The effect of substrate temperature on the etching properties and the etched surfaces of magnetic tunnel junction materials in a CH3OH inductively coupled plasma system

Lee, Minsuk; Lee, Won-Jong

doi:10.1016/j.apsusc.2012.05.003

Cited by 16 publications

(10 citation statements)

References 16 publications

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“…The micrometer structures are mainly manufactured by shadow mask inductively coupled plasma (ICP) and gray scale lithography. But mask ICP etching needs a special mask during the etching process [10]. Compared with femtosecond laser writing and ICP etching, gray scale lithography has the potential for the low-cost fabrication of complex multilevel micro-optical structures.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional polymer waveguide using hybrid lithography

et al. 2015

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A three dimensional polymer waveguide with taper structure was demonstrated and fabricated by a reliable and effective hybrid lithography. The hybrid lithography consists of lithography to fabricate a polymer waveguide and gray scale lithography to fabricate a polymer taper structure. Laser ablation and shadow aluminum evaporation were designed for gray scale lithography. The length of the gray scale region ranging from 20 to 400 μm could be controlled by the laser power, the ablation speed, and the aluminum thickness. The slope angle was determined by the length of the gray scale region and the thickness of the photoresist. The waveguide taper structure could be transferred to the lower layer by the etching method. The taper structure can be used for integration of the waveguide with different dimensions.

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Section: Introductionmentioning

confidence: 99%

Three dimensional polymer waveguide using hybrid lithography

et al. 2015

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“…A previous study on the etching of MTJ materials by the substrate heating to 120 C with CH 3 OH gas in a conventional ICP system showed the increase of etch rates of MTJ materials at the elevated substrate temperature even though they concluded that the increase of MTJ etch rate is more responsible for the formation of pure metal at the elevated temperature than by the formation of volatile and stable etch compounds. 18 In this study, the effect of rf pulse-biasing and substrate heating on the etching of MTJ materials using an ICP system have been studied with a CH 4 /N 2 O gas mixture (after the optimization of the optimum CH 4 :N 2 O ratio). The etch characteristics have been investigated to increase the etch rates and etch selectivities of MTJ materials over mask materials further and to investigate the possibility of forming volatile and more stable etch compounds.…”

Section: Introductionmentioning

confidence: 99%

Etch Characteristics of Magnetic Tunnel Junction Materials Using Bias Pulsing in the CH<SUB>4</SUB>/N<SUB>2</SUB>O Inductively Coupled Plasma

Jeon¹,

Youn²,

Yang³

et al. 2014

j nanosci nanotechnol

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The etch characteristics of magnetic tunneling junction (MTJ) related materials such as CoFeB, MgO, FePt, Ru, and W as hard mask have been investigated as functions of rf pulse biasing, substrate heating, and CH4/N2O gas combination in an inductively coupled plasma system. When CH4/N2O gas ratio was varied, at CH4/N2O gas ratio of 2:1, not only the highest etch rates but also the highest etch selectivity over W could be obtained. By increasing the substrate temperature, the linear increase of both the etch rates of MTJ materials and the etch selectivity over W could be obtained. The use of the rf pulse biasing improved the etch selectivity of the MTJ materials over hard mask such as W further. The surface roughness and residual thickness remaining on the etched surface of the CoFeB were also decreased by using rf pulse biasing and with the decrease of rf duty percentage. The improvement of etch characteristics by substrate heating and rf pulse biasing was possibly related to the formation of more stable and volatile etch compounds and the removal of chemically reacted compounds more easily on the etched CoFeB surface. Highly selective etching of MTJ materials over the hard mask could be obtained by using the rf pulse biasing of 30% of duty ratio and by increasing the substrate temperature to 200 degrees C in the CH4/N2O (2:1) plasmas.

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“…[13][14][15][16] Various etch gases that possibly form volatile etch compounds with MTJ-related materials have been studied by some research groups to improve the etch selectivity and etch profile. [16][17][18][19] Other research groups have studied etch techniques such as pulse-biasing 20 and substrate heating 21 during etching in the RIE system to reduce the redeposited etch residue on the sidewall of the etched feature by increasing reactivity Delivered by Ingenta to: Sung Kyun Kwan University IP: 115.145.196.174 On: Tue, 01 Nov 2016 07:00:24…”

Section: Introductionmentioning

confidence: 99%

Etching of Magnetic Tunnel Junction Materials Using Reactive Ion Beam

Hwan¹,

Chae²,

Woo³

et al. 2016

j nanosci nanotechnol

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Magnetic tunnel junction (MTJ) materials such as CoPt, CoFeB, and MgO and the hard mask material such as W were etched with a reactive ion beam system using Ar, NF 3 , CH 3 OH, and CO/NH 3 as etch gases. The effects of etch gas and the energy of the ion beam on the etch characteristics were then investigated. When the MTJ materials were etched with an Ar ion beam, the etch selectivities of the MTJ materials over W and the etch profiles of the etched MTJ patterns masked with W were generally poor, possibly due to the nonselective etching, physical sputtering without chemical reaction, and severe redeposition of the nonvolatile etch residues on the sidewall of the etched features. The use of NF 3 → CH 3 OH → CO/NH 3 reactive ion beam showed better etch selectivities over W and better etch profiles due to the higher etch selectivities of MTJ materials over W and less sidewall deposition. For reactive gases such as CH 3 OH and CO/NH 3 , the use of higher ion energy by increasing the 1st grid voltage of the ion beam up to +250 V also improved the MTJ etch profiles, possibly due to the increased effective chemical assisted physical sputtering of the etch products and the minimization of sidewall etch residues by removing etch products more effectively.

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The effect of substrate temperature on the etching properties and the etched surfaces of magnetic tunnel junction materials in a CH3OH inductively coupled plasma system

Cited by 16 publications

References 16 publications

Three dimensional polymer waveguide using hybrid lithography

Three dimensional polymer waveguide using hybrid lithography

Etch Characteristics of Magnetic Tunnel Junction Materials Using Bias Pulsing in the CH<SUB>4</SUB>/N<SUB>2</SUB>O Inductively Coupled Plasma

Etching of Magnetic Tunnel Junction Materials Using Reactive Ion Beam

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