MRAM device formation with controlled ion beam etch of MTJ

US11158786B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Ashim Dutta · Clifton Park, US
• Chih-Chao Yang · Glenmont, US
• Lijuan Zou · Eden Prairie, US
• John C. Arnold · North Chatham, US

Key dates

• Filing date: Sep 25, 2019
• Grant date: Oct 26, 2021
• Expiry date: Oct 22, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10N50/85

Abstract

Controlled IBE techniques for MRAM stack patterning are provided. In one aspect, a method of forming an MRAM device includes: patterning an MRAM stack disposed on a dielectric into individual memory cells using IBE landing on the dielectric while dynamically adjusting an etch time to compensate for variations in a thickness of the MRAM stack, wherein each of the memory cells includes a bottom electrode, an MTJ, and a top electrode; removing foot flares from the bottom electrode of the memory cells which are created during the patterning of the MRAM stack; removing residue from sidewalls of the memory cells which includes metal redeposited during the patterning of the MRAM stack and during the removing of the foot flares; and covering the memory cells in a dielectric encapsulant. An MRAM device is also provided.