Patent ID: 6890792

Claim:
A method of formation of a capacitor forming part of an electric circuit when producing a circuit board with that electric circuit built in, including the steps of: forming at a scheduled position for formation of the capacitor of the circuit board in the process of production a bottom electrode layer comprised of at least one type of valve metal selected from the group comprised of aluminum, tantalum, niobium, tungsten, vanadium, bismuth, titanium, zirconium, and hafnium; forming on said bottom electrode layer a dielectric layer comprised of an oxide of at least one type of valve metal selected from said group; and integrally forming on said dielectric layer a solid electrolyte layer comprised of an organic semiconductor and a top electrode layer comprised of metal foil on top; said step of integrally forming on said dielectric layer said solid electrolyte layer and top electrode layer including the steps of: making one surface of the top electrode metal foil carry powder of said organic semiconductor by compression bonding and forming a solid electrolyte layer comprised of said organic semiconductor sandwiched between said metal foil and said dielectric layer and closely bonded to the two by thermo-compression bonding of organic semiconductor powder carried by compression bonding on said dielectric layer through said metal foil.