A Method for Copper Film Deposition with Cl[sub 2] Plasma

Sakamoto, Hitoshi; Ogura, Yuzuru; Ooba, Y.; Nishimori, Toshihiko; Yahata, Naoki

doi:10.1149/1.1645264

Cited by 10 publications

(14 citation statements)

References 11 publications

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“…By analogy with previous studies of Cu CVD with MCR, 8,9 we tentatively assume the gas reactions as follows Cl radical generation: Cl 2 ! 2Cl Ã [1] WClx generation: xCl Ã þ W !…”

Section: Methodsmentioning

confidence: 99%

“…In MCR-CVD, it is likely that the Cl radical etches solid metal at higher temperatures while it reduces the metal chloride at lower temperatures. [8][9][10][11][12] In the present work, the temperature difference of the solid W (800 C) and the substrate ($ 500 C) enables the continuous W deposition on the substrate. The film crystallinity of the grown W film was evaluated by xray diffraction.…”

Section: Methodsmentioning

confidence: 99%

“…5 In the field of Cu CVD for metal wiring in the LSI production, on the other hand, Sakamoto et al developed a unique metal CVD using metal chloride reduction (MCR). [8][9][10][11][12] In this process, bulk metal is exposed to Cl radicals to produce metal chloride species in the reaction chamber. The metal chloride species are delivered as gas molecules to the wafer to be reduced by the additional Cl radicals, where the pure metal film is grown on the surface.…”

mentioning

confidence: 99%

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Tungsten Deposition by Metal-Chloride-Reduction Chemical Vapor Deposition

Hirose

Watanabe

Shibata

et al. 2011

Electrochem. Solid-State Lett.

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We successfully developed a fluorine-free tungsten deposition technique on a Si substrate at a substrate temperature in the range from 450 to 520 C by metal chloride reduction chemical vapor deposition (MCR-CVD). In this process, we first prepared a tungsten coil as a source material that can be heated by passing a current directly in itself at a temperature of 800 C. In a reaction chamber, the heated tungsten coil is exposed to RF excited Cl radicals to produce W chlorides to be delivered to the Si substrate. The adsorbed W chlorides are reduced to W by the Cl radical and a W film is grown on the Si surface. The residual Cl and F levels in the deposited W film were measured under the detection limit by x-ray photoelectron spectroscopy. The deposited W exhibited very low resistivity in the order of 10 À5 X cm. The film conformality was examined using a trench-filling experiment, which suggests the suitability of the present process for the plug filling in VLSI production.Recent years due to the strong demands for higher integration in large scale integration (LSI), metal deposition has been developed as a plug filling process for interlayer connecting. W chemical vapor deposition (CVD) is extensively studied for the plug filling as W has a relatively good electrical conductivity and a high electromigration durability due to its high melting point of 3380 C. The conventional method was CVD with a precursor of WF 6 and reducing agents of In case of the W CVD using WF 6 , however, difficulties of interfacial Si consumption and corrosion of devices by HF gas as a byproduct have been reported. 5 To avoid the corrosion, all the surface to be protected should be coated with a barrier metal of TiN although this additional process is a disadvantage in the production cost. To avoid the byproduct, metal organic precursors have been investigated, though the deposited film exhibited unacceptably high resistivity due to the residual carbon in the film. 6 Ammerlaan et al. have reported a W CVD with tungsten hexachloride (WCl 6 ) with H 2 reduction in a temperature range 480-670 C, where deficiencies in the film uniformity and reproducibility were indicated. 7 Lai et al. investigated W deposition from W(CO) 6 using a low-pressure CVD at 375 C, though the film resistivity was still more than 1000 X cm, that is much higher than the W bulk resistivity of 5.6 X cm. 5 Additional vacuum annealing at 900 C was necessary to reduce the resistivity down to 19 X cm. 5 In the field of Cu CVD for metal wiring in the LSI production, on the other hand, Sakamoto et al. developed a unique metal CVD using metal chloride reduction (MCR). [8][9][10][11][12] In this process, bulk metal is exposed to Cl radicals to produce metal chloride species in the reaction chamber. The metal chloride species are delivered as gas molecules to the wafer to be reduced by the additional Cl radicals, where the pure metal film is grown on the surface. Since this process requires no organic precursors, the source material cost is very cheap. MCR-CVD has been applied to...

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“…By analogy with previous studies of Cu CVD with MCR, 8,9 we tentatively assume the gas reactions as follows Cl radical generation: Cl 2 ! 2Cl Ã [1] WClx generation: xCl Ã þ W !…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Tungsten Deposition by Metal-Chloride-Reduction Chemical Vapor Deposition

Hirose

Watanabe

Shibata

et al. 2011

Electrochem. Solid-State Lett.

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show abstract

“…In order to achieve copper interconnection of minimized scale, a novel CVD method called metal chloride reduction-chemical vapor deposition (MCR-CVD) has been under development [2,3]. Raw materials needed in the MCR-CVD process are only copper block and chlorine gas, therefore copper films can be fabricated at very low cost.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, deposited copper films have some problems which need to be improved, even if their purities are sufficient. For example, surface morphology of copper films deposited by MCR-CVD is grain-like [3]. Information of reaction mechanisms is required for improvement of film properties.…”

Section: Introductionmentioning

confidence: 99%