发明名称 |
METHOD OF DOUBLE PATTERNING AND ETCHING MAGNETIC TUNNEL JUNCTION STRUCTURES FOR SPIN-TRANSFER TORQUE MRAM DEVICES |
摘要 |
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 CH3OH. Preferably, a photoresist mask layer is removed by oxygen plasma between the fluorocarbon and CH3OH 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. |
申请公布号 |
EP2412003(A1) |
申请公布日期 |
2012.02.01 |
申请号 |
EP20100756454 |
申请日期 |
2010.03.22 |
申请人 |
MAGIC TECHNOLOGIES INC. |
发明人 |
BELEN, RODOLFO;ZHONG, TOM;KULA, WITOLD;TORNG, CHYU-JIUH |
分类号 |
H01L43/12;H01L27/22 |
主分类号 |
H01L43/12 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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