal filling step was set to 0.01 mg / L.

[0107] [evaluation] <Filling height variation> The metal packed structures produced in Examples 1 to 16 and Comparative Examples 1 to 3 were cut in the thickness direction using FIB, and their cross sections were photographed using FE-SM. The heights of the highest and lowest packed heights were measured and the difference calculated. Similar measurements and calculations were performed on five cross sections, and the average value of the differences was taken as the packing height variation. The results are shown in Table 1 below.

[0108] [Table 1]

[0109] The results shown in Table 1 reveal that when a plating solution not containing a compound having a mercapto group was used, the variation in filling height exceeded 20 μm (Comparative Example 1). Furthermore, it was found that when the content of the compound having a mercapto group was 2000 mg / L, filling defects occurred (Comparative Example 2). Furthermore, it was found that when the content of the compound having a mercapto group was 0.01 mg / L, the variation in the filling height exceeded 20 μm (Comparative Example 3). In contrast, when a plating solution containing a compound having a mercapto group was used, the variation in filling height was found to be 20 μm or less (Examples 1 to 16). Furthermore, a comparison of Examples 1, 4 and 5 revealed that when the compound having a mercapto group is sulfonic acid or a salt thereof, the variation in filling height can be further suppressed. Furthermore, a comparison between Example 1 and Example 4 revealed that when the compound having a mercapto group is sodium 3-mercapto-1-propanesulfonate, the variation in filling height can be further suppressed. Furthermore, a comparison of Examples 1 to 3 and 7 to 10 revealed that when the content of the compound having a mercapto group is 0.1 to 1000 mg / L, the variation in filling height can be further suppressed. For the same reason, it was found that the content of the compound having a mercapto group is more preferably 1 to 500 mg / L, even more preferably 10 to 400 mg / L, and most preferably 20 to 300 mg / L. Furthermore, a comparison between Example 1 and Example 15 revealed that when the aspect ratio (average depth / average opening diameter) of the through holes filled with metal is 500 to 5000, the effect of suppressing variations in the filling height of the metal filled into the through holes becomes more pronounced. [Explanation of symbols]

[0110] 10 Structure 12 insulating film 12a surface 12b Back 13 pores 14 Conductors 14a Protrusion 14b Projection 15 Anodic oxide film 20, 21, 22 Resin layers 20a, 22a Resin layer part 20b, 22b space 30 Aluminum substrate 30a surface 31 Barrier Layer 32c bottom 32d surface 35 metal 35a metal layer 35b metal 40 Stacked Devices 41 Zygote 42, 44, 46 Semiconductor elements 45 Anisotropic conductive material 50 Semiconductor Device Section 51 Interposer board 52, 53 electrode 54, 55 Insulation layer 54a, 55a, 60a surface 60 First semiconductor wafer Ds stacking direction Dt thickness direction d average diameter H Height hm average thickness ht Thickness p Center distance

Claims

1. A plating solution used when filling metal into a structure having a plurality of through holes, the plating solution comprising: The electrolytic solution contains a metal salt to be filled into the through holes and a compound having a mercapto group, The plating solution has a content of the compound having a mercapto group of 20 to 300 mg / L.

2. The plating solution according to claim 1 , wherein the compound having a mercapto group includes a sulfonic acid or a salt thereof.

3. 3. The plating solution according to claim 1, wherein the compound having a mercapto group includes sodium 3-mercapto-1-propanesulfonate.

4. 4. The plating solution according to claim 1, wherein the ratio of the depth to the opening diameter of the plurality of through holes is 10 or more.

5. A method for manufacturing a metal-filled structure, which is manufactured by filling a metal into a structure having a plurality of through holes, the through holes comprising: A method for producing a metal-filled structure, wherein the plating solution according to any one of claims 1 to 4 is used when filling the through holes of the structure with metal.

Images