Magnetic core, inductor, and method for fabricating the magnetic core

• US 9,893,141 B2
• Filed: 02/26/2015
• Issued: 02/13/2018
• Est. Priority Date: 02/26/2015
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Su, Yen-Shuo, Kuo, Chun-Tsung, Lu, Jiech-Fun
• Primary Examiner(s): Armand, Marc
• Assistant Examiner(s): Kilpatrick, Warren H
• Application Number:
  US14/632,519
• Publication Number:
  US 20160254342A1
• Time in Patent Office: 1,083 Days
• Field of Search: 257531
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 28/10 Inductors

Abstract

A magnetic core includes a center section having a substantially uniform thickness, and an edge section connected to and surrounding the center section. The edge section includes a bottom portion and a top portion disposed on the bottom portion, in which the bottom portion has a gradual side surface since the top portion has a steep side surface. The profile of the magnetic core can be more rectangular thereby providing better inductor performance.

Claims

1. A semiconductor device, comprising:

a semiconductor substrate; and

a magnetic core over the semiconductor substrate, the magnetic core comprising;

a center section having a substantially uniform thickness; and

an edge section connected to and surrounding the center section, the edge section comprising a bottom portion and a top portion disposed on the bottom portion, wherein the bottom portion has an inclined side surface, and the top portion has a curve side surface.

2. The semiconductor device of claim 1, wherein a sum of a thickness of the bottom portion and a thickness of the top portion is substantially equal to the thickness of the center section.

3. The semiconductor device of claim 2, wherein a ratio of the thickness of the bottom portion to the thickness of the top portion is in a range from about 2/3 to about 3/2.

4. The semiconductor device of claim 1, wherein a width of the bottom portion extended from the center section is greater than a width of the top portion.

5. The semiconductor device of claim 1, further comprising a middle portion disposed between the bottom portion and the top portion, wherein the middle portion has a steep side surface.

6. The semiconductor device of claim 5, wherein the middle portion has a curve side surface.

7. A semiconductor device, comprising:

a substrate;

a bottom conductive layer disposed on the substrate;

a bottom dielectric layer formed on the bottom conductive layer;

a magnetic core formed on the bottom dielectric layer, the magnetic core comprising;

a center section having a substantially uniform thickness; and

an edge section connected to and surrounding the center section, the edge section comprising a bottom portion and a top portion disposed on the bottom portion, wherein the bottom portion is between the top portion and the substrate and is wider than the top portion;

a top dielectric layer formed on the magnetic core; and

a top conductive layer formed on the top dielectric layer.

8. The semiconductor device of claim 7, wherein the bottom conductive layer and the top conductive layer form a winding wire wound on the magnetic core.

9. The semiconductor device of claim 7, wherein the bottom portion has an inclined side surface, and the top portion has a curve side surface.

10. The semiconductor device of claim 7, further comprising a middle portion disposed between the bottom portion and the top portion, wherein a side surface of the middle portion is steeper than a side surface of the bottom portion.

11. The semiconductor device of claim 7, wherein the magnetic core is made of cobalt zirconium tantalum (CZT), nickel iron (NiFe), or iron nitride (FeN).

12. The semiconductor device of claim 10, wherein the bottom portion has an inclined side surface, the middle portion has a curve surface, and the top portion has a curve surface.

13. The semiconductor device of claim 7, wherein the bottom conductive layer and the top conductive layer are made of W, Co, Al, or Cu.

14. The semiconductor device of claim 7, wherein the bottom dielectric layer and the top dielectric layer are made of silicon nitride, silicon carbide, nitrogen-doped silicon carbide, silicon oxynitride, oxygen-doped silicon carbide, or silicon oxide.

15. The semiconductor device of claim 7, wherein the edge section comprises an anisotropic etched surface.

16. The semiconductor device of claim 7, wherein a sum of a thickness of the bottom portion and a thickness of the top portion is substantially equal to the thickness of the center section.

17. The semiconductor device of claim 7, wherein the magnetic core is not in a shape of triangle.

18. The semiconductor device of claim 7, wherein the bottom portion is wider than the top portion.

19. A semiconductor device, comprising:

a semiconductor substrate; and

a magnetic core over the semiconductor substrate, the magnetic core comprising;

a center section having a substantially uniform thickness; and

an edge section connected to and surrounding the center section, wherein a side surface of the edge section has at least two different slopes.

20. The semiconductor device of claim 19, wherein the center section and the edge section comprise a magnetic material.