Study of the influence of gas chemistry on notching in metal etching

Tabara, Suguru

doi:10.1116/1.589861

Cited by 3 publications

(5 citation statements)

References 8 publications

(3 reference statements)

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“…As discussed in the introduction, a possible mechanism of the sidewall attack is the surface charging or ion trajectory distortion. 12,14 However, this mechanism does not apply to this case because the Ni/Pd hard mask and the thick Cu layer are conductors that do not accumulate electrons on the sidewall. The mouse bites are probably caused by excessive Cl reaction near the bottom interface.…”

Section: Resultsmentioning

confidence: 96%

“…11 The local sidewall attack, i.e., "notching," is a serious problem in plasma etching of metals. [12][13][14] There are several possible reasons for the notch formation. For example, neutral radicals in the plasma phase can impinge the wafer surface obliquely, which results in excessive attack of the sidewall.…”

mentioning

confidence: 98%

“…The upper part of the photoresist sidewall can be negatively charged due to trapping of electrons generated in the plasma phase, which distorts the trajectory of the incident ions and intensifies the ion bombardment at the bottom sidewall to form the notch. 12 It was also reported that the stress at the filmfilm interface could induce spontaneous etching and cause sidewall notch. 15 The sidewall attack can be reduced by adjusting the plasmaphase chemistry.…”

mentioning

confidence: 98%

“…For example, in aluminum ͑Al͒ etch, by reducing BCl 3 ratio in Cl 2 /BCl 3 plasma, the heavy ion concentration was reduced, which resulted in less sidewall attack. 12 By lowering the reactive radical concentration, the sidewall attack can be reduced. A notch-free Al pattern was obtained in the HCl/He plasma in which the Cl concentration was lowered by the He diluent and H scavenge effect.…”

mentioning

confidence: 99%

“…A notch-free Al pattern was obtained in the HCl/He plasma in which the Cl concentration was lowered by the He diluent and H scavenge effect. 12 Another way of reducing the sidewall attack is to form a passivation layer on the sidewall surface. The introduction of CH 4 into the Cl 2 plasma promoted the formation of a polymeric surface layer which resulted in a smooth sidewall.…”

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confidence: 99%

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Additive-Gas Effects on Cl[sub 2] Plasma-Based Copper-Etch Process and Sidewall Attack

Liu

Kuo

2008

J. Electrochem. Soc.

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The influence of the additive gas in Cl 2 plasma-based copper etch and sidewall attack was investigated. The additive gas, such as Ar, N 2 , and CF 4 , drastically changed the plasma-phase chemistry, i.e., the Cl radical concentration, and the ion-bombardment energy, which resulted in changes of the copper chlorination rate and the sidewall roughness. The addition of Ar increased the Cl concentration, which increased the copper chlorination rate and the sidewall attack. The addition of N 2 enhanced ion bombardment, which increased the copper chlorination rate. Meanwhile, the addition of N 2 diluted the Cl concentration and formed a copper nitride passivation layer, which protected the sidewall and reduced roughness. The addition of CF 4 induced a fluorocarbon passivation layer, which decreased the copper chlorination rate in the vertical direction but protected the sidewall from vigorous Cl attack and resulted in a smooth sidewall surface. Therefore, the additive gas not only affected the Cu chlorination rate but also influenced sidewall roughness.

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Section: Resultsmentioning

confidence: 96%

mentioning

confidence: 98%

mentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Additive-Gas Effects on Cl[sub 2] Plasma-Based Copper-Etch Process and Sidewall Attack

Liu

Kuo

2008

J. Electrochem. Soc.

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Notching Effect on Metal Etch: A Very Simple Predictive Model

Garozzo

Beffumo

Magna

2005

IEEE Trans. Semicond. Manufact.

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Process effects of copper film over a step etched with a plasma-based process

Lin

Kuo

2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The additive gas effect of a new plasma-based process for etching the copper film over a dielectric step has been investigated. The addition of different gases, such as Ar, N 2 , and CF 4 , affected the copper vertical and lateral conversion rates, which are critical to the attack of the cusp region and the sidewall as well as the residue formation. This is due to changes of plasma phase chemistry and ion bombardment energy. Excessive attacks of the cusp region and the sidewall were observed when the chlorine radical concentration was high except for the short plasma exposure time or the sidewall passivation condition. When the slope angle of the dielectric step was small, the cusp structure of the copper film was barely visible; therefore, the excessive plasma attack of the cusp region was negligible. A two step etch process that minimizes excessive attacks of the cusp region and the sidewall as well as the residue formation has been developed. This new process is critical to the practical application of copper in microelectronic products.

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Study of the influence of gas chemistry on notching in metal etching

Cited by 3 publications

References 8 publications

Additive-Gas Effects on Cl[sub 2] Plasma-Based Copper-Etch Process and Sidewall Attack

Additive-Gas Effects on Cl[sub 2] Plasma-Based Copper-Etch Process and Sidewall Attack

Notching Effect on Metal Etch: A Very Simple Predictive Model

Process effects of copper film over a step etched with a plasma-based process

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