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MTJ Patterning by Collimated Deposition and CMP

IP.com Disclosure Number: IPCOM000019668D
Publication Date: 2003-Sep-24
Document File: 2 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Related People

Ihar Kasko: AUTHOR [+4]

Abstract

Processing of magnetic cells requires patterning of the multilayer magnetic stack consisting of several layers of magnetic films and a tunnel dielectric barrier. The known structuring processes (ion milling, reactive ion etching) do affect sidewalls of magnetic stack resulting in degradation of memory cell properties. Collimated deposition of magnetic films into a patterned trench in the dielectric enables processing of magnetic cells with desired shape. Combination of collimated deposition of magnetic films with a conformal deposition of a tunnel barrier prevents electrical shorting between top and bottom electrodes. No etching of magnetic materials is required.

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Method of Fabricating Magnetic Random Access Memory

(MTJ patterning by collimated deposition and CMP)

Ihar Kasko, Kia-Seng Low, John Hummel, Kwong Hong (Keith) Wong

Processing of magnetic cells requires patterning of the multilayer magnetic stack consisting of several layers of magnetic films and a tunnel dielectric barrier. The known structuring processes (ion milling, reactive ion etching) do affect sidewalls of magnetic stack resulting in degradation of memory cell properties. Collimated deposition of magnetic films into a patterned trench in the dielectric enables processing of magnetic cells with desired shape. Combination of collimated deposition of magnetic films with a conformal deposition of a tunnel barrier prevents electrical shorting between top and bottom electrodes. No etching of magnetic materials is required.

Magnetic random access memory (MRAM) has the advantages of non-volatility, capability of 3-dimentional cell packaging, low power consumption, simpler and cheaper process compared to conventional DRAM and FLASH. It uses the relative orientation of the magnetization in the ferromagnetic materials to store information. The processing of the magnetic cells requires patterning of the magnetic stack which consists of several layers of magnetic films and a dielectric layer. The patterning of the magnetic stack is usually done by Ion Milling or Reactive Ion Etching (RIE). The drawbacks of Ion Milling are tapering of the side walls, re-deposition of the etched material, fences and a low throughput. Reactive Ion Etching of multilayer magnetic may stack...