Multilayer ceramic substrate and method for manufacturing same

1. A multilayer ceramic substrate, comprising:

a plurality of ceramic layers stacked together;

a via hole provided in each of the plurality of ceramic layers, the via holes of the plurality of ceramic layers being connected together in a layer stacking direction of the plurality of ceramic layers;

a via wire including an electrical conductor filled into each of the via holes;

a first conductor provided on an upper surface of at least one of the plurality of ceramic layers, the first conductor having an annular or partially annular shape surrounding the via wire; and

a second conductor including a first portion and a second portion, the first portion being located outside the first conductor on the upper surface of the at least one ceramic layer, the second portion underlying and directly connected to the lower surface of the first conductor, and an inner rim of the second portion being located outside an inner rim of the first conductor,

wherein a thickness of the first conductor is greater than a thickness of the second conductor,

wherein the via wire further includes a pad formed on at least one of the electrical-conductor-filled via holes of the plurality of ceramic layers, the pad being electrically and physically separated from the first conductor,

wherein the second conductor has an opening,

wherein the second conductor is a solid electrode and the first portion of the second conductor extends from the first conductor to the end of the solid electrode,

wherein bottoms of both the first portion of the second conductor and the first conductor are on the same one of the plurality of ceramic layers,

wherein the opening of the second conductor is greater than the inner rim of the first conductor, and a rim of the opening is located inside an outer rim of the first conductor, and

wherein bottoms of the first conductor, second conductor and the pad physically contact the same ceramic layer of at least one of the plurality of ceramic layers.

2. The multilayer ceramic substrate of claim 1 , wherein the via wire has the shape of a cylinder or a truncated cone.

3. The multilayer ceramic substrate of claim 2 , wherein the first conductor has the shape of a circular ring.

4. The multilayer ceramic substrate of claim 1 , wherein the second conductor is a ground electrode or an inner electrode of a capacitor.

5. The multilayer ceramic substrate of claim 1 , wherein each of the plurality of ceramic layers includes another via hole and another via wire which is formed by an electrical conductor filled into the another via hole, in the at least one ceramic layer, the another via wire is surrounded by the first conductor, and the another via wires of the plurality of ceramic layers are connected together.

6. A multilayer ceramic substrate, comprising:

a sintered ceramic body including a plurality of ceramic layers;

a via wire buried in the sintered ceramic body;

a first conductor located on a plane generally perpendicular to a center axis of the via wire, the first conductor having an annular or partially annular shape surrounding the via wire on the plane; and

a second conductor including a first portion and a second portion, the first portion being located outside the first conductor on the plane, the second portion underlying and directly connected to the lower surface of the first conductor, and an inner rim of the second portion being located outside an inner rim of the first conductor,

wherein a thickness of the first conductor is greater than a thickness of the second conductor,

wherein the via wire further includes a pad formed on at least one of the electrical-conductor-filled via holes of the plurality of ceramic layers, the pad being electrically and physically separated from the first conductor,

wherein the second conductor has an opening,

wherein the second conductor is a solid electrode and the first portion of the second conductor extends from the first conductor to the end of the solid electrode,

wherein bottoms of both the first portion of the second conductor and the first conductor are on the same one of the plurality of ceramic layers,

wherein the opening of the second conductor is greater than the inner rim of the first conductor, and a rim of the opening is located inside an outer rim of the first conductor, and

wherein bottoms of the first conductor, second conductor and the pad physically contact the same ceramic layer of at least one of the plurality of ceramic layers.

7. A method for manufacturing a multilayer ceramic substrate, comprising:

a first step of forming a via hole in each of a plurality of ceramic green sheets;

a second step of printing a conductor paste on an upper surface of at least one of the plurality of ceramic green sheets, thereby forming a second conductor pattern having an opening that surrounds the via hole on the upper surface of the at least one ceramic green sheet, the second conductor pattern including a first portion and a second portion, the first portion being located outside a first conductor pattern on the upper surface of the at least one ceramic green sheet, the second portion defining the opening;

a third step of printing a conductor paste on an upper surface of each of the ceramic green sheets, thereby forming a via wire pattern in which the via hole of each of the ceramic green sheets is filled with the conductor paste and forming the first conductor pattern at the at least one ceramic green sheet, the first conductor pattern being located on the second portion of the second conductor pattern and part of the upper surface located inside the second portion of the second conductor pattern, the second portion underlying and directly connected to the lower surface of the first conductor pattern, the first conductor pattern having a greater thickness than that of the second conductor pattern, and the first conductor pattern having an annular or partially annular shape surrounding the via wire; and

a fourth step of stacking up the plurality of ceramic green sheets and connecting the via wire patterns,

wherein the via wire pattern further includes a pad pattern formed on at least one of the conductor-paste filled via holes of the plurality of ceramic green sheets, the pad pattern being electrically and physically separated from the first conductor pattern,

wherein the second conductor pattern is a solid electrode pattern and the first portion of the second conductor pattern extends from the first conductor pattern to the end of the solid electrode,

wherein bottoms of both the first portion of the second conductor pattern and part of the first conductor are on the same one of the plurality of ceramic green sheets,

wherein the opening of the second conductor pattern is greater than the inner rim of the first conductor pattern, and a rim of the opening is located inside an outer rim of the first conductor pattern, and

wherein bottoms of the first conductor pattern, second conductor pattern and the pad physically contact the same ceramic green sheet of at least one of the plurality of ceramic green sheets.

8. The method of claim 7 , wherein

the first step includes forming the via hole by laser or a punch die, and

the via hole has the shape of a cylinder or a truncated cone.

9. The method of claim 7 , wherein in the third step the via wire pattern and the first conductor pattern are printed using a same mask.