Filling of Sub-µm Through-holes by Self-sputter Deposition

Asamaki, Tatsuo; Miura, Tsutomu; Takagi, Akira; Mori, Ryuji; Hirata, Keiji

doi:10.1143/jjap.33.4566

Cited by 14 publications

(5 citation statements)

References 13 publications

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“…Sputtering is an alternative to electroplating as a Cu filling method. [8][9][10][11][12][13] Sputtering has the advantages of producing highly reliable results since the era of Al wiring and being accomplished with equipment that is easy to operate. Even now, it is used to form trench barrier layers 14,15) and Cu seed layers.…”

Section: Introductionmentioning

confidence: 99%

Cu filling of 10 nm trenches by high-magnetic-field magnetron sputtering

Itoh

Uhara

Saito

2014

Jpn. J. Appl. Phys.

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Ru and Cu sputterings were performed with two different high-vacuum sputtering systems. The Ru sputtering was performed by high-vacuum sputtering. On the other hand, the Cu sputtering was performed by high-magnetic-field sputtering. High-magnetic-field sputtering, which entails a Cu deposition rate of 80 nm/min (target-substrate distance: 200 mm) at a sputtering pressure of 7 ' 10 %2 Pa, is used for the Cu filling of 10-nmwide Ru-lined trenches with an aspect ratio of 6.5. The complete Cu filling of trenches is accomplished within 1 min of sputtering time using a 1 at. % N 2 -Ar sputtering gas. The reason for the complete Cu filling is considered in terms of the capillary theory, focusing on the wettability of Cu on Ru. The improvement in Cu wettability with the use of a N 2 additive is also evaluated in terms of the contact angle for Cu on Ru and surface shape.

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Section: Introductionmentioning

confidence: 99%

Cu filling of 10 nm trenches by high-magnetic-field magnetron sputtering

Itoh

Uhara

Saito

2014

Jpn. J. Appl. Phys.

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“…To solve these problems, the PVD technology has been continuously improved for a long time. [4][5][6][7][8][9][10][11][12][13] To obtain a high bottom and side coverage, it is necessary to increase the ionization ratio, and then a self-ionization sputtering (SIS) method has been developed because Ar gas is not injected during the sputtering process and the discharge is maintained only by Cu atoms. Recently, Sakamoto et al have reported that the number of Cu ions incident to the substrate was increased by magnetic-field-assisted ionized sputtering (MFIS) and the step coverage and asymmetric profile were improved.…”

Section: Introductionmentioning

confidence: 99%

Performance of Integrated Cu Gap-Filling Process with Chemical Vapor Deposition Cobalt Liner

Kokaze¹,

Kodaira²,

Endo³

et al. 2013

Jpn. J. Appl. Phys.

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Cu interconnects are used in semiconductor devices and their dimensions are downscaled markedly. Cu interconnects are fabricated by a damascene process, and it becomes difficult to fill Cu into trenches and vias structures by electroplating below the 20 nm feature size. We evaluated the process integration for Cu interconnects using a Co wetting layer by chemical vapor deposition (CVD), a Cu seed by magnetic-field-assisted ionized sputtering (MFIS) and a Cu reflow technique. The properties of a CVD-Co film, such as composition, resistivity, step coverage, and adhesion between Cu and Co, were investigated. By using CVD-Co as the wetting layer, the properties of Cu gap filling in a trench structure were improved, and the filling of Cu into a 14-nm-wide trench structure was achieved.

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“…[1][2][3][4][5][6][7] In this process, the Ar was only used for ignition and was shut off afterwards. Magnetron sputter deposition is widely used for metal deposition due to its simplicity, low cost, and high purity.…”

Section: Introductionmentioning

confidence: 99%

Deposition of copper by using self-sputtering

Fu¹,

Ding²,

Dorleans³

et al. 1999

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

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A magnetron sputtering source using sustained self-sputtering has been developed for uniform deposition of copper on large wafers ͑200 mm in diameter͒. Usually, Ar gas is used in sputter deposition. In sustained self-sputtering, no Ar gas was used for deposition, the sputtered Cu atoms were ionized in the magnetron plasma, and some Cu ions were accelerated to sputter more Cu atoms out of the target. In this work, the magnetron was optimized to allow sustained self-sputter deposition of Cu on 200 mm wafers with reasonable power ͑9-12 kW͒. When sputtering a target of 325 mm in diameter, the minimum power density to sustain plasma without using Ar gas was found to be 10.8 W/cm 2 . This was much lower than the threshold power density reported in the literature. A chamber employing a large spacing between the target and wafer ͑16 cm͒ was used. The resulting deposition rate was about 320 nm/min, when a 12 kW of dc power was applied. The standard deviation in film thickness was less than 2.5% in our limited experiments. The pressure during sputtering was less than 4ϫ10 Ϫ4 Pa. In comparison with Ar sputtering at an Ar pressure of 0.13 Pa, the bottom coverage, defined by the ratio of film thickness on the trench bottom to the film thickness on the open field area, was increased by about 20% by using sustained self-sputtering. The bottom coverage can be further increased when the throw distance is increased. However, we did not observe significant enhancement of bottom coverage by applying dc and rf biases to the wafer during sustained self-sputtering, although about 20% of Cu species arriving at the wafers was ionized.

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Filling of Sub-µm Through-holes by Self-sputter Deposition

Cited by 14 publications

References 13 publications

Cu filling of 10 nm trenches by high-magnetic-field magnetron sputtering

Cu filling of 10 nm trenches by high-magnetic-field magnetron sputtering

Performance of Integrated Cu Gap-Filling Process with Chemical Vapor Deposition Cobalt Liner

Deposition of copper by using self-sputtering

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