Method for manufacturing substrate with conductive via, substrate with conductive via, method for manufacturing circuit board with conductive via, and circuit board with conductive via

Abstract

The objective of the present invention is to provide a method for manufacturing a substrate with a conductive via that can exhibit sufficiently low connection resistance even after interconnect formation, and whereby the resulting circuit board can have excellent connection reliability.　The method for manufacturing a substrate with a conductive via comprises: a step S1 for preparing a substrate with a sintered metal body comprising a substrate with a hole opening in one or both main surfaces thereof and a sintered metal body having a porous structure provided inside the hole, the sintered metal body being exposed at the opening of the hole; and a step S2 for providing a resin-containing portion including a photosensitive resin composition or a curing thereof on the sintered metal body of the substrate with a sintered metal body.　The method for manufacturing a substrate with a conductive via is also useful as a technology for reducing the environmental impact of plating.

Description

Method for manufacturing a substrate with conductive vias, a substrate with conductive vias, and a method for manufacturing a wiring substrate with conductive vias and a wiring substrate with conductive vias

[0001] The present invention relates to a method for manufacturing a substrate with conductive vias, a substrate with conductive vias, and a method for manufacturing a wiring substrate with conductive vias and a wiring substrate with conductive vias.

[0002] In recent years, in order to miniaturize, enhance functionality, and integrate electronic devices or components, attention has been focused on three-dimensional packaging technology in which semiconductor chips are stacked at high density in the vertical direction (height direction) by electrically connecting silicon substrates arranged above and below via electrodes called through-silicon vias (TSVs) on silicon substrates. Also attracting attention is a method in which glass substrates are used instead of silicon substrates and the glass substrates arranged above and below are electrically connected via electrodes called through-glass vias (TGVs).

[0003] As a method for forming a through electrode, for example, Patent Document 1 discloses a method for manufacturing a semiconductor device having a through-silicon electrode, which includes a step of electroplating a non-through via formed in a silicon substrate with copper using a specific copper plating solution. However, this method has problems in terms of productivity, such as the environmental impact of plating and the need to perform plating while suppressing the deposition rate of the copper coating, which increases the working time.

[0004] Another known method is to fill a through-hole in a heat-resistant substrate with a copper conductor paste containing copper powder, glass powder, an organic vehicle, etc., and then sinter it to form a copper conductor in the through-hole (see, for example, Patent Document 2 below).

[0005] Furthermore, Patent Document 3 listed below proposes a method for manufacturing a substrate having a silicon through-electrode by forming a copper sintered body having a porous structure in a through-via formed in a silicon substrate, impregnating the copper sintered body with a curable resin composition, and then performing a resin curing step.

[0006] JP 2019-16712 A JP 2010-108917 A Japanese Patent No. 7226531

[0007] Recently, as silicon substrates and glass substrates have been reduced in size to accommodate the miniaturization of electronic devices and components, the inner diameters of through holes have also been reduced to a minimum, making it necessary to form conductive vias with sufficient conductivity even within such through holes. Furthermore, wiring may be further provided on the surface of the substrate on which the conductive vias are formed by plating or the like, and even in this case, a sufficiently low connection resistance value is required.

[0008] Furthermore, in recent years, progress has been made in reducing power consumption by increasing signal speeds, miniaturizing substrates, and shortening transmission distances, and this has resulted in a demand for even greater improvements in connection reliability than before. Under these circumstances, a substrate with conductive vias (wiring substrate) on which the above-mentioned wiring is formed is required to have not only excellent conductivity but also excellent properties such as being less likely to increase connection resistance even when subjected to temperature changes (hereinafter also referred to as "connection reliability").

[0009] Therefore, the present invention aims to provide a method for manufacturing a substrate with conductive vias, which can exhibit a sufficiently low connection resistance value even after wiring formation and the resulting wiring board has excellent connection reliability, and a substrate with conductive vias, as well as a method for manufacturing a wiring board with conductive vias and a wiring board with conductive vias that has excellent connection reliability.

[0010] One aspect of the present invention relates to the following method for manufacturing a substrate with conductive vias. [1] A method for manufacturing a substrate with conductive vias, comprising: step S1 of preparing a substrate with a metal sintered body, the substrate including a substrate having holes opening on one or both of its main surfaces, and a metal sintered body having a porous structure provided inside the holes, the metal sintered body being exposed at the openings of the holes; and step S2 of providing a resin-containing portion containing a photosensitive resin composition or a cured product thereof in the metal sintered body of the substrate with conductive vias. [2] In step S2, the resin-containing portion and a resin-free portion not containing the resin composition or a cured product thereof are provided in the metal sintered body so that the resin-containing portion is unevenly distributed on the opening side. [3] The method for manufacturing a substrate with conductive vias according to [1] or [2], wherein step S2 includes: a step S2-1a of laminating a film-like negative photosensitive resin composition on the surface of the substrate with metal sintered body, thereby impregnating at least a portion of the metal sintered body with the negative photosensitive resin composition; and a step S2-2a of removing the film-like negative photosensitive resin composition by a development treatment after step S2-1a, thereby exposing the metal sintered body having the resin-containing portion containing the negative photosensitive resin composition at the opening of the hole. [4] The method for manufacturing a substrate with conductive vias according to [3], wherein step S2 further includes a step S2-3a of curing the negative photosensitive resin composition contained in the resin-containing portion after step S2-2a. [5] The method for manufacturing a substrate with conductive vias according to [4], wherein step S2 further includes a step S2-4a of performing a desmear treatment on at least the exposed surface of the metal sintered body after step S2-3a. [6] The method for manufacturing a substrate with conductive vias according to [1] or [2], wherein the step S2 includes a step S2-1b of applying a liquid negative photosensitive resin composition to the surface of the substrate with metal sintered body, thereby impregnating at least a portion of the metal sintered body with the negative photosensitive resin composition, and a step S2-2b of removing the coating film of the liquid negative photosensitive resin composition by a development treatment after the step S2-1b, thereby exposing the metal sintered body having the resin-containing portion containing the negative photosensitive resin composition at the opening of the hole.[7] The method for manufacturing a substrate with conductive vias according to [6], wherein the step S2 further comprises, after the step S2-2b, a step S2-3b of curing the negative photosensitive resin composition contained in the resin-containing portion. [8] The method for manufacturing a substrate with conductive vias according to [7], wherein the step S2 further comprises, after the step S2-3b, a step S2-4b of desmearing at least an exposed surface of the metal sintered body. [9] The method for manufacturing a substrate with conductive vias according to [1] or [2], wherein step S2 includes: a step S2-1c of applying a liquid positive photosensitive resin composition or laminating a film-like positive photosensitive resin composition on the surface of the substrate with metal sintered body to impregnate at least a portion of the metal sintered body with the positive photosensitive resin composition; and a step S2-2c of removing the coating of the liquid positive photosensitive resin composition or the film-like positive photosensitive resin composition by exposure and development treatment to expose the metal sintered body having the resin-containing portion containing the positive photosensitive resin composition at the opening of the hole.

[10] The method for manufacturing a substrate with conductive vias according to [9], wherein the positive photosensitive resin composition includes a thermosetting component, and step S2 further includes a step S2-3c of thermally curing the positive photosensitive resin composition contained in the resin-containing portion after step S2-2c.

[11] The method for manufacturing a substrate with conductive vias according to

[10] , wherein the step S2 further includes a step S2-4c of performing a desmear treatment on at least the exposed surface of the metal sintered body after the step S2-3c.

[0011] According to the method for manufacturing a substrate with conductive vias described in [1], it is possible to obtain a substrate with conductive vias that exhibits sufficiently low connection resistance even after wiring formation, and the resulting wiring substrate has excellent connection reliability. The inventors speculate as follows about the reason for this effect. First, forming conductive vias using a metal sintered body with a porous structure provides stress relaxation and is more likely to suppress cracking of the material around the metal sintered body. On the other hand, metal sintered bodies with a porous structure are susceptible to the adverse effects of oxidation due to the penetration of chemicals used in wiring formation (e.g., oxidation of the metal sintered body due to the penetration of an aqueous solution). In contrast, the method described in [1] is thought to be able to sufficiently mitigate the above adverse effects by providing a resin-containing portion in the metal sintered body. Note that while the method described in Patent Document 3 can incorporate a cured product of a curable resin composition into a copper sintered body with a porous structure, the cured resin tends to remain on the surface of the copper sintered body, which inhibits the deposition of an electrolytic copper plating film during subsequent wiring formation processes, resulting in increased conduction resistance after reliability tests under more severe conditions. In contrast, the method described in [1] is based on the finding that when a photosensitive resin composition is used, the resin composition on the surface of the metal sintered body can be removed by a corresponding development treatment while the resin composition can be left in the metal sintered body.

[0012] Another aspect of the present invention relates to a method for manufacturing a wiring board with conductive vias, as follows:

[12] A method for manufacturing a wiring board with conductive vias, comprising a step S3 of forming wiring electrically connected to the conductive vias in a substrate with conductive vias obtained by the method according to any one of [1] to

[11] .

[0013] Another aspect of the present invention relates to the following substrate with conductive vias or wiring substrate with conductive vias.

[13] A substrate with conductive vias, comprising: a substrate having a through hole; and a conductive via provided in the through hole, wherein the conductive via comprises a metal sintered body having a porous structure, and the metal sintered body comprises a resin-containing portion containing a photosensitive resin composition or a cured product thereof.

[14] The substrate with conductive vias according to

[13] , wherein the metal sintered body further comprises a resin-free portion that does not contain a resin composition or a cured product thereof, and the resin-containing portion is unevenly distributed on the opening side of the through hole in the metal sintered body. "15" A wiring substrate with conductive vias, comprising: the substrate with conductive vias according to

[13] or

[14] ; and wiring provided on the substrate with conductive vias, electrically connected to the conductive vias.

[0014] According to the present invention, it is possible to provide a method for manufacturing a substrate with conductive vias, which can exhibit a sufficiently low connection resistance value even after wiring formation, and the resulting wiring board has excellent connection reliability, as well as a method for manufacturing a wiring board with conductive vias and a wiring board with conductive vias having excellent connection reliability.

[0015] The method for manufacturing a substrate with conductive vias and the substrate with conductive vias of the present invention are also useful as a technology for reducing the environmental load caused by plating.

[0016] FIG. 1 is a schematic diagram showing an example of a method for manufacturing a substrate with conductive vias according to the present embodiment; FIG. 2 is a schematic diagram showing an example of a method for manufacturing a substrate with conductive vias according to the present embodiment; FIG. 3 is a schematic diagram showing an example of a method for manufacturing a substrate with conductive vias according to the present embodiment; FIG. 4 is a schematic diagram showing an example of a method for manufacturing a substrate with conductive vias according to the present embodiment; FIG. 5 is a schematic diagram showing an example of a method for manufacturing a substrate with conductive vias according to the present embodiment; FIG. 6 is a schematic diagram showing an example of a method for manufacturing a wiring board with conductive vias according to the present embodiment; FIG. 7 is a schematic diagram showing a test piece.

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0018] <Method for manufacturing substrate with conductive via> The method for manufacturing a substrate with conductive via of this embodiment includes a step S1 of preparing a substrate with a metal sintered body, which includes a substrate having holes opening on one or both of its main surfaces and a metal sintered body having a porous structure provided inside the holes, and in which the metal sintered body is exposed at the openings of the holes, and a step S2 of providing a resin-containing portion containing a photosensitive resin composition or a cured product thereof in the metal sintered body of the substrate with metal sintered body.

[0019] [Step S1] Step S1 may include the steps of: preparing a substrate having holes; and providing a metal paste portion containing metal particles and a volatile solvent so as to fill the insides of the holes and cover at least the surface of the substrate around the holes; heating the metal paste portion to remove part of the volatile solvent; removing part of the metal paste portion after heating so that the surface is exposed, and forming a metal sintered body precursor containing metal particles and the remainder of the volatile solvent and having a flattened exposed surface inside the holes; and firing the metal sintered body precursor to form a metal sintered body having a porous structure.

[0020] 1 to 3 are schematic diagrams showing an example of step S1. FIG. 1 shows an example of a substrate used in the method for manufacturing a substrate with conductive vias. Hereinafter, the method for manufacturing a substrate with conductive vias of this embodiment will be described with reference to these figures. Note that this embodiment illustrates a case where the metal paste contains the above-mentioned copper particles as metal particles, and therefore the copper particles, copper layer, and copper sintered body can be read as metal particles, metal layer, and metal sintered body, respectively.

[0021] [Step a] Examples of the substrate having holes prepared in this step include an organic substrate, a silicon substrate, a glass substrate, a ceramic substrate, a printed wiring board, and a semiconductor package substrate. The silicon substrate may be a substrate made of polycrystalline silicon, or may be a rectangular silicon substrate made of polycrystalline silicon. The holes may be through-holes or blind holes. In this embodiment, for example, as shown in FIG. 1A, a silicon substrate 40 can be prepared, which includes a silicon wafer 1 having through-holes 30 and a metal coating 2 provided on the wall surfaces of the through-holes and on the surface of the silicon wafer 1. The through-holes 30 communicate with both main surfaces of the silicon substrate 40. While the following description will be given using an example in which conductive vias are provided in this silicon substrate 40, the silicon wafer may be replaced with another insulating substrate in the description below.

[0022] The thickness of the silicon wafer 1 may be 100 μm or more, 200 μm or more, or 300 μm or more from the viewpoint of suppressing warpage of the substrate after sintering, and may be 800 μm or less, 300 μm or less, 200 μm or less, or 100 μm or less from the viewpoint of reducing the weight and increasing the density of the substrate. Furthermore, when a polycrystalline silicon substrate or the like is used, the thickness may be 0.05 to 2 mm, 0.1 mm to 1.5 mm, or 0.2 to 1 mm.

[0023] The upper limit of the diameter of the through hole 30 may be 200 μm or less, 100 μm or less, or 60 μm or less, from the viewpoint of increasing the density of the resulting semiconductor device, and the lower limit of the diameter of the through hole 30 is not particularly limited, but may be 10 μm or more, 20 μm or more, 30 μm or more, or 50 μm or more.

[0024] The ratio of the depth to the hole diameter of the through-holes 30 [(depth) / (hole diameter)] may be 0.5-40, 1-20, or 2-10.

[0025] The number of through holes 30 provided in the silicon substrate 40 is set per 1 cm of the main surface of the substrate from the viewpoint of increasing the density of the semiconductor device to be obtained. ２ There may be 100 or more, 200 or more, or 300 or more per unit area.

[0026] The metal coating 2 may be provided on both main surfaces of the silicon wafer 1 and on the wall surfaces of the through holes 30, or on at least one main surface of the silicon wafer 1 and on the wall surfaces of the through holes 30, or may be provided only on the wall surfaces of the through holes 30, or may not be provided at all. In the embodiment shown in Figure 1 (a) , a silicon substrate 40 has metal coatings 2 on both main surfaces of the silicon wafer 1 and on the wall surfaces of the through holes 30.

[0027] Examples of the metal coating 2 include titanium, nickel, chromium, copper, aluminum, palladium, platinum, and gold. From the viewpoint of adhesion, the metal coating 2 is preferably a coating in which titanium, nickel, and copper are layered in this order. Adhesion is improved by oxidizing the surface of the silicon wafer 1 to form silicon oxide and then forming a titanium layer on the silicon oxide. Furthermore, by providing a nickel layer on the titanium layer and then providing a copper layer on that, diffusion of copper into the silicon wafer 1 can be suppressed compared to when a copper layer is provided directly on the titanium layer. Furthermore, providing a copper layer on the surface improves adhesion between the copper layer and copper particles in the metal paste, thereby improving reliability.

[0028] 1B, when a silicon substrate 41 having non-through holes 31 formed therein is prepared, conductive vias serving as through electrodes can be formed by grinding the surface of the silicon substrate opposite to the surface on which the non-through holes 31 are formed after step a, step b, step c, or step d. Grinding methods include, for example, mechanical polishing and chemical mechanical polishing.

[0029] The metal paste portion 3 can be provided, for example, by applying a metal paste containing metal particles and a volatile solvent directly onto the silicon substrate 40, or by preparing a film on which the metal paste has been applied in advance and pressing it onto the substrate.

[0030] Examples of methods for applying or filling the metal paste include printing methods such as screen printing, inkjet printing, intaglio printing, lithographic printing, offset printing, and flexographic printing, as well as combinations of these printing methods, spin coating, dipping, rolling, squeegeeing, and pressing. Of these methods, the screen printing and squeegee methods in which the paste is directly applied to a substrate in a vacuum atmosphere, and the vacuum pressing method in which a film previously coated with the metal paste is pressed in a vacuum atmosphere are preferred.

[0031] The content of metal particles in the metal paste of this embodiment may be 95.0% by mass or more, 95.2% by mass or more, 95.5% by mass or more, 95.7% by mass or more, or 96% by mass or more, based on the total amount of the metal paste; 98% by mass or less, 97% by mass or less, or 96.5% by mass or less; or 95.0 to 98% by mass, 95.2 to 97% by mass, or 95.7 to 96.5% by mass.

[0032] Examples of metal particles include particles of nickel, silver, copper, gold, palladium, platinum, solder, etc. The metal particles may contain multiple metals, such as silver-coated copper particles. When the metal paste contains copper particles, it is easy to obtain a conductor that has sufficient conductivity and is resistant to increases in resistance even when subjected to temperature changes, and a substrate that has sufficient conductivity and through electrodes with excellent connection reliability.

[0033] In this embodiment, the metal particles may include first metal particles having a volume average particle size of 0.8 μm or more and second metal particles having a volume average particle size of 0.5 μm or less.

[0034] In this specification, the volume average particle size of particles (hereinafter sometimes referred to as "average particle size") means the 50% volume average particle size (D50). The volume average particle size of metal particles can be determined by, for example, dispersing raw material metal particles in a dispersion medium such as water or alcohol and measuring the dispersion using a laser diffraction / scattering particle size distribution analyzer.

[0035] The first metal particles and the second metal particles may be copper particles from the viewpoints of reducing resistance, ensuring ion migration resistance, and facilitating wiring formation. This embodiment will be described in detail using as an example a case in which the first metal particles are copper particles (hereinafter referred to as "first copper particles") and the second metal particles are copper particles (hereinafter referred to as "second copper particles").

[0036] (First Copper Particles) The average particle size of the first copper particles may be 0.8 μm or more, 1.0 μm or more, 2.0 μm or more, or 3.0 μm or more from the viewpoint of improving the sintering density in holes (e.g., through holes or blind holes) of the substrate and suppressing voids and cracks occurring in the holes; for example, from the viewpoint of suppressing particle clogging in microvias with an inner diameter of 100 μm or less and improving filling properties, it may be 10 μm or less, 8.0 μm or less, 5.0 μm or less, or 4.0 μm or less; and from the viewpoint of suppressing voids and cracks and suppressing particle clogging in microvias, it may be 0.8 μm to 4.0 μm, 1.0 μm to 3.5 μm, or 1.2 μm to 3.0 μm. The ratio (DC1 / DH) of the average particle diameter DC1 of the first copper particles to the inner diameter DH of the hole may be 0.01 or more, 0.03 or more, or 0.04 or more from the viewpoint of suppressing particle clogging in the microvias and improving filling properties, and may be 0.15 or less, 0.1 or less, or 0.05 or less from the viewpoint of suppressing voids and cracks by reducing shrinkage due to firing. Furthermore, from the above viewpoint, the ratio (DC1 / DH) may be 0.01 to 0.15, or 0.03 to 0.1.

[0037] The shape of the first copper particles may be, for example, spherical, blocky, needle-like, flat (flake-like), or approximately spherical. The first metal particles may be aggregates of copper particles having these shapes. The metal paste of this embodiment may contain spherical copper particles as the first copper particles, from the viewpoint of reducing the step between the conductive via portion to be formed and the substrate surface and suppressing fluctuations in connection resistance even after a reliability test (e.g., a temperature cycle test).

[0038] From the viewpoint of improving the printability of the metal paste, the first copper particles may contain spherical particles or other particles having an aspect ratio of 2 or less in an amount of 40% by mass or more, 50% by mass or more, 60% by mass or more, 80% by mass or more, or 100% by mass, or may be 40 to 90% by mass, 50 to 80% by mass, or 60 to 70% by mass. The aspect ratio (major axis / minor axis) of the particles can be determined, for example, by observing an SEM image of the particles and measuring the major axis and minor axis (e.g., thickness).

[0039] The metal paste of this embodiment may contain flaky copper particles as the first copper particles in order to reduce shrinkage due to firing and thereby suppress voids and cracks, or may contain spherical copper particles and flaky copper particles in order to reduce the viscosity of the metal paste, improve filling of microvias, and reduce shrinkage due to firing and thereby suppress voids and cracks. When spherical copper particles and flaky copper particles are used in combination, the mass ratio thereof (spherical copper particles) / (flaky copper particles) may be 1 to 9, 1.2 to 2.5, or 1.4 to 4.

[0040] The flaky copper particles may have an aspect ratio of 1.5 or more, 2 or more, or 3 or more.

[0041] When spherical copper particles having an aspect ratio of 2 or less and flaky copper particles having an aspect ratio of more than 2 are used in combination, the mass ratio thereof (spherical copper particles) / (flaky copper particles) may be 0.6 to 9, 1.0 to 4.0, or 1.5 to 2.4.

[0042] The first copper particles may be produced by a chemical reduction method, an atomization method, an electrolysis method, a pulverization method, a plasma rotating electrode method, a uniform liquid spray method, a heat treatment method, or the like, and may be wet copper powder or atomized copper powder from the viewpoint of easily obtaining a uniform diameter and improving the dispersibility of the metal paste.

[0043] The first copper particles may contain wet-processed copper powder. In this case, conductive vias with excellent conductivity are easily obtained. This effect is thought to be achieved by the wet-processed copper powder's ability to easily bond with the copper particles blended as the second metal. The wet-processed copper powder may have a D90 / D50 ratio of 1.5 or less.

[0044] The copper particles may also contain wet-processed copper powder and atomized copper powder. In this case, the printability of the metal paste is improved, the step between the formed conductive via and the substrate surface is reduced, and fluctuations in connection resistance are easily suppressed even after reliability tests (e.g., temperature cycle tests). The reason for this effect is presumed to be the following: The coexistence of wet-processed copper powder, which is easily bonded to the second copper particles and has a uniform particle size, and atomized copper powder, which has a wide particle size distribution, allows the wet-processed copper powder to bond between the atomized copper powder particles while also bonding to the second copper particles, thereby forming a strong sintered body with a close-packed structure and suppressing shrinkage during sintering, thereby suppressing the occurrence of voids and cracks and depressions. The atomized copper powder may have a D90 / D50 ratio of 1.6 or more, 1.7 or more, or 1.8 or more.

[0045] When the first copper particles contain a wet copper powder and an atomized copper powder, the content of the wet copper powder may be more than 0 parts by mass and less than 100 parts by mass, or may be 20 to 80 parts by mass, relative to 100 parts by mass of the total amount of the wet copper powder and the atomized copper powder.

[0046] Commercially available first copper particles can be used. Examples of commercially available first copper particles include 1050Y (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 0.81 μm, D90: 1.1 μm, spherical, wet-process copper powder), 1100Y (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 1.1 μm, D90: 1.6 μm, spherical, wet-process copper powder), 1200Y (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 2.1 μm, D90: 3.1 μm, spherical, wet-process copper powder), 1300Y (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 3.5 μm, D90: 5 μm, spherical, wet-process copper powder), and 1100YP (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 1.4 μm, D90: 2.3 μm, flat, wet-process copper powder), 1200YP (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 3.1 μm, D90: 5.3 μm, flat, wet-process copper powder), MA-C02K (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 1.8 μm, D90: 3.6 μm, spherical, atomized copper powder), MA-C025K (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 2.4 μm, D90: 5.2 μm, spherical, atomized copper powder), and MA-C03K (manufactured by Mitsui Kinzoku Co., Ltd., trade name, average particle size (D50): 3.4 μm, D90: 6.3 μm, spherical, atomized copper powder).

[0047] The first copper particles may be treated with a surface treatment agent from the viewpoint of dispersion stability and oxidation resistance. The surface treatment agent may be one that is removed during wiring formation (sintering of the copper particles). Examples of such surface treatment agents include aliphatic carboxylic acids such as palmitic acid, stearic acid, arachidic acid, and oleic acid; aromatic carboxylic acids such as terephthalic acid, pyromellitic acid, and o-phenoxybenzoic acid; aliphatic alcohols such as cetyl alcohol, stearyl alcohol, isobornylcyclohexanol, and tetraethylene glycol; aromatic alcohols such as p-phenylphenol; alkylamines such as octylamine, dodecylamine, and stearylamine; aliphatic nitriles such as stearonitrile and decanenitrile; silane coupling agents such as alkylalkoxysilanes; and polymer treatment agents such as polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and silicone oligomers. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

[0048] The amount of the surface treatment agent may be an amount equivalent to one molecular layer or more on the particle surface. The amount of the surface treatment agent varies depending on the specific surface area of ​​the first copper particles, the molecular weight of the surface treatment agent, and the minimum coverage area of ​​the surface treatment agent. The amount of the surface treatment agent is usually 0.001% by mass or more.

[0049] The amount of the surface treatment agent is determined based on the number of molecular layers (n) attached to the surface of the first copper particles and the specific surface area (A ｐ ) (unit m ２ / g) and the molecular weight of the surface treatment agent (M ｓ ) (unit: g / mol) and the minimum coverage area of ​​the surface treatment agent (S Ｓ ) (unit m ２ / piece) and Avogadro's number (N Ａ ) (6.02 x 10 ２３ Specifically, the amount of surface treatment agent can be calculated from the following formula: Treatment amount of surface treatment agent (mass%) = {(n × A ｐ ×M ｓ ) / (S Ｓ ×N Ａ + n × A ｐ ×M ｓ )} × 100%.

[0050] The specific surface area of ​​the first copper particles can be calculated by measuring the dried copper particles using a BET specific surface area measurement method. When the surface treatment agent is a linear saturated fatty acid, the minimum coverage area of ​​the surface treatment agent is 2.05 × 10 －１９ m ２ / 1 molecule. In the case of other surface treatment agents, it can be measured, for example, by calculation from a molecular model or by the method described in "Chemistry and Education" (Kamieda Katsuhiro, Inafuku Sumio, Mori Iwao, 40(2), 1992, pp. 114-117). An example of a method for quantifying the surface treatment agent is shown below. The surface treatment agent can be identified by a thermal desorption gas / gas chromatograph mass spectrometer for the dried powder obtained by removing the dispersant from the metal paste, thereby determining the carbon number and molecular weight of the surface treatment agent. The carbon content of the surface treatment agent can be analyzed by carbon content analysis. Examples of carbon content analysis methods include high-frequency induction heating furnace combustion / infrared absorption method. The amount of the surface treatment agent can be calculated using the above formula from the carbon number, molecular weight, and carbon content of the identified surface treatment agent.

[0051] (Second Copper Particles) The average particle size of the second copper particles may be 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, or 0.2 μm or less from the viewpoint of sinterability, and may be 0.01 μm or more, 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, or 0.1 μm or more from the viewpoint of suppressing synthesis costs, good dispersibility, and suppressing the amount of surface treatment agent used. From the viewpoint of obtaining low-temperature sinterability and good dispersibility in the paste, it may be 0.1 μm to 0.3 μm, 0.12 μm to 0.28 μm, or 0.15 μm to 0.25 μm.

[0052] The second copper particles can act as copper particles that suitably bond the first copper particles together. Furthermore, the second copper particles have superior sinterability to the first copper particles and can promote sintering of the copper particles. For example, the copper particles can be sintered at a lower temperature than when the first copper particles are used alone.

[0053] The second copper particles may be wet copper powder produced by a chemical reduction method.

[0054] The shape of the second copper particles may be, for example, spherical, blocky, needle-like, flat (flake-like), or approximately spherical. The second copper particles may also be an aggregate of copper particles having these shapes. From the viewpoint of dispersibility and packing ability, the shape of the second copper particles may be spherical, approximately spherical, or flat (flake-like). From the viewpoint of combustibility and mixability with the first copper particles, the shape may be spherical or approximately spherical.

[0055] The aspect ratio of the second copper particles may be 5 or less, 4 or less, or 3 or less, from the viewpoints of dispersibility, packing ability, and mixability with the first copper particles.

[0056] The second copper particles may be synthesized or commercially available. Examples of commercially available second copper particles include CH0200L1 (manufactured by Mitsui Mining & Smelting Co., Ltd., trade name, average particle size (D50): 200 nm, spherical) and Tn-Cu100 (manufactured by Taiyo Nippon Sanso Co., Ltd., average particle size (D50): 120 nm, spherical).

[0057] The second copper particles may be treated with a specific surface treatment agent. Examples of the specific surface treatment agent include organic acids having 8 to 16 carbon atoms. Examples of organic acids having 8 to 16 carbon atoms include caprylic acid, methylheptanoic acid, ethylhexanoic acid, propylpentanoic acid, pelargonic acid, methyloctanoic acid, ethylheptanoic acid, propylhexanoic acid, capric acid, methylnonanoic acid, ethyloctanoic acid, propylheptanoic acid, butylhexanoic acid, undecanoic acid, methyldecanoic acid, ethylnonanoic acid, propyloctanoic acid, butylheptanoic acid, lauric acid, methylundecanoic acid, ethyldecanoic acid, propylnonanoic acid, butyloctanoic acid, Saturated fatty acids such as pentylheptanoic acid, tridecanoic acid, methyl dodecanoic acid, ethyl undecanoic acid, propyl decanoic acid, butyl nonanoic acid, pentyl octanoic acid, myristic acid, methyl tridecanoic acid, ethyl dodecanoic acid, propyl undecanoic acid, butyl decanoic acid, pentyl nonanoic acid, hexyl octanoic acid, pentadecanoic acid, methyl tetradecanoic acid, ethyl tridecanoic acid, propyl dodecanoic acid, butyl undecanoic acid, pentyl decanoic acid, hexyl nonanoic acid, palmitic acid, methyl pentadecanoic acid, ethyl tetradecanoic acid, propyl tridecanoic acid, butyl dodecanoic acid, pentyl undecanoic acid, hexyl decanoic acid, heptyl nonanoic acid, methyl cyclohexane carboxylic acid, ethyl cyclohexane carboxylic acid, propyl cyclohexane carboxylic acid, butyl cyclohexane carboxylic acid, pentyl cyclohexane carboxylic acid, hexyl cyclohexane carboxylic acid, heptyl cyclohexane carboxylic acid, octyl cyclohexane carboxylic acid, and nonyl cyclohexane carboxylic acid; octene Examples of the organic acid include unsaturated fatty acids such as nonenoic acid, methylnonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, myristoleic acid, pentadecenoic acid, hexadecenoic acid, palmitoleic acid, and sapienic acid; and aromatic carboxylic acids such as terephthalic acid, pyromellitic acid, o-phenoxybenzoic acid, methylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, pentylbenzoic acid, hexylbenzoic acid, heptylbenzoic acid, octylbenzoic acid, and nonylbenzoic acid. One organic acid may be used alone, or two or more organic acids may be used in combination.By combining such an organic acid with the second copper particles, it tends to be possible to achieve both the dispersibility of the second copper particles and the elimination of the organic acid during sintering.

[0058] The amount of the surface treatment agent to be applied may be an amount sufficient to adhere to the surface of the second copper particles in a monolayer to trilayer form. The amount of the surface treatment agent to be applied may be 0.07% by mass or more, 0.10% by mass or more, or 0.2% by mass or more, and may be 2.1% by mass or less, 1.6% by mass or less, or 1.1% by mass or less. The amount of the surface treatment agent to be applied to the second copper particles can be calculated by the method described above for the first copper particles. The same applies to the specific surface area, the molecular weight of the surface treatment agent, and the minimum coverage area of ​​the surface treatment agent.

[0059] The content of the second metal particles in the metal paste is 50 mass % or less based on the total amount of metal particles from the viewpoint of connection reliability, and may be 10 to 50 mass % or 20 to 40 mass % from the viewpoints of lowering the sintering temperature to improve adhesion to the base metal layer, reducing the porosity of the sintered body, suppressing shrinkage during sintering, and suppressing the occurrence of cracks.

[0060] The total content of the first copper particles and the second copper particles in the metal paste may be 100 parts by mass, 85 to 99.5 parts by mass, 90 to 99 parts by mass, or 95 to 98 parts by mass, when the total mass of the metal particles is 100 parts by mass.

[0061] The contents of the first copper particles and the second copper particles may be 50 to 90 parts by mass and 50 to 10 parts by mass, 55 to 85 parts by mass and 45 to 15 parts by mass, or 60 to 80 parts by mass and 40 to 20 parts by mass, respectively, relative to 100 parts by mass of the total of the first copper particles and the second copper particles.

[0062] The metal paste of this embodiment may contain copper particles and metal particles other than copper particles (hereinafter also referred to as "other metal particles"). In this case, the other metal particles may be nickel particles, silver particles, gold particles, palladium particles, platinum particles, or solder particles. One or more of these may be contained. The average particle size of the other metal particles may be 0.01 μm or more, 0.03 μm or more, or 0.05 μm or more, and may be 5 μm or less, 3.0 μm or less, or 2.0 μm or less. The average particle size of the solder particles may be 1.0 μm or more, 1.5 μm or more, 2.0 μm or more, 3.0 μm or more, or 4.0 μm or more, and may be 15 μm or less, 10 μm or less, 8.0 μm or less, or 5.0 μm or less.

[0063] The content of the other metal particles may be 5 parts by mass or less, 3 parts by mass or less, 1 part by mass or less, or 0.8 parts by mass or less, when the total mass of the copper particles is 100 parts by mass. The metal paste of this embodiment may not include solder particles as the other metal particles.

[0064] [Volatile Solvent] Examples of the volatile solvent include monohydric and polyhydric alcohols such as pentanol, hexanol, heptanol, octanol, decanol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol (e.g., 1,3-butanediol), α-terpineol, and isobornylcyclohexanol (MTPH); ethylene glycol butyl ether, ethylene glycol phenyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether (ethyl carbitol), diethylene glycol butyl ether (e.g., diethylene glycol mono-n-butyl ether), diethylene glycol isobutyl ether, diethylene glycol hexyl ether, triethylene glycol methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, and propanediol. ethers such as propylene glycol propyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, and tripropylene glycol dimethyl ether; esters such as dimethyl phthalate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, propylene glycol diacetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dipropylene glycol methyl ether acetate (DPMA), ethyl lactate, butyl lactate, γ-butyrolactone, and propylene carbonate; acid amides such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide; aliphatic hydrocarbons such as cyclohexane, octane, nonane, decane, and undecane; aromatic hydrocarbons such as benzene, toluene, and xylene; mercaptans having an alkyl group having 1 to 18 carbon atoms;Examples of mercaptans having a cycloalkyl group having 5 to 7 carbon atoms include mercaptans having an alkyl group having 1 to 18 carbon atoms include ethyl mercaptan, n-propyl mercaptan, i-propyl mercaptan, n-butyl mercaptan, i-butyl mercaptan, t-butyl mercaptan, pentyl mercaptan, hexyl mercaptan, and dodecyl mercaptan. Examples of mercaptans having a cycloalkyl group having 5 to 7 carbon atoms include cyclopentyl mercaptan, cyclohexyl mercaptan, and cycloheptyl mercaptan. The volatile solvents may be used alone or in combination of two or more.

[0065] The metal paste of this embodiment may contain, as a volatile solvent, a solvent having a vapor pressure of 4 Pa ​​or more and 30 Pa or less at 20° C. (hereinafter also referred to as a "high vapor pressure solvent"), from the viewpoints of printability and suppressing volumetric shrinkage before and after firing the metal sintered body precursor (for example, between step c of forming the metal sintered body precursor and step d of firing the metal sintered body precursor) to suppress voids and cracks. One type of high vapor pressure solvent may be used alone, or two or more types may be used in combination.

[0066] Examples of high vapor pressure solvents include α-terpineol, 1,3-butanediol, ethyl carbitol, and propylene glycol diacetate.

[0067] The metal paste of this embodiment may contain, as a volatile solvent, a solvent having a vapor pressure of less than 4 Pa ​​at 20° C. (hereinafter also referred to as a “low vapor pressure solvent”), from the viewpoint of suppressing powdering due to drying accompanying solvent volatilization during printing or paste preparation. One type of low vapor pressure solvent may be used alone, or two or more types may be used in combination.

[0068] Examples of low vapor pressure solvents include isobornylcyclohexanol (MTPH), dimethyl phthalate, and diethylene glycol mono-n-butyl ether.

[0069] From the viewpoint of achieving both printability and suppressing volume shrinkage before and after firing the metal sintered body precursor (for example, between step c of forming the metal sintered body precursor and step d of firing the metal sintered body precursor) to suppress voids and cracks, the metal paste of this embodiment may contain a high vapor pressure solvent and a low vapor pressure solvent. In this case, the high vapor pressure solvent and the low vapor pressure solvent may each be used alone or in combination of two or more. The content ratio of the high vapor pressure solvent and the low vapor pressure solvent may be 20 / 80 to 80 / 20 or 30 / 70 to 70 / 30 in mass ratio [high vapor pressure solvent / low vapor pressure solvent].

[0070] The content of the volatile solvent in the metal paste of this embodiment may be 2 mass% or more, 3 mass% or more, or 3.5 mass% or more, based on the total mass of the metal paste, and may be 5 mass% or less, 4.8 mass% or less, 4.5 mass% or less, 4.3 mass% or less, or 4 mass% or less, or may be 2 to 5 mass%, 3 to 4.8 mass%, or 3.5 to 4.5 mass%.

[0071] The metal paste of the present embodiment may contain a resin component such as an epoxy resin. The metal paste of the present embodiment may have a resin component content of 10% by mass or less, or 5% by mass or less, or may not contain a resin component.

[0072] The metal paste can be prepared by mixing metal particles such as the copper particles and optional components (additives, etc.) with the volatile solvent. After mixing the components, stirring may be performed. The maximum particle size of the dispersion may be adjusted by classification. Furthermore, the components can be mixed using a three-roll mill, kneader, planetary mixer, or other means.

[0073] When the metal paste contains the first copper particles and the second copper particles, the second copper particles, the surface treatment agent, and the dispersion medium may be mixed in advance, followed by a dispersion treatment to prepare a dispersion of the second copper particles, and then the first copper particles, and optionally other metal particles and optional additives may be mixed therewith. This procedure improves the dispersibility of the second copper particles, improving their mixability with the first copper particles and further improving the performance of the metal paste. The dispersion of the second copper particles may be subjected to a classification operation to remove aggregates.

[0074] From the viewpoint of printability, the metal paste of this embodiment may have a viscosity of 100 to 600 Pa·s, or 150 to 400 Pa·s at 25° C. The viscosity of the metal paste is measured using a micro spiral viscometer PCU-02V (manufactured by Malcom Co., Ltd., product name) at a rotation speed of 10 rpm and a temperature of 25° C.

[0075] When a film on which a metal paste has been applied in advance is used, as shown in Figures 2(a) to 2(c), the metal paste portion 3 can be provided, for example, by preparing a metal particle film on a support film 7 and providing a metal particle-containing layer 3p made of a metal paste containing metal particles and a volatile solvent, and then pressing this metal particle film against a substrate.

[0076] Examples of the support film 7 include a polyimide film, a polyethylene naphthalate film, and a polyethylene terephthalate film. From the viewpoint of workability in forming the metal particle-containing layer by coating, the thickness of the support film may be 20 to 200 μm, 25 to 175 μm, or 30 to 150 μm.

[0077] The composition of the metal particles and volatile solvent in the metal particle-containing layer can be appropriately set so as to satisfy the conditions for the metal paste of this embodiment described above. The thickness of the metal particle-containing layer may be set to 100 μm or less so as to sufficiently fill the through holes or non-through holes with the metal paste. From the viewpoint of easily ensuring sufficient filling of the through holes or non-through holes, the thickness of the metal particle-containing layer may be 30 μm or more, 40 μm or more, or 50 μm or more.

[0078] From the viewpoint of suppressing the generation of voids in the through holes or non-through holes, the metal particle-containing layer may have a waviness (height difference) of 20 μm or less on the surface opposite to the support film, or may have a waviness (height difference) of 10 μm or less. By reducing the waviness (height difference), when the metal particle film is pressed to fill the holes in the substrate with the metal particle composition, it becomes easier to simultaneously fill the numerous through holes or non-through holes present in the substrate, and it becomes easier to reduce the number of through holes or non-through holes that are completely unfilled or through holes or non-through holes where voids are partially generated. The waviness (height difference) can be evaluated by a non-contact method using a laser displacement meter or the like.

[0079] The above-mentioned metal particle film can be produced by applying the metal paste of the present embodiment described above onto a support film to form a metal particle-containing layer having a metal particle concentration of 95.0 mass % or more, or by applying a metal paste in which the content of a volatile solvent has been increased (for example, increased to an amount such that the metal particle concentration is less than 94.0 mass %) and drying the applied film to form a metal particle-containing layer having a metal particle concentration of 95.0 mass % or more.

[0080] Examples of methods for applying the metal paste include screen printing, transfer printing, offset printing, jet printing, and methods using a dispenser, jet dispenser, needle dispenser, comma coater, slit coater, die coater, gravure coater, slit coat, letterpress printing, intaglio printing, gravure printing, stencil printing, soft lithography, bar coating, applicator, particle deposition method, spray coater, spin coater, dip coater, etc.

[0081] From the viewpoint of ease of application and uniformity of the applied film thickness, the metal paste can be applied onto the support film by screen printing.

[0082] The thickness of the coating film may be 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more, and may be 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, or 50 μm or less.

[0083] The step of drying the coating film to form the metal particle-containing layer can be carried out at room temperature or at a temperature of room temperature to 100° C. or less, and the atmosphere may be air or nitrogen.

[0084] In step a, the metal particle film described above is pressed against the silicon substrate 40 so that the metal particle-containing layer 3p of the metal particle film contacts the silicon substrate 40, and the through-holes 30 in the silicon substrate 40 are filled with a metal paste. In this case, for example, as shown in FIG. 2B, the metal particle film and the silicon substrate 40 can be sandwiched and pressed from above and below by a pressing jig A. The pressing jig A is not particularly limited, but may be a commercially available one, or may be fabricated using a metal member having a flat portion. For example, a pressing jig having two or more of the above-described metal members can press the metal particle film against the silicon substrate by sandwiching the metal particle film and the silicon substrate between the metal members arranged with their flat portions facing each other. The pressing jig A may have a mechanism for adjusting the pressure applied to the metal particle film and the silicon substrate. A spring or the like can be used as the pressure adjustment means. In this embodiment, a vacuum pressing method in which pressing is performed in a vacuum atmosphere may be used.

[0085] The pressing conditions can be, for example, room temperature to 50°C or lower, and the atmosphere may be a vacuum, air, or nitrogen. To reduce voids, the metal particle film may be pressed onto the silicon substrate after being maintained at a vacuum of 1000 Pa or lower, or a vacuum of 200 Pa or lower. The pressure of the pressing tool used to press the metal particle film onto the silicon substrate may be any pressure within a range that does not crack the silicon wafer, and may be, for example, 0.01 MPa or higher, 0.1 MPa or higher, or 1 MPa or higher.

[0086] The metal paste portion 3 may be formed to fill the inside of the hole and cover at least the surface of the substrate around the hole. However, as shown in FIGS. 2(b) and 2(c), the metal paste portion 3 may be formed to cover the opening of the through-hole (VP in FIG. 2(a)) located on the opposite side of the substrate from the side where the metal particle film is pressed. ０ The metal paste portion may protrude from the hole and cover the surface around the hole.

[0087] [Step b] In this step, the metal paste portion is heated to remove a portion of the volatile solvent, i.e., the metal paste portion is heated so that a portion of the volatile solvent remains. Note that, when using the above-mentioned metal particle film, the metal paste portion can be heated after peeling off the support film.

[0088] For heating, for example, a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far-infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, a heater heating device, a steam heating furnace, a hot plate press device, etc. can be used.

[0089] The heating atmosphere may be air, an oxygen-free atmosphere such as nitrogen and rare gas, or a reducing atmosphere such as hydrogen and formic acid. In the air, copper particles are prone to oxidation when the heating temperature exceeds 100 ° C. However, if the metal paste portion contains the high vapor pressure solvent described above as a volatile solvent, part of the volatile solvent can be removed at a temperature below 100 ° C., 95 ° C. or less, or 90 ° C. or less. In addition, if the metal paste portion does not contain a high vapor pressure solvent as a volatile solvent, for example, if it contains only the low vapor pressure solvent described above, by heating in an oxygen-free atmosphere or a reducing atmosphere at 110 ° C. or more, 130 ° C. or more, or 150 ° C. or more, oxidation of the copper particles can be suppressed while part of the volatile solvent is removed.

[0090] When the metal paste portion contains a high vapor pressure solvent, the heating temperature may be 70°C or higher but lower than 100°C, or 80°C or higher but lower than 95°C, from the viewpoint of suppressing oxidation of the copper particles, and the heating time may be 5 to 60 minutes, or 10 to 30 minutes, from the viewpoint of suppressing oxidation of the copper particles.

[0091] Furthermore, in order to suppress volumetric shrinkage before and after firing the metal sintered body precursor (for example, between step c of forming the metal sintered body precursor and step d of firing the metal sintered body precursor) and thereby suppress voids and cracks, the metal paste portion may be heated so that the concentration of metal particles becomes 96 mass % or more, 97.5 mass % or more, or 98 mass % or more.

[0092] [Step c] In this step, as shown in (a) to (d) of Figure 3, the metal paste portion 3a obtained in step b after heating is subjected to planarization (or smoothing) of the metal paste filled in the hole while removing the metal paste covering the surface of the substrate. As a result, the planarized exposed surface VP １ In this case, a metal sintered body precursor 3b containing metal particles and the remainder of the volatile solvent can be formed inside the hole (through hole 30) ((d) of FIG. 3).

[0093] The metal paste portion can be removed using, for example, a rubber squeegee 42 as shown in (b) and (d) of Figure 3. This allows the surface SP of the substrate 40 to be removed. ０ and the exposed surface VP of the metal sintered body precursor 3b １ A portion of the metal paste portion (the metal paste covering the surface of the substrate and the metal paste protruding from the holes) can be removed so that the surface is flush with the metal paste. Another method is to remove the metal paste using a metal squeegee such as SUS.

[0094] Surface SP of substrate 40 ０ and the exposed surface VP of the metal sintered body precursor 3b １ The step between the hole (via) and the exposed surface of the metal sintered body precursor may be 5 μm or less, or 3 μm or less, in the direction perpendicular to the substrate surface. The average step calculated by the following method may be within the above range. (Average Step) An image of a cross section passing through the center of the hole (via) is acquired and binarized to determine the cross-sectional area Sa enclosed by the inner wall of the hole (via), the exposed surface of the metal sintered body precursor, and the opening surface of the hole (via), and the average step is calculated by dividing this by the spacing Wa of the inner walls of the hole.

[0095] [Step d] In this step, the metal sintered body precursor 3b formed in step c is fired. This allows for the formation of a metal sintered body having a porous structure. The porosity of the metal sintered body may be 10% or less, 1.0 to 6.5%, or 1.5 to 5.0%, from the viewpoint of suppressing penetration of chemicals into the metal sintered body when immersed in a chemical solution such as a resist stripper or plating pretreatment solution in a subsequent step and improving reliability. When the metal sintered body is made of a copper sintered body, the porosity of the copper sintered body may be in the above range. The porosity can be determined by the method described in the examples.

[0096] The firing can be carried out by a heating treatment, which can be performed using a heating means such as a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far-infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, a heater heating device, or a steam heating furnace.

[0097] The atmosphere during firing may be an oxygen-free atmosphere from the viewpoint of suppressing oxidation of the copper sintered body, or a reducing atmosphere from the viewpoint of removing surface oxides of the copper particles in the metal sintered body precursor. Examples of oxygen-free atmospheres include the introduction of oxygen-free gases such as nitrogen and rare gases, or under vacuum. Examples of reducing atmospheres include pure hydrogen gas, a mixed gas of hydrogen and nitrogen such as forming gas, nitrogen containing formic acid gas, a mixed gas of hydrogen and rare gas, and a rare gas containing formic acid gas. When the metal sintered body precursor is sintered by heating without pressure, pure hydrogen gas or a mixed gas of hydrogen and nitrogen such as forming gas is preferred, and pure hydrogen gas is preferable. Heating in pure hydrogen gas makes it possible to lower the sintering temperature of the copper particles, for example. When pure hydrogen gas is used, even if the substrate is as thick as 600 μm and the through holes 30 have a small diameter of 10 μm, the gas reaches the center of the through holes 30, making it easy to obtain a metal body containing a copper sintered body.

[0098] The maximum temperature reached during the heat treatment may be 150°C or higher, and may be 350°C or lower, 300°C or lower, or 260°C or lower, from the viewpoint of reducing thermal damage to each component and improving yield. If the maximum temperature reached is 150°C or higher, sintering tends to proceed sufficiently when the maximum temperature is held for 60 minutes or less. From the viewpoint of volatilizing all the volatile solvent and improving yield, the maximum temperature holding time may be 1 minute or higher, and may be 60 minutes or lower, 40 minutes or lower, or 30 minutes or lower.

[0099] In this embodiment, by using the metal paste of this embodiment, sintering can be performed in an atmosphere containing formic acid gas at a low temperature of 300° C. or less, 200° C. or less, or 150° C. or less, and firing may be performed at 100 to 300° C., 100 to 200° C., or 100 to 150° C. In this case as well, a conductive via with excellent conductivity and connection reliability can be formed.

[0100] The firing of the metal sintered body precursor may be carried out without pressure or under pressure. In the latter case, in an atmosphere containing pure hydrogen gas, the pressure may be 0.05 MPa or more, 0.1 MPa or more, or 0.3 MPa or more, and 20 MPa or less, 15 MPa or less, or 10 MPa or less. In addition, in an atmosphere containing nitrogen gas, the pressure may be 1 MPa or more, or 3 MPa or more, and 20 MPa or less, 15 MPa or less, or 10 MPa or less.

[0101] By setting the pressure to 0.05 MPa or more when pure hydrogen gas is used, or 1 MPa or more when nitrogen gas is used, it becomes easier to suppress the generation of voids in the conductive via formed in the center of the through hole 30, and it becomes easier to obtain a conductive via with good conductivity. Furthermore, by setting the pressure to the above-mentioned lower limit or more, when the silicon substrate 40 has a metal coating 2, it becomes easier to improve the bonding strength between the metal coating 2 and the conductive via.

[0102] Furthermore, if the pressure applied during firing is within the above range, no special pressure device is required, and therefore voids can be reduced and the bonding strength and connection reliability can be further improved without impairing yield. Methods for applying pressure to the silicon substrate having the metal sintered body precursor formed in the through hole include, for example, a method of placing a weight, a method of applying pressure using a pressure device, and a method of applying pressure using a fixing jig for applying pressure.

[0103] When the metal sintered body is a copper sintered body, the proportion of copper element among the constituent elements excluding light elements may be 95 mass% or more, 97 mass% or more, 98 mass% or more, or even 100 mass%. If the proportion of copper element in the copper sintered body is within the above range, the formation of intermetallic compounds or the precipitation of heterogeneous elements at the copper metal grain boundaries can be suppressed, the properties of the copper metal constituting the copper sintered body are likely to be strengthened, and even better connection reliability is likely to be obtained.

[0104] In step d, the metal sintered body precursor is formed into an exposed surface VP that is flat and has a sufficiently small step with the substrate surface. １ and has a composition that is resistant to volume shrinkage due to firing. ０ and the exposed surface VP of the conductive via 3c ２ The difference in level between the two can be made sufficiently small.

[0105] Surface SP of substrate 40 ０ and the exposed surface VP of the conductive via 3c ２ The step (or the depression of the conductive via 3c) between the hole (via) and the exposed surface of the conductive via 3c may be 5 μm or less, or may be 3 μm or less, in the direction perpendicular to the substrate surface. The average step calculated by the following method may be within the above range. (Average Step) An image of a cross section passing through the center of the hole (via) is acquired and binarized to determine the cross-sectional area Sb enclosed by the inner wall of the hole (via), the exposed surface of the conductive via, and the opening surface of the hole (via), and this is divided by the spacing Wb of the inner walls of the hole to calculate the average step.

[0106] Through the above-described steps a to d, a substrate 50 with a metal sintered body can be obtained, which has a metal sintered body 3c having a porous structure 32 provided in the through-hole 30 of the silicon substrate 40. In the substrate 50 with a metal sintered body, the exposed surface of the metal sintered body is flat (smooth), and the surface SP of the substrate 40 ０ Since the step between the wiring and the substrate is sufficiently small, the wiring can be easily formed and a sufficiently low connection resistance can be exhibited even after the wiring is formed.

[0107] Furthermore, a metal coating may be further formed on the surface of the metal sintered body-attached substrate 50 obtained through the above-described steps a to d. Examples of metal coatings include titanium, nickel, chromium, copper, aluminum, palladium, platinum, and gold. From the viewpoints of adhesion and subsequent etching, the metal coating is preferably copper. The metal coating can be formed by plating or sputtering, but sputtering is more preferable. In this case, in the resist formation step, plating step, resist removal step, and etching step described later, the intrusion of chemicals into the copper sintered body, which has a porous structure, can be prevented, thereby suppressing oxidation of the copper sintered body and improving reliability.

[0108] [Step S2] In step S2, a resin-containing portion containing a photosensitive resin composition or a cured product thereof is provided in the metal sintered body of the metal sintered body-attached substrate. The metal sintered body may also be provided with the resin-containing portion and a resin-free portion not containing the resin composition or a cured product thereof, with the resin-containing portion being concentrated toward the opening. In this case, an increase in connection resistance due to the resin-containing portion can be suppressed, while adverse effects due to penetration of chemicals or the like during wiring formation in a subsequent process can be prevented.

[0109] The photosensitive resin composition may be either negative or positive, as long as it can form a predetermined pattern by exposure and development.

[0110] Methods for providing a resin-containing portion containing a photosensitive resin composition on a metal sintered body include laminating a film-like photosensitive resin composition or applying a liquid photosensitive resin composition. When providing a resin-containing portion containing a cured product of a photosensitive resin composition on a metal sintered body, the photosensitive resin composition can be cured after providing the resin-containing portion containing the photosensitive resin composition. In this case, the photosensitive resin composition may contain a thermosetting component and be thermoset.

[0111] Step S2 may include a step S2-1a (see (a) and (b) of FIG. 4) of laminating a film-like negative photosensitive resin composition 80 on the surface of the substrate with a metal sintered body, thereby impregnating at least a portion of the metal sintered body 3c with the negative photosensitive resin composition, and a step S2-2a (see (c) of FIG. 4) of removing the film-like negative photosensitive resin composition by a development treatment after step S2-1a, thereby exposing the metal sintered body 3c having a resin-containing portion containing the negative photosensitive resin composition 34a at the opening of the hole.

[0112] As the film-like negative photosensitive resin composition, a dry film resist such as a photocurable dry film resist or a thermosetting dry film resist can be used, and for example, commercially available products such as RD-1619 (product name, manufactured by Resonac Corporation), HM-4035 (product name, manufactured by Resonac Corporation), HM-4056 (product name, manufactured by Resonac Corporation), TMMF NA1000 (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), and PSR-800 AUS SR-1 (product name, manufactured by Taiyo Ink Mfg. Co., Ltd.) may be used.

[0113] The film-like negative photosensitive resin composition can be laminated using a roll laminator, a laminator, a press, or the like.

[0114] The pressure may be 0.1 MPa or more, 0.4 MPa or more, or 1 MPa or more from the viewpoint of facilitating impregnation of the metal sintered body with the photosensitive resin composition. The upper limit of the pressure may be 10 MPa or less from the viewpoint of minimizing the influence on the substrate.

[0115] From the viewpoint of facilitating impregnation of the photosensitive resin composition into the metal sintered body, lamination may be performed while heating. The heating temperature is not particularly limited as long as it is within a range in which the photosensitive resin composition does not harden, and may be 50°C to 100°C, or 70°C to 90°C.

[0116] From the viewpoint of facilitating impregnation of the photosensitive resin composition into the metal sintered body, the metal sintered body may be maintained at a vacuum of 1000 Pa or less, or a vacuum of 200 Pa or less, and then laminated with a film-like negative photosensitive resin composition.

[0117] From the viewpoint of connection reliability, the depth to which the photosensitive resin composition is impregnated into the metal sintered body may be 0.2% or more, 0.5% or more, or 1% or more of the total length of the metal sintered body in the thickness direction of the substrate, and the distance from the exposed surface of the metal sintered body may be 1 μm or more, 2 μm or more, or 3 μm or more.

[0118] In step S2-2a, a development process suitable for the photosensitive resin composition can be carried out. Examples of the developer that can be used include an alkaline aqueous solution obtained by dissolving an alkaline compound such as sodium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, or choline in water to a concentration of about 1 to 10% by mass, and an alkaline aqueous solution such as ammonia water. Examples of the development method include shower development, spray development, immersion development, and paddle development.

[0119] After step S2-2a, a substrate 51a with conductive vias is obtained (see FIG. 4(c)).

[0120] Step S2 may further include, after step S2-2a, step S2-3a of curing the negative photosensitive resin composition contained in the resin-containing portion.

[0121] In the case of photocuring, examples of actinic rays used for exposure include light emitted from a g-line stepper as a light source; ultraviolet light emitted from a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an i-line stepper, etc. as a light source; electron beams; laser beams; etc. The exposure dose is appropriately selected depending on the light source used, the thickness of the impregnated photosensitive resin composition, etc.

[0122] When the negative photosensitive resin composition contains a thermosetting component, it may be thermally cured.

[0123] Step S2 may further include, after step S2-3a, step S2-4a of performing a desmear treatment on at least the exposed surface of the metal sintered body.

[0124] Examples of the desmear treatment include plasma cleaning and treatment with a desmear solution containing permanganate and a caustic composition (for example, an alkali metal hydroxide).

[0125] In another embodiment, step S2 may include step S2-1b (see FIG. 5(a)) of applying a liquid negative photosensitive resin composition 82 to the surface of the substrate with a metal sintered body, thereby impregnating at least a portion of the metal sintered body 3c with the negative photosensitive resin composition, and step S2-2b (see FIG. 5(b)) of removing the coating film of the liquid negative photosensitive resin composition by a development treatment after step S2-1b, thereby exposing the metal sintered body 3c having a resin-containing portion containing the negative photosensitive resin composition 34b at the opening of the hole.

[0126] As the liquid negative photosensitive composition, for example, commercially available products such as PSR-4000 G24K / CA-40 G24 (product name, manufactured by Taiyo Ink Mfg. Co., Ltd.), TER-20HF (product name, manufactured by Taiyo Ink Mfg. Co., Ltd.), and TMMR NA1000PM (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) may be used.

[0127] Examples of methods for applying a liquid negative photosensitive composition include screen printing, transfer printing, offset printing, jet printing, a dispenser, a jet dispenser, a needle dispenser, a comma coater, a slit coater, a die coater, a gravure coater, a slit coater, letterpress printing, intaglio printing, gravure printing, stencil printing, soft lithography, a bar coater, an applicator, a particle deposition method, a spray coater, a spin coater, and a dip coater. From the viewpoints of workability in application and uniformity of the thickness of the coating film, application may be by screen printing or spin coating.

[0128] The depth to which the metal sintered body is impregnated with the photosensitive resin composition and the method for developing the coating film of the liquid negative photosensitive resin composition may be the same as those in the above-mentioned steps S2-1a and S2-2a.

[0129] After step S2-2b, a substrate 51b with conductive vias is obtained (see FIG. 5(b)).

[0130] Furthermore, after step S2-2b, similarly to the above-described steps S2-3a and S2-4a, step S2-3b of curing the negative photosensitive resin composition contained in the resin-containing portion may be carried out, and after step S2-3b, step S2-4b of performing a desmear treatment on at least the exposed surface of the metal sintered body may be carried out.

[0131] In another embodiment, step S2 may include a step S2-1c (see (a) of FIG. 6) of applying a liquid positive photosensitive resin composition to the surface of the substrate with a metal sintered body, or laminating a film-like positive photosensitive resin composition, thereby impregnating at least a portion of the metal sintered body with the positive photosensitive resin composition, and a step S2-2c (see (b) and (c) of FIG. 6) of removing the coating film of the liquid positive photosensitive resin composition or the film-like positive photosensitive resin composition by exposure and development treatment after step S2-1c, thereby exposing the metal sintered body having a resin-containing portion containing the positive photosensitive resin composition at the opening of the hole.

[0132] As the positive photosensitive composition, for example, commercially available products such as AH-3000 (product name, manufactured by Resonac Corporation), AR-5100 (product name, manufactured by Resonac Corporation), and OFPR-8600 (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) may be used.

[0133] The above-mentioned methods can be used for applying the photosensitive composition and laminating the photosensitive composition.

[0134] The depth to which the photosensitive resin composition is impregnated into the metal sintered body may be the same as in the above-mentioned step S2-1a.

[0135] The exposure in step S2-2c can be, for example, light emitted from a g-line stepper as a light source; ultraviolet light emitted from a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an i-line stepper, or the like as a light source; electron beams; laser beams; etc. The exposure dose is appropriately selected depending on the light source used, the thickness of the impregnated photosensitive resin composition, etc.

[0136] The method for developing the coating film of the liquid positive photosensitive resin composition and the film-like positive photosensitive resin composition may be the same as in the above-mentioned step S2-2a.

[0137] After step S2-2c, a substrate 51c with conductive vias is obtained (see FIG. 5(c)).

[0138] In addition, when the positive photosensitive resin composition contains a thermosetting component, step S2-2c may be followed by step S2-3c of thermally curing the positive photosensitive resin composition contained in the resin-containing portion. Furthermore, step S2-4c of desmearing at least the exposed surface of the metal sintered body may be followed by step S2-4c, similar to step S2-4a described above.

[0139] <Method for manufacturing a wiring board with conductive vias> The method for manufacturing a wiring board with conductive vias of this embodiment includes a step S3 of forming wiring electrically connected to the conductive vias in the substrate with conductive vias obtained by the method for manufacturing a wiring board with conductive vias of this embodiment.

[0140] Step S3 can include a resist forming step, a plating step, a resist removing step, and an etching step, which will be described below.

[0141] <Resist Forming Process> In the resist forming process, for example, as shown in (a) and (b) of FIG. 7, a negative photosensitive dry film 8 for etching resist is laminated on the main surface of the silicon substrate 40 and on the conductive vias, and then a light-transmitting photomask is placed over the wiring shape, exposed to ultraviolet light, and the unexposed areas are removed with a developer, thereby forming an etching resist 8a.

[0142] Other methods for forming the etching resist 8a include, for example, a method of silk-screen printing resist ink and a method of laminating a dry film resist using a laminator.

[0143] When the substrate with conductive vias is obtained through step S2 including steps S2-1a and S2-2a, before step S2-2a, a film-like negative photosensitive resin composition may be irradiated with light in the shape of a wiring to form an etching resist 8a.

[0144] <Plating Step> In the plating step, for example, as shown in FIG. 7C, the wiring 9 can be formed in the opening of the etching resist 8a by a method such as electrolytic plating or electroless plating.

[0145] <Resist Removal Step> In the resist removal step, for example, as shown in FIG. 7D , the etching resist 8 a can be removed by a method such as stripping by a wet process using an alkaline aqueous solution or an organic solvent-based chemical liquid such as an organic amine-based liquid such as TMAH or a ketone-based liquid such as acetone, or stripping by a dry process using plasma, ozone, or the like.

[0146] <Etching Step> In the etching step, the metal coating 2 in the portion not covered by the wiring 9 can be removed by etching. In this embodiment, a portion of the metal coating 2 provided on both main surfaces of the silicon wafer 1 is removed by etching.

[0147] Examples of etching methods include methods using chemical etching solutions typically used for wiring boards, such as a solution of cupric chloride and hydrochloric acid, a ferric chloride solution, a solution of sulfuric acid and hydrogen peroxide, or an ammonium persulfate solution.

[0148] By the above step e, a wiring substrate 52 with conductive vias as shown in FIG. 7(e) can be obtained.

[0149] In the above-described method, a step of removing at least a part of the conductor such as the sintered body of the metal base or the metal coating 2 remaining on the main surface of the silicon substrate 40 may be performed before the step e.

[0150] The means for removing the conductor include chemical polishing, mechanical polishing, chemical mechanical polishing, fly-cutting, plasma treatment, etc. Fly-cutting refers to cutting and flattening with a surface planer.

[0151] According to the manufacturing method of the wiring board with conductive vias of this embodiment, by providing wiring on the wiring board with conductive vias of this embodiment, it is possible to obtain a wiring board with conductive vias that exhibits a sufficiently low connection resistance value and has excellent connection reliability.

[0152] <Substrate with conductive via> The substrate with conductive via of this embodiment comprises a substrate having a through hole and a conductive via provided in the through hole, wherein the conductive via comprises a metal sintered body having a porous structure, and the metal sintered body comprises a resin-containing portion containing a photosensitive resin composition or a cured product thereof.

[0153] The substrate with conductive vias of this embodiment can be obtained by the method for manufacturing a substrate with conductive vias of this embodiment described above.

[0154] <Wiring Board with Conductive Vias> The wiring board with conductive vias of this embodiment includes the substrate with conductive vias of this embodiment, and wiring provided on the substrate with conductive vias and electrically connected to the conductive vias.

[0155] The wiring board with conductive vias of this embodiment can be obtained by the method for manufacturing a wiring board with conductive vias of this embodiment described above, and can exhibit a sufficiently low connection resistance value and have excellent connection reliability.

[0156] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0157] [Preparation of Metal Paste] (Preparation Examples A to J) The raw materials shown below were mixed in the proportions shown in Tables 1 and 2 using a triple roll mill to prepare metal pastes.

[0158] <First copper particles> (Wet copper powder) Spherical copper particles W1: 1050Y (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 0.81 μm, spherical) Spherical copper particles W4: 1300Y (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 3.5 μm, spherical) Flat copper particles W2: 1200YP (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 3.1 μm, flat) (Atomized copper powder) Spherical copper particles A2: MA-C025K (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 2.4 μm, spherical)

[0159] <Second copper particles> Spherical copper particles W5: CH0200L1 (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 200 nm, spherical)

[0160] <Solder particles> Solder particle 1: SnBi58 solder STC-3 (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 4.1 μm, spherical) Solder particle 2: Sn96.5Ag3Cu0.5 solder STC-3 (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size (D50): 4.1 μm, spherical)

[0161] <Nickel Particles> Nickel particle 1: nickel nanoparticles (manufactured by EM Japan, average particle size (D50): 0.1 μm, spherical) Nickel particle 2: nickel particles (manufactured by METAL FOIL & POWDERS MFG CO., average particle size (D50): 3.0 μm, spherical)

[0162] <Silver particles> Silver particles 1: OS fine silver particles (manufactured by Osaka Soda Co., Ltd., average particle size (D50): 0.2 μm, spherical) Silver particles 2: NP-AG-15 (manufactured by EM Japan, average particle size (D50): 3 μm, spherical) Silver particles 3: AgC-271B (manufactured by Fukuda Metal Foil & Powder Co., Ltd., average particle size (D50): 2.1 μm, flat)

[0163] <Silver-coated copper particles> Silver-coated copper particles 1: 10% Ag coated Cu-HWQ 5 μm (manufactured by Fukuda Metal Foil & Powder Co., Ltd., average particle size (D50): 5.9 μm, spherical) Silver-coated copper particles 2: 10% Ag coated 2L3 (manufactured by Fukuda Metal Foil & Powder Co., Ltd., average particle size (D50): 10.9 μm, flat)

[0164] <Resin Components> Resin R1: A mixture of "KFA-2000" (acrylic binder manufactured by GOO Chemical Industry Co., Ltd.) as an organic binder and a mixture of carbitol and terpineol as an organic solvent (the mass ratio of carbitol to terpineol in the mixture [carbitol:terpineol] = 1:1) in a mass ratio of 1:2.

[0165] <Volatile solvents> (High vapor pressure solvent: vapor pressure of 4 Pa ​​or more and 30 Pa or less at 20°C) α-Terpineol: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., vapor pressure of 6.5 Pa at 20°C (Low vapor pressure solvent: vapor pressure of less than 4 Pa ​​at 20°C) Isobornylcyclohexanol: manufactured by Nippon Terpene Chemical Industry Co., Ltd., trade name "Tersolve MTPH", vapor pressure of 0.004 Pa at 20°C Diethylene glycol mono-n-butyl ether: manufactured by Showa Chemical Co., Ltd., vapor pressure of 1.3 Pa at 20°C

[0166]

[0167]

[0168] [Preparation of Glass Substrates with Conductive Vias] (Examples 1 to 32 and Comparative Examples 1 to 9) Glass substrates with conductive vias were prepared according to the following procedure.

[0169] <Preparation of Glass Substrate> A glass substrate "D263Teco" (trade name, manufactured by SCHOTT GmbH, material: borosilicate glass, average linear thermal expansion coefficient α: 7.2 × 10) having through holes and on both main surfaces and wall surfaces of the through holes, a titanium layer (thickness 100 nm) and a copper layer (thickness 300 nm) formed in this order was used. －６ The glass substrate had a diameter of 6 inches and a thickness of 300 μm, and the titanium layer and copper layer were formed in that order by sputtering. Substrates with through holes having diameters (via diameters) of 50, 90, 150, and 200 μm were prepared.

[0170] <Preparation of Metal Particle Film> The metal paste of Preparation Example A prepared above was printed on a 100 μm thick PET film in an 8-inch diameter (circular shape with a diameter of 20 cm) using a screen printing plate (line diameter: 23 μm, mesh number: 400, mesh size: 41 μm, void ratio: 41 μm) using a screen printing machine, to obtain a metal particle film provided with a metal particle-containing layer.

[0171] <Formation of Metal Sintered Body> Using a bonding device VJ-35 (manufactured by Ayumi Industries Co., Ltd.), the metal particle film was bonded to the glass substrate from the metal particle-containing layer side, and the laminate was then vacuum-pressed at room temperature under a pressure of 3 MPa to fill the through holes with the metal paste. At this time, the metal paste was protruded from the side of the glass substrate opposite to the side where the metal particle film was bonded.

[0172] Next, the PET film was peeled off from the laminate, and the resulting product was dried in the air for 10 minutes at 90° C. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0173] For the dried laminate, as shown in Figures 3(a) to 3(d), the metal paste on the main surface of the glass substrate on which the metal particle film was bonded was removed using a rubber squeegee, and then the metal paste protruding from the side of the glass substrate opposite to the side on which the metal particle film was bonded was removed using a rubber squeegee.

[0174] Next, the glass substrate with the metal sintered body precursor formed in the through-holes by the above-mentioned process was placed in a tube furnace (manufactured by AVC Corporation), and argon gas was flowed at 1 L / min to replace the air in the tube furnace with argon gas. Thereafter, while flowing hydrogen gas at 300 mL / min, the temperature was raised to 300 ° C over 10 minutes, and a sintering treatment was performed at 300 ° C for 60 minutes to sinter the metal sintered body precursor. Thereafter, argon gas was flowed at a flow rate of 0.3 L / min to cool the substrate, and the substrate was removed into air at 50 ° C or below to obtain a glass substrate with a metal sintered body.

[0175] For the glass substrate with a sintered metal body obtained above, the porosity of the metal sintered body was evaluated according to the following method.

[0176] (Porosity of Metal Sintered Body) A glass substrate with a metal sintered body that had been subjected to mechanical polishing was cut in the thickness direction, and the cross section of the central portion of the metal sintered body on the glass substrate was exposed using a focused ion beam, and this cross section was observed. When observing the cross section of the central portion of the through hole in the glass substrate, a range of ±5 μm from the center of the through hole in the thickness direction of the glass substrate and ±5 μm in the direction perpendicular to the thickness direction of the glass substrate was observed. A focused ion beam processing observation device, MI4050 (manufactured by Hitachi High-Technologies Corporation), was used. For observation, a scanning electron microscope S-3700N (manufactured by Hitachi High-Technologies Corporation) was used at a magnification of 5000x, and cross-sectional images (approximately 10 μm square) of the metal sintered body were taken. Five observation locations were used. The obtained cross-sectional images were binarized using image analysis software (Adobe Photoshop (registered trademark) Elements) to separate the sintered copper portion from the porous (void) portion. For each of the five observation points, the ratio of the area of ​​the porous (void) portion to the total area of ​​the cross section of the metal sintered body was calculated, and this was taken as the porosity. The average value of the porosities observed at the five observation points was taken as the porosity of the metal sintered body. For the observation, a scanning electron microscope S-3700N (manufactured by Hitachi High-Technologies Corporation) was used at a magnification of 5000x, and cross-sectional images (approximately 10 μm square) of the metal sintered body were taken.

[0177] [Preparation of wiring board] (Examples 1 to 4) Conductive vias having a resin-containing portion containing a photosensitive resin composition were formed in a glass substrate with a sintered metal body (via diameter: 50, 90, 150, 200 μm) prepared in the same manner as above, by the following procedure, and wiring was further formed to obtain a wiring board, which was then evaluated.

[0178] On the surface of the glass substrate with a sintered metal body obtained above, a dry film for ultraviolet curable etching resist "RD-1619" (product name, manufactured by Resonac Corporation) (photosensitive resin composition F1) was laminated by atmospheric pressure lamination under conditions of a roll pressure of 0.4 MPa, a processing temperature of 120°C, and a conveying speed of 1.0 m / s to form a dry film resist layer. Next, the dry film resist layer was laminated using a direct imaging exposure machine "DE-1UH" (product number, manufactured by Via Mechanics Co., Ltd.) at 55 mJ / cm ２The resist was exposed to light in a predetermined pattern under the following conditions. One minute later, a post-exposure bake (PEB) treatment was performed at 70°C for 1 minute. This was followed by a treatment using a 1% sodium carbonate developer at a spray pressure of 0.17 MPa and 30°C for 70 seconds. Residues were then removed by oxygen plasma treatment to form a resist pattern. Surface treatment was performed using an etching treatment (ammonium persulfate: 100 g / L, R.T., 30 seconds) and an aqueous sulfuric acid solution (100 g / L, R.T., 30 seconds), followed by electroplating of the resist openings. After the resist was stripped and the seed layer was etched, wiring with a 300 μm x 600 μm wiring pattern was formed, yielding a test piece 55 (wiring substrate) as shown in FIG. 8 . The wiring pattern was finished to a thickness of approximately 10 μm after etching the seed layer. In the test piece 55, the conductive vias formed in the through holes were electrically connected by wiring provided on the substrate surface.

[0179] Examples 5 to 8 Wiring boards were obtained and evaluated in the same manner as in Examples 1 to 4, except that the roll pressure of the dry film "RD-1619" was changed to 1.0 MPa.

[0180] Examples 9 to 12 Wiring boards were obtained and evaluated in the same manner as in Examples 1 to 4, except that the roll pressure of the dry film "RD-1619" was changed to 3.0 MPa.

[0181] (Examples 13 to 16) Conductive vias having resin-containing portions containing a cured product of a photosensitive resin composition were formed on glass substrates with sintered metal bodies (via diameters: 50, 90, 150, and 200 μm) prepared in the same manner as described above, by the following procedure. Wiring was then formed to obtain wiring substrates, which were then evaluated.

[0182] On the surface of the glass substrate with the metal sintered body obtained above, a photosensitive film type TMMF NA1000 (manufactured by Tokyo Ohka Kogyo Co., Ltd., product name) (photosensitive resin composition F2) was laminated by atmospheric pressure lamination under conditions of a roll pressure of 1.0 MPa, a processing temperature of 120 ° C, and a conveying speed of 1.0 m / s to form a dry film resist layer. Next, PEB treatment was performed at 80 ° C for 5 minutes, followed by treatment with PEGMEA (developer) at a spray pressure of 0.17 MPa and 30 ° C for 1 minute to completely peel off the dry film resist layer formed on the glass substrate surface. Next, heat treatment was performed at 200 ° C for 2 minutes to harden the photosensitive resin composition (TMMF NA1000) impregnated into the porous portion of the copper sintered body. Further, oxygen plasma treatment was performed to remove the photosensitive resin composition remaining on the surface of the copper sintered body and the residue of the cured product.

[0183] [Wiring Formation Step A] On the surface of the glass substrate with conductive vias obtained above, a dry film for ultraviolet curable etching resist "RD-1619" (trade name, manufactured by Resonac Corporation) was laminated by atmospheric pressure lamination under conditions of a roll pressure of 0.4 MPa, a processing temperature of 120°C, and a conveying speed of 1.0 m / s to form a dry film resist layer. Next, the dry film resist layer was laminated using a direct writing exposure machine "DE-1UH" (manufactured by Via Mechanics Co., Ltd., product number) at 55 mJ / cm ２ The resist was exposed to light in a predetermined pattern under the following conditions. One minute later, a PEB treatment was performed at 70°C for 1 minute, followed by treatment with a 1% sodium carbonate developer at a spray pressure of 0.17 MPa and 30°C for 70 seconds. Residues were then removed by oxygen plasma treatment to form a resist pattern. Next, electrolytic plating was performed on the resist openings, followed by resist stripping and seed layer etching to form wiring with a 300 μm × 600 μm wiring pattern, thereby obtaining a test piece 55 (wiring substrate) as shown in FIG. 8 . The wiring pattern was finished to a thickness of approximately 10 μm after etching the seed layer. In the test piece 55, the conductive vias formed in the through holes were electrically connected by wiring provided on the substrate surface.

[0184] (Examples 17 to 20) A conductive via having a resin-containing portion containing a cured product of a photosensitive resin composition was formed on a glass substrate with a sintered metal body (via diameter: 50, 90, 150, 200 μm) prepared in the same manner as above, by the following procedure, and further wiring was formed to obtain a wiring substrate, which was then evaluated.

[0185] On the surface of the glass substrate with the metal sintered body obtained above, developable dry film solder resist PSR-800 AUS SR-1 (manufactured by Taiyo Ink Mfg. Co., Ltd., trade name) (photosensitive resin composition F3) was laminated using a vacuum laminator MVLP series (manufactured by The Japan Steel Works, Ltd., trade name) at a vacuum of 3 hPa and a cycle time of 30 seconds, followed by lamination under conditions of 100 ° C., 0.5 MPa, and a cycle time of 30 seconds, and then press processing was performed under conditions of 80 ° C., 0.8 MPa, and a cycle time of 60 seconds. Next, a development process was performed using a 1 mass% sodium carbonate solution at 30 ° C., a spray pressure of 0.15 MPa, and 1 minute, followed by water washing under conditions of 25 ° C., a spray pressure of 0.10 MPa, and 1 minute. The dry film resist layer formed on the surface of the glass substrate was peeled off entirely. Next, post-curing was performed at 150°C for 60 minutes to harden the photosensitive resin composition (PSR-800 AUS SR-1) impregnated into the porous portion of the copper sintered body. Further, oxygen plasma treatment was performed to remove the photosensitive resin composition and its cured residue remaining on the surface of the copper sintered body.

[0186] Wiring was formed on the surface of the glass substrate with conductive vias obtained above in the same manner as in the wiring forming step A, to obtain a test piece 55 (wiring substrate) as shown in FIG.

[0187] (Examples 21 to 24) Conductive vias having resin-containing portions containing a cured product of a photosensitive resin composition were formed on glass substrates with sintered metal bodies (via diameters: 50, 90, 150, and 200 μm) prepared in the same manner as described above, and wiring was further formed to obtain wiring substrates, which were then evaluated.

[0188] On one side of the surface of the glass substrate with sintered metal body obtained above, a developable screen printing solder resist PSR-4000 G24K / CA-40 G24 (trade name, manufactured by Taiyo Ink Mfg. Co., Ltd.) (photosensitive resin composition L1) was printed using a screen printer to a thickness of approximately 20 μm. After pre-drying at 80°C for 30 minutes, the other side was similarly printed using a screen printer to a thickness of approximately 20 μm and pre-dried at 80°C for 30 minutes. Next, the substrate was developed using a 1% by mass sodium carbonate solution at 30°C and a spray pressure of 0.15 MPa for 1 minute, and then washed with water at 25°C and a spray pressure of 0.10 MPa for 1 minute. The solder resist layer formed on the surface of the glass substrate was completely peeled off. Next, post-curing was performed at 150°C for 60 minutes to harden the photosensitive resin composition (PSR-4000 G24K / CA-40 G24) impregnated into the porous portion of the copper sintered body. Further, oxygen plasma treatment was performed to remove the photosensitive resin composition and its cured residue remaining on the surface of the copper sintered body.

[0189] Wiring was formed on the surface of the glass substrate with conductive vias obtained above in the same manner as in the wiring forming step A, to obtain a test piece 55 (wiring substrate) as shown in FIG.

[0190] (Examples 25 to 28) Conductive vias having resin-containing portions containing a cured product of a photosensitive resin composition were formed on glass substrates with sintered metal bodies (via diameters: 50, 90, 150, and 200 μm) prepared in the same manner as described above, and wiring was further formed to obtain wiring substrates, which were then evaluated.

[0191] The surface of the glass substrate with sintered metal body obtained above was treated by spin coating with positive photosensitive resin AH-3000 (manufactured by Resonac Corporation, product name) (photosensitive resin composition L2) at 1000 rpm for 5 seconds and 2000 rpm for 20 seconds, to form a coating on one side to a thickness of approximately 5 μm. After pre-drying at 120°C for 150 seconds, the other side was similarly treated by spin coating at 1000 rpm for 5 seconds and 2000 rpm for 20 seconds, to form a coating on the other side to a thickness of approximately 5 μm. A direct imaging exposure machine "DE-1UH" (manufactured by Via Mechanics Co., Ltd., product number) was used to apply 500 mJ / cm ２The entire surfaces of both sides of the substrate were exposed under the conditions. Subsequently, a treatment was carried out using 2.38%-TMAH (developer) at a spray pressure of 0.17 MPa and 30°C for 1 minute, and the positive photosensitive resin composition layer formed on the surface of the glass substrate was entirely peeled off. Next, a heat treatment was carried out at 230°C for 60 minutes, and the positive photosensitive resin composition (AH-3000) impregnated into the porous portion of the copper sintered body was cured. Furthermore, the photosensitive resin composition remaining on the surface of the copper sintered body and the residue of the cured product were removed by oxygen plasma treatment.

[0192] Wiring was formed on the surface of the glass substrate with conductive vias obtained above in the same manner as in the wiring forming step A, to obtain a test piece 55 (wiring substrate) as shown in FIG.

[0193] (Examples 29 to 32) Conductive vias having resin-containing portions containing a cured product of a photosensitive resin composition were formed on glass substrates with sintered metal bodies (via diameters: 50, 90, 150, and 200 μm) prepared in the same manner as described above, and wiring was further formed to obtain wiring substrates, which were then evaluated.

[0194] On the surface of the glass substrate with conductive vias obtained above, a positive photosensitive resin AH-3000 (manufactured by Resonac Corporation, trade name) (photosensitive resin composition L2) was applied by spin coating at 1000 rpm for 5 seconds to a thickness of approximately 20 μm. One side was then coated with the positive photosensitive resin composition (AH-3000). The chamber was then evacuated to a vacuum of 3 hPa, and the porous portion of the copper sintered body was impregnated with the positive photosensitive resin composition (AH-3000). Pre-drying was performed at 120 ° C. for 150 seconds. The opposite side was also similarly treated by spin coating at 1000 rpm for 5 seconds to a thickness of approximately 20 μm. The chamber was then evacuated to a vacuum of 3 hPa, and the porous portion of the copper sintered body was impregnated with the positive photosensitive resin composition (AH-3000). Pre-drying was then performed at 120 ° C. for 150 seconds. Direct imaging exposure machine "DE-1UH" (Via Mechanics Co., Ltd., product number) was used to achieve 500 mJ / cm ２The entire surfaces of both sides of the substrate were exposed under the conditions. Subsequently, a 2.38%-TMAH (developer) was used, and the substrate was treated at a spray pressure of 0.17 MPa and 30°C for 1 minute to completely peel off the positive photosensitive resin composition layer formed on the surface of the glass substrate. The substrate was then heat-treated at 230°C for 60 minutes to harden the positive photosensitive resin composition (AH-3000) impregnated into the porous portions of the copper sintered body. Furthermore, the photosensitive resin composition remaining on the surface of the copper sintered body and the residue of the cured product were removed by oxygen plasma treatment.

[0195] Wiring was formed on the surface of the glass substrate with conductive vias obtained above in the same manner as in the wiring forming step A, to obtain a test piece 55 (wiring substrate) as shown in FIG.

[0196] Comparative Examples 1 to 4 Wiring boards were obtained and evaluated in the same manner as in Examples 1 to 4, except that the roll pressure of the dry film "RD-1619" was changed to 0.1 MPa and the etching treatment time was set to 5 minutes.

[0197] Comparative Examples 5 to 8 Conductive vias having resin-containing portions containing a cured product of a thermosetting resin composition were formed in glass substrates with sintered metal bodies (via diameters: 50, 90, 150, and 200 μm) prepared in the same manner as described above, and wiring was further formed to obtain wiring substrates, which were then evaluated.

[0198] The curable resin composition shown below was applied to one side of the glass substrate with a sintered metal body obtained above using a roll coater. The glass substrate with a sintered metal body was then placed in a container, and the container was evacuated to a gauge pressure of 100 kPa to create a vacuum. The glass substrate with a sintered metal body was held in the vacuum state for 10 minutes, after which the glass substrate with a sintered metal body was removed from the container. It was confirmed that the curable resin composition had impregnated the copper sintered body in the through-hole and reached the side of the copper sintered body in the through-hole opposite to the side on which the curable resin composition had been applied. The curable resin composition remaining on the surface of the glass substrate with a sintered metal body to which the curable resin composition had been applied was removed with a rubber spatula. Next, the curable resin composition was applied and removed from the side opposite to the side on which the curable resin composition had been applied in the same manner as described above. [Curable resin composition] YDF-170 (trade name, manufactured by Tohto Kasei Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent = 170): 95 parts by mass 2PZ-CN (trade name, manufactured by Shikoku Kasei Co., Ltd., imidazole compound): 5 parts by mass

[0199] The glass substrate with the metal sintered body, in which the copper sintered body was impregnated with the curable resin composition, was held in a nitrogen atmosphere at 180°C for 1 hour to obtain a glass substrate with conductive vias having through electrodes. Next, oxygen plasma treatment was performed for 5 minutes to remove the curable resin composition and its cured product remaining on the via surfaces.

[0200] Comparative Example 9 A glass substrate with a metal sintered body was produced and its porosity was measured in the same manner as above, except that a glass substrate (via diameter: 90 μm) and the metal paste of Preparation Example J were used. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 94.7 mass % and 96.0 mass %, respectively.

[0201] A wiring board was obtained in the same manner as in Example 1, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0202] [Impregnation depth of photosensitive resin composition into porous portion of metal sintered body] The cross section of the conductive via of the glass substrate with conductive via was exposed by cross-section polishing, the surface was cleaned by ion milling, and this cross section was observed. Using a scanning electron microscope S-3700N (manufactured by Hitachi High-Technologies Corporation), the impregnation depth of the photosensitive resin composition (or its cured product) into the porous portion was measured. The distance from the via surface to the porous (void) portion was measured at 10 points, and the average value was taken as the impregnation depth.

[0203] [Evaluation of Wiring Board] The test pieces obtained above were evaluated for initial resistance, connection reliability, and depressions on the surface of the wiring pattern formed on the conductive vias according to the following methods.

[0204] <Initial Resistance Value> The resistance value of 1000 connected vias was measured as the initial resistance value of the test piece 55 (wiring board). Based on this connected resistance value, the initial resistance value was evaluated according to the following criteria. (Number of vias) 1000 (Criteria) A: Resistance value less than 6Ω B: Resistance value 6Ω or more and less than 10Ω C: Resistance value 10Ω or more and less than 20Ω D: Resistance value 20Ω or more and less than 50Ω E: Resistance value 50Ω or more

[0205] <Connection Reliability - Temperature Cycle Test> Test piece 55 (wiring board) was placed in a temperature cycle tester (TSA-72SE-W, manufactured by Espec Corporation), and a temperature cycle connection reliability test was performed under the following conditions: low temperature side: -55°C, 15 minutes; room temperature: 2 minutes; high temperature side: 125°C, 15 minutes; defrosting cycle: automatic; number of cycles: 50, 100, 300, 500, 1000. For the test pieces that had undergone each number of cycles, the resistance value of the connection of the above number of vias was measured. Based on this connected connection resistance value, connection reliability was evaluated according to the following criteria. (Evaluation criteria) A: Resistance change rate is less than 1% of the initial resistance value. B: Resistance change rate is 1% or more and less than 3% of the initial resistance value. C: Resistance change rate is 3% or more and less than 5% of the initial resistance value. D: Resistance change rate is 5% or more and less than 10% of the initial resistance value. E: Resistance change rate is 10% or more and less than 20% of the initial resistance value. F: Resistance change rate is 20% or more of the initial resistance value. G: Poor continuity occurs.

[0206] <Connection reliability - 150°C> Test piece 55 was placed in a high-temperature chamber (precision incubator DH612, manufactured by Yamato Scientific Co., Ltd.) and left at 150°C for 50, 100, 300, and 500 hours to conduct a high-temperature storage test. For each test piece that had been left for each time, the resistance value of the connected vias of the above number was measured. Based on this connected connection resistance value, connection reliability was evaluated according to the following criteria. (Criteria) A: Resistance change rate is less than 1% of the initial resistance value B: Resistance change rate is 1% or more but less than 3% of the initial resistance value C: Resistance change rate is 3% or more but less than 5% of the initial resistance value D: Resistance change rate is 5% or more but less than 10% of the initial resistance value E: Resistance change rate is 10% or more but less than 20% of the initial resistance value F: Resistance change rate is 20% or more of the initial resistance value G: Conduction failure occurred

[0207] <Connection Reliability -200°C> Test piece 55 was placed in a high-temperature chamber (Precision Incubator DH612, manufactured by Yamato Scientific Co., Ltd.) and left at 200°C for 50, 100, 300, and 500 hours to conduct a high-temperature storage test. For each test piece that had been left for each time, the resistance value of the connected vias indicated above was measured. Based on this connected connection resistance value, connection reliability was evaluated according to the following criteria. (Criteria) A: Resistance change rate is less than 1% of the initial resistance value B: Resistance change rate is 1% or more but less than 3% of the initial resistance value C: Resistance change rate is 3% or more but less than 5% of the initial resistance value D: Resistance change rate is 5% or more but less than 10% of the initial resistance value E: Resistance change rate is 10% or more but less than 20% of the initial resistance value F: Resistance change rate is 20% or more of the initial resistance value G: Conduction failure occurred

[0208] <Dent on the surface of the wiring pattern formed on the conductive vias> The surface of the wiring pattern formed on the conductive vias of test piece 55 (wiring board) was observed for 30 conductive vias using a digital microscope (VHX-6000, manufactured by Keyence Corporation), the deepest points were measured, and the average value was taken as the dent on the surface of the wiring pattern. (Evaluation criteria) A: Average value of average step height is less than 2 μm B: Average value of average step height is 2 μm or more and less than 4 μm C: Average value of average step height is 4 μm or more and less than 6 μm D: Average value of average step height is 6 μm or more and less than 8 μm E: Average value of average step height is 8 μm or more

[0209]

[0210]

[0211]

[0212]

[0213]

[0214] Examples 33 to 43 Glass substrates with sintered metal bodies were prepared and the porosity was measured in the same manner as in Examples 1 to 4, except for using the metal paste of Preparation Example B. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0215] Wiring boards were obtained in the same manner as in Examples 1 to 4, except that the glass substrate with the sintered metal body prepared above was used, and the wiring boards were evaluated.

[0216] Example 37 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except that the metal paste of Preparation Example C was used. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0217] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with the sintered metal body prepared above was used and the roll pressure of the dry film "RD-1619" was changed to 3 MPa, and the wiring board was evaluated.

[0218] Example 38 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except that the metal paste of Preparation Example D was used. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0219] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with the sintered metal body prepared above was used and the roll pressure of the dry film "RD-1619" was changed to 3 MPa, and the wiring board was evaluated.

[0220] Example 39 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except for using the metal paste of Preparation Example E. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0221] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0222] Example 40 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except that the metal paste of Preparation Example F was used. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0223] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0224] Example 41: A glass substrate having a metal sintered body precursor formed in the through-holes was obtained in the same manner as in Example 3, except that the metal paste of Preparation Example G was used. The glass substrate was then placed in a tube furnace (manufactured by AVC Corporation) and heated to 300°C in 10 minutes under atmospheric pressure. The metal sintered body precursor was sintered by sintering at 300°C for 60 minutes. The glass substrate was then cooled by flowing argon gas at a flow rate of 0.3 L / min and removed into air at 50°C or below, yielding a glass substrate with a metal sintered body. The concentrations (mass%) of metal particles in the metal paste portion before and after drying were 95.7% by mass and 97.8% by mass, respectively.

[0225] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0226] Example 42 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except that the metal paste of Preparation Example H was used. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0227] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0228] Example 43 A glass substrate with a sintered metal body was produced and the porosity was measured in the same manner as in Example 3, except for using the metal paste of Preparation Example I. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0229] A wiring board was obtained in the same manner as in Example 3, except that the glass substrate with a sintered metal body prepared above was used, and the wiring board was evaluated.

[0230] Comparative Example 10 In the same manner as in Example 41, a glass substrate with a sintered metal body was produced.

[0231] Using the glass substrate with sintered metal body prepared above, a wiring board was obtained in the same manner as in Example 3, except that the roll pressure of the dry film "RD-1619" was changed to 0.1 MPa and the processing time in the etching process was set to 5 minutes, and then the wiring board was evaluated.

[0232]

[0233]

[0234] [Fabrication of Silicon Substrates with Conductive Vias] (Examples 44 to 47) Silicon substrates with conductive vias were fabricated according to the following procedure.

[0235] <Preparation of Silicon Substrate> Silicon substrates were prepared that had through holes and had titanium layers, nickel layers, and copper layers formed in that order on both main surfaces and the wall surfaces of the through holes. The silicon substrates had a diameter of 6 inches and a thickness of 300 μm, and the titanium layers, nickel layers, and copper layers were formed in that order by sputtering. The substrates were provided with through holes with diameters (via diameters) of 50, 90, 150, and 200 μm.

[0236] <Preparation of Metal Particle Film> The metal paste of Preparation Example A prepared above was printed on a 100 μm thick PET film in an 8-inch diameter (circular shape with a diameter of 20 cm) using a screen printing plate (line diameter: 23 μm, mesh number: 400, mesh size: 41 μm, void ratio: 41 μm) using a screen printing machine, to obtain a metal particle film provided with a metal particle-containing layer.

[0237] <Formation of Metal Sintered Body> Using a bonding device VJ-35 (manufactured by Ayumi Industries Co., Ltd.), the metal particle film was bonded to the silicon substrate from the metal particle-containing layer side, and the laminate was then vacuum-pressed at room temperature under a pressure of 3 MPa to fill the through holes with the metal paste. At this time, the metal paste protruded from the side of the silicon substrate opposite to the side where the metal particle film was bonded.

[0238] Next, the PET film was peeled off from the laminate, and the resulting product was dried in the air for 10 minutes at 90° C. The concentrations (mass %) of metal particles in the metal paste portion before and after drying were 95.7 mass % and 97.8 mass %, respectively.

[0239] For the dried laminate, as shown in Figures 3(a) to 3(d), the metal paste on the main surface of the silicon substrate on which the metal particle film was bonded was removed using a rubber squeegee, and then the metal paste protruding from the side opposite to the side on which the metal particle film was bonded was removed using a rubber squeegee.

[0240] Next, the silicon substrate with the metal sintered body precursor formed in the through-holes by the above-mentioned process was placed in a tube furnace (manufactured by AVC Corporation), and argon gas was flowed at 1 L / min to replace the air in the tube furnace with argon gas. Then, while flowing hydrogen gas at 300 mL / min, the temperature was raised to 300 ° C over 10 minutes, and sintering treatment was performed at 300 ° C for 60 minutes to sinter the metal sintered body precursor. Then, argon gas was flowed at a flow rate of 0.3 L / min to cool the substrate, and it was removed into air at 50 ° C or below to obtain a silicon substrate with a metal sintered body.

[0241] For the silicon substrate with the metal sintered body obtained above, the porosity of the metal sintered body was evaluated according to the method described above.

[0242] Using the silicon substrate with sintered metal body obtained above, a wiring board was obtained in the same manner as in Examples 1 to 4, except that the roll pressure of the dry film "RD-1619" was changed to 3 MPa, and the wiring board was evaluated.

[0243] [Preparation of Organic Substrates with Conductive Vias] (Examples 48 to 50) Organic substrates with conductive vias were prepared according to the following procedure.

[0244] <Preparation of Organic Substrate> A 300 μm thick high Tg glass epoxy multilayer material MCL-E-679F(J) (manufactured by Resonac Corporation) with 1 μm copper foil laminated on both sides was prepared, and through holes with hole diameters (via diameters) of 90, 150, and 200 μm were formed. A 0.5 μm thick copper plating film was formed inside the vias by electroless copper plating.

[0245] An organic substrate with a metal sintered body was obtained in the same manner as in the production method of the silicon substrate with a metal sintered body described above, except that the organic substrate was heated to 225° C. in 10 minutes and sintered for 60 minutes at 225° C. The porosity of the metal sintered body of the obtained organic substrate with a metal sintered body was evaluated according to the method described above.

[0246] Using the organic substrate with the metal sintered body obtained above, a wiring board was obtained in the same manner as in Examples 2 to 4, except that the roll pressure of the dry film "RD-1619" was changed to 3 MPa, and the wiring board was evaluated.

[0247]

[0248] It was confirmed that the substrate with conductive vias of the examples could provide a wiring substrate that exhibited a sufficiently low connection resistance value and had excellent connection reliability.

[0249] Furthermore, for the wiring substrates produced in Examples 1 and 29, a focused ion beam processing and observation device (manufactured by Hitachi High-Technologies Corporation, product name: MI4050) was used to expose the cross section of the central portion of the conductive via with a focused ion beam, and the cross section was observed, and the following findings were obtained.

[0250] In the wiring board produced in Example 1, the photosensitive resin composition was not impregnated in the center of the conductive via, and voids were observed between the copper particles, but no deterioration due to seepage of the aqueous solution used in forming the electrolytic copper plating film was observed.In addition, in the wiring board produced in Example 29, the photosensitive resin composition was also impregnated in the center of the conductive via, and no voids were observed between the copper particles.

[0251] In this way, the conductive via substrate of the example was impregnated with a photosensitive resin composition, which allowed the resin composition on the surface of the metal sintered body to be removed by development treatment while leaving the resin composition inside the metal sintered body, which is thought to have made it possible to achieve both good wiring formation and suppression of penetration of aqueous solutions, etc.

[0252] 1...silicon wafer, 2...metal coating, 3...metal paste portion, 3b...metal sintered body precursor, 3c...conductive via, 3p...metal particle-containing layer, 7...support film, 8a...etching resist, 9...wiring, 30...through hole, 31...blind hole, 32...porous structure, 34a, 34b, 34c...resin composition, 40, 41...silicon substrate, 42...rubber squeegee, 50...substrate with conductive via, 52...wiring substrate with conductive via, 55...test piece, 80, 82, 84...photosensitive resin composition, A...pressure jig.

Claims

1. A method for manufacturing a substrate with a conductive via, comprising: a step S1 of preparing a substrate with a sintered metal body having a porous structure, the sintered metal body being provided inside a hole that opens on one or both of the main surfaces and being exposed at the opening of the hole; and a step S2 of providing a resin-containing portion containing a photosensitive resin composition or a cured product thereof on the sintered metal body of the substrate with the sintered metal body.

2. The method for manufacturing a substrate with a conductive via according to claim 1, wherein in step S2, the sintered metal body is provided with the resin-containing portion and a resin non-containing portion that does not contain the resin composition or its cured product such that the resin-containing portion is unevenly distributed on the opening side.

3. The method for manufacturing a substrate with a conductive via according to claim 1, wherein step S2 includes: a step S2-1a of impregnating at least a part of the sintered metal body with a negative-type photosensitive resin composition by laminating a film-shaped negative-type photosensitive resin composition on the surface of the substrate with the sintered metal body; and a step S2-2a of removing the film-shaped negative-type photosensitive resin composition by development treatment after step S2-1a and exposing the sintered metal body having the resin-containing portion containing the negative-type photosensitive resin composition at the opening of the hole.

4. The method for manufacturing a substrate with a conductive via according to claim 3, wherein step S2 further includes a step S2-3a of curing the negative-type photosensitive resin composition contained in the resin-containing portion after step S2-2a.

5. The method for manufacturing a substrate with a conductive via according to claim 4, wherein step S2 further includes a step S2-4a of performing desmear treatment on at least the exposed surface of the sintered metal body after step S2-3a.

6. The method for manufacturing a substrate with a conductive via according to claim 1, wherein step S2 includes: a step S2-1b of impregnating at least a part of the sintered metal body with a negative-type photosensitive resin composition by applying a liquid negative-type photosensitive resin composition to the surface of the substrate with the sintered metal body; and a step S2-2b of removing the coating film of the liquid negative-type photosensitive resin composition by development treatment after step S2-1b and exposing the sintered metal body having the resin-containing portion containing the negative-type photosensitive resin composition at the opening of the hole.

7. The method for manufacturing a substrate with conductive vias according to claim 6, wherein the step S2 further includes a step S2-3b of curing the negative photosensitive resin composition contained in the resin-containing portion after the step S2-2b.

8. The method for manufacturing a substrate with conductive vias according to claim 7, wherein the step S2 further includes a step S2-4b of performing a desmear treatment on at least the exposed surface of the metal sintered body after the step S2-3b.

9. The method for manufacturing a substrate with conductive vias according to claim 1, wherein the step S2 includes: a step S2-1c of impregnating at least a part of the metal sintered body with a positive photosensitive resin composition by applying a liquid positive photosensitive resin composition on the surface of the substrate with the metal sintered body or laminating a film-shaped positive photosensitive resin composition; and a step S2-2c of removing the coating film of the liquid positive photosensitive resin composition or the film-shaped positive photosensitive resin composition by exposure and development treatment after the step S2-1c, and exposing the metal sintered body having the resin-containing portion containing the positive photosensitive resin composition at the opening of the hole.

10. The method for manufacturing a substrate with conductive vias according to claim 9, wherein the positive photosensitive resin composition contains a thermosetting component, and the step S2 further includes a step S2-3c of thermally curing the positive photosensitive resin composition contained in the resin-containing portion after the step S2-2c.

11. The method for manufacturing a substrate with conductive vias according to claim 10, wherein the step S2 further includes a step S2-4c of performing a desmear treatment on at least the exposed surface of the metal sintered body after the step S2-3c.

12. The method for manufacturing a wired substrate with conductive vias, comprising: a step S3 of forming a wiring electrically connected to the conductive via on the substrate with conductive vias obtained by the method according to any one of claims 1 to 11.

13. A substrate with conductive vias, comprising: a substrate having through holes; and conductive vias provided in the through holes, wherein the conductive vias include a metal sintered body having a porous structure, and the metal sintered body includes a resin-containing portion containing a photosensitive resin composition or a cured product thereof.

14. The substrate with conductive vias according to claim 13, wherein the metal sintered body further includes a resin-free portion not containing a resin composition or a cured product thereof, and the resin-containing portion is unevenly distributed on the opening side of the through hole of the metal sintered body.

15. A wiring substrate with conductive vias, comprising the substrate with conductive vias according to claim 13 or 14, and wiring provided on the substrate with conductive vias and electrically connected to the conductive vias.

Images