Granted Patent B2

US 12,477,957 · App. 18/045,504 · Granted Nov 18, 2025

Inventors: Sanjeev Aggarwal (Scottsdale, AZ); Shimon (Singapore, SG); Kerry Joseph Nagel (Scottsdale, AZ)

Assignee: Everspin Technologies, Inc.

H10N52/01H10B61/22H10N52/00H10N52/80

Abstract

Claims (81)

1 . A method of manufacturing a magnetoresistive device, the method comprising:

forming a first magnetic region, an intermediate region, and a second magnetic region of a magnetoresistive stack;

before forming the first magnetic region, the intermediate region, and the second magnetic region of the magnetoresistive stack, forming one or more regions including an interlayer dielectric and a via;

performing an etching process for a first etch, comprising:

monitoring the etching process to detect the presence of a predetermined material composition;

removing a portion of the second magnetic region, a first portion of the intermediate region, and a first portion of the first magnetic region; and

stopping the etching process when the presence of the predetermined material composition is detected, thereby exposing a surface of at least one of the one or more regions below the magnetoresistive stack;

performing a second etch, wherein the second etch removes a second portion of the intermediate region and a second portion of the first magnetic region; and

rendering a redeposited material electrically non-conductive by exposing the magnetoresistive stack to a mixture of oxygen (O 2 ) and argon (Ar).

2 . The method of claim 1 , further comprising, after rendering the redeposited material remaining on the magnetoresistive stack electrically non-conductive, forming an encapsulation material on the magnetoresistive stack.

3 . The method of claim 1 , wherein the second magnetic region is formed on the intermediate region and the intermediate region is formed on the first magnetic region.

4 . The method of claim 1 , wherein the first etch is a reactive ion etch (RIE) and the second etch is an ion beam etch (IBE) at an angle of approximately 35° to approximately 55°.

5 . The method of claim 1 , wherein the mixture of O 2 and Ar has a molar ratio of O 2 to Ar of approximately 1:3 to approximately 1:10.

6 . The method of claim 1 , wherein the magnetoresistive stack is a first magnetoresistive stack, and the method further comprises forming a second magnetoresistive stack, wherein a pitch between the first magnetoresistive stack and the second magnetoresistive stack is less than or equal to approximately 70 nm.

7 . The method of claim 1 , wherein forming the one or more regions includes:

forming the interlayer dielectric;

forming a trench in the interlayer dielectric; and

depositing a conductive material in the trench to form the via,

wherein the via is coaxial to the magnetoresistive stack and a width of the via is less than a width of a surface of the magnetoresistive stack in contact with the via.

8 . The method of claim 1 , further comprising:

monitoring the etching process to detect the presence of a predetermined material composition through an endpoint monitoring process; and

stopping the etching process when the presence of the predetermined material composition is detected by the endpoint monitoring process.

9 . A method of manufacturing a magnetoresistive device, the method comprising:

forming an interlayer dielectric;

forming a trench in the interlayer dielectric;

depositing a conductive material in the trench to form a via;

forming a first magnetic region, an intermediate region, and a second magnetic region of a magnetoresistive stack above the via;

performing a first etch by monitoring an etching process to detect the presence of a predetermined material composition and stopping the etching process when the presence of the predetermined material composition is detected, thereby removing a portion of the second magnetic region and exposing a surface of the interlayer dielectric;

removing a portion of the intermediate region and a portion of the first magnetic region using a second etch;

oxidizing at least a first portion of redeposited material on the magnetoresistive stack;

removing the oxidized first portion;

oxidizing at least a second portion of the redeposited material on the magnetoresistive stack; and

removing the oxidized second portion.

10 . The method of claim 9 , wherein oxidizing at least the second portion of the redeposited material includes exposing the magnetoresistive stack to a mixture of oxygen (O 2 ) and argon (Ar).

11 . The method of claim 9 , wherein the second etch is an ion-beam etch performed at an angle of approximately 35° to approximately 55°.

12 . The method of claim 9 , wherein removing the oxidized first portion, removing the oxidized second portion, or both, includes an ion-beam etch.

13 . The method of claim 12 , wherein the ion-beam etch is performed at an angle of approximately 35° to approximately 55°.

14 . The method of claim 9 , wherein the first etch exposes a surface of the intermediate region and the second etch exposes a surface of an interlayer dielectric.

15 . The method of claim 9 , wherein the first portion of redeposited material is formed during the first etch and/or the second etch; and

the second portion of redeposited material is formed during the first etch and/or the second etch.

16 . A method of manufacturing a magnetoresistive device, the method comprising:

forming a first magnetic region, an intermediate region, and a second magnetic region of a magnetoresistive stack above a via;

removing a portion of the second magnetic region using a first etch;

monitoring the first etch to detect the presence of a predetermined material composition and stopping the first etch when the presence of the predetermined material composition is detected, such that a surface of an interlayer dielectric surrounding the via is exposed;

removing a portion of the intermediate region using a second etch, wherein the first etch, the second etch, or both, generate redeposited material on the first magnetic region, the intermediate region, and/or the second magnetic region;

oxidizing at least a first portion of redeposited material on the first magnetic region, the intermediate region, and/or the second magnetic region;

removing the oxidized first portion;

oxidizing at least a second portion of the redeposited material on the first magnetic region, the intermediate region, and/or the second magnetic region; and

removing the oxidized second portion.

17 . The method of claim 16 , wherein the first etch exposes a portion of the intermediate region or a portion of the first magnetic region.

18 . The method of claim 17 , wherein the second etch exposes a portion of the interlayer dielectric below the first magnetic region.

19 . The method of claim 16 , wherein the first magnetic region is a free magnetic region and the second magnetic region is a fixed magnetic region.

20 . The method of claim 16 , wherein the first etch or the second etch is an angled ion beam etch at an angle of approximately 35° to approximately 55°.

21 . The method of claim 16 , wherein the magnetoresistive stack is a first magnetoresistive stack, and the method further comprises forming a second magnetoresistive stack, wherein a pitch between the first magnetoresistive stack and the second magnetoresistive stack is less than or equal to approximately 70 nm.

22 . A method of manufacturing a magnetoresistive device, the method comprising:

forming a first magnetic region, an intermediate region, and a second magnetic region of a magnetoresistive stack above an interlayer dielectric including a via;

removing at least a portion of the second magnetic region using a first etch;

monitoring the first etch to detect the presence of a predetermined material composition and stopping the first etch when the presence of the predetermined material composition is detected, such that a surface of an interlayer dielectric is exposed;

removing at least a portion of the intermediate region and at least a portion of the first magnetic region using a second etch;

removing at least a portion of material redeposited on the magnetoresistive stack using a third etch;

rendering at least a portion of the redeposited material remaining on the magnetoresistive stack electrically non-conductive, wherein rendering at least a portion of the redeposited material remaining on the magnetoresistive stack electrically non-conductive includes:

oxidizing at least a first portion of redeposited material remaining on the magnetoresistive stack;

removing the oxidized first portion;

oxidizing at least a second portion of the redeposited material remaining on the magnetoresistive stack; and

removing the oxidized second portion.

23 . A method of manufacturing a magnetoresistive device, the method comprising:

forming a first magnetic region, an intermediate region, and a second magnetic region of a magnetoresistive stack above a via;

before forming the first magnetic region, the intermediate region, and the second magnetic region of the magnetoresistive stack, forming one or more regions including an interlayer dielectric and the via;

removing at least a portion of the second magnetic region using a first etch, wherein during the first etch, an etching process of the first etch is monitored to detect the presence of a predetermined material composition and the etching process is stopped when the presence of the predetermined material composition is detected, thereby exposing a surface of at least one of the one or more regions, wherein the first etch is an ion beam etch (IBE);

removing at least a portion of the intermediate region and at least a portion of the first magnetic region using a second etch, wherein the second etch is a reactive ion etch (RIE);

trimming at least a portion of redeposited material on the magnetoresistive stack, wherein trimming at least a portion of redeposited material on the magnetoresistive stack includes:

removing at least a portion of material redeposited on the magnetoresistive stack using a third etch; and

rendering at least a portion of the redeposited material remaining on the magnetoresistive stack electrically non-conductive by exposing the magnetoresistive stack to a mixture of oxygen (O 2 ) and argon (Ar).

24 . A method of manufacturing a magnetoresistive device, the method comprising:

forming an interlayer dielectric;

forming a trench in the interlayer dielectric;

depositing a conductive material in the trench to form a via;

forming a free magnetic region, an intermediate region, and a fixed magnetic region of a magnetoresistive stack above the via;

performing a first etch of a two-step etch process, wherein the first etch removes at least a portion of the fixed magnetic region and is stopped when the presence of the interlayer dielectric is detected, thereby exposing a surface of the interlayer dielectric;

performing a second etch of the two-step etch process, wherein the second etch removes at least a portion of the intermediate region and at least a portion of the free magnetic region;

removing a first redeposited material using an ion beam etch (IBE), wherein the first redeposited material is formed during the first etch, the second etch, or both; and rendering at least the portion of the redeposited material remaining on the magnetoresistive stack electrically non-conductive by exposing the magnetoresistive stack to a mixture of oxygen (O 2 ) and argon (Ar).

Assignments (1)

Continuity (2)

References Cited (37)