Method to improve inductance with a high-permeability slotted plate core in an integrated circuit

• US 7,436,281 B2
• Filed: 07/30/2004
• Issued: 10/14/2008
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Brennan, Kenneth D., Williams, Byron, Papa Rao, Satyavolu S.
• Primary Examiner(s): Enad; Elvin
• Assistant Examiner(s): BAISA, JOSELITO SASIS
• Application Number:
  US10/909,046
• Publication Number:
  US 20060022787A1
• Time in Patent Office: 1,537 Days
• Field of Search: 336/200
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 2017/008 Electric or magnetic shielding of printed inductances
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: Y10T 29/49073 by assembling coil and core

Abstract

An inductor structure (102) formed in an integrated circuit (100) is disclosed, and includes a first isolation layer (106) and a first core plate (104) disposed over or within the first isolation layer (106, 114). The first core plate (104) includes a plurality of electrically coupled conductive traces composed of a conductive ferromagnetic material layer. A second isolation layer (108) overlies the first isolation layer and an inductor coil (102) composed of a conductive material layer (118) is formed within the second isolation layer (108). Another core plate may be formed over the coil. The one or more core plates increase an inductance (L) of the inductor coil (102).

Claims

1. An inductor structure formed in an integrated circuit, comprising:

a first isolation layer;

a first core plate comprising a plurality of substantially parallel discrete conductive traces, the plurality of parallel traces electrically coupled with a single conductive transverse web, the conductive traces comprising a conductive ferromagnetic material layer disposed over an upper surface of the first isolation layer;

a second isolation layer overlying the first isolation layer; and

an inductor coil comprising a conductive material layer formed within the second isolation layer;

wherein the first core plate increases an inductance of the inductor coil.

2. The inductor structure of claim 1, wherein the conductive ferromagnetic material comprises one of cobalt, nickel, tantalum, a TiN/Co/TiN stack, a TaN/Co stack, and a high-permeability ferromagnetic core material.

3. The inductor structure of claim 1, further comprising:

a third isolation layer formed over the inductor coil conductive layer; and

a second core plate comprising a plurality of substantially parallel discrete conductive traces, the plurality of parallel traces electrically coupled with a single conductive transverse web, the conductive traces comprising a conductive ferromagnetic layer disposed over an upper surface of the third isolation layer, thereby providing a ferromagnetic core plate above and below the inductor coil.

4. The inductor structure of claim 3, wherein the conductive material layer of the inductor coil comprises one of copper, aluminum, tantalum, and a TaN/Al stack.

5. The inductor structure of claim 3, wherein at least one of the first and second core plates of the inductor further comprises a plate of a capacitor.

6. The inductor structure of claim 5, wherein one of the first and second core plates of the capacitor is electrically connected to the inductor coil.

7. The inductor structure of claim 3, wherein the traces of the first core plate of the inductor are aligned orthogonal to the traces of the second core plate.

8. The inductor structure of claim 1, wherein the material of at least one of the isolation layers comprises one of TaN, SiO2, an etch-stop material, SiN, SiC, SiC:

H, and an insulative or dielectric material.

9. The inductor structure of claim 1 wherein the inductor coil is formed completely within the metal layers of the integrated circuit.

10. The inductor structure of claim 1, wherein the inductor coil is formed in one or more protective overcoat layers of the integrated circuit.

11. The inductor structure of claim 1, wherein the isolation layers comprise one of OSG, FSG, TEOS, a low-k dielectric material, and an ultra low-k dielectric material.

12. A method of forming an integrated inductor structure over a semiconductor substrate, comprising:

providing a first isolation layer disposed over the semiconductor substrate;

forming a first core plate comprising a plurality of substantially parallel discrete conductive traces, the plurality of parallel traces electrically coupled with a single conductive transverse web, the conductive traces comprising a conductive ferromagnetic material layer disposed over an upper surface of the first isolation layer;

forming a second isolation layer over the first isolation layer and the first core plate; and

forming an inductor coil comprising a conductive material layer disposed within trenches in the second isolation layer;

wherein the first core plate increases an inductance of the inductor coil.

13. The method of claim 12, further comprising:

forming a third isolation layer formed over the inductor coil conductive layer; and

forming a second core plate comprising a plurality of substantially parallel discrete conductive traces, the plurality of parallel traces electrically coupled with a single conductive transverse web, the conductive traces comprising a conductive ferromagnetic layer disposed over an upper surface of the third isolation layer, thereby providing a ferromagnetic core plate above and below the inductor coil.

14. The method of claim 13, wherein at least one of the first and second core plates of the inductor further comprises a plate of a capacitor.

15. The method of claim 14, wherein the plate of the capacitor is electrically connected to the inductor coil.

16. The method of claim 13, wherein the traces of the first core plate of the inductor are aligned orthogonal to the traces of the second core plate.

17. The method of claim 12, wherein the inductor coil is formed completely within the metal layers of the integrated circuit.

18. The method of claim 12, wherein the inductor coil is formed in one or more protective overcoat layers of the integrated circuit.