# US 10,483,460 B2 · Method of manufacturing a magnetoresistive stack/ structure using plurality of encapsulation layers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,460 B2 - Document ID: US10483460B2 - Status: Granted - Kind: B2 - Application number: 15/337,123 - Filed: 2016-10-28 - Published: 2017-05-04 - Granted: 2019-11-19 - Earliest claimed: 2015-10-31 - Assignees: Everspin Technologies, Inc. - Applicants: Everspin Technologies, Inc. - Inventors: Kerry Joseph Nagel; Wenchin Lin; Sarin A. Deshpande; Jijun Sun; Sanjeev Aggarwal; Chaitanya Mudivarthi - Web page: https://patentgrep.com/patent/US10483460B2 ## CPC - H10N 50/01: Manufacture or treatment - G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell} - H10N 50/10: Magnetoresistive devices - G11C 2211/5615: Multilevel magnetic memory cell using non-magnetic non-conducting interlayer, e.g. MTJ - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - G11C: STATIC STORES (semiconductor memory devices H10B) ## Abstract A method of manufacturing a magnetoresistive stack/structure comprising etching through a second magnetic region to (i) provide sidewalls of the second magnetic region and (ii) expose a surface of a dielectric layer; depositing a first encapsulation layer on the sidewalls of the second magnetic region and over the dielectric layer; etching the first encapsulation layer which is disposed over the exposed surface of the dielectric layer. The method further includes (a) depositing a second encapsulation layer: (i) on the first encapsulation layer disposed on the sidewalls of the second magnetic region and (ii) over the exposed surface of the dielectric layer and (b) depositing a third encapsulation layer: (i) on the second encapsulation layer which is on the first encapsulation layer and the exposed surface of the dielectric layer. The method also includes etching the remaining layers of the stack/structure (via one or more etch processes). ## Claims ### Claim 1 A method of manufacturing a magnetoresistive stack/structure from: (i) a first magnetic region including one or more layers of magnetic material, (ii) a dielectric layer disposed over the first magnetic region, (iii) a second magnetic region including one or more layers of magnetic material, wherein the second magnetic region is disposed over the dielectric layer, the method comprising: (a) etching through the second magnetic region to (i) partially form the magnetoresistive stack/structure and provide sidewalls of the second magnetic region and (ii) expose a surface of the dielectric layer in a field region adjacent to the partially formed magnetoresistive stack/structure; (b) depositing a first encapsulation layer on or over the sidewalls of the second magnetic region and on the exposed surface of the dielectric layer, wherein the first encapsulation layer is a first material; (c) depositing a second encapsulation layer on the first encapsulation layer disposed (i) on or over the sidewalls of the second magnetic region and (ii) on the exposed surface of the dielectric layer, wherein the second encapsulation layer is a second material; (d) after step (c), etching the exposed surface of the dielectric layer together with the first encapsulation layer and the second encapsulation layer disposed on or over the exposed surface of the dielectric layer to form a tunnel barrier, wherein, after the etching in step (d), a portion of the first encapsulation layer and a portion of the second encapsulation layer remain on or over the sidewalls of the second magnetic region; and (e) after etching through the exposed surface of dielectric layer in step (d), etching the first magnetic region to provide sidewalls thereof. ### Claim 2 (depends on 1) The method of claim 1, wherein the first material is an insulator, and the second material is a conductor. ### Claim 3 (depends on 2) The method of claim 2, wherein depositing a first encapsulation layer includes (i) depositing a metal and (ii) thereafter converting the metal to an insulator. ### Claim 4 (depends on 2) The method of claim 2, wherein the insulator is a silicon nitride. ### Claim 5 (depends on 4) The method of claim 4, wherein the conductor is an aluminum, a magnesium, or alloys thereof. ### Claim 6 (depends on 2) The method of claim 2, wherein the insulator is an aluminum oxide, a silicon oxide, a TEOS or an aluminum nitride. ### Claim 7 (depends on 6) The method of claim 6, wherein the conductor is an aluminum, a magnesium or alloys thereof. ### Claim 8 (depends on 1) The method of claim 1, further including: after depositing the second encapsulation layer in step (c) and before the etching in step (d), depositing a third encapsulation layer on the second encapsulation layer disposed over (i) the sidewalls of the second magnetic region and (ii) the exposed surface of the dielectric layer, wherein the third encapsulation layer is a third material, and wherein the etching in step (d) includes etching the exposed surface of the dielectric layer together with the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer disposed on or over the exposed surface of the dielectric layer. ### Claim 9 (depends on 1) The method of claim 1, wherein the first encapsulation layer has a thickness less than 35 Angstroms, and the second encapsulation layer has a thickness less than 50 Angstroms. ### Claim 10 (depends on 1) The method of claim 1, wherein the first encapsulation layer has a thickness between 10 and 25 Angstroms, and the second encapsulation layer has a thickness between 10 and 40 Angstroms. ### Claim 11 A method of manufacturing a magnetoresistive stack/structure from: (i) a first magnetic region including one or more layers of magnetic material, (ii) a dielectric layer disposed over the first magnetic region, (iii) a second magnetic region including one or more layers of magnetic material, wherein the second magnetic region is disposed over the dielectric layer, the method comprising: (a) etching the second magnetic region to expose a portion of the dielectric layer and form sidewalls and a top surface of the second magnetic region; (b) depositing a first encapsulation material on (i) the sidewalls and top surface of the second magnetic region and (ii) the exposed portion of the dielectric layer; (c) after depositing the first encapsulation material in step (b), depositing a second encapsulation material on the first encapsulation material disposed on (i) the sidewalls and top surface of the second magnetic region and (ii) the exposed portion of the dielectric layer; (d) etching the first and second encapsulation materials disposed over the exposed portion of the dielectric layer and the exposed portion of the dielectric layer to form a tunnel barrier, wherein, after the etching in step (d), at least a portion of the first and second encapsulation materials remains on or over the sidewalls of the second magnetic region; and (e) after the etching in step (d), etching the first magnetic region to form sidewalls on the first magnetic region. ### Claim 12 (depends on 11) The method of claim 11, wherein the first encapsulation material is an insulator, and the second encapsulation material is a conductor. ### Claim 13 (depends on 12) The method of claim 12, wherein the insulator is a silicon nitride. ### Claim 14 (depends on 11) The method of claim 11, wherein depositing the first encapsulation material in step (b) includes depositing a conductive metal, and the method further includes converting, at least partially, the deposited conductive metal to an insulative material. ### Claim 15 (depends on 14) The method of claim 14, wherein the conductive material is aluminum, magnesium, or alloys thereof. ### Claim 16 (depends on 11) The method of claim 11, wherein depositing the first encapsulation material in step (b) includes depositing a conductive metal, and wherein depositing the second encapsulation material in step (c) includes converting, at least partially, the deposited conductive metal to an insulative material. ### Claim 17 (depends on 11) The method of claim 11, wherein the first encapsulation material has a thickness less than 35 Angstroms, and the second encapsulation material has a thickness less than 50 Angstroms. ### Claim 18 (depends on 11) The method of claim 11, wherein the first encapsulation material has a thickness between 10 and 25 Angstroms, and the second encapsulation material has a thickness between 10 and 40 Angstroms. ### Claim 19 (depends on 11) The method of claim 11 further including, after depositing the second encapsulation material in step (c) and before the etching in step (d), depositing a third encapsulation material on the second encapsulation material disposed over (i) the sidewalls of the second magnetic region and (ii) the exposed surface of the dielectric layer, wherein the etching in step (d) includes etching the exposed surface of the dielectric layer together with the first, second, and third encapsulation materials disposed on or over the exposed surface of the dielectric layer. ### Claim 20 (depends on 19) The method of claim 19, wherein the third enacapsulation material has a thickness between 10 and 25 Angstroms.