Metal-filled microstructures

Abstract

To provide a metal-filled microstructure that can achieve excellent conduction reliability when used as an anisotropically conductive joining member.SOLUTION: A metal-filled microstructure includes an insulating base material made of an inorganic material, and a plurality of conductive paths made of conductive members, penetrating in the thickness direction of the insulating base material, and insulated from each other. Each of the conductive paths has a protruding portion protruding from the surface of the insulating base material, and the surface of the protruding portion is in contact with a layer containing non-azole organic molecules having acid groups and nitrogen atoms.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to metal-filled microstructures. [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 anisotropic conductive bonding materials. This anisotropic conductive bonding member 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. Therefore, it is widely used as an electrical connecting member for electronic components such as semiconductor elements, and as an inspection connector for functional testing. In particular, electronic components such as semiconductor elements are becoming significantly smaller, and conventional methods such as wire bonding, which directly connects wiring boards, flip-chip bonding, and thermocompression bonding cannot fully guarantee connection stability. Therefore, anisotropic conductive bonding materials are attracting attention as electronic connection materials.

[0003] As an example of such an anisotropic conductive bonding member, Patent Document 1 describes a conductive path protruding from the surface of an insulating substrate, which is embedded in an adhesive layer containing an antioxidant material and a polymer material ([Claim 1]). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 150058 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have examined the metal-filled microstructures used as anisotropic conductive joining members described in Patent Document 1 and have found that, depending on the type of antioxidant material contained in the adhesive layer, oxidation of the protruding portions of the conductive paths may progress over time, resulting in poor conductivity reliability.

[0006] Therefore, an object of the present invention is to provide a metal-filled microstructure that can achieve excellent electrical connection reliability when used as an anisotropic conductive joining member. [Means for solving the problem]

[0007] As a result of intensive research to achieve the above object, the inventors have found that excellent conduction reliability can be achieved by bringing the surface of the protruding portion of the conductive path into contact with a layer containing non-azole organic molecules having an acid group and a nitrogen atom, and have completed the present invention. That is, the present inventors have found that the above problems can be solved by the following configuration.

[0008] [1] A metal-filled microstructure having an insulating base material made of an inorganic material and a plurality of conductive paths made of a conductive material that penetrate the insulating base material in a thickness direction and are insulated from each other, each conductive path having a protruding portion protruding from a surface of the insulating substrate; The metal-filled microstructure has a surface of the protruding portion in contact with a layer containing non-azole organic molecules having an acid group and a nitrogen atom. [2] The metal-filled microstructure according to [1], wherein the non-azole organic molecule has a plurality of acid groups. [3] The metal-filled microstructure according to [1] or [2], wherein the non-azole organic molecule has three or more acid groups. [4] The metal-filled microstructure according to any one of [1] to [3], wherein the acid group is a carboxyl group. [5] The metal-filled microstructure according to any one of [1] to [4], wherein the non-azole organic molecule has one or two nitrogen atoms. [6] The metal-filled microstructure according to any one of [1] to [5], wherein the non-azole organic molecule is nitrilotriacetic acid. [7] The metal-filled microstructure according to any one of [1] to [6], wherein the protruding portions are copper. [Effects of the Invention]

[0009] As will be described below, the present invention can provide a metal-filled microstructure that can achieve excellent electrical connection reliability when used as an anisotropic conductive joining member. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view of a schematic diagram showing an example of a preferred embodiment of a metal-filled microstructure of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line IB-IB in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing another preferred embodiment of the metal-filled microstructure 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. In addition, in this specification, each component may be a single substance corresponding to the component, or two or more substances may be used in combination. Here, when two or more substances are used in combination for each component, the content of that component refers to the total content of the substances used in combination, unless otherwise specified.

[0012] [Metal-filled microstructure] The metal-filled microstructure of the present invention comprises an insulating substrate made of an inorganic material and a plurality of conductive paths made of a conductive material that penetrate the insulating substrate in the thickness direction and are insulated from each other. Each conductive path has a protruding portion protruding from the surface of the insulating substrate, and the surface of the protruding portion of each conductive path is in contact with a layer containing a non-azole organic molecule having an acid group and a nitrogen atom (hereinafter also abbreviated as "specific organic molecule-containing layer").

[0013] In the present invention, as described above, excellent conduction reliability can be achieved by bringing the surface of the protruding portion of the conductive path into contact with the specific organic molecule-containing layer. Although the mechanism is not clear in detail, it is presumed to be as follows. That is, since the surface of the protruding portion of the conductive path is made of a conductive material, oxidation progresses over time. Note that oxidation over time is thought to progress even if the protruding portion of the conductive path is embedded in the adhesive layer. Therefore, in the present invention, it is believed that by contacting the surface of the protruding portion of the conductive path with the specific organic molecule-containing layer, the organic molecules are adsorbed or coordinated to the surface of the protruding portion of the conductive path via the acid groups, thereby suppressing oxidation over time. It is also presumed that this is because the organic molecules contain nitrogen atoms, which have high coordination properties with metals, and that this allows for both oxidation suppression and desorption upon heating, which is due to the fact that the organic molecules are non-azole-based.

[0014] Next, the configuration of the metal-filled microstructure of the present invention will be described with reference to FIGS. The metal-filled microstructure 1 shown in FIGS. 1 and 2 has an insulating substrate 2 and a plurality of conductive paths 3 made of a conductive material. As shown in Figures 1 and 2, the conductive paths 3 are insulated from each other and are provided so as to penetrate the insulating substrate 2 in the thickness direction Z (Z1: direction from the back surface to the front surface in Figure 1, Z2: direction from the front surface to the back surface in Figure 1). Furthermore, as shown in FIG. 2, the conductive path 3 has protruding portions 3a and 3b protruding from the surfaces 2a and 2b of the insulating substrate 2, and the surfaces of these protruding portions 3a and 3b are in contact with the specific organic molecule-containing layer 4. Here, "insulated from each other" means that the conductive paths present inside (in the thickness direction of) the insulating base material are insulated from each other inside the insulating base material. Furthermore, the manner in which the surfaces of the protruding portions 3a and 3b come into contact with the specific organic molecule-containing layer 4 may be the manner shown in FIG. 2, i.e., the manner in which the specific organic molecule-containing layer 4 is coated along the shapes of the protruding portions 3a and 3b, or the manner shown in FIG. 3, i.e., the manner in which the protruding portions 3a and 3b are embedded in the specific organic molecule-containing layer 4. Next, the materials, dimensions, forming methods, etc. of the insulating substrate, conductive paths, and specific organic molecule-containing layer of the metal-filled microstructure of the present invention will be described.

[0015] [Insulating substrate] The insulating substrate of the metal-filled microstructure of the present invention is made of an inorganic material and has electrical resistivity (10 14 There are no particular limitations as long as the material has a resistivity of about Ω·cm. The term "made of inorganic material" does not limit the insulating base material to one made of inorganic material only, but refers to an insulating base material whose main component is inorganic material (50% by mass or more).

[0016] Examples of the insulating substrate include metal oxide substrates, metal nitride substrates, glass substrates, ceramic substrates (e.g., silicon carbide, silicon nitride, etc.), carbon substrates (e.g., diamond-like carbon, etc.), polyimide substrates, and composite materials thereof. Alternatively, the insulating substrate may be a material in which a film is formed on an organic material having through holes with an inorganic material containing 50% by mass or more of a ceramic material or a carbon material.

[0017] In the present invention, the insulating substrate is preferably a metal oxide substrate, and more preferably an anodized film of a valve metal, because micropores having a desired average opening diameter are formed as through-holes, and the conductive paths described below are easily formed. Specific examples of the valve metal 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.

[0018] In the present invention, the thickness of the insulating base material (the portion indicated by reference numeral 6 in FIG. 2) is preferably 1 μm to 1000 μm, more preferably 5 μm to 500 μm, and even more preferably 10 μm to 300 μm. When the thickness of the insulating base material is in this range, the insulating base material becomes easy to handle. Here, the thickness of the insulating substrate refers to the average value of thicknesses measured at 10 points on the cross section of the metal-filled microstructure observed with a field emission scanning electron microscope.

[0019] In the present invention, the interval between the conductive paths in the insulating base material 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 interval between the conductive paths in the insulating base material is within this range, the insulating base material functions satisfactorily as an insulating partition wall. Here, the spacing between each conductive path refers to the width between adjacent conductive paths (the part indicated by the symbol 7 in Figure 2), and refers to the average value of the width between adjacent conductive paths measured at 10 points when the cross section of the metal-filled microstructure is observed at a magnification of 200,000 times using a field emission scanning electron microscope.

[0020] [Conduction path] The plurality of conductive paths in the metal-filled microstructure of the present invention are conductive paths made of a conductive material that penetrate the insulating substrate in the thickness direction and are insulated from one another. The conductive paths have protruding portions that protrude from the surface of the insulating substrate, and the surface of the protruding portion of each conductive path is in contact with a specific organic molecule-containing layer, which will be described later.

[0021] <Conductive materials> The conductive material constituting the conductive path has an electrical resistivity of 10 3 There are no particular limitations on the material as long as it has a resistivity of Ω·cm or less, and specific examples of suitable materials include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), and indium-doped tin oxide (ITO). Among these, from the viewpoint of electrical conductivity, copper, gold, aluminum, and nickel are preferred, copper and gold are more preferred, and copper is even more preferred.

[0022] <Protruding part> The protruding portion of the conductive path is a portion of the conductive path that protrudes from the surface of the insulating substrate, and the surface of the protruding portion is in contact with the specific organic molecule-containing layer, which will be described later.

[0023] In the present invention, when the metal-filled microstructure is used as an anisotropic conductive joining member, the aspect ratio (height of the protruding portion / diameter of the protruding portion) of the protruding portion of the conductive path is preferably 0.5 or more and less than 50, more preferably 0.8 to 20, and even more preferably 1 to 10, in order to ensure sufficient insulation in the planar direction in the event that the protruding portion is crushed when connecting (joining) the metal-filled microstructure to an electrode by a method such as crimping.

[0024] Furthermore, in the present invention, when the metal-filled microstructure is used as an anisotropic conductive joining member, from the viewpoint of conforming to the surface shape of the semiconductor chip or wiring board to be connected, the height of the protruding portion of the conductive path is preferably 50 nm to 3000 nm, more preferably 100 to 2000 nm, and even more preferably 200 to 1000 nm. Similarly, the diameter of the protruding portion of the conductive path is preferably more than 5 nm and not more than 10 μm, and more preferably 20 nm to 1000 nm. Here, the height of the protruding portion of the conductive path refers to the average value of the height of the protruding portion of the conductive path measured at 10 points when the cross section of the metal-filled microstructure is observed at 20,000 magnification using a field emission scanning electron microscope. Similarly, the diameter of the protruding portion of the conductive path is the average value of the diameters of the protruding portions of the conductive path measured at 10 points when the cross section of the metal-filled microstructure is observed with a field emission scanning electron microscope.

[0025] <Other shapes> The conductive paths are columnar, and their diameter (the part indicated by reference numeral 8 in FIG. 2) is preferably more than 5 nm and not more than 10 μm, similar to the diameter of the protruding parts, and more preferably 20 nm to 1000 nm.

[0026] The conductive paths are insulated from one another by the insulating substrate, and their density is 20,000 / mm 2 It is preferable that the number of particles 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 density is 100 million / mm or more. 2 This is most preferable.

[0027] Furthermore, the center-to-center distance between adjacent conductive paths (the portion indicated by reference numeral 9 in FIGS. 1 and 2) is preferably 20 nm to 500 nm, more preferably 40 nm to 200 nm, and even more preferably 50 nm to 140 nm.

[0028] [Specific organic molecule-containing layer] The specific organic molecule-containing layer of the metal-filled microstructure of the present invention is a layer containing a non-azole organic molecule having an acid group and a nitrogen atom. Here, the specific organic molecule-containing layer is in contact with the surface of the protruding portion of the conductive path, and the form of this contact may be, as described above, a form in which the specific organic molecule-containing layer is coated along the shape of the protruding portion of the conductive path, or a form in which the protruding portion of the conductive path is embedded in the specific organic molecule-containing layer. Of these forms, the form in which the specific organic molecule-containing layer is coated along the shape of the protruding portion of the conductive path is preferred because it provides better conduction reliability and better adhesion to the semiconductor chip or the like to be connected.

[0029] <Non-azole organic molecules> The non-azole organic molecules contained in the specific organic molecule-containing layer are, as described above, non-azole compounds having an acid group and a nitrogen atom. Here, the non-azole compounds refer to compounds that do not fall under the category of five-membered heterocyclic compounds containing one or more nitrogen atoms (e.g., triazole compounds, tetrazole compounds, benzotriazole compounds, etc.).

[0030] Examples of the acid group contained in the non-azole organic molecule include a carboxyl group, a sulfo group, a phosphate group, and a phenolic hydroxyl group. Of these, a carboxylic acid group is preferred because it has an acidity that ensures a sufficient amount of adsorption without corroding the substrate, and a polarity that allows easy desorption by heating.

[0031] In the present invention, the non-azole organic molecule preferably has a plurality of acid groups. Furthermore, for reasons of improving the conduction reliability, the non-azole organic molecule preferably has three or more acid groups, and more preferably has three or four acid groups. Furthermore, it is particularly preferable that the non-azole organic molecule has three acid groups, because this improves adhesion to the semiconductor chip or the like to be connected.

[0032] In the present invention, the non-azole organic molecule preferably has one or two nitrogen atoms from the viewpoint of achieving both the ability to adsorb or coordinate to the filling metal and the ability to be desorbed by heating.

[0033] In the present invention, the molar mass of the non-azole organic molecule is not particularly limited, but is preferably 100 to 500 g / mol, and more preferably 150 to 300 g / mol, in order to improve adhesion to the semiconductor chip or the like to be connected.

[0034] Examples of non-azole organic molecules include aminopolycarboxylic acids, amino acids, sulfo group-containing organic molecules, phosphate group-containing organic molecules, and phenolic hydroxyl group-containing organic molecules. Specific examples of aminopolycarboxylic acids include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), ethylenediaminediacetic acid (EDDA), and ethyleneglycoldiethyletherdiaminetetraacetic acid (GEDA). Specific examples of amino acids include glycine, aminosuccinic acid, valine, leucine, and isoleucine. Specific examples of sulfo group-containing organic molecules include 3-pyridinesulfonic acid and 1-naphthylamine-2,7-disulfonic acid. Specific examples of the phosphate group-containing organic molecule include N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid) and nitrilotrismethylenephosphonic acid. Specific examples of organic molecules containing a phenolic hydroxyl group include compounds such as p-aminophenol and 4-aminocatechol. These may be used alone or in combination of two or more. Of these, aminopolycarboxylic acids are preferred, ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are more preferred, and nitrilotriacetic acid (NTA) is even more preferred.

[0035] In the present invention, the content of the non-azole organic molecules contained in the specific organic molecule-containing layer is not particularly limited. However, in a mode in which the specific organic molecule-containing layer is coated along the shape of the protruding portion of the conductive path, the content is preferably 50 to 100 mass %, more preferably 70 to 100 mass %, and even more preferably 90 to 100 mass %, relative to the total mass of the specific organic molecule-containing layer. On the other hand, in an embodiment in which the protruding portion of the conductive path is embedded in the specific organic molecule-containing layer, the content of the non-azole organic molecule contained in the specific organic molecule-containing layer is preferably 0.01 to 10 mass %, more preferably 0.05 to 5 mass %, and even more preferably 0.1 to 3 mass %, relative to the total mass of the specific organic molecule-containing layer. Here, the content of the non-azole organic molecule being 100% by mass relative to the total mass of the specific organic molecule-containing layer means that the specific organic molecule-containing layer is composed of a single film of the non-azole organic molecule.

[0036] The thickness of the specific organic molecule-containing layer is not particularly limited, but in a mode in which the specific organic molecule-containing layer covers the shape of the protruding portion of the conductive path, it is preferably 0.1 to 10 nm, and more preferably 0.1 to 5 nm. On the other hand, in the case where the protruding portions of the conductive paths are embedded in the specific organic molecule-containing layer, the thickness of the specific organic molecule-containing layer is preferably 50 nm to 1500 nm, and more preferably 250 nm to 1000 nm. Here, the thickness of the specific organic molecule-containing layer refers to the average value of thicknesses measured at 10 points when the cross section of the metal-filled microstructure is observed under an electron microscope.

[0037] [Method of manufacturing metal-filled microstructures] The method for manufacturing the metal-filled microstructure of the present invention (hereinafter also formally referred to as the "manufacturing method of the present invention") is not particularly limited, but examples include a manufacturing method having a conductive path forming step in which the conductive material is present in the through hole provided in the insulating substrate to form the conductive path, a protruding step in which, after the conductive path forming step, only a portion of the surface of the insulating substrate is removed to make the conductive path protrude, and a specific organic molecule-containing layer forming step in which, simultaneously with or after the protruding step, a specific organic molecule-containing layer is formed on the surface of the insulating substrate and the protruding portion of the conductive path.

[0038] [Preparation of insulating substrate] The insulating substrate can be, for example, a glass substrate having a through hole (Through Glass Via: TGV) as it is. However, from the viewpoint of keeping the opening diameter of the conductive path and the aspect ratio of the protruding portion within the above-mentioned ranges, a method of subjecting a valve metal to an anodizing treatment is preferred. For example, when the insulating base material is an anodized aluminum film, the anodized aluminum substrate can be anodized and then perforated, in that order, to form micropores formed by the anodization. In the present invention, the aluminum substrate used in producing the insulating base material and the treatment steps performed on the aluminum substrate can be the same as those described in paragraphs

[0041] to

[0121] of JP 2008-270158 A.

[0039] [Conducting path formation process] The conductive path forming step is a step of causing the conductive material to be present in the through-holes provided in the insulating base material. Here, examples of methods for providing a metal in the through holes include methods similar to those described in paragraphs

[0123] to

[0126] and [Figure 4] of JP-A-2008-270158 (electrolytic plating method or electroless plating method). In the electrolytic plating method or electroless plating method, it is preferable to previously provide an electrode layer made of gold, nickel, copper, etc. Examples of methods for forming this electrode layer include gas phase treatments such as sputtering, liquid phase treatments such as electroless plating, and treatments combining these. The metal filling step provides a metal-filled microstructure before the protruding portions of the conductive paths are formed.

[0040] On the other hand, instead of the method described in JP 2008-270158 A, the above-mentioned conductive path forming process may be a method having steps including, for example, an anodizing process in which one surface (hereinafter also referred to as "one side") of an aluminum substrate is anodized to form an anodized film on one side 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 process in which the barrier layer of the anodized film is removed after the anodizing process; a metal filling process in which an electrolytic plating process is performed after the barrier layer removal process to fill metal inside the micropores; and a substrate removal process in which the aluminum substrate is removed after the metal filling process to obtain a metal-filled microstructure.

[0041] <Anodizing process> The anodizing process is a process of forming an anodized film on one side of the aluminum substrate by anodizing the surface of the aluminum substrate, the anodized film having micropores extending in the thickness direction and a barrier layer located at the bottom of the micropores. The anodizing treatment in the manufacturing method of the present invention can be performed using a conventionally known method, but from the viewpoint of increasing the regularity of the micropore arrangement and ensuring anisotropic conductivity, 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.

[0042] <Barrier layer removal process> The barrier layer removal step is a step of removing the barrier layer of the anodized film after the anodizing treatment step, and by removing the barrier layer, a part of the aluminum substrate is exposed through the micropores. The method for removing the barrier layer is not particularly limited, and examples thereof include a method of electrochemically dissolving the barrier layer at a potential lower than the potential in the anodizing treatment in the anodizing treatment step (hereinafter also referred to as "electrolytic removal treatment"); a method of removing the barrier layer by etching (hereinafter also referred to as "etching removal treatment"); and a method combining these (particularly a method of performing electrolytic removal treatment and then removing the remaining barrier layer by etching removal treatment).

[0043] <Electrolytic removal treatment> The electrolytic removal treatment is not particularly limited as long as it is an electrolytic treatment carried out at a potential lower than the potential (electrolytic potential) in the anodizing treatment in the anodizing treatment step. In the present invention, the electrolytic dissolution treatment can be carried out continuously with the anodizing treatment, for example, by lowering the electrolytic potential at the end of the anodizing treatment step.

[0044] In the electrolytic removal treatment, 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 electrolytic removal treatment and the anodizing treatment are carried out successively as described above, it is preferable to carry out the treatments using the same electrolyte.

[0045] (electrolytic potential) The electrolytic potential in the electrolytic removal treatment is preferably lowered continuously or stepwise (in steps) to a potential lower than the electrolytic potential in the anodizing treatment. Here, the reduction width (step width) when the electrolytic potential is reduced stepwise is preferably 10 V or less, more preferably 5 V or less, and even more preferably 2 V or less, from the viewpoint of the withstand voltage of the barrier layer. Furthermore, the voltage drop rate when the electrolytic potential is lowered continuously or stepwise is preferably 1 V / sec or less, more preferably 0.5 V / sec or less, and even more preferably 0.2 V / sec or less, from the viewpoint of productivity and the like.

[0046] Etching removal process The etching removal treatment is not particularly limited, but may be a chemical etching treatment in which an acid aqueous solution or an alkaline aqueous solution is used to dissolve the film, or may be a dry etching treatment.

[0047] (chemical etching process) The barrier layer can be removed by chemical etching, for example, by immersing the structure after the anodizing process in an acidic or alkaline aqueous solution, filling the micropores with the acidic or alkaline aqueous solution, and then contacting the surface of the anodized film on the micropore opening side with a pH buffer solution, thereby selectively dissolving only the barrier layer.

[0048] When an acidic 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. The concentration of the acidic aqueous solution is preferably 1 to 10% by mass. The temperature of the acidic aqueous solution is preferably 15 to 80°C, more preferably 20 to 60°C, and even more preferably 30 to 50°C. On the other hand, 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 10 to 60°C, more preferably 15 to 45°C, and even more preferably 20 to 35°C. The alkaline aqueous solution may contain zinc or other metals. 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, a 0.5 g / L, 30° C. aqueous solution of potassium hydroxide, etc. are preferably used. As the pH buffer solution, a buffer solution corresponding to the above-mentioned acidic aqueous solution or alkaline aqueous solution can be used appropriately.

[0049] The immersion time in the acid or alkaline aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and even more preferably 15 to 60 minutes.

[0050] (Dry etching process) In the dry etching process, it is preferable to use a gas species such as Cl2 / Ar mixed gas.

[0051] <Metal filling process> The metal filling step is a step of filling the interior of the micropores in the anodized film with metal by performing an electrolytic plating process after the barrier layer removal step, and examples of such a method include those described in paragraphs

[0123] to

[0126] and FIG. 4 of JP 2008-270158 A (electrolytic plating method or electroless plating method). In the electrolytic plating method or electroless plating method, the aluminum substrate exposed through the micropores after the barrier layer removal step can be used as an electrode.

[0052] <Substrate removal process> The substrate removal step is a step of removing the aluminum substrate after the metal filling step to obtain a metal-filled microstructure. Examples of methods for removing the aluminum substrate include a method in which a treatment liquid is used to dissolve only the aluminum substrate without dissolving the metal filled inside the micropores in the metal filling step or the anodized film serving as an insulating base material.

[0053] Examples of the treatment liquid include aqueous solutions of mercury chloride, bromine / methanol mixtures, bromine / ethanol mixtures, aqua regia, and hydrochloric acid / copper chloride mixtures, with hydrochloric acid / copper chloride mixtures being preferred. The concentration of the treatment liquid is preferably 0.01 to 10 mol / L, and more preferably 0.05 to 5 mol / L. The treatment temperature is preferably from -10°C to 80°C, more preferably from 0°C to 60°C.

[0054] [Protrusion process] The protruding step is a step of partially removing only the insulating base material on the surface of the metal-filled microstructure after the conductive path forming step, thereby protruding the conductive path. The treatment for protruding the conductive paths is not particularly limited as long as the conditions do not dissolve the metal that constitutes the conductive paths. For example, when using an acidic aqueous solution, 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 acidic aqueous solution is preferably 1 to 10 mass %. The temperature of the acidic aqueous solution is preferably 25 to 60°C. On the other hand, 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 50°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. The immersion time in the acid or alkaline 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.

[0055] In the manufacturing method of the present invention, when the height of the protruding portion of the conductive path is to be strictly controlled in the protruding step, it is preferable to process the insulating base material and the end of the conductive path so as to be flush with each other after the conductive path forming step, and then selectively remove (trim) the insulating base material. Here, examples of methods for processing into the same plane include physical polishing (for example, free abrasive polishing, back grinding, surface planing, etc.), electrochemical polishing, and polishing using a combination of these.

[0056] In the manufacturing method of the present invention, a heat treatment can be carried out after the conductive path forming step or the protruding step in order to reduce distortion in the conductive path that occurs due to filling with metal. The heat treatment is preferably carried out in a reducing atmosphere from the viewpoint of suppressing oxidation of the metal, specifically, the heat treatment is preferably carried out at an oxygen concentration of 20 Pa or less, and more preferably in a vacuum. Here, vacuum refers to a state of space with a lower gas density or pressure than the atmosphere. Furthermore, the heat treatment is preferably carried out while applying pressure to the material for the purpose of straightening.

[0057] [Specific organic molecule-containing layer formation process] The specific organic molecule-containing layer forming step is a step of forming a specific organic molecule-containing layer on the surface of the insulating substrate and on the protruding portions of the conductive paths simultaneously with or after the protruding step. Here, the method for forming the specific organic molecule-containing layer is not particularly limited, but when the specific organic molecule-containing layer is formed to cover the shape of the protruding portion of the conductive path, examples of the method include a method in which a solution in which the non-azole organic molecule described above is dissolved in a solvent (hereinafter also abbreviated as "specific organic molecule-containing layer-forming solution") is supplied to the protruding portion of the conductive path by a dipping method, a spraying method, a coating method, etc. Among these, the dipping method is preferred. The treatment time in the above method is preferably 10 to 180 seconds, more preferably 30 to 120 seconds. The pH of the solution for forming the specific organic molecule-containing layer may be set arbitrarily, but is preferably 6-14, more preferably 8-13, and even more preferably 9-12. The concentration of the non-azole organic molecule in the solution for forming the specific organic molecule-containing layer is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and even more preferably 0.1 to 3% by mass. The solvent used in the solution for forming the specific organic molecule-containing layer is not particularly limited as long as it dissolves non-azole organic molecules, and examples thereof include water, alcohol, ketones, ethers, and petroleum-based solvents. In the present invention, the specific organic molecule-containing layer forming step is preferably carried out simultaneously with the above-mentioned protruding step, because this improves the conduction reliability. When the specific organic molecule-containing layer forming step is carried out simultaneously with the above-mentioned protruding step, the specific organic molecule-containing layer forming solution can be a solution obtained by dissolving a non-azole organic molecule in an acid aqueous solution or an alkaline aqueous solution used in the treatment for protruding the conductive path.

[0058] On the other hand, in the case where the protruding portion of the conductive path is embedded in the specific organic molecule-containing layer, the specific organic molecule-containing layer may be formed, for example, by blending a non-azole organic molecule with a material used for the underfill material or adhesive layer and forming the layer as an underfill material or adhesive layer.

[0059] In the manufacturing method of the present invention, each of the above-mentioned steps can be performed on a sheet basis, or an aluminum coil can be used as a raw web for continuous processing. In the case of continuous treatment, it is preferable to provide an appropriate washing step and drying step between each step. [Example]

[0060] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. 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 should not be construed as being limited by the examples shown below.

[0061] [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.

[0062] <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

[0063] <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 sample was subjected to a re-anodizing treatment for 3 hours and 45 minutes in an electrolyte solution of 0.50 mol / L oxalic acid under the conditions of a voltage of 40 V, a liquid temperature of 16°C, and a liquid flow rate of 3.0 m / min, to obtain an anodized film with a 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).

[0064] <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 anodic oxide film after the barrier layer removal step was 30 μm.

[0065] <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 microstructure in which nickel was filled inside 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 ·Temperature 25℃ ·Current density 10A / dm 2

[0066] <Protrusion process (surface)> The structure after the metal filling process was immersed in a solution of potassium hydroxide aqueous solution (concentration: 5% by mass, liquid temperature: 20°C) in which nitrilotriacetic acid, a non-azole organic molecule, was dissolved to a concentration of 1% by mass. The immersion time was adjusted so that the height of the protruding parts was 400 nm, selectively dissolving the surface of the aluminum anodized film, causing the filling metal, copper, to protrude, and producing a structure in which a specific organic molecule-containing layer was in contact with the surface of the protruding parts of the copper.

[0067] <Resin substrate formation process> A thermally peelable resin substrate with an adhesive layer (REVALPHA 3195MS, manufactured by Nitto Denko Corporation) was attached to the surface on the side where the aluminum substrate was not provided. This resin substrate was used to support the structure produced in the "protrusion process (surface)" described above during the "substrate removal process" described below.

[0068] <Substrate removal process> Next, the aluminum substrate was dissolved and removed by immersion in a mixed solution of copper chloride and hydrochloric acid, to produce a metal-filled microstructure with an average thickness of 30 μm. The diameter of the conductive paths in the fabricated metal-filled microstructure was 60 nm, the pitch between the conductive paths was 100 nm, and the density of the conductive paths was 57.7 million / mm 2 It was.

[0069] <Protrusion process (back side)> After the substrate removal process, the structure was immersed in a solution of sodium hydroxide aqueous solution (concentration: 5% by mass, liquid temperature: 20°C) in which nitrilotriacetic acid, a non-azole organic molecule, was dissolved to a concentration of 1% by mass. The immersion time was adjusted so that the height of the protruding parts was 400 nm, selectively dissolving the surface of the aluminum anodized film, causing the filling metal, copper, to protrude, and producing a structure in which a specific organic molecule-containing layer was in contact with the surface of the protruding copper parts.

[0070] <Thermal peeling process> After the protruding step (rear surface), the substrate was heated at 110°C for 1 minute in the atmosphere, and the resin substrate was peeled off to produce a metal-filled microstructure.

[0071] [Example 2] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecules used in the front and back protrusion steps were changed to ethylenediaminetetraacetic acid.

[0072] [Example 3] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecules used in the front and back protrusion steps were changed to iminodiacetic acid.

[0073] [Example 4] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecules used in the front and back protrusion steps were changed to ethylenediaminediacetic acid.

[0074] [Example 5] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecules used in the front and back protrusion steps were changed to ethylene glycol diethyl ether diamine tetraacetic acid.

[0075] [Example 6] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that no non-azole organic molecules were used in the front and back protrusion processes, and a process of immersing the structure for 60 seconds in an aqueous solution (1 wt%, liquid temperature 25°C) containing nitrilotriacetic acid, a non-azole organic molecule, was added immediately after each of the front and back protrusion processes.

[0076] [Example 7] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that non-azole organic molecules were not used in the front and back protrusion processes, and the following underfill material was formed immediately after each of the front and back protrusion processes.

[0077] <Formation of underfill material> The materials shown below were mixed to prepare coating liquid 1. Next, the prepared coating solution 1 was applied to the front and back surfaces after the protrusion step using a spin coater to a thickness of 400 nm. ---------------------------------------------------------------------------------- Coating liquid 1 ---------------------------------------------------------------------------------- Methyl ethyl ketone 50 parts by mass Ethyl acrylate-acrylonitrile copolymer (Mw.1600000, copolymerization ratio 95:5) 16 parts by mass Maleimide compound (product name: BMI5100, Daiwa Chemical Industry Co., Ltd.) 21 parts by mass Bisphenol (product name: DABPA, (manufactured by Daiwa Chemical Industry Co., Ltd.) 12 parts by mass Nitrilotriacetic acid (Tokyo Chemical Industry Co., Ltd.) 1 part by mass ----------------------------------------------------------------------------------

[0078] [Example 8] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecule used in the front and back protrusion steps was changed to 1-naphthylamine-2,7-disulfonic acid.

[0079] [Example 9] A metal-filled microstructure was produced in the same manner as in Example 1, except that the non-azole organic molecules used in the front and back protrusion steps were changed to nitrilotrismethylenephosphonic acid.

[0080] [Example 10] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecule used in the front and back protrusion steps was changed to 4-aminocatechol.

[0081] [Comparative Example 1] A metal-filled microstructure was fabricated in the same manner as in Example 1, except that the non-azole organic molecules were not used in the front and back surface protrusion steps.

[0082] Comparative Example 2 A metal-filled microstructure was fabricated in the same manner as in Example 7, except that nitrilotriacetic acid, a non-azole organic molecule, was not used in the coating liquid for forming the underfill material.

[0083] Comparative Example 3 A metal-filled microstructure was fabricated in the same manner as in Example 1, except that 1,2,3-triazole was used instead of the non-azole organic molecule in the front and back surface protrusion steps.

[0084] [evaluation] <Conductivity> Each of the fabricated metal-filled microstructures was left in an atmospheric environment at 35°C for 6 hours, 12 hours, 24 hours, 72 hours, and 168 hours. Thereafter, a TEG chip (daisy chain pattern) and an interposer manufactured by WALTS were prepared, and these were placed above and below the chip bonder, and the alignment was adjusted in advance. After adjusting the alignment, each of the fabricated metal-filled microstructures was placed on top of the Cu post side of the interposer placed underneath, and then bonded by thermocompression bonding at 250°C, 1 minute, and 6 MPa using a room-temperature bonding device (WP-100, manufactured by PMT). For the bonded samples, the electrical resistance between the chip wiring was measured, and the ratio D was calculated using the following formula, with the sample that was not placed in a 35°C environment (sample using a metal-filled microstructure immediately after production) designated as A0, and the samples that were placed in a 35°C environment (samples using a metal-filled microstructure after being placed for each of the above periods) designated as A1, A2, A3, A4, and A5, respectively. The calculation results, rounded to the nearest whole number, are shown in Table 1 below. D = (An / A0) × 100-100 (n = 1 to 5)

[0085] <Adhesion> For the samples for evaluating conductivity (samples using metal-filled microstructures after 168 hours), a load was applied to the TEG chip using a universal bond tester (DAGE4000, manufactured by DAGE) to measure the peel strength. As a result, peel strengths of 15 N or more were evaluated as "A," those of 10 N or more but less than 15 N were evaluated as "B," those of 5 N or more but less than 10 N were evaluated as "C," and those of less than 5 N were evaluated as "D." The results are shown in Table 1 below.

[0086] [Table 1]

[0087] From the results shown in Table 1 above, it was found that when a metal-filled microstructure was used in which the surface of the protruding portion of the conductive path was not in contact with a layer containing non-azole-based organic molecules having an acid group and a nitrogen atom, the rate of change in conductivity increased over time, resulting in poor conductivity reliability (Comparative Examples 1 to 2). Furthermore, it was found that when a metal-filled microstructure was used in which the surface of the protruding portion of the conductive path was in contact with a layer containing 1,2,3-triazole, an azole-based organic molecule, the conductive reliability was poor (Comparative Example 3).

[0088] In contrast, it was found that excellent conductive reliability could be achieved when a metal-filled microstructure was used in which the surface of the protruding portion of the conductive path was in contact with a layer containing non-azole organic molecules having an acid group and a nitrogen atom (Examples 1 to 10). In particular, a comparison of Examples 1 to 5 revealed that when the non-azole organic molecule has three or more acid groups, the conduction reliability becomes better. Furthermore, a comparison between Example 1 and Example 2 revealed that when the non-azole organic molecule has three acid groups, the adhesion to the semiconductor chip or the like to be connected is improved. Furthermore, a comparison between Example 2 and Example 4 revealed that when the molar mass of the non-azole organic molecule is 100 to 500 g / mol, good adhesion to the semiconductor chip or the like to be connected is achieved. Furthermore, a comparison between Example 1 and Example 7 revealed that the conduction reliability was improved when the specific organic molecule-containing layer was configured to cover the protruding portion of the conductive path along its shape. [Explanation of symbols]

[0089] 1 Metal-filled microstructure 2. Insulating substrate 2a, 2b Surface of insulating substrate 3 Conduction Path 3a,3b Projecting part of conduction path 4 Specific organic molecule-containing layer 6. Thickness of insulating substrate 7 Spacing between conductive paths 8 Conduction path diameter 9 Center distance (pitch) of conductive paths

Claims

1. A metal-filled microstructure comprising an insulating substrate made of an inorganic material and a plurality of conductive paths made of a conductive member, the conductive paths penetrating the insulating substrate in a thickness direction and being insulated from one another, each of the conductive paths has a protruding portion protruding from a surface of the insulating substrate; a surface of the protruding portion is in contact with a layer containing a non-azole organic molecule having an acid group and a nitrogen atom; The non-azole organic molecule is at least one selected from the group consisting of aminopolycarboxylic acids, sulfo group-containing organic molecules, phosphate group-containing organic molecules, and phenolic hydroxyl group-containing organic molecules.

2. The metal-filled microstructure of claim 1 , wherein the non-azole organic molecule has a plurality of the acid groups.

3. 3. The metal-filled microstructure according to claim 1, wherein the non-azole organic molecule has three or more acid groups.

4. 4. The metal-filled microstructure according to claim 1, wherein the acid group is a carboxyl group.

5. 5. The metal-filled microstructure according to claim 1, wherein the non-azole organic molecule has one or two nitrogen atoms.

6. 6. The metal-filled microstructure of claim 1, wherein the non-azole organic molecule is nitrilotriacetic acid.

7. The metal-filled microstructure of any one of claims 1 to 6, wherein the protruding portions are copper.

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