A study on the plating and wetting ability of ruthenium-tungsten multi-layers for advanced Cu metallization

Tai Chen Kuo, Yin Hsien Su, Wen-Shi Lee, Wei Hsiang Liao, Yu Sheng Wang, Chi Cheng Hung, Ying Lang Wang

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In this study, the plating and wetting ability of Cu/Ruthenium-Tungsten (RuW)/silicon oxide (SiO 2 ) multi-layer stacks were investigated. RuW alloy films were prepared on a SiO 2 layer by sputtering, followed by a deposition of a Cu thin film by electro-plating. Scanning electron microscopy (SEM) top view images shows that Cu films can be electroplated on RuW, with smaller Cu nuclei size but in a more highly concentrated and uniform distribution than Cu films electroplated on Ta or TaN. The rate of Cu nucleation decreases and larger Cu clusters were formed on the RuW alloy films with increasing W content. Cu/RuW/SiO 2 samples were annealed at 400 °C for 30 min and then characterized using SEM. There were fewer pin holes on the surface of a pure Cu/Ru stack compared to Cu/RuW multilayers. Cu/RuW/SiO 2 multi-layers had fewer pin holes than Cu/Ta/SiO 2 structures processed under similar conditions. The wetting angle, measured by SEM, of Cu on a RuW substrate (43°) was still lower than that of Cu on a Ta substrate (123°), which suggests that the adhesion strength of Cu onto RuW alloy is better than that onto Ta. Preliminary studies of Cu diffusion through 25 nm RuW layers at 650 °C showed no Cu penetration into the underlying Si in a Cu/RuW/Si multi-layer test structure.

Original languageEnglish
Pages (from-to)27-33
Number of pages7
JournalMicroelectronic Engineering
Volume162
DOIs
Publication statusPublished - 2016 Aug 16

Fingerprint

Tungsten
Ruthenium
Metallizing
plating
Plating
ruthenium
wetting
Wetting
tungsten
Scanning electron microscopy
scanning electron microscopy
Bond strength (materials)
Silicon oxides
Substrates
tungsten oxides
Sputtering
Multilayers
silicon oxides
Nucleation
adhesion

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

Cite this

Kuo, Tai Chen ; Su, Yin Hsien ; Lee, Wen-Shi ; Liao, Wei Hsiang ; Wang, Yu Sheng ; Hung, Chi Cheng ; Wang, Ying Lang. / A study on the plating and wetting ability of ruthenium-tungsten multi-layers for advanced Cu metallization. In: Microelectronic Engineering. 2016 ; Vol. 162. pp. 27-33.
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A study on the plating and wetting ability of ruthenium-tungsten multi-layers for advanced Cu metallization. / Kuo, Tai Chen; Su, Yin Hsien; Lee, Wen-Shi; Liao, Wei Hsiang; Wang, Yu Sheng; Hung, Chi Cheng; Wang, Ying Lang.

In: Microelectronic Engineering, Vol. 162, 16.08.2016, p. 27-33.

Research output: Contribution to journalArticle

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