JP2010278217A - Capacitor, wiring board, and methods of manufacturing these - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacity having little manufacturing variations in capacitance value and a wiring board having the same, and to provide methods of efficiently manufacturing these. <P>SOLUTION: The capacitor includes a substrate 5; a bottom electrode 4 provided on the substrate 5; a dielectric layer 3 that is provided at least on the bottom electrode 4 and contains a resin having at least a thermosetting property and a dielectric filler; a top electrode 2, that is provided on the dielectric layer 3 and has a rigidity higher than that of the dielectric before heat-cured. The top electrode 2 has a projection 15 for defining the distance between the substrate 5 and the top electrode 2, in at least a part thereof. Furthermore, at least part of a face of the top electrode 2 that faces the dielectric layer 3 is not to be in contact with the dielectric layer 3. In manufacturing the capacitor, a dielectric paste containing a thermosetting resin and a high dielectric-constant filler is supplied on the bottom electrode 4 and then the top electrode 2 is pressed against the dielectric paste from above it and the dielectric paste is heat-cured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capacitor, a wiring board, and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, in order to reduce the size and thickness of electronic devices, capacitors are often provided by soldering to the surface of a component mounting board as surface mount type chip components. However, when a chip capacitor is soldered, there is a limit to thinning the component mounting board, and a method of thinning the capacitor using printing is disclosed. For example, as disclosed in JP-A-9-17689, a method of forming a dielectric layer, a carbon paste layer as a migration prevention layer, and a conductor paste layer as an upper electrode on an electrode by printing, As in 9-17689, there is a method in which after the dielectric layer is printed, flattening is performed by pressing in a temporarily cured state, and further main curing is performed. In addition, there has been a method of repeating multi-layering by repeating temporary curing and flattening as disclosed in JP-A-8-279669. Japanese Patent Application Laid-Open No. 2006-120326 discloses a capacitor of a type in which a substrate and an upper electrode are in contact with each other.

JP 09-17689 A Japanese Patent Laid-Open No. 08-279669 JP 2006-120326 A

“Survey Report on the Possibility of Utilization Technology of System Technology Development Research 17-R-4 Porous Metal”, p20-26 “Fabrication of lotus-type porous irons and its mechanical properties”, S.M. K. Hyun, T .; Ikeda and H.M. Nakajima, Sci. Tech. Adv. Mater. , 5, 201 (2004). "Evaluation of porosity in porous fabric manufactured by unified solidified hydrogen", S. Yamamura, H .; Shiota, K .; Murakami and H.M. Nakajima, Mater. Sci. Eng. , A318, 137 (2001). “Pore morphology and microstructure of porous magnesium alloys produced by unidirectional solidification in a hydrogen atmosphere”, Hideo Hoshiyama, Teruyuki Ikeda, Kenji Murakami, Hideo Nakajima: Journal of the Japan Institute of Metals, 67, 714 (2003). “Fabrication of Lotus-type Porous Metals and the Physical Properties”, H.C. Nakajima, T .; Ikeda and S.M. K. Hyun, Adv. Eng. Mater. , 6, 377 (2004). “Fabrication of Lotus-Type Porous Stainless Steel by Continuous Zone Melting Technology and Mechanical Property”, T. et al. Ikeda, T .; Aoki and H.K. Nakajima, Metall. Mater. Trans. , 36A, 77 (2005). “Anisotropic electrical conductivity of lotus-type porous nickel”, M.M. Tane, S.M. K. Hyun, H .; Nakajima, J .; Appl. Phys. 97, 103701 (2005). “Sound absorption charactaristics of lotus-type porous copper fabricated by unidirectional solidification”, Z. K. Xie, T .; Ikeda, Y .; Okuda and H.M. Nakajima, Mater. Sci. Eng. , A386, 390-395 (2004) “Anisotrophic mechanical properties of porous copper fabricated by unidirectional solidification”, S.M. K. Hyun, K .; Murakami and H.M. Nakajima, Mater. Sci. Eng. , A299, 241 (2001).

  However, when the capacitor is manufactured by a printing method, it is difficult to control the film thickness of the dielectric layer, and there is a problem that the capacitance value during repeated manufacturing is not stable. Further, the method of pressing the dielectric layer in a temporarily cured state and performing the main curing as in Patent Document 1 and Patent Document 2 has a problem that the number of steps is large and the production efficiency of the capacitor is low. Also in Patent Document 3, the upper electrode is formed after the dielectric layer is formed first, and the film thickness of the dielectric layer cannot be mechanically controlled.

  An object of the present invention is to provide a capacitor having a small manufacturing variation in capacitance value, a wiring board having the capacitor, and a manufacturing method for manufacturing them with high efficiency.

  In a first aspect of the present invention, a capacitor according to the present invention includes a substrate, a lower electrode provided on the substrate, a resin and a dielectric filler provided at least on the lower electrode and having at least thermosetting properties. And an upper electrode provided on the dielectric layer and having higher rigidity than the dielectric before thermosetting. Further, at least a part of the upper electrode has a protrusion for defining a distance between the substrate and the upper electrode, and at least a part of a surface of the upper electrode facing the dielectric layer is It is characterized by not being in contact with the dielectric layer.

  In a second aspect of the present invention, a capacitor according to the present invention includes a substrate, a lower electrode provided on the substrate, a resin provided on the substrate and the lower electrode, and having at least thermosetting property. A dielectric layer made of a dielectric filler, and an upper electrode provided on the dielectric layer and having higher rigidity than the dielectric before thermosetting. Further, at least a part of the upper electrode has a protrusion for defining a distance between the substrate and the upper electrode, and the dielectric layer protrudes from between the upper electrode and the lower electrode. It is characterized by.

  In a third aspect, the wiring board according to the present invention is characterized in that the capacitor is installed on the surface or built in.

  In a fourth aspect, the method for manufacturing a capacitor according to the present invention includes a step of supplying a dielectric material before thermosetting higher than a desired capacitor film thickness on a lower electrode placed on a substrate, and before the thermosetting A step of pressing the dielectric with an upper electrode, and a step of thermosetting the dielectric.

  In a fifth aspect, a method of manufacturing a wiring board having a capacitor according to the present invention includes a step of installing a lower electrode on an insulating layer of the wiring board, and a desired dielectric material before thermosetting is formed on the lower electrode. The method includes a step of supplying higher than the capacitor film thickness, a step of pressing the dielectric before thermosetting with an upper electrode, and a step of thermosetting the dielectric.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method which produces a capacitor | condenser with a small manufacturing variation of a capacitance value, the wiring board which has the said capacitor | condenser, and them efficiently can be provided.

  That is, the capacitor of the present invention has a protrusion that defines the interval between the mounting substrate and the upper electrode on at least a part of the upper electrode having a higher rigidity than the time point before the thermosetting of the dielectric provided on the lower electrode. According to the structure, the thickness of the dielectric can be automatically controlled with high accuracy by a simple method of supplying the pre-thermosetting dielectric on the lower electrode and then pressing the upper electrode from the lower dielectric. Moreover, by using this manufacturing method, the dielectric planarization process and temporary hardening process described in Patent Document 2 can be omitted, and the production efficiency can be improved. Further, by spreading the pre-thermosetting dielectric with the upper electrode, air can be prevented from entering the upper electrode / dielectric interface, and the capacitance value can be prevented from lowering.

1 is a schematic cross-sectional view of a first embodiment according to the present invention. 1 is a schematic perspective view of a first embodiment according to the present invention. It is a schematic sectional drawing which shows the manufacturing method of 1st Embodiment which concerns on this invention. It is one form of the dielectric paste supply method of the first embodiment according to the present invention. It is a schematic sectional drawing of the 2nd Embodiment which concerns on this invention. It is a schematic sectional drawing of the 3rd Embodiment concerning this invention. It is a schematic perspective view of 3rd Embodiment based on this invention. It is a schematic sectional drawing of the 4th Embodiment which concerns on this invention. It is a schematic sectional drawing of the 5th Embodiment which concerns on this invention. It is a schematic sectional drawing of the 6th Embodiment concerning this invention. It is a schematic sectional drawing of the 7th Embodiment which concerns on this invention. It is a schematic sectional drawing of the 8th Embodiment which concerns on this invention. It is a schematic perspective view of 9th Embodiment based on this invention. It is a schematic sectional drawing of 10th Embodiment which concerns on this invention. It is a schematic perspective view of 10th Embodiment based on this invention. It is a schematic perspective view of the single-layer capacitor on the wiring board according to the eleventh embodiment of the present invention. It is a schematic perspective view of the multilayer capacitor on a wiring board according to an eleventh embodiment of the present invention. It is a schematic sectional drawing of the multilayer capacitor | condenser on a wiring board of 11th Embodiment based on this invention. It is a schematic sectional drawing of 12th Embodiment based on this invention. It is a schematic sectional drawing which shows the manufacturing method of 12th Embodiment based on this invention.

  In the first and second viewpoints, it is preferable that the protrusion disposed on at least a part of the outer peripheral portion of the upper electrode has a tapered shape.

  The upper electrode is preferably made of metal.

  Moreover, it is preferable that at least a part of the upper electrode is porous.

  The upper electrode is preferably made of a metal and an insulator.

  Further, it is preferable that at least a part of the protrusion of the upper electrode is an insulator, and the insulator contacts the substrate.

  The upper electrode includes at least one of an insulating layer made of the insulator having higher rigidity than a metal, a via made of a conductor and penetrating the insulating layer, and a surface of the insulating layer adjacent to the dielectric layer. A first metal layer covering a part, and a second metal layer covering at least a part of a surface opposite to the surface covered by the metal layer of the insulating layer, and through the via It is preferable that the first metal layer and the second metal layer of the upper electrode are electrically connected.

  The insulator is preferably a ceramic.

  Further, it is preferable that at least a part of the upper electrode and the lower electrode have irregularities.

  A second dielectric layer made of a thermosetting resin and a dielectric filler provided on the upper electrode; and a dielectric provided on the second dielectric layer and before thermosetting. It is preferable that a second upper electrode having a high rigidity is further provided, and a protrusion for contacting the substrate is provided on at least a part of the second upper electrode.

  The resin constituting the dielectric layer is preferably an epoxy resin, a silicon resin, a phenol resin, a fluororubber resin, or a composite material thereof.

  Moreover, it is preferable that the dielectric filler which comprises the said dielectric material layer is a titanium oxide.

  In a third aspect, the wiring board is provided with a capacitor having a tapered protrusion, and the upper electrode and the metal pad or wiring on the wiring board are electrically connected by conductive resin or wire bonding. It is preferable that they are connected.

  A wiring board in which a plurality of capacitors are laminated, the uppermost electrode is provided with a tapered shape, and the uppermost electrode is electrically connected to a metal pad or wiring on the wiring board by a conductive resin. preferable.

  In the fourth aspect, in the step of supplying the dielectric material before thermosetting onto the lower electrode, the heat before and after the dielectric material before thermosetting is expanded during pressing by the upper electrode in the next step. It is preferable to control the application amount, application position, and application shape of the thermosetting dielectric so that the dielectric before curing does not contact the contact portion between the substrate and the upper electrode protrusion.

  In the fifth aspect, in the step of supplying the dielectric material before thermosetting onto the lower electrode, the heat curing material is spread after the dielectric material before thermosetting is expanded at the time of pressing by the upper electrode in the next step. It is preferable to control the coating amount, coating position, and coating shape of the thermosetting dielectric so that the dielectric before curing does not contact the contact portion between the wiring board and the upper electrode protrusion.

  In addition, after the step of thermosetting the dielectric, a step of providing an inclined portion of an insulator between the upper electrode and the sidewall of the dielectric and the upper surface of the wiring board, and the inclined portion of the insulator through the inclined portion Preferably, the method further includes a step of electrically connecting the upper electrode and the electrode or wiring on the wiring board.

  Hereinafter, the structure of the capacitor according to the present invention, its manufacturing method, and effects will be described with specific embodiments.

(First embodiment)
(Construction)
FIG. 1 is a sectional view of a capacitor according to the first embodiment of the present invention, and FIG. 2 is a perspective view. The capacitor 1 includes an upper electrode 2, a dielectric layer 3 and a lower electrode 4, and is formed on a substrate 5.

  The upper electrode 2 has a projection 15 for defining the distance between the substrate 5 and the upper electrode 2 and is made of a material having higher rigidity than the dielectric layer before thermosetting. Examples of the material having higher rigidity than the dielectric layer before thermosetting include metal. Specific examples include Au, Ag, Cu, Al, Fe, Ni, Co, and Cr.

  The dielectric layer 3 is made of a material including a thermosetting resin and a high dielectric constant material (hereinafter referred to as a dielectric filler). Examples of the thermosetting resin include an epoxy resin, a silicone resin, a phenol resin, a melamine resin, a polyimide resin, A fluororubber resin or a composite material of these can be used. As the dielectric filler, titanium oxide such as barium titanate, strontium titanate, magnesium titanate, zircon zinc titanate or the like, or a composite material thereof, and a material obtained by adding a small amount of Ca or rare earth to these materials should be used. Can do. In addition, as the proportion of the dielectric filler in the dielectric layer is increased, a higher dielectric constant can be obtained. However, when the proportion of the resin component is excessively small, sufficient adhesion strength between the dielectric layer itself and / or the electrode can be obtained. Since it cannot be maintained, the proportion of the dielectric filler is preferably 70 to 90 wt% of the entire dielectric layer. In addition, the particle size of the dielectric filler is preferably about 0.1 to 100 μm because the dielectric constant decreases due to the size effect if it is too small, and if it is too large, it adversely affects the controllability of the film thickness.

  The lower electrode 4 is made of metal. Examples of the metal include Au, Ag, Cu, Al, Fe, Ni, Co, Cr, Mn, Ti, W, and Mo.

(Production method)
FIG. 3 is a schematic view of the manufacturing method according to the first embodiment of the present invention. The capacitor 1 supplies a dielectric paste 3a made of the thermosetting resin, the dielectric filler, a viscosity adjusting solvent or a dielectric filler dispersion material on the lower electrode 4 formed on the substrate 5, The upper electrode 2 is formed by pressing from above the dielectric paste 3a and thermosetting.

  In FIG. 3A, the lower electrode 4 is formed on the substrate 5. The lower electrode 4 is formed by depositing a metal layer on the entire surface of the substrate 5 by a method such as sputtering, plating, or vapor deposition, and removing unnecessary portions by chemical or physical etching, or removing unnecessary portions. It is obtained by simultaneously performing metal layer deposition and patterning after masking.

  Next, in FIG. 3B, the dielectric paste 3 a is supplied onto the lower electrode 4. The dielectric paste 3a can be applied onto the lower electrode 4 using gravure printing or screen printing. The supply amount of the dielectric paste 3a needs to be equal to or more than the product of the desired film thickness and the electrode area, and more preferably 10% to 30% more than that. Even when the dielectric paste 3a is applied to the entire surface, it is possible to improve the controllability of the capacity by applying 10% to 30% thicker than the desired film thickness.

  Finally, in FIG. 3C, the capacitor 1 is formed by pressing the upper electrode 2 from above the dielectric paste 3a and thermosetting it. Since the upper electrode 2 has the protrusion 15, the protrusion 15 is in contact with the substrate 5, so that the distance between the substrate 5 and the upper electrode 2 is mechanically defined. You can control. Further, since the dielectric paste 3a is a fluid material, pressing the upper electrode 2 wets and spreads between the upper electrode 2 and the lower electrode 4 and can prevent a decrease in capacity due to voids.

  The upper electrode 2 having a contact portion with the substrate 5 can be formed by laser processing, cutting, or pressing. In addition, when the height of the protrusion 15 is a minute height of about several tens nm to several μm, it can be formed by patterning by photolithography and wet etching or dry etching.

  The pressing force during pressing is within a range in which the dielectric paste 3a can flow and the upper electrode 2 does not deform. Thereby, the upper electrode 2 can be pressed with a low load, and the upper electrode 2 itself is not easily deformed or cracked. In addition, when the electrode is pressed with a support having the same shape as the electrode, for example, the electrode 2 is not easily deformed or cracked so that the electrode is evenly loaded during pressing. Moreover, thermosetting can be performed in the temperature range of 100-200 degreeC for 0.5 to 1.5 hours.

  Furthermore, the method of supplying the dielectric paste 3a can use dispensing instead of printing. FIG. 4 is a schematic view when the dielectric paste 3a is supplied by dispensing. The total supply amount of the dielectric paste 3a is controlled to increase by about 10% to 30% of the dielectric layer volume obtained from the product of the electrode area and the film thickness. Then, with the dielectric paste 3a supplied on the lower electrode 4 as the center, the upper electrode is outside the circle whose area is a size obtained by dividing the supply amount of the dielectric paste 3a by the desired capacitor film thickness or at a distance far from the center. It supplies so that the 2 projection part 15 may be located. By using this supply method, the dielectric paste 3a can be prevented from entering the gap between the contact portion between the protrusion 15 of the upper electrode 2 and the substrate 5, and the film thickness of the capacitor can be controlled with higher accuracy. I can do things.

(effect)
Since the film thickness can be automatically and mechanically controlled by the protrusion 15 provided on the upper electrode 2, a capacitor structure with a small manufacturing variation in capacitance value can be obtained. In addition, since the flattening step and the temporary curing step described in JP-A-8-279669 can be omitted by the pressing step for forming the upper electrode 2 and the dielectric layer 3 at once, the production efficiency can be increased. It is.

(Second Embodiment)
(Construction)
FIG. 5 is a cross-sectional view of a capacitor according to the second embodiment of the present invention. The difference from FIGS. 1 and 2 is that the dielectric layer 3 protrudes from between the upper electrode 2 and the lower electrode 4.

(Production method)
The manufacturing method is the same as that in the first embodiment except that the amount of the dielectric paste 3a supplied onto the lower electrode 4 is made larger than the space volume between the lower electrode 4 and the upper electrode 2.

(effect)
Even if the dielectric paste 3a protrudes from between the upper electrode 2 and the lower electrode 4, there is no relation to the variation in capacitance value. For this reason, a wider margin can be taken when controlling the amount of the dielectric paste 3a.

(Third embodiment)
(Construction)
FIG. 6 is a sectional view of a capacitor according to a third embodiment of the present invention, and FIG. 7 is a perspective view. The difference from FIGS. 1 and 2 is that the outer peripheral portion of the upper electrode 2 is provided with a protruding portion 15 that is tapered (inclined) outward. In the first and second embodiments, the protrusions 15 of the upper electrode 2 are arranged only at the corners. However, in the third embodiment, the inclined protrusions 15 are extended over a wide range. . This is to facilitate printing of the connection wiring as will be described later. Assuming that wiring is formed on the substrate 5 from the upper electrode 2 by printing, it is preferable that the taper angle is 50 ° or more.

(Production method)
The tapered electrode 2a can be formed by laser processing using a YAG laser or the like. First, the outer periphery of the plate-like metal is scraped off so that the taper angle is 50 ° or more. Since the taper shape only needs to be provided at the place where the printed wiring is formed, it is not necessary to provide a taper shape as a whole. Next, the taper-shaped electrode 2a is formed by punching a metal plate having a tapered shape on the outer peripheral portion with a laser.

(effect)
When it is assumed that the capacitor is formed on the wiring board, it is necessary to electrically connect the upper electrode 2 and the wiring provided on the surface of the wiring board. This connection is preferably performed by a printed wiring made of a conductive resin formed by screen printing or gravure printing. In screen printing or gravure printing, the paste is transferred when the printing plate follows the substrate. However, if the upper electrode 2 has a steep step, the printing plate cannot follow the step, so that the paste is not applied at the step. Therefore, by providing a taper shape, in screen printing or gravure printing, the printing plate can easily follow the upper electrode 2, and disconnection failure can be avoided. Moreover, also in wiring formation by inkjet printing, providing a taper makes it easier for droplets to adhere to and adhere to the substrate 5, so that disconnection defects can be avoided. Thereby, wiring can be reliably formed from the upper electrode 2 by printing.

(Fourth embodiment)
(Structure, manufacturing method)
FIG. 8 is a cross-sectional view of a capacitor according to a fourth embodiment of the present invention. The difference from FIG. 1 is that a porous metal electrode 2b is used as the upper electrode. There are innumerable holes in the metal or on the surface of the porous metal electrode 2b. The hole diameter (pore size) can be used from several μm to several mm in diameter, and the conductivity decreases when the porosity (porosity) is high. Therefore, 5 to 50% is preferable. Cu, Fe, Ni, Mg, Al, and Ti can be used as the porous metal.

(Production method)
The porous metal can be purified using, for example, a continuous melting method performed by Hideo Nakajima et al., Osaka University. References are listed below.
(References)
1) “Survey Report on the Possibility of Utilization Technology of 17-R-4 Porous Metals”, p20-26
2) “Fabrication of lotus-type porous irons and it's mechanical properties”, S.M. K. Hyun, T .; Ikeda and H.M. Nakajima, Sci. Tech. Adv. Mater. , 5, 201 (2004).
3) “Evaluation of porosity in porous manufactured by unified solidification under pressured hydrogen”, S. et al. Yamamura, H .; Shiota, K .; Murakami and H.M. Nakajima, Mater. Sci. Eng. , A318, 137 (2001).
4) “Pore morphology and microstructure of porous magnesium alloy produced by unidirectional solidification in hydrogen atmosphere”, Hideo Hoshiyama, Teruyuki Ikeda, Kenji Murakami, Hideo Nakajima: Journal of the Japan Institute of Metals, 67, 714 (2003).
5) “Fabrication of Lotus-type Porous Metals and the Physical Properties”, H.C. Nakajima, T .; Ikeda and S.M. K. Hyun, Adv. Eng. Mater. , 6, 377 (2004).
6) “Fabrication of Lotus-Type Porous Stainless Steel by Continuous Zone Melting Technique and Mechanical Property”, T. et al. Ikeda, T .; Aoki and H.K. Nakajima, Metall. Mater. Trans. , 36A, 77 (2005).
7) “Anisotropic electrical conductivity of lotus-type porous nickel”, M.M. Tane, S.M. K. Hyun, H .; Nakajima, J .; Appl. Phys. 97, 103701 (2005).
8) “Sound abstraction charactaristics of lotus-type porous copper fabricated by unidirectional solidification”, Z. K. Xie, T .; Ikeda, Y .; Okuda and H.M. Nakajima, Mater. Sci. Eng. , A386, 390-395 (2004)
9) “Anisotrophic mechanical properties of porous copper fabricated by unidirectional solidification”, S.M. K. Hyun, K .; Murakami and H.M. Nakajima, Mater. Sci. Eng. , A299, 241 (2001).

  The continuous melting method is a method of forming bubbles (pores) by gas atoms that cannot be completely dissolved during solidification by utilizing the difference between the solubility of gas atoms in the molten metal and the solid solubility in the solid metal. Yes, the porous metal by the continuous melting method can freely control the pore direction, pore size, and porosity. Needless to say, the method for producing the porous metal is not limited to the continuous melting method.

(effect)
The dielectric paste 3a contains a solvent for viscosity adjustment or as a filler dispersion. These solvents volatilize and escape at the time of thermosetting, but if the dielectric paste 3a is pressed from above with a metal electrode, the solvent component escapes only on the side surface of the dielectric paste 3a. For this reason, when a sudden temperature change is applied, the solvent volatilizes at a time, and the volatile matter that has not been emitted from the side surface forms a void near the interface between the upper electrode 2 and the dielectric layer 3, causing a reduction in capacity. There is sex. Therefore, by using a porous metal electrode as the upper electrode 2, there is a solvent escape path in the upward direction, so that it can be volatilized without creating a void even with a rapid temperature change. As a result, it is possible to prevent the capacity from being reduced due to voids, so that the capacity can be stabilized at a higher level. In addition, since the surface area of the electrode in contact with the dielectric layer 3 is increased by making it porous, the capacitance value can also be increased.

(Fifth embodiment)
(Construction)
FIG. 9 is a cross-sectional view of a capacitor according to a fifth embodiment of the present invention. The difference from FIG. 1 is that an insulator-metal composite electrode 2c in which an upper electrode 2 is composed of a metal portion 9 and an insulator portion 8 The protrusion 15 of the composite electrode 2c is an insulator.

(Production method)
The insulator-metal composite electrode 2c composed of the metal portion 9 and the insulator portion 8 is formed by supplying a thermosetting resin, which is an insulator, to the metal plate by a method such as screen printing, gravure printing, dispensing, and curing. I can do it. Since the capacitance value becomes unstable when the insulator functions as the dielectric layer 3, a thermosetting resin having a low dielectric constant is preferable. As the thermosetting resin, an epoxy resin, a silicone resin, a phenol resin, a melamine resin, a polyimide resin, or a fluororubber resin can be used, and thermosetting is performed at a temperature range of 100 to 200 ° C., 0.5 to 1. Can be done in 5 hours.

(effect)
By using the protrusion 15 as an insulator, the risk of short-circuit failure between the lower electrode 4 and the upper electrode 2c via the protrusion 15 can be reduced, and a capacitor can be manufactured more stably.

(Sixth embodiment)
(Construction)
FIG. 10 is a cross-sectional view of a capacitor according to the sixth embodiment of the present invention. The difference from FIG. 1 is that the upper electrode 2 is made of ceramic (insulator part 8) as a core material, the front and back surfaces of the core material are covered with a metal film (metal part 9), and the vias provided in the core material are used. The insulator-metal composite electrode 2c in which the front and back surfaces are electrically connected is used. As the ceramic, aluminum nitride, zirconia, silicon nitride, silicon carbide, or the like can be used. Moreover, Au, Ag, Cu, Al, Fe, Ni, Co, Cr, Mn, Ti, W, and Mo can be used for the metal.

(Production method)
The core material (insulator portion 8) is formed into a shape having a protrusion 15 by any one of laser processing, cutting, and pressing. Thereafter, vias are provided by any of laser processing, cutting, punching, and plasma etching. If the via diameter is small, processing is difficult and the resistance of the via increases, so it is better to have a diameter of 0.5 mm or more. The metal film (metal portion 9) can be formed by any one of sputtering, electroless plating, and vapor deposition. In any method, the metal film can be formed on the side surfaces of the vias simultaneously with the formation of the metal films on the front and back surfaces, and both surfaces can be electrically connected via the vias.

  However, if the ratio of the core material thickness (via height) to the via diameter, that is, the aspect ratio of the via is large, the electroless plating may not efficiently perform a substitution reaction. Is preferred. Furthermore, since the sputtering method deposits metal at a lower vacuum than the vapor deposition method, the mean free path can be shortened and a metal film can be easily formed on the side surface of the via. Therefore, the sputtering method is more preferable than the vapor deposition method. If electrical connection cannot be established between the front and back surfaces even by sputtering, or if it is desired to reduce the wiring resistance of the via portion, the via may be filled by applying a conductive resin by printing and curing. .

  The conductive resin includes a conductive filler, a thermosetting resin, a viscosity adjusting solvent, a conductive filler dispersant, and the like. As the conductive filler, Ag, Au, Cu, Pd, Ni, C, and These alloy materials or those plated on the surface can be used. As the thermosetting resin, an epoxy resin, a silicone resin, a phenol resin, a melamine resin, a polyimide resin, a fluororubber resin, and a composite material thereof can be used. Can be used. The conductive resin can be cured in a temperature range of 100 ° C. to 200 ° C. in 0.5 to 1 hour.

(effect)
If a hard material is selected by using ceramics as the core material, strong rigidity can be obtained by the insulator-metal composite electrode 2c, so that the insulator-metal composite electrode 2c can be formed thinner. In addition, if the capacitor is built in the substrate or mounted on the substrate 5, warpage can be reduced by selecting a core material in accordance with the material of the substrate 5. As a result, the capacitor built-in substrate can be manufactured flat, and an electronic device can be mounted on the built-in substrate without any problem.

(Seventh embodiment)
(Construction)
FIG. 11 is a cross-sectional view of a capacitor according to a seventh embodiment of the present invention. The difference from FIG. 1 is that an uneven surface is formed by forming unevenness on the surface of the upper electrode 2 that contacts the dielectric layer 3. It is a point to be. Concavities and convexities are produced differently depending on the desired height of the concavities and convexities, and the shapes are accordingly different. In the convex production by screen printing, it becomes a spherical shape, and if it is a vapor deposition method, a sputtering method, or a Gas Deposition (hereinafter, GD method), it becomes a conical shape. In addition, when the recess is formed by reactive etching such as laser processing or wet etching, sagging occurs in the pattern, and in physical etching such as Ar sputtering, etching is performed vertically. If the unevenness height is about 0.1 μm to 1 mm, it can be arbitrarily produced. As the shape, a spherical shape that can increase the surface area most is suitable.

(Production method)
The convex part having a height of 10 to 100 μm can be formed by printing and curing the conductive resin by screen printing. Moreover, if the height of the convex portion is about 20 to 50 μm, Au bumps can be produced by the Gas Deposition method (GD method) performed by Mr. Aoyagi of AIST. Furthermore, if it is a convex part exceeding several tens of micrometers, it can be formed by press work. A convex portion that is smaller than the convex portion can be formed by either a sputtering method or a vapor deposition method using a hard mask.

  On the other hand, the recess can be formed by a method such as laser processing or cutting. In addition, a recess having a depth of several μm or less can be formed by patterning by photolithography and wet or dry etching. However, unless the concave portion has a larger area than the average cross-sectional area of the dielectric filler contained in the dielectric, the dielectric filler cannot fill the concave portion, leading to a decrease in capacitance value. For this reason, it is better that the size of the recess is 10 times or more the average particle size of the dielectric filler.

(effect)
Since the electrode area is increased by the concavo-convex electrode, the capacitance can be increased even with the same capacitor thickness.

(Eighth embodiment)
(Construction)
FIG. 12 is a cross-sectional view of a capacitor according to an eighth embodiment of the present invention. The difference from FIG. 1 is that a dielectric layer 3 is laminated. FIG. 12 shows a structure in which two layers are stacked, but the structure is not limited to a two-layer structure, and the same applies regardless of the number of dielectric layers 3.

(Production method)
In the present embodiment, the upper electrode 2 can be used as an intermediate electrode or an uppermost electrode, and the electrode manufacturing method is also as described above. The multilayer capacitor supplies the dielectric paste 3a onto the lower electrode 4 and presses the intermediate electrode 2 from above. In addition, the dielectric paste 3a is supplied onto the intermediate electrode 2 and the pressing of the intermediate electrode 2 is repeated in the same procedure. Finally, after supplying the dielectric paste 3a, the uppermost electrode 2 is pressed, and the whole is cured. The dielectric paste 3a can be cured only once after it is pressed by the uppermost electrode 2, but the dielectric paste 3a may be pressed out by the electrode and may protrude outside the electrode. It may be cured each time the electrode is pressed.

(effect)
By increasing the number of layers, the capacity can be increased even within a limited area.

(Ninth embodiment)
(Construction)
FIG. 13 is a perspective view of a capacitor formed on the wiring board 5a according to the ninth embodiment of the present invention. The wiring substrate 5a is obtained by forming a Cu pattern on an insulating substrate 5 made of an insulating resin film such as an epoxy resin and glass fiber.

(Production method)
The wiring board 5a can be manufactured by a subtractive method or an additive method. The wiring 6 and the lower electrode 4 are made of Cu. At this time, the wiring 6 and the lower electrode 4 are formed without connection points. Since the capacitor described in this specification is manufactured in the atmosphere, the surface of the lower electrode 4 is often oxidized. Since this oxide film forms a series low capacitor component, it causes a decrease in capacitance value. Therefore, it is preferable to apply NiAu plating to the Cu surface for preventing oxidation.

  After the capacitor according to each embodiment and each claim is manufactured on the lower electrode 4, the upper electrode 2 and the wiring 6 (or metal pad) are connected by wire bonding (hereinafter referred to as WB) 16, and the wiring having the capacitor The substrate 5a is completed.

(effect)
By using a capacitor on a wiring board, the application to electronic equipment can be expanded.

(Tenth embodiment)
(Construction)
FIG. 14 is a cross-sectional view of a capacitor formed on a wiring board 5a according to the tenth embodiment of the present invention, and FIG. 15 is a perspective view. Unlike FIG. 13, a slope is formed between the upper electrode 2 and the substrate 5 by resin, and the upper electrode 2 and the wiring 6 (or metal pad) are connected via the printed wiring 6a. As the resin, an underfill agent (hereinafter referred to as UF agent) is suitable. The printed wiring 6a is formed by printing and curing a conductive resin comprising a conductive filler, a thermosetting resin, a viscosity adjusting solvent, and a conductive filler dispersant. As the conductive filler, Ag, Au, Cu, Pd, Ni, C and alloy materials thereof, or those plated on the surface can be used. As the thermosetting resin, epoxy resin, silicone resin, phenol Resins, melamine resins, polyimide resins, fluororubber resins, and composite materials thereof can be used.

(Production method)
The space between the substrate 5 and the upper electrode 2 is filled with the UF agent, and the inclination is made so that the angle formed between the substrate 5 and the UF agent is 40 ° or less. Thereafter, the conductive resin is supplied so as to cover the space between the upper electrode 2 and the wiring 6 through the inclination. The conductive resin can be applied by a method such as screen printing, gravure printing, or ink jet printing. Then, the printed wiring 6a which connects the upper electrode 2 and the wiring 6 can be formed by thermosetting the conductive resin in a temperature range of 100 ° C. to 250 ° C. for 0.5 to 1 hour. Further, when the capacitor height is smaller than the printed wiring film thickness, it is possible to form the printed wiring without providing an inclination, and in this case, it is not necessary to insert a UF agent.

(effect)
Since the height can be reduced as compared with WB connection, it is suitable for thin electronic devices such as mobile phone devices.

(Eleventh embodiment)
(Construction)
FIG. 16 is a perspective view of a capacitor formed on a wiring board according to the eleventh embodiment of the present invention. Unlike FIG. 15, the upper electrode 2 or the uppermost electrode 2 of the multilayer capacitor is provided with a tapered shape, and a printed wiring can be formed without filling the space between the upper electrode 2 and the substrate 5 with an underfill resin. . FIG. 17 is a perspective view when a multilayer capacitor is used, and FIG. 18 is a cross-sectional view.

(Production method)
It can be produced by the same production method as in the tenth embodiment except that the UF agent is not inserted.

(effect)
Since it is not necessary to insert the UF agent, the production efficiency increases.

(Twelfth embodiment)
(Construction)
FIG. 19 is a cross-sectional view of a wiring board 5b incorporating a capacitor according to the twelfth embodiment of the present invention. A capacitor is built in the wiring board, and the lower electrode 4 and the upper electrode 2 are connected to the Cu wiring 6 respectively.

(Production method)
FIG. 20 is a schematic view of a method for manufacturing the capacitor built-in substrate shown in FIG. First, in FIG. 20A, a capacitor is fabricated on a wiring board according to the eighth to tenth embodiments of the present invention.

  Next, in FIG. 20B, the surface of the wiring board is coated with the resin 7 together with the capacitor. The coating of the resin 7 can be formed, for example, by vacuum-pressing a sheet-like resin with a vacuum laminator. At this time, the degree of vacuum and the applied pressure are adjusted so that the resin surface after lamination becomes flat. The resin 7 can be an insulating resin.

  Furthermore, in FIG.20 (c), the part which forms the wiring 6 is opened. At this time, since connection must be established between the capacitor upper electrode 2 and the wiring 6, at least a part of the upper electrode 2 is exposed. The opening can be formed by laser processing using, for example, a YAG laser.

  Further, in FIG. 20D, a Cu wiring 6 is formed in the opening. The Cu wiring 6 can be formed by, for example, forming a seed layer on the resin surface by sputtering, and then forming Cu wiring 6 by electroplating. The seed layer has a two-layer structure of Ti and Cu in order from the resin.

  By repeating the procedure shown in FIGS. 20B to 20D, the wiring layer can be multilayered. The method for embedding the capacitor in the substrate is not limited to the above.

(effect)
Since the capacitor element is built in, other components can be mounted on the surface of the capacitor built-in substrate.

  This example is performed for the tenth embodiment of the present invention. The capacitor 1 on the wiring board 5a shown in FIGS. 14 and 15 includes an upper electrode 2, a dielectric layer 3, and a lower electrode 4, and the lower electrode 4 and the wiring 6 are connected without connection points. Further, an inclination is provided between the wiring substrate 5a and the upper electrode 2 by the resin 7, and the upper electrode 2 and the wiring 6 are connected by the printed wiring 6a.

  The upper electrode 2 has a protrusion 15 and is made of Cu that is more rigid than the pre-thermosetting dielectric layer. In addition, since this manufacturing process is performed in the atmosphere, NiAu plating (not shown) is applied to the surface for preventing oxidation. The thickness of the NiAu plating is about 2 μm for Ni and about 0.05 μm for Au.

  The dielectric layer 3 is made of a material containing an epoxy resin which is a thermosetting resin and barium titanate (hereinafter referred to as BTO) which is a high dielectric constant material, and the epoxy resin and BTO are kneaded at a mass ratio of 8: 2, The average filler particle size is 0.5 μm.

  The lower electrode 4 is made of Cu and has a thickness of about 18 μm. Similar to the upper electrode 5, the surface was plated with NiAu (not shown).

  The wiring substrate 5a is obtained by forming a Cu pattern on an insulating substrate made of an insulating resin film such as an epoxy resin and glass fiber.

(Production method)
The capacitor 1 has a lower electrode 4 and wiring 6 made of Cu formed on a substrate made of a glass epoxy substrate. An epoxy resin that is a thermosetting resin, a BTO filler that is a high dielectric constant material, and a viscosity adjusting material are formed on the lower electrode 4. A dielectric paste made of butyl carbitol was supplied, and the upper electrode 2 was pressed from above the dielectric paste 3a and thermally cured.

  The lower electrode 4 and the wiring 6 were produced by a subtractive method. In addition, the oxide film formed by oxidizing the surface of the lower electrode 4 creates a series low capacitor component, which causes a decrease in capacitance value. Therefore, NiAu plating was applied to the Cu surface as an antioxidant. The upper electrode 2 having the protrusions 15 was produced by laser processing, and the protrusion height was 50 μm.

  The dielectric layer 3 is formed by applying the dielectric paste on the entire surface of the lower electrode 4 on the average by 50 μm using screen printing, and then applying the upper electrode 2 on the dielectric paste at a rate of about 0.2 kg / cm 2. After pressing with pressure, it was thermoset. Thermosetting was performed at 170 ° C. for 60 minutes.

  Next, the space between the upper electrode 2 and the wiring 6 was filled with the resin 7 to create a gentle slope. At this time, a UF agent was used as the resin, and the resin was formed so as to be inclined at an angle of 5 ° with respect to the wiring board 5a. The UF agent was cured at 150 ° C. for 20 minutes. Then, the upper electrode 2 and the wiring 6 were connected by forming the printed wiring 6a by screen printing through the inclination formed with the UF agent. The printed wiring 6a was obtained by thermally curing a conductive resin including an Ag filler and an epoxy resin, the wiring thickness was about 30 μm, and the thermosetting was 170 ° C. for 60 minutes.

(effect)
With the protrusion provided on the upper electrode 2, the film thickness can be controlled automatically and mechanically, and a capacitor structure with a small manufacturing variation in capacitance value can be obtained, and the manufacturing efficiency is improved.

  The present invention has been described with reference to the above embodiment, but the present invention is not limited only to the configuration of the above embodiment, and various modifications that can be made by those skilled in the art within the scope of the present invention. Of course, including modifications.

DESCRIPTION OF SYMBOLS 1 Capacitor 1a Multilayer capacitor 2 Upper electrode 2a Tapered electrode 2aa Taper angle 2b Porous metal electrode
2c Insulator-metal composite electrode 2d Uneven electrode 3 Dielectric layer 3a Dielectric paste 4 Lower electrode 5 Substrate 5a Wiring substrate 5b Built-in substrate 6 Wiring 6a Printed wiring 7 Resin 8 Insulator portion 9 of upper electrode Metal portion 10 of upper electrode Via 15 Protrusion 16 Wire bonding

Claims (22)

A substrate,
A lower electrode provided on the substrate;
A dielectric layer provided on at least the lower electrode and comprising at least a thermosetting resin and a dielectric filler;
An upper electrode provided on the dielectric layer and having higher rigidity than the dielectric before thermosetting;
At least a part of the upper electrode has a protrusion for defining a distance between the substrate and the upper electrode,
The capacitor according to claim 1, wherein at least a part of a surface of the upper electrode facing the dielectric layer is not in contact with the dielectric layer. A substrate,
A lower electrode provided on the substrate;
A dielectric layer provided on the substrate and on the lower electrode and comprising at least a thermosetting resin and a dielectric filler;
An upper electrode provided on the dielectric layer and having higher rigidity than the dielectric before thermosetting;
At least a part of the upper electrode has a protrusion for defining a distance between the substrate and the upper electrode,
The capacitor, wherein the dielectric layer protrudes between the upper electrode and the lower electrode.   3. The capacitor according to claim 1, wherein a protrusion disposed on at least a part of an outer peripheral portion of the upper electrode has a tapered shape.   The capacitor according to claim 1, wherein the upper electrode is made of metal.   The capacitor according to claim 4, wherein at least a part of the upper electrode is porous.   The capacitor according to claim 1, wherein the upper electrode is made of a metal and an insulator.   The capacitor according to claim 6, wherein at least a part of the protruding portion of the upper electrode is an insulator, and the insulator is in contact with the substrate. The upper electrode has an insulating layer made of the insulator having higher rigidity than metal,
A via made of a conductor and penetrating the insulating layer;
A first metal layer covering at least a part of a surface of the insulating layer adjacent to the dielectric layer;
A second metal layer covering at least a part of the surface opposite to the surface covered with the metal layer of the insulating layer,
The first metal layer and the second metal layer of the upper electrode are electrically connected via the via;
The capacitor according to claim 6, wherein:   The capacitor according to claim 6, wherein the insulator is ceramic.   The capacitor according to claim 1, wherein at least a part of the upper electrode and the lower electrode has irregularities. A second dielectric layer comprising a thermosetting resin provided on the upper electrode and a dielectric filler;
A second upper electrode provided on the second dielectric layer and having a higher rigidity than the dielectric before thermosetting,
11. The capacitor according to claim 1, wherein at least a part of the second upper electrode has a protrusion for contacting the substrate. 11.   12. The capacitor according to claim 1, wherein the resin constituting the dielectric layer is an epoxy resin, a silicon resin, a phenol resin, a fluororubber resin, or a composite material thereof. .   The capacitor according to any one of claims 1 to 12, wherein the dielectric filler constituting the dielectric layer is titanium oxide.   A wiring board, wherein the capacitor according to claim 1 is installed on a surface.   A wiring board on which the capacitor according to claim 3 is installed, wherein the upper electrode and a metal pad or wiring on the wiring board are electrically connected by a conductive resin or wire bonding. The wiring board according to claim 14.   A wiring board on which the capacitor according to claim 11 is installed, wherein the uppermost electrode is tapered, and the uppermost electrode is electrically connected to a metal pad or wiring on the wiring board by a conductive resin. A wiring board characterized by being made.   A wiring board comprising the capacitor according to claim 1. Supplying a dielectric material before thermosetting higher than the desired capacitor film thickness on the lower electrode placed on the substrate;
Pressing the dielectric before thermosetting with an upper electrode;
And a step of thermosetting the dielectric.   In the step of supplying the dielectric material before thermosetting onto the lower electrode, the dielectric material before thermosetting is spread even after the dielectric material before thermosetting is expanded at the time of pressing by the upper electrode in the next step. 19. The method of manufacturing a capacitor according to claim 18, wherein a coating amount, a coating position, and a coating shape of the thermosetting dielectric are controlled so as not to contact a contact portion between the substrate and the upper electrode protrusion. Method. Installing a lower electrode on the insulating layer of the wiring board;
On the lower electrode, supplying a dielectric material before thermosetting higher than a desired capacitor film thickness;
Pressing the dielectric before thermosetting with an upper electrode;
And a step of thermally curing the dielectric. A method of manufacturing a wiring board having a capacitor.   In the step of supplying the dielectric material before thermosetting onto the lower electrode, the dielectric material before thermosetting is spread even after the dielectric material before thermosetting is expanded at the time of pressing by the upper electrode in the next step. 21. The capacitor according to claim 20, wherein an application amount, an application position, and an application shape of the thermosetting dielectric are controlled so as not to contact a contact portion between the wiring board and the upper electrode protrusion. A method for manufacturing a wiring board. After the step of thermosetting the dielectric,
Providing an inclined portion of an insulator between the upper electrode and the sidewall of the dielectric and the upper surface of the wiring board;
Electrically connecting the upper electrode and the electrode or wiring on the wiring board through the inclined portion of the insulator;
The manufacturing method of the wiring board which has a capacitor | condenser of Claim 20 or 21 characterized by the above-mentioned.

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