Inductor built-in substrate and method for manufacturing the same

1. An inductor built-in substrate, comprising:

a core substrate having an opening and a first through hole;

a copper foil formed on the core substrate;

a first plating film structure formed in the first through hole of the core substrate;

a magnetic resin body having a second through hole and comprising a magnetic resin filled in the opening of the core substrate;

a second plating film structure formed in the second through hole of the magnetic resin body and comprising an electrolytic plating film such that the electrolytic plating film of the second plating film structure is formed in contact with the magnetic resin body; and

a through-hole land comprising a third plating film structure and formed on a surface of the magnetic resin body such that the third plating film structure in the through-hole land is formed in contact with the surface of the magnetic resin body and that the through-hole land is extending over an opening of the second through hole in the magnetic resin body,

wherein the first plating film structure comprises an electroless plating film and is formed such that the electroless plating film of the first plating film structure is formed in contact with the core substrate, and the third plating film structure includes a plating film formed such that the plating film extends on an end portion of the magnetic resin body and extends on the copper foil, and that a thickness of the plating film formed on the copper foil is larger than a thickness of the plating film formed on the end portion of the magnetic resin body.

2. The inductor built-in substrate according to claim 1 , wherein the second plating film structure includes the electrolytic plating film forming an innermost layer, an electroless plating film formed on the electrolytic plating film, and a second electrolytic plating film formed on the electroless plating film.

3. The inductor built-in substrate according to claim 1 , wherein the first plating film structure includes the electroless plating film forming an innermost layer, and an electrolytic plating film formed on the electroless plating film.

4. The inductor built-in substrate according to claim 1 , wherein the magnetic resin body includes an iron filler.

5. The inductor built-in substrate according to claim 2 , wherein the magnetic resin body includes an iron filler.

6. The inductor built-in substrate according to claim 3 , wherein the magnetic resin body includes an iron filler.

7. The inductor built-in substrate according to claim 1 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

8. The inductor built-in substrate according to claim 2 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

9. The inductor built-in substrate according to claim 3 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

10. The inductor built-in substrate according to claim 2 , wherein the first plating film structure includes the electroless plating film forming an innermost layer, and an electrolytic plating film formed on the electroless plating film.

11. The inductor built-in substrate according to claim 10 , wherein the magnetic resin body includes an iron filler.

12. The inductor built-in substrate according to claim 4 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

13. The inductor built-in substrate according to claim 5 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

14. The inductor built-in substrate according to claim 6 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

15. The inductor built-in substrate according to claim 10 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

16. The inductor built-in substrate according to claim 11 , wherein the plating film is formed such that the plating film has a height difference at a boundary portion between the end portion of the magnetic resin body and the copper foil.

17. The inductor built-in substrate according to claim 1 , wherein the second plating film structure includes the electrolytic plating film forming an innermost layer, and the first plating film structure includes the electroless plating film forming an innermost layer.

18. A method for manufacturing an inductor built-in substrate, comprising:

forming an opening in a core substrate comprising a copper-clad laminated plate including a copper foil;

forming a first through hole in the core substrate;

filling a magnetic resin in the opening such that a magnetic resin body is formed in the opening of the core substrate;

forming a second through hole in the magnetic resin body;

forming a first electrolytic plating film such that the first electrolytic plating film is formed on first and second surfaces of the core substrate and first and second end portions of the magnetic resin body and forms a second plating film structure comprising the first electrolytic plating film inside the second through hole of the magnetic resin body and in contact with the magnetic resin body;

forming a first electroless plating film such that the first electroless plating film is formed on the first electrolytic plating film and forms a first plating film structure comprising the first electroless plating film inside the first through hole of the core substrate and in contact with the core substrate;

forming a second electrolytic plating film such that the second electrolytic plating film is formed on the first electroless plating film; and

forming a through-hole land comprising a third plating film structure including the first and second electrolytic plating films on the first end portion of the magnetic resin body such that the first electrolytic plating film in the through-hole land is formed in contact with the first and second end portions of the magnetic resin body and that the through-hole land is extending over an opening of the second through hole in the magnetic resin body,

wherein the third plating film structure includes a plating film formed such that the plating film extends on an end portion of the magnetic resin body and extends on the copper foil, and that a thickness of the plating film formed on the copper foil is larger than a thickness of the plating film formed on the end portion of the magnetic resin body.

19. The method for manufacturing an inductor built-in substrate according to claim 18 , further comprising:

filling a filler in the first through hole of the core substrate and the second through hole of the magnetic resin body;

forming a second electroless plating film such that the second electroless plating film is formed on the core substrate;

forming a third electrolytic plating film such that the third electrolytic plating film is formed on the core substrate; and

removing portions of the first electrolytic plating film, first electroless plating film, second electrolytic plating film, second electroless plating film, and third electrolytic plating film from the core substrate such that a circuit pattern is formed on the core substrate.

20. The method for manufacturing an inductor built-in substrate according to claim 18 , further comprising:

forming a second electroless plating film such that the second electroless plating film is formed on the second electrolytic plating film; and

forming a third electrolytic plating film such that the third electrolytic plating film is formed on the second electroless plating film.