Method for patterning of laminated magnetic layer

Patent metadata

Field	Value
Publication number	US-9633866-B2
Application number	US-201514715546-A
Country	US
Kind code	B2
Filing date	May 18, 2015
Priority date	May 18, 2015
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A microelectronic device is formed by forming a stack of alternating layers of a magnetic material and a dielectric material. An etch mask is formed over the magnetic laminate layer. An aqueous wet etch including 5 percent to 10 percent nitric acid, 0.5 percent to 2 percent sulphuric acid, and 0.5 percent to 3 percent hydrofluoric acid is used to etch the magnetic laminate layer where exposed by the etch mask to form a patterned magnetic laminate layer. An optional adhesion layer, if present, is also removed by the aqueous wet etch solution where exposed by the etch mask. The etch mask is subsequently removed.

First claim

What is claimed is:

1. A method of forming a microelectronic device, comprising the steps:
providing a substrate comprising a dielectric material;
forming a magnetic laminate layer over the substrate, the magnetic laminate layer comprising at least two layers of magnetic material alternating with at least one layer of dielectric material, wherein the magnetic material in the magnetic laminate layer includes at least 80 percent cobalt, at least 1 percent tantalum and at least 1 percent zirconium;
forming an etch mask over the magnetic laminate layer;
removing the magnetic laminate layer in areas exposed by the etch mask using an aqueous wet etch solution comprising nitric acid, sulphuric acid, hydrofluoric acid, and deionized water, to form a patterned magnetic laminate layer; and
subsequently removing the etch mask.

2. The method of claim 1 , wherein removing the magnetic laminate layer is performed by immersing the magnetic laminate layer in the aqueous wet etch solution.

3. The method of claim 1 , wherein removing the magnetic laminate layer is performed by spraying the aqueous wet etch solution onto the magnetic laminate layer.

4. The method of claim 1 , wherein removing the magnetic laminate layer is performed with the aqueous wet etch solution at a temperature of 20° C. to 25° C.

5. The method of claim 1 , wherein each layer of the magnetic material in the magnetic laminate layer is 0.5 microns to 1.5 microns thick.

6. The method of claim 1 , wherein the dielectric material in the magnetic laminate layer includes aluminum nitride.

7. The method of claim 1 , wherein each layer of the dielectric material in the magnetic laminate layer is 1 nanometer to 1000 nanometers thick.

8. The method of claim 1 , wherein the magnetic laminate layer includes at least five layers of the magnetic material and at least five layers of the dielectric material.

9. The method of claim 1 , wherein the dielectric material in the substrate includes silicon dioxide.

10. The method of claim 1 , wherein the substrate contains a metal interconnect comprising copper.

11. The method of claim 10 , wherein the metal interconnect comprising copper extends to a top surface of the substrate.

12. The method of claim 1 , comprising forming an adhesion layer over the substrate before forming the magnetic laminate layer, and wherein the adhesion layer is removed by the aqueous wet etch solution.

13. The method of claim 12 , wherein the adhesion layer comprises a material selected from the group consisting of titanium, titanium nitride, tantalum and tantalum nitride.

14. The method of claim 1 , comprising forming a dielectric layer over the patterned magnetic laminate layer, after removing the etch mask.

15. The method of claim 14 , comprising forming metal interconnect elements on the microelectronic device, after removing the etch mask.

16. The method of claim 15 , wherein the metal interconnect elements and the patterned magnetic laminate layer are parts of a component selected from the group consisting of a solenoid inductor, a transformer and a magnetic sensor.

17. A method of forming a microelectronic device, comprising the steps:
providing a substrate comprising a dielectric material, the substrate containing an interconnect comprising copper extending to a top surface of the substrate;
forming an adhesion layer over the substrate, the adhesion layer comprising a material selected from the group consisting of titanium, titanium nitride, tantalum and tantalum nitride;
forming a magnetic laminate layer over the substrate, the magnetic laminate layer comprising at least two layers of magnetic material 0.5 microns to 1.5 microns thick alternating with at least one layer of dielectric material 1 nanometer to 1000 nanometers thick, the magnetic material including at least 80 percent cobalt, at least 1 percent tantalum and at least 1 percent zirconium, and the dielectric material including aluminum nitride;
forming an etch mask over the magnetic laminate layer;
removing the magnetic laminate layer and the adhesion layer in areas exposed by the etch mask by immersing the magnetic laminate layer in an aqueous wet etch solution comprising 5 percent to 10 percent nitric acid, 0.5 percent to 2.0 percent sulphuric acid, 0.5 percent to 3 percent hydrofluoric acid, and at least 80 percent deionized water, to form a patterned magnetic laminate layer, the aqueous wet etch solution being at a temperature of 20° C. to 25° C.;
subsequently removing the etch mask;
forming a dielectric layer over the patterned magnetic laminate layer after removing the etch mask; and
forming metal interconnect elements on the microelectronic device after removing the etch mask.

18. A method of forming a microelectronic device, comprising the steps:
providing a substrate comprising a dielectric material;
forming an adhesion layer over the substrate;
forming a magnetic laminate layer over the substrate, the magnetic laminate layer comprising at least two layers of magnetic material 0.5 microns to 1.5 microns thick alternating with at least one layer of dielectric material 1 nanometer to 1000 nanometers thick, the magnetic material including at least 80 percent cobalt, at least 1 percent tantalum and at least 1 percent zirconium, and the dielectric material including aluminum nitride;
forming an etch mask over the magnetic laminate layer;
removing the magnetic laminate layer and the adhesion layer in areas exposed by the etch mask by immersing the magnetic laminate layer in an aqueous wet etch solution comprising 5 percent to 10 percent nitric acid, 0.5 percent to 2 percent sulphuric acid, 0.5 percent to 3 percent hydrofluoric acid, and at least 80 percent deionized water, to form a patterned magnetic laminate layer, the aqueous wet etch solution being at a temperature of 20° C. to 25° C.; and
subsequently removing the etch mask.

Assignees

• Texas Instruments Inc

Inventors

• Shulver Byron J R

Classifications

• H10P50/283

  by chemical means · CPC title

• H10P50/71

  using masks for conductive or resistive materials · CPC title

• H10W44/501

  Inductive arrangements (H10W44/20 takes precedence) · CPC title

• H10W20/4446

  Refractory-metal alloys · CPC title

• H10W20/497

  Inductive arrangements or effects of, or between, wiring layers · CPC title