Method for fabricating a vertical trench inductor

• US 5,372,967 A
• Filed: 05/02/1994
• Issued: 12/13/1994
• Est. Priority Date: 01/27/1992
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Sundaram, Lalgudi M. G., Tracht, Neil
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): TSAI, H JEY
• Application Number:
  US08/236,079
• Time in Patent Office: 225 Days
• Field of Search: 437/203, 437/228, 437/186-187, 437/192-195, 437/60, 156/664, 148/DIG. 50, 29/602.1, 29/625, 29/825, 365/145, 365/149, 365/173, 257/295, 257/306, 257/310, 336/200, 336/223
• US Class Current: 438/381
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 2017/004 with the coil helically wound around an axis without a core
• CPC Class Codes: H01L 27/08 including only semiconductor components of a single kind
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

A method of forming vertical trench inductor (10) includes providing a layer (11) and forming a plurality of trenches (12) vertically therein. The trenches (12) are filled with a conductive material (16) and etched using a photolithographically defined mask (17). The etching produces a conductive liner (18) covering two sidewalls (13) and a bottom surface (14) of the trench (12). A second conductive layer is formed and patterned to couple the conductive liner (18) covering a sidewall (13) of a first trench (12) to the conductive liner (18) of an opposite sidewall (13) of an adjacent trench (12) to form an inductive coil.

Claims

1. A method of fabricating a vertical trench inductor comprising the steps of:

providing a layer to have a conductive region formed therein;

forming a plurality of trenches vertically into the layer, wherein each trench has a bottom surface, a first set of opposed sidewalls, and a second set of opposed sidewalls;

filling each trench with a conductive material;

etching the conductive material to remove the conductive material from the second set of opposed sidewalls thereby forming a conductive liner covering the bottom surface and the first set of opposed sidewalls;

covering the conductive liner with a dielectric material; and

forming a conductive interconnect to couple one end of the conductive liner in a first trench to an opposite end of the conductive liner in an adjacent trench.

2. The method of claim 1 wherein the providing a layer step comprises providing an insulating layer on a semiconductor substrate.

3. The method of claim 1 wherein providing a layer step comprises providing a semiconductor layer, and further comprising lining the bottom surface and the first and second set of opposed sidewalls with a dielectric material after the step of forming the trenches.

4. The method of claim 1 wherein the covering the conductive liner with a dielectric step further comprises providing a dielectric liner covering the conductive liner and the method further comprises the step of covering the dielectric liner with a high permeability core material.

5. The method of claim 1 wherein the etching the conductive material step further comprises forming a mask layer which extends over the first set of opposed sidewalls and anisotropically etching the conductive material.

6. The method of claim 5 further comprising the step of removing material between adjacent trenches using the mask layer as an etch mask after the etching the conductive material step.

7. A method for fabricating a vertical trench inductor comprising the steps of:

providing a first layer;

forming a plurality of trenches vertically into the first layer, wherein each trench has a bottom surface, a first set of opposed sidewalls, and a second set of opposed sidewalls;

depositing a blanket layer comprising a conductive material, wherein the blanket layer fills the plurality of trenches and covers the first layer;

planarizing the blanket layer so that the conductive material just fills the plurality of trenches;

forming a mask layer which extends over the first set of opposed sidewalls;

etching the conductive material to remove the conductive material from the second set of opposed sidewalls thereby forming a conductive liner covering the bottom surface and the first set of opposed sidewalls;

covering the conductive liner with a dielectric material; and

forming a conductive interconnect to couple one end of the conductive liner in a first trench to an opposite end of the conductive liner in an adjacent trench.

8. The method of claim 7 wherein the step of providing the first layer comprises providing an insulating layer on a semiconductor substrate.

9. The method of claim 7 wherein the step of providing the first layer comprises providing a semiconductor layer and further comprising the step of lining the bottom surface and the first and the second set of opposed sidewalls of each trench with a dielectric material after the step of forming the trenches.

10. The method of claim 7 wherein the step of depositing the blanket layer comprising the conductive material comprises depositing a blanket layer selected from the group consisting of aluminum, aluminum alloy, and doped polysilicon.

11. The method of claim 7 further comprising the step of removing portions of the first layer between adjacent trenches using the mask layer as an etch mask after the step of etching the conductive material.

12. The method of claim 11 wherein the step of covering the conductive liner with the dielectric further comprises providing a dielectric liner covering the conductive liner and the method further comprises the step of covering the dielectric liner with a high permeability core material.

13. A process for making a vertical trench inductor comprising the steps

providing an insulating layer;

forming a plurality of trenches vertically into the insulating layer, wherein each trench has a bottom surface, a first set of opposed sidewalls, and a second set of opposed sidewalls;

depositing a blanket layer comprising a conductive material, wherein the blanket layer fills the plurality of trenches and covers the insulating layer;

planarizing the blanket layer so that the conductive material just fills the plurality of trenches;

forming a mask layer which extends over the first set of opposed sidewalls;

etching the conductive material to remove the conductive material from the second set of opposed sidewalls thereby forming a conductive liner covering the bottom surface and the first set of opposed sidewalls;

covering the conductive liner with a dielectric material; and

forming a conductive interconnect to couple one end of the conductive liner in a first trench to an opposite end of the conductive liner in an adjacent trench.

14. The process of claim 13 further comprising the step of planarizing the dielectric material after the step of covering the conductive liner with the dielectric material so that the dielectric layer is flush with an upper surface of the insulating layer.

15. The process of claim 13 further comprising the step of removing portions of the insulating layer between adjacent trenches using the mask layer as an etch mask after the step of etching the conductive material.

16. The process of claim 15 wherein the step of covering the conductive liner with the dielectric further comprises providing a dielectric liner covering the conductive liner and the method further comprises the steps of covering the dielectric liner with a high permeability core material and planarizing the high permeability core material so that it is flush with an upper surface of the insulating layer.

17. The process of claim 13 wherein the step of providing the insulating layer comprises providing a layer selected from the group consisting of silicon oxide, silicon nitride, and an organic insulator.

18. The process of claim 13 wherein the step of forming the plurality of trenches into the insulating layer comprises forming the plurality of trenches into the insulating layer so that the first set of opposed sidewalls form right angles with respect to the second set of opposed sidewalls.