Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G4/00—Fixed capacitors; Processes of their manufacture
  • H01G4/002—Details
  • H01G4/224—Housing; Encapsulation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G4/00—Fixed capacitors; Processes of their manufacture
  • H01G4/002—Details
  • H01G4/228—Terminals

Definitions

• the present invention relates to a capacitor.
• Patent Document 1 discloses a capacitor in which a capacitance forming portion is provided by a metal porous body, a dielectric film covering the surface of the metal porous body, and a conductive film covering the dielectric film. In this capacitor, the capacitance forming portion is sealed by a conductive plating portion.
• the plating solution used to form the plating portion may remain in multiple tiny spaces inside the capacitance forming portion.
• the plating solution may expand due to a thermal load applied during the manufacture of the capacitor or after mounting, causing blisters to form, which may apply stress to the capacitance forming portion and cause cracks in the dielectric film.
• the metal porous body may be dissolved by the plating solution residue coming into contact with the metal porous body.
• the present invention has therefore been made to solve the above-mentioned problems, and aims to improve the reliability after mounting in a capacitor that has a capacitance forming portion made of a metal porous body, a dielectric film, and a conductive film, and a plated portion that seals this.
• the capacitor according to the present invention comprises an insulating substrate having a main surface, a capacitance forming portion provided on the main surface, and a first external connection wiring and a second external connection wiring connected to the capacitance forming portion.
• the capacitance forming portion includes a conductive metal porous body connected to the first external connection wiring, a dielectric film covering the surface of the metal porous body, and a conductive film covering the dielectric film and connected to the second external connection wiring.
• the second external connection wiring includes a conductive plating portion provided on the outer periphery of the capacitance forming portion, and a conductive intervening film interposed between the capacitance forming portion and the plating portion.
• the capacitance forming portion is sealed by the insulating substrate and the plating portion.
• the present invention makes it possible to improve the reliability of a capacitor having a capacitance forming portion made of a metal porous body, a dielectric film, and a conductive film, and a plated portion that seals this.
• FIG. 11 is a schematic cross-sectional view of a capacitor according to a first modified example.
• FIG. 11 is a schematic cross-sectional view of a capacitor according to a second modified example.
• FIG. 11 is a schematic cross-sectional view of a capacitor according to a second embodiment.
• 16 is an enlarged cross-sectional view of a main portion of the capacitor shown in FIG. 15 .
• FIG. 11 is a flow diagram showing a method for manufacturing a capacitor according to a second embodiment.
• FIG. 1 is a schematic front view of a capacitor according to a first embodiment.
• FIG. 2 is a schematic bottom view of the capacitor as viewed from the direction of the arrow II shown in FIG. 1.
• FIG. 3 is a schematic cross-sectional view of the capacitor taken along line III-III shown in FIG. 2.
• FIG. 4 is an enlarged cross-sectional view of a main part of region IV of the capacitor shown in FIG. 3.
• FIG. 5 is an enlarged cross-sectional view of a main part for explaining an example of a method for measuring a distance.
• capacitor 1A has a flat, roughly rectangular parallelepiped outer shape, with its bottom surface configured as a mounting surface for a wiring board or the like.
• Capacitor 1A mainly comprises an insulating substrate 10, a capacitance forming portion 20, and a plating portion 50.
• the capacitance forming portion 20 is provided so as to face the insulating substrate 10.
• the capacitance forming portion 20 is located inside capacitor 1A by being sealed by the insulating substrate 10 and the plating portion 50 provided on the insulating substrate 10.
• the insulating substrate 10 is provided with a first via conductor 13 and a first bump 16.
• the first via conductor 13 and the first bump 16 constitute one of a pair of external connection wirings for electrically connecting the capacitance forming portion 20 located inside the capacitor 1A to an external circuit.
• the pair of external connection wirings includes a first external connection wiring as an anode and a second external connection wiring as a cathode.
• the first external connection wiring is composed of the first via conductor 13 and the first bump 16.
• the second external connection wiring is composed of a plating portion 50, etc., which will be described in detail later.
• the insulating substrate 10 is a flat plate-shaped member having a first main surface 10a as a main surface and a second main surface 10b located on the opposite side to the first main surface 10a.
• a substrate having electrical insulation properties, and it is preferable to use a substrate mainly composed of an inorganic material. More specifically, as the insulating substrate 10, it is possible to use a substrate mainly composed of any of Si , Al2O3 , ZrO2 , BN , Si3N4 , AlN, MgO, Mg2SiO4 , BaTiO3 , SrTiO3 , and CaTiO3 .
• the thickness and size of the insulating substrate 10 are not particularly limited, but it is preferable to use an alumina substrate that is rectangular in plan view, for example, with a thickness of 5 ⁇ m to 75 ⁇ m and a side length of 500 ⁇ m to 2000 ⁇ m.
• the insulating substrate 10 has a first through hole 11.
• the first through hole 11 penetrates the insulating substrate 10 so as to reach from the first main surface 10a to the second main surface 10b.
• the first through hole 11 is filled with a first via conductor 13.
• the shape of the first via conductor 13 is, for example, approximately cylindrical.
• the first via conductor 13 constitutes part of the first external connection wiring described above. When viewed along the normal direction of the first main surface 10a of the insulating substrate 10, the first via conductor 13 is provided within the region in which the capacitance forming portion 20 is arranged.
• the first via conductor 13 can be made of various wiring materials, but is preferably made of a metal material with particularly high electrical conductivity.
• the material of the first via conductor 13 can be, for example, a metal material whose main material is any of Ni, Ag, Cu, Au, Pt, Mo, and W.
• the material of the first via conductor 13 can be changed as appropriate to suit the mounting environment of the capacitor 1A according to this embodiment.
• the first via conductor 13 is made of Ni.
• the axial length and size of the first via conductor 13 are not particularly limited, and are set appropriately according to the thickness and size of the insulating substrate 10.
• the axial length of the first via conductor 13 is preferably, for example, 5 ⁇ m or more and 75 ⁇ m or less, and the diameter is preferably, for example, 15 ⁇ m or more and 150 ⁇ m or less.
• the first via conductor 13 is made of Ni, has an axial length of 75 ⁇ m, and a diameter of 150 ⁇ m.
• a first bump 16 is provided on the second main surface 10b of the insulating substrate 10 so as to cover the first via conductor 13.
• the first bump 16 serves as a bonding material for mounting the capacitor 1A on a wiring board or the like, and for electrically connecting the capacitance forming portion 20 of the capacitor 1A to an external circuit.
• the first bump 16 is provided so as to protrude from the second main surface 10b of the insulating substrate 10.
• the shape of the first bump 16 is approximately semispherical.
• the first bump 16 constitutes part of the first external connection wiring described above.
• the first bump 16 can be made of various wiring materials, but is preferably made of a metal material with particularly high electrical conductivity.
• the material of the first bump 16 can be, for example, a metal material whose main component is any of Ni, Ag, Cu, Au, and Sn. In this embodiment, the first bump 16 is made of Au.
• the size of the first bump 16 is not particularly limited and is set appropriately according to the size of the first via conductor 13.
• the capacitance forming portion 20 is provided on the first main surface 10a of the insulating substrate 10.
• the capacitance forming portion 20 includes a conductive metal porous body 21 having a plurality of fine pores therein, a dielectric film 22 covering the surface of the metal porous body 21, and a conductive film 23 further covering the surface of the dielectric film 22.
• the metal porous body 21 is connected to the first via conductor 13. At least some of the multiple fine pores provided inside the metal porous body 21 are not closed by the metal porous body 21 itself, and preferably most or all of the multiple fine pores provided inside are not closed by the metal porous body 21 itself.
• a metal porous body 21 is composed of, for example, a sintered body of metal particles.
• the metal porous body 21 can be made of various conductive metal materials, but is preferably made of a metal material whose main component is any of Ni, Mo, W, Al, Ti, Ta, Nb, Cu, Pt, Au, and Ag.
• the metal porous body 21 may also be made of an alloy material whose main components are two or more selected from these metal materials.
• the thickness and size of the metal porous body 21 are not particularly limited, and the size is set appropriately according to the size of the insulating substrate 10.
• the metal porous body 21 is made of Ni and has a thickness of 200 ⁇ m.
• the metal porous body 21 is preferably composed of a sintered body of metal particles.
• the metal particles may be of various shapes, such as spherical, elliptical, flat, plate-like, or needle-like.
• the particle size of the metal particles is not particularly limited, but the average particle size is preferably 600 nm or less, and more preferably 20 nm or more and 500 nm or less.
• the dielectric film 22 can be made of various insulating materials, for example, metal oxides such as AlOx , SiOx , HfOx, TiOx , TaOx , ZrOx , SiAlOx, HfAlOx, ZrAlOx, AlTiOx, SrTiOx, HfSiOx, ZrSiOx, TiZrOx , TiZrWOx , BaTiOx , PbTiOx , BaSrTiOx , BaCaTiOx , metal nitrides such as AlNx , SiNx , AlScNx , AlOxNy , SiOxNy , HfOxNy , SiCxOyN It can be composed of metal oxynitrides such as AlO x (for example, Al 2 O 3 ), SiO x (for example, SiO 2 ), HfO x , TiO x
• the dielectric film 22 is composed of any of these.
• the above chemical formulas simply indicate the composition of the materials and do not limit the composition. That is, x, y, and z attached to O, N, and C may be any value greater than 0, and the abundance ratio of each element including the metal element is arbitrary.
• the dielectric film 22 may also be composed of a laminated film consisting of a plurality of dielectric layers made of different materials.
• the thickness of the dielectric film 22 is not particularly limited, but is preferably 3 nm to 100 nm, and more preferably 5 nm to 50 nm.
• the dielectric film 22 is made of AlSiO and has a thickness of approximately 20 nm.
• the conductive film 23 covers the surface of the dielectric film 22. More specifically, the conductive film 23 not only covers the surface of the dielectric film 22 in the portion located on the outermost side of the capacitance forming section 20, but also covers the surface of the dielectric film 22 in the portion located inside the capacitance forming section 20. Furthermore, the conductive film 23 covers the surface of the dielectric film 22 in the portion covering the side surface of the insulating substrate 10 and the surface of the dielectric film 22 in the portion covering the surface of the edge of the second main surface 10b.
• the conductive film 23 can be made of various conductive materials, including metal materials whose main component is any of Ni, Cu, Ru, Al, W, Ti, Ag, Au, Zn, Ta, and Nb; alloy materials whose main components are two or more selected from these metal materials; metal nitrides such as TiN, TiAlN, TiSiN, TaN, NbN, and WN; metal oxynitrides such as TiON and TiAlON; conductive polymers such as PEDOT (poly(3,4-ethylenedioxythiophene)), polypyrrole, and polyaniline; and conductive oxide films such as RuO2 , ZnO, (Zn,Al)O, and NiO.
• metal materials whose main component is any of Ni, Cu, Ru, Al, W, Ti, Ag, Au, Zn, Ta, and Nb
• alloy materials whose main components are two or more selected from these metal materials
• metal nitrides such as TiN, TiAlN, TiSiN, Ta
• the conductive film 23 can be preferably formed by CVD, ALD, PLD, plating, bias sputtering, sol-gel, a method using conductive polymer filling, or a method using supercritical fluid, and is particularly preferably formed by ALD.
• the conductive film 23 may also be composed of a laminated film made up of multiple conductive layers made of different materials. In that case, the film can be formed by another method after being formed by ALD.
• the thickness of the conductive film 23 is not particularly limited, but is preferably 3 nm or more, and more preferably 10 nm or more.
• the conductive film 23 is made of TiN and has a thickness of approximately 25 nm.
• the outer periphery 20a of the capacitance forming portion 20 is covered by a conductive intervening film 40.
• the intervening film 40 includes an outer portion 41 that does not penetrate into the internal space of the capacitance forming portion 20 and is located between the conductive film 23 and the plating portion 50 in the portion that defines the outer periphery 20a of the capacitance forming portion 20.
• the intervening film 40 is interposed between the capacitance forming portion 20 and the plating portion 50.
• the "outer periphery of the capacitance forming portion” means the portion that surrounds the outside of the capacitance forming portion, and does not limit the shape of the capacitance forming portion to, for example, a cylindrical or spherical shape.
• the intervening film 40 further includes an inner portion 42 that is positioned within the internal space of the capacitance forming portion 20.
• the intervening film 40 By configuring the intervening film 40 in this manner, it is possible to effectively prevent a short circuit from occurring in the capacitance forming portion 20, the details of which will be described later.
• the intermediate film 40 can be made of various conductive materials, including metal materials mainly made of any of Ni, Cu, Ru, Al, W, Ti, Ag, Au, Zn, Ta, and Nb, alloy materials mainly made of two or more selected from these metal materials, metal nitrides such as TiN, TiAlN, TiSiN, TaN, NbN, and WN, metal oxynitrides such as TiON and TiAlON, conductive polymers such as PEDOT (poly(3,4-ethylenedioxythiophene)), polypyrrole, and polyaniline, and conductive oxide films such as RuO 2 , ZnO, (Zn,Al)O, and NiO.
• the intermediate film 40 is made of Cu.
• the maximum and second largest values, and the minimum and second smallest values are excluded, and the average of the six measured values is calculated.
• the average value thus calculated becomes the above-mentioned distance d1.
• three of the distances measured at these 10 locations are illustrated as line segment lengths da, db, and dc.
• the plating portion 50 is provided on the outer periphery 20a of the capacitance forming portion 20. As a result, the capacitance forming portion 20 is sealed by the insulating substrate 10 and the plating portion 50.
• the plating portion 50 defines an outer surface 50a located on the opposite side of the capacitance forming portion 20 from the insulating substrate 10 side. More specifically, the plating portion 50 is located so as to cover the upper and side of the capacitance forming portion 20, which is provided to face the first main surface 10a of the insulating substrate 10. As described above, an intervening film 40 is interposed between the capacitance forming portion 20 and the plating portion 50.
• the above-mentioned first bump 16 and the plating portion 50 formed in a ring shape along the edge of the second main surface 10b of the insulating substrate 10 define the bottom surface of the capacitor 1A, and this bottom surface is configured as the mounting surface for a wiring board or the like.
• the plated portion 50 can be made of various conductive materials, but is preferably made of a metal material with particularly high electrical conductivity.
• the material of the plated portion 50 can be, for example, a metal material whose main component is any of Ni, Ag, Cu, Au, Pt, Mo, and W.
• the plated portion 50 is made of Cu.
• the plated portion 50 can be formed by various plating methods.
• the thickness and size of the plated portion 50 are not particularly limited, and the size is set appropriately according to the size of the insulating substrate 10.
• the thickness of the plated portion 50 is preferably, for example, 0.5 ⁇ m or more and 50 ⁇ m or less, and the size is preferably such that it covers the entire first main surface 10a of the insulating substrate 10.
• step S4 the green sheet with the conductive paste applied is fired.
• the firing of the green sheet is carried out, for example, in an air atmosphere at a temperature of 700°C to 1000°C.
• step S7 a conductive film is formed. More specifically, a conductive film 23 is formed so as to cover the dielectric film 22 formed in step S6.
• a capacitance forming portion 20 consisting of a conductive metal porous body 21, a dielectric film 22, and a conductive film 23 is formed on the first main surface 10a of the insulating substrate 10, as shown in FIG. 10.
• the method for forming the intervening film 40 is not particularly limited, but the CVD method is preferably used.
• the intervening film 40 made of Cu is formed using the CVD method.
• a first bump is formed on the insulating substrate.
• a first bump 16 is formed on the second main surface 10b of the insulating substrate 10 so as to cover the first via conductor 13 provided on the insulating substrate 10.
• the intervening film 40 acts as a physical obstacle, effectively preventing the plating solution from entering the internal space of the capacitance forming portion 20.
• (First Modification) 13 is a schematic cross-sectional view of a capacitor according to a first modified example.
• a capacitor 1A1 according to a first modified example based on the above-mentioned first embodiment will be described with reference to FIG.
• the capacitor 1A1 according to the first modified example can be manufactured basically in accordance with the manufacturing method of the capacitor 1A according to the first embodiment described above.
• a through hole 20c is provided in the capacitance forming portion 20.
• the through hole 20c penetrates the capacitance forming portion 20 so as to reach from one end to the other end in the height direction of the capacitance forming portion 20.
• the through hole 20c is filled with a plated portion 50.
• An intervening film 40 is interposed between the plated portion 50 that is filled in the through hole 20c and the capacitance forming portion 20 that defines the through hole 20c.
• a second bump 17 is provided on the second main surface 10b of the insulating substrate 10 so as to cover the second via conductor 14.
• the second bump 17 is provided so as to protrude from the second main surface 10b of the insulating substrate 10.
• the shape of the second bump 17 is approximately semispherical.
• the material and shape of the second bump 17 are configured, for example, in the same manner as the first bump 16 described above.
• the first bump 16 and the second bump 17 define the bottom surface of the capacitor 1A2, and this bottom surface is configured as the mounting surface for a wiring board or the like.
• FIG. 15 is a schematic cross-sectional view of a capacitor according to embodiment 2.
• Fig. 16 is an enlarged cross-sectional view of a main portion of region XVI of the capacitor shown in Fig. 15.
• a capacitor 1B according to the present embodiment will be described with reference to Figs. 15 and 16.
• the capacitor 1B of this embodiment has a different configuration of the capacitance forming portion 20 compared to the capacitor 1A of the above-mentioned embodiment 1.
• the water-repellent film 24 may be made of an insulating material, or may be made of a conductive material. When an insulating water-repellent film 24 is used, the water-repellent film 24 may be made of a material such as a silane coupling agent or an organic fluorine compound. When a conductive water-repellent film 24 is used, the water-repellent film 24 may be made of a material such as a fluoride compound. In this embodiment, an insulating water-repellent film 24 made of a silane coupling agent is used.
• the method for forming the water-repellent film 24 is not particularly limited, but is preferably formed by an impregnation method.
• the thickness of the water-repellent film 24 is not particularly limited, but is preferably 10 nm or more and 1 ⁇ m or less.
• Appendix 2 A capacitor as described in Appendix 1, wherein the intervening film includes an inner portion that extends into the internal space of the capacitance forming portion, and an outer portion that does not extend into the internal space of the capacitance forming portion and is located between the outer periphery of the capacitance forming portion and the plating portion.
• Appendix 3 A capacitor as described in Appendix 2, wherein the distance in the thickness direction of the intervening film between the part of the inner portion of the intervening film that penetrates deepest into the internal space of the capacitance forming portion and the outer periphery of the capacitance forming portion is 15 ⁇ m or less.
• Appendix 4 A capacitor as described in Appendix 2 or 3, wherein the distance in the thickness direction of the intervening film between the portion of the outer portion of the intervening film that is in contact with the plating portion and the outer periphery of the capacitance forming portion is 100 nm or more.
• the capacitance forming portion further includes an insulating water-repellent film, 4.
• the capacitance forming portion further includes a conductive water-repellent film, 4.
• Appendix 7 A capacitor as described in Appendix 5 or 6, wherein the distance in the thickness direction of the intervening film between the portion of the outer portion of the intervening film that is in contact with the plating portion and the outer periphery of the capacitance forming portion is 50 nm or more.

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Citations (3)

• 2024
  • 2024-07-30 JP JP2024570496A patent/JP7768433B1/ja active Active
  • 2024-07-30 CN CN202480009787.XA patent/CN120615221A/zh active Pending
  • 2024-07-30 WO PCT/JP2024/027075 patent/WO2025150213A1/ja active Pending
• 2025
  • 2025-04-21 US US19/184,013 patent/US20250246371A1/en active Pending

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