Capacitor and method for producing the same, and circuit board with a built-in capacitor and method for producing the same

A method for producing an electrolytic capacitor comprising:

• forming a dielectric oxide film by oxidizing a surface of a valve metal element for an anode which includes a capacitor forming part and an electrode lead part;
• forming a through hole(s) in the electrode lead part of the valve metal element for an anode;
• and
• forming a solid electrolyte layer on the dielectric oxide film, followed by forming a charge collecting element for a cathode on the solid electrolyte layer, in the stated order.

A method producing a circuit board with a built-in capacitor comprising:

• preparing a first circuit board in which a wiring layer is formed in a predetermined wiring pattern on a surface of an electrically insulating layer;
• preparing an electrically conductive adhesive containing an electrically conductive filler and an uncured thermosetting resin;
• preparing a sheet member formed of an thermosetting resin composition containing an uncured thermosetting resin and an inorganic filler, as an electrically insulating substrate;
• applying the electrically conductive adhesive to a predetermined position of a surface of the wiring layer of the first circuit board;
• fixing an electrolytic capacitor to the first circuit board by disposing the capacitor on the applied adhesive and then by curing the adhesive through a heat treatment;
• and
• superposing the electrically insulating substrate on the first circuit board to which the electrolytic capacitor is fixed, followed by heating and pressurization, so as to form an electrically insulating layer within which the electrolytic capacitor is disposed,
• in which the electrolytic capacitor is an electrolytic capacitor comprising:
• a valve metal element for an anode including a capacitor forming part and an electrode lead part;
• a dielectric oxide film provided on a surface of the valve metal element for an anode;
• a solid electrolyte layer provided on the dielectric oxide film;
• and
• a charge collecting element for a cathode provided on the solid electrolyte layer,
• wherein at least one through hole is formed in the electrode lead part of the valve metal element for an anode to expose core of the valve metal element outside.

A method producing a circuit board with a built-in capacitor comprising:

• preparing an electrically conductive adhesive containing an electrically conductive filler and an uncured thermosetting resin;
• preparing a sheet member formed of a thermosetting resin composition containing an uncured thermosetting resin and an inorganic filler, as an electrically insulating substrate;
• applying the electrically conductive adhesive to a predetermined position of a surface of a metal foil;
• fixing an electrolytic capacitor to the metal foil by disposing the capacitor on the applied adhesive and then by curing the adhesive through a heat treatment;
• superposing the electrically insulating substrate on the metal foil to which the electrolytic capacitor is fixed, followed by heating and pressurization, so as to form an electrically insulating layer within which the capacitor is disposed, and
• patterning the metal foil so as to form a wiring layer in a predetermined wiring pattern,
• in which the electrolytic capacitor is an electrolytic capacitor comprising:
• a valve metal element for an anode including a capacitor forming part and an electrode lead part;
• a dielectric oxide film provided on a surface of the valve metal element for an anode;
• a solid electrolyte layer provided on the dielectric oxide film;
• and
• a charge collecting element for a cathode provided on the solid electrolyte layer,
• wherein at least one through hole is formed in the electrode lead part of the valve metal element for an anode to expose core of the valve metal element outside.

A method producing a circuit board with a built-in capacitor comprising:

• forming a wiring layer in a predetermined wiring pattern on one surface of a releasable carrier;
• preparing an electrically conductive adhesive containing an electrically conductive filler and an uncured thermosetting resin;
• preparing a sheet member formed of a thermosetting resin composition containing an uncured thermosetting resin and an inorganic filler, as an electrically insulating substrate;
• applying the electrically conductive adhesive to a predetermined position of a surface of the wiring layer;
• fixing an electrolytic capacitor to the releasable carrier by disposing the capacitor on the applied adhesive and then by curing the adhesive through a heat treatment;
• superposing the electrically insulating substrate on the releasable carrier to which the electrolytic capacitor is fixed, followed by heating and pressurization, so as to form an electrically insulating layer within which the electrolytic capacitor is disposed;
• and
• exposing the wiring layer by removing the releasable carrier,
• in which the electrolytic capacitor is an electrolytic capacitor comprising:
• valve metal element for an anode including a capacitor forming part and an electrode lead part;
• a dielectric oxide film provided on a surface of the valve metal element for an anode;
• a solid electrolyte layer provided on the dielectric oxide film;
• and
• a charge collecting element for a cathode provided on the solid electrolyte layer,
• wherein at least one through hole is formed in the electrode lead part of the valve metal element for an anode to expose core of the valve metal element outside.