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Damascene Scheme for Patterning Magnetic Tunnel Junctions

IP.com Disclosure Number: IPCOM000019666D
Publication Date: 2003-Sep-24
Document File: 3 page(s) / 132K

Publishing Venue

The IP.com Prior Art Database

Related People

Walter Glashauser: AUTHOR [+4]

Abstract

Processing of magnetoresistive random access memory (MRAM) requires patterning of magnetic tunnel junction. They consist of multilayer metal stack separated by a thin dielectric tunnel barrier. An integration scheme for structuring magnetic stack using a damascene approach is proposed

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Damascene Scheme for Patterning Magnetic Tunnel Junctions

Walter Glashauser, Arkalgud Sitaram, Gerhard Mueller, Igor Kasko

Abstract

Processing of magnetoresistive random access memory (MRAM) requires patterning of magnetic tunnel junction. They consist of multilayer metal stack separated by a thin dielectric tunnel barrier. An integration scheme for structuring magnetic stack using a damascene approach is proposed.

One of the most critical processes in the fabrication of MRAM (magnetoresistive random access memory) is etching of magnetic materials. Between 6 and 10 different materials are stacked together. Re-deposition of metal during etch creates fences on sidewalls of the magnetic stack. This results mostly in a shortening of the magnetic tunnel junctions (MTJs). Current standard processes, used for MRAM, do also create a very high topography. This high topography is very difficult to fill with an insulation layer like silicone dioxide or other materials. Therefore, following planarization with CMP is difficult as well. A damascene process to create patterned MTJ’s would solve the problems.

Several options to realize a damascene scheme for patterning magnetic memory cells are described below.

Process flow

Dual Damascene VA and MA

Deposition MTJ SiN

Etch of MTJ space

(for better magnetic stack deposition conformity sidewalls can be tapered)

Deposition of Magnetic stack

Deposition of SiO2

CMP SiO2 stop on Magnetic stack

CMP Magnetic stack removal on top

Etch contact to MTJ

M2 V2 copper process

 
Trench Magnet Version A

Trench Magnet Version B

Process flow

Dual Damascene VA and MA

Deposition MTJ SiN

Etch of MTJ space

Deposition of Magnetic stack

Deposition of SiO2

CMP SiO2 stop on Magnetic stack

CMP Magnetic stack removal on top

(optional wet etch to clean magnetic stack on si...