Damage-free selective etching of Si native oxides using NH3/NF3 and SF6/H2O down-flow etching

Nishino, Hirotaka; Hayasaka, N.; Okano, Haruo

doi:10.1063/1.354890

Cited by 80 publications

(65 citation statements)

References 12 publications

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“…The NH 4 ϩ salt layer is not deposited, but rather converted from the silicon nitride film. This film is water soluble, Nishino et al 9 also reported that NH 4 ϩ and SiF 6 2Ϫ peaks were observed in infrared spectra from deposited films on an oxide surface after NF 3 /NH 3 microwave down-flow etching, and proposed ͑NH 4 ͒ 2 SiF 6 as the deposited film.…”

Section: E Nh 3 Flow Ratementioning

confidence: 92%

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Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Wang¹,

Luo²

1998

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

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A very high-selectivity silicon nitride etch process has been developed on an inductively coupled plasma etching system which uses a NF3/O2/NH3 (nonchlorine) chemistry. Etch selectivity of low-pressure chemical vapor deposition nitride to thermal oxide greater than 100:1 was achieved at a nitride etch rate of 500 Å/min. A NF3/O2 chemistry was optimized for nitride to oxide selectivity of about 12:1, with a nitride etch rate of 1200 Å/min. The addition of NH3 inhibits oxide etching thus enhancing selectivity. The net etch rate for oxide may be reduced to zero while maintaining a reasonably high etch rate for nitride thus resulting in essentially infinite selectivity. The process is stable, repeatable and creates no particles. A split lot test on device wafers against standard wet etch process demonstrates superior process and device performance.

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Section: E Nh 3 Flow Ratementioning

confidence: 92%

“…Knolle et al 8 and Nishino et al 9 The deposited films were found soluble in deionized water. Because our process conditions and postetch properties are similar to Knolle's and Nishino's, the NH 4 ϩ salt film on our wafers are assigned to ͑NH 4 ͒ 2 SiF 6 .…”

Section: E Nh 3 Flow Ratementioning

confidence: 98%

Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Wang¹,

Luo²

1998

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

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“…This process was originally conceived as a continuous etching process, with the salt formation simultaneous with heating. 110 The difference in ALE is that the salt formation and heating are separated self-limiting reaction steps.…”

Section: Oxidesmentioning

confidence: 99%

Overview of atomic layer etching in the semiconductor industry

Kanarik¹,

Lill²,

Hudson³

et al. 2015

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

484

372

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Atomic layer etching (ALE) is a technique for removing thin layers of material using sequential reaction steps that are self-limiting. ALE has been studied in the laboratory for more than 25 years. Today, it is being driven by the semiconductor industry as an alternative to continuous etching and is viewed as an essential counterpart to atomic layer deposition. As we enter the era of atomic-scale dimensions, there is need to unify the ALE field through increased effectiveness of collaboration between academia and industry, and to help enable the transition from lab to fab. With this in mind, this article provides defining criteria for ALE, along with clarification of some of the terminology and assumptions of this field. To increase understanding of the process, the mechanistic understanding is described for the silicon ALE case study, including the advantages of plasma-assisted processing. A historical overview spanning more than 25 years is provided for silicon, as well as ALE studies on oxides, III–V compounds, and other materials. Together, these processes encompass a variety of implementations, all following the same ALE principles. While the focus is on directional etching, isotropic ALE is also included. As part of this review, the authors also address the role of power pulsing as a predecessor to ALE and examine the outlook of ALE in the manufacturing of advanced semiconductor devices.

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“…Previous studies have shown that H 2 plasmas can sputter quartz causing the oxygen seen on the surface to increase (19)(20)(21). To test if chemical etching from the pure H 2 was causing the increase in oxidized silicon, pure H 2 was switched for a mixture of 5% H 2 in Ar since this was expected to reduce the density of energetic H atoms colliding with the plasma tube; however, this introduced the possibility of physical sputtering of the sapphire tube or aluminum chamber/flange by Ar ions, as the sputtering capability of Ar ions has been well documented in literature (22)(23)(24).…”

Section: Resultsmentioning

confidence: 99%

(Invited) Rapid In-Situ Carbon and Oxygen Cleaning of In_0.53Ga_0.47As(001) and Si_0.5Ge_0.5(110) Surfaces via a H₂ RF Downstream Plasma

Wolf

Edmonds

Jiang³

et al. 2016

ECS Trans.

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The In0.53Ga0.47As(001) and Si0.5Ge0.5(110) surfaces were cleaned using a downstream RF plasma. On the air-exposed In0.53Ga0.47As(001) surface, a 2 second 100 millitorr H2 plasma dose fully removed carbon and oxygen. On the ex-situ wet cleaned Si0.5Ge0.5(110) surface, nearly all carbon and oxygen are removed via a 2 second exposure of 5% H2 in Ar plasma. To prevent oxygen deposition from the plasma tube while maximizing the atomic H flux, for Si0.5Ge0.5(110), the plasma power, pressure, and gas composition must be controlled. The Si0.5Ge0.5(110) surface is more sensitive than the In0.53Ga0.47As(001) surface to trace oxygen in the plasma stream consistent with the higher heat of formation per Si of SiO2 than the heat of formation per Ga of Ga2O3. The higher heat of formation of SiO2 is expected to both increase oxygen adsorption and prevent the atomic H from forming volatile products with SiO2 on Si0.5Ge0.5(110), in contrast to In0.53Ga0.47As(001).

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Damage-free selective etching of Si native oxides using NH3/NF3 and SF6/H2O down-flow etching

Cited by 80 publications

References 12 publications

Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Overview of atomic layer etching in the semiconductor industry

(Invited) Rapid In-Situ Carbon and Oxygen Cleaning of In_0.53Ga_0.47As(001) and Si_0.5Ge_0.5(110) Surfaces via a H₂ RF Downstream Plasma

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Damage-free selective etching of Si native oxides using NH3/NF3 and SF6/H2O down-flow etching

Cited by 80 publications

References 12 publications

Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Ultrahigh-selectivity silicon nitride etch process using an inductively coupled plasma source

Overview of atomic layer etching in the semiconductor industry

(Invited) Rapid In-Situ Carbon and Oxygen Cleaning of In0.53Ga0.47As(001) and Si0.5Ge0.5(110) Surfaces via a H2 RF Downstream Plasma

Contact Info

Product

Resources

About

(Invited) Rapid In-Situ Carbon and Oxygen Cleaning of In_0.53Ga_0.47As(001) and Si_0.5Ge_0.5(110) Surfaces via a H₂ RF Downstream Plasma