High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma

Kim, Eun Ho; Lee, Tea Young; Min, Byoung‐Chul; Chung, Chee Won

doi:10.1016/j.tsf.2011.11.072

Cited by 17 publications

(6 citation statements)

References 16 publications

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“…They found that etching proceeded mainly via physical sputtering of the film assisted by minor chemical reactions between the gas species and the film (such as oxidation), and that the etch rate ranged from 2 to 10 nm/ min. The etching of CoFeB thin films in a CH 4 /Ar and H 2 O/CH 4 /Ar gas mixture was reported by Kim et al and Lee et al [10,11], who found etch rates of approximately 2e30 nm/min, which was considerably faster than the etch rates of the previously mentioned gas chemistries. The etch mechanism was mainly driven by physical sputtering, formation of carbon containing compounds and formation of a hydrocarbon inhibition layer.…”

Section: Introductionmentioning

confidence: 73%

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Garay

Hwang

Choi

et al. 2015

Vacuum

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Section: Introductionmentioning

confidence: 73%

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Garay

Hwang

Choi

et al. 2015

Vacuum

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“…The etchings of the TiN hard masks, CoFeB, FePt and MgO thin films using CH 4 /Ar and CH 4 /O 2 /Ar gas mixes have been reported. 18 Xray photoelectron spectroscopy showed that O 2 and CH 4 /Ar gas played a significant role in achieving good etch profiles without redeposition.…”

Section: Resultsmentioning

confidence: 99%

Influence of O₂Gas on Etch Profile of Magnetic Tunnel Junction Stacks Etched in a CH₄/O₂/Ar Plasma

Lee

Kim

Lee

et al. 2012

ECS J. Solid State Sci. Technol.

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The etch characteristics of magnetic tunnel junction (MTJ) stacks patterned with W/TiN films were examined using an inductively coupled plasma of a CH 4 /O 2 /Ar gas mix. The effect of the O 2 concentration on the etch rate, etch selectivity and etch profile of the MTJ stacks was examined. The etch profile of the MTJ stacks in 60% CH 4 /Ar gas appeared to be the best. The addition of 10% O 2 gas in CH 4 /Ar gas led to an improved etch profile with less redeposition on the sidewall of the MTJ stacks. This was attributed to the increase in [H]/[Ar] and [O]/[Ar] intensity ratios with increasing O 2 concentration to 20%. Transmission electron microscopy of the etched MTJ stacks revealed redeposited materials on the sidewall of the MTJ stacks etched in CH 4 /Ar gas that were indentified to be mainly Pt, Mn, Co, Ru and Ti. On the other hand, the amount of redeposited materials decreased significantly with the addition of 10% O 2 in CH 4 /Ar gas. The formation of metal oxides and protection layer in CH 4 /O 2 /Ar gas mix resulted in a high degree of anisotropy without redeposited materials in the etch profile of MTJ stacks.The rapid growth of smart devices such as smart phone, smart tab and smart TV requires new emerging semiconductor memory with the features of high density, fast speed, high endurance and nonvolativity. Among a variety of memory devices containing phase-change random access memory (PCRAM), resistive random access memory (ReRAM) and magnetic random access memory (MRAM), MRAM devices have attracted considerable attention as a replacement for current dynamic random access memory (DRAM) and flash memory. MRAM devices can provide nonvolatility, fast access time, unlimited read/write endurance, low operating voltage, and high storage density. 1,2 MRAM devices are composed of a magnetic tunnel junction (MTJ) stack and CMOS. The MTJ stack is a key part of MRAM devices and the realization of high-density MRAMs as a nonvolatile emerging memory requires new etching processes of MTJ stacks that can delineate the nanometer-sized patterns on the MTJ stacks. 3,4 The development of an etch process for patterning MTJ stacks, which consist of magnetic materials, metals and metal oxides, is important for the fabrication of high density MRAM with nanometersized patterns. Generally, dry etching of magnetic thin films is extremely difficult because the metals and magnetic materials barely react with the chemically active species in plasma. Initially, ion beam etching of magnetic thin films was used to etch the magnetic materials and metals but often, several undesirable attributes were produced, including slow etch rate, sidewall redeposition, and etching damages because of the etch mechanism by physical sputtering. Therefore, ion beam etching was of limited use in etching MTJ stacks as well as magnetic films. Chemically assisted ion etching and reactive ion etching were applied to etch the magnetic films but similar etch results to those obtained by ion beam etching were achieved. 5-7 Recently, high density plasma etching ...

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“…Halogen chemistries were used in conjunction with Ar or the aforementioned H 2 , while incorporation of numerous organics, such as CH 4 , CH 3 OH, and CH 3 COOH, were also employed but suffered from undesirable carbon deposition or oxidation caused from methanol and acetic acid fragmentation. [45][46][47][48] None of the chemistries reported exhibits etch rates higher than 20-30 nm/min, with moderate selectivity to Ti or TiN masks.…”

Section: C203-5 Altieri Et Almentioning

confidence: 93%

Review Article: Plasma–surface interactions at the atomic scale for patterning metals

Altieri

Chen

Minardi

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Building upon the depth and breadth of Harold Winters's work, this paper pays tribute to his pioneering contribution in the field of plasma etching of metals, and how that knowledge base helps guide the fundamental research in these areas. The fundamental understanding of the plasma–surface interactions during metal etch is key to achieve desirable etch efficacy and selectivity at the atomic scale. This paper presents a generalized methodology, combining thermodynamic assessment and kinetic verification of surface reactions, using copper, magnetic metals, and noble metals as examples, in an effort to demonstrate the applicability of this strategy in tailoring plasma–surface interactions at the atomic scale for a wide range of materials.

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High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma

Cited by 17 publications

References 16 publications

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Influence of O₂Gas on Etch Profile of Magnetic Tunnel Junction Stacks Etched in a CH₄/O₂/Ar Plasma

Review Article: Plasma–surface interactions at the atomic scale for patterning metals

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High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma

Cited by 17 publications

References 16 publications

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture

Influence of O2Gas on Etch Profile of Magnetic Tunnel Junction Stacks Etched in a CH4/O2/Ar Plasma

Review Article: Plasma–surface interactions at the atomic scale for patterning metals

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Influence of O₂Gas on Etch Profile of Magnetic Tunnel Junction Stacks Etched in a CH₄/O₂/Ar Plasma