# US 10,312,434 B2 · Selective deposition and nitridization of bottom electrode metal for MRAM applications

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- Number: US 10,312,434 B2
- Document ID: US10312434B2
- Status: Granted
- Kind: B2
- Application number: 15/805,882
- Filed: 2017-11-07
- Published: 2018-08-23
- Granted: 2019-06-04
- Earliest claimed: 2017-02-17
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Benjamin D. Briggs; Joe Lee; Christopher J. Penny; Michael Rizzolo; Chih-Chao Yang
- Web page: https://patentgrep.com/patent/US10312434B2

## CPC

- H10N 50/01: Manufacture or treatment
- H10N 50/10: Magnetoresistive devices
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A method is presented for forming a semiconductor structure. The method includes depositing an insulating layer over a semiconductor substrate, etching the insulating layer to form trenches for receiving a metal, depositing one or more sacrificial layers, and etching portions of the one or more sacrificial layers to expose a top surface of the metal of one or more of the trenches. The method further includes selectively depositing an electrode over the top surface of the exposed metal and nitridizing the electrode to form a diffusion barrier between chip components and the metal.

## Claims

### Claim 1

A method for forming a semiconductor structure, the method comprising:
depositing an insulating layer over a semiconductor substrate;
etching the insulating layer to form trenches for receiving a metal;
depositing one or more sacrificial layers;
etching portions of the one or more sacrificial layers to expose a top surface of the metal of one or more of the trenches;
selectively depositing an electrode over the top surface of the exposed metal;
nitridizing the electrode to form a nitride cap over the electrode;
forming a magnetic tunnel junction (MTJ) in direct contact with a portion of a top surface of the nitride cap; and
forming a first dielectric cap over exposed portions of the top surface of the nitride cap, the first dielectric cap in direct contact with sidewalls of the nitride cap and the electrode.

### Claim 2 (depends on 1)

The method of claim 1, wherein the electrode is a metal selected from the group consisting of: cobalt (Co), ruthenium (Ru), manganese (Mn), tungsten (W), tantalum (Ta), and molybdenum (Mo).

### Claim 3 (depends on 1)

The method of claim 1, wherein the metal received within the trenches is copper (Cu).

### Claim 4 (depends on 1)

The method of claim 1, wherein the metal is recessed before receiving the nitride cap.

### Claim 5 (depends on 1)

The method of claim 1, wherein the electrode extends along an entire surface of the metal received within the trench to create a blocking boundary directly beneath the respective MTJ.

### Claim 6 (depends on 1)

The method of claim 1, wherein a block mask is deposited over the one or more sacrificial layers to separate MTJ regions from non-MTJ regions.

### Claim 7 (depends on 1)

The method of claim 1, wherein a via is formed such that it aligns with the electrode forming a barrier between the MTJ and the metal.

### Claim 8

A method for forming a semiconductor structure, the method comprising:
depositing an insulating layer over a semiconductor substrate;
etching the insulating layer to form trenches for receiving a metal;
depositing one or more sacrificial layers;
etching portions of the one or more sacrificial layers to expose a top surface of the metal of one or more of the trenches;
selectively recessing the exposed metal of one or more of the trenches;
selectively depositing an electrode within the recessed portion of the exposed metal;
nitridizing the electrode to form a nitride cap over the electrode;
forming a magnetic tunnel junction in direct contact with a portion of a top surface of the nitride cap; and
forming a first dielectric cap over exposed portions of the top surface of the nitride cap, the first dielectric cap in direct contact with sidewalls of the nitride cap and the electrode.

### Claim 9 (depends on 8)

The method of claim 8, wherein the electrode is a metal selected from the group consisting of: cobalt (Co), ruthenium (Ru), manganese (Mn), tungsten (W), tantalum (Ta), and molybdenum (Mo).

### Claim 10 (depends on 8)

The method of claim 8, wherein the metal received within the trenches is copper (Cu).

### Claim 11 (depends on 8)

The method of claim 8, wherein the metal is recessed before receiving the nitride cap.

### Claim 12 (depends on 8)

The method of claim 8, wherein the electrode extends along an entire surface of the metal received within the trench to create a blocking boundary directly beneath the respective MTJ component.

### Claim 13 (depends on 8)

The method of claim 8, wherein a block mask is deposited over the one or more sacrificial layers to separate MTJ regions from non-MTJ regions.

### Claim 14 (depends on 8)

The method of claim 8, wherein a via is formed such that it aligns with the electrode forming a barrier between the MTJ and the metal.