The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 2011
Filed:
Mar. 23, 2009
Rodolfo Belen, San Jose, CA (US);
Tom Zhong, Saratoga, CA (US);
Witold Kula, Cupertino, CA (US);
Chyu-jiuh Torng, Pleasanton, CA (US);
Rodolfo Belen, San Jose, CA (US);
Tom Zhong, Saratoga, CA (US);
Witold Kula, Cupertino, CA (US);
Chyu-Jiuh Torng, Pleasanton, CA (US);
MagIC Technologies, Inc., Milpitas, CA (US);
Abstract
A method for forming a MTJ in a STT-MRAM is disclosed in which the easy-axis CD is determined independently of the hard-axis CD. One approach involves two photolithography steps each followed by two plasma etch steps to form a post in a hard mask which is transferred through a MTJ stack of layers. The hard mask has an upper Ta layer with a thickness of 300 to 400 Angstroms and a lower NiCr layer less than 50 Angstroms thick. The upper Ta layer is etched with a fluorocarbon etch while lower NiCr layer and underlying MTJ layers are etched with a CHOH. Preferably, a photoresist mask layer is removed by oxygen plasma between the fluorocarbon and CHOH plasma etches. A lower hard mask layer made of NiCr or the like is inserted to prevent formation and buildup of Ta etch residues that can cause device shunting.