Co-fired ceramic capacitor and method for forming ceramic capacitors for use in printed wiring boards
AssigneeE. I. Du Pont de Nemours and Company
InventorWilliam J. Borland
Life of this patent
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Abstract
A capacitor structure is fabricated by forming a pattern of first dielectrics over a foil, forming first electrodes over the first dielectrics, and co-firing the first dielectrics and the first electrodes. Co-firing of the dielectrics and the electrodes alleviates cracking caused by differences in thermal coefficient of expansion (TCE) between the electrodes and the dielectrics. Co-firing also ensures a strong bond between the dielectrics and the electrodes. In addition, co-firing allows multi-layer capacitor structures to be constructed, and allows the capacitor electrodes to be formed from copper.
Claims13
A capacitor structure, comprising:
- a metallic foil;
- at least one dielectric layer disposed over a portion of the foil;
- and
- at least one first electrode disposed over a portion of the dielectric layer;
- wherein upon cofiring the at least one dielectric layer with the at least one first electrode, the at least one dielectric layer exhibits a high dielectric constant, and the foil, the at least one dielectric layer and the at least one first electrode form a high capacitance capacitor.
A multi-layer capacitor structure, comprising:
- a metallic foil;
- a first dielectric layer disposed over a portion of the foil;
- a first electrode disposed over a portion of to dielectric layer and a portion of the foil;
- a second dielectric layer disposed over a portion of the first dielectric layer and the first electrode;
- and
- at least one second electrode disposed over a portion of the second dielectric layer and over a portion of the foil, wherein, upon cofiring the first and second dielectric layers with the first and second electrodes, and after etching the foil to form a trench, the dielectric exhibits a high dielectric constant and the foil, the first and second dielectric layers and the first and second electrodes form a high capacitance capacitor.
Dependencies are inferred from the claim text.