Thermal stability of grain structure for Ag nanotwinned films sputtered with substrate bias

Lai, Yu-Chang; Wu, Po‐Ching; Chuang, Tung‐Han

doi:10.1016/j.mtla.2021.101215

Cited by 7 publications

(4 citation statements)

References 27 publications

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“…Chuang et al reported that a (002) Ti adhesive layer not only enhances the bonding strength between a metallic film and Si substrate but also alleviates the lattice mismatch, allowing the epitaxial growth of nanotwinned Ag films on Si substrates, which in turn decreases the thickness of the transition layer [26]. Lai also reported that a thicker transition layer tends to have poorer thermal stability due to the tendency of grain growth of the random grains to replace the Ag nanotwinned structure, especially at high temperatures [27]. The above studies aimed to decrease the thickness of the transition layer and optimize highdensity nanotwinned films with a strong (111) surface orientation, but few studies have considered the optimization of nanotwinned films in the sputtering process.…”

Section: Introductionmentioning

confidence: 99%

Ultra-Thin Cu Nano-Twinned Films Sputtered On Si Wafers for Low Temperature Hybrid Bonding Of Advanced 3D-IC Packages

Yang,

Chen,

Chen

et al. 2024

IJMMME

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The nanotwinned structure has been attracting a great deal of attention due to its excellent mechanical and electrical properties. In this study, ultra-thin nanotwinned Cu (nt-Cu) films with a thickness of 1.5 μm were fabricated by DC magnetron sputtering with moderate substrate bias. Within these films, an equiaxed-grain transition layer only 100-400 nm thick formed between the nanotwinned region and Si substrate and was observed by focused ion beam (FIB). The XRD and EBSD analyses indicated that the as-deposited nanotwinned films had a strong (111) preferred orientation. The surface roughness of the films, as measured with an atomic force microscope (AFM), was below 10 nm, which was sufficiently smooth for chip bonding at low temperature with minor pressure. Direct bonding of Si chips sputtered with such ultra-thin nt-Cu films with a (111) preferred orientation has been evidenced to yield a sound interface, and this bonding method can be applied for the manufacturing of 3D-IC packages.

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Section: Introductionmentioning

confidence: 99%

Ultra-Thin Cu Nano-Twinned Films Sputtered On Si Wafers for Low Temperature Hybrid Bonding Of Advanced 3D-IC Packages

Yang,

Chen,

Chen

et al. 2024

IJMMME

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show abstract

“…It is proved that the Ti adhesive layer not only enhances the bonding strength between the nanotwinned film and Si substrate but also reduces the lattice mismatch for the epitaxial growth of nanotwinned Ag films on Si substrates as well as the proportion of transition layer. In addition, the film with a thinner transition layer tends to possess better thermal stability, which is attributed to the fact that there would be fewer random grains replacing the nanotwinned structure, especially at high temperatures [23] [24]. Moreover, applying negative bias voltages during sputtering can facilitate the formation of dense nanotwinned columnar structures, lower the transition layer thickness, enhance (111) texture, and increase indentation hardness due to the Ar + ion bombardment effect [25].…”

Section: Introductionmentioning

confidence: 99%

Sputtering of Ultra-thin Ag Nano-twinned Films on Si Wafers for the Applications in TSV Interconnection of 3D-IC Advanced Packages Copper Solvent Extraction

Chen,

Yang,

Chen

et al. 2023

Proceedings of the 9th World Congress on Mechanical, Chemical, and Material Engineering

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Nanotwinned structure has been attracting a great deal of attention due to their excellent mechanical and electrical properties. In this study, ultra-thin nanotwinned Ag films can be fabricated by DC magnetron sputtering with moderate substrate bias. Within these nanotwinned films, only 100-400 nm thick equiaxed-grin transition layer was formed between the nanotwinned region and Si substrate observed by Focused ion Beam (FIB). For the analysis of nanotwinned films, the as-deposited films are shown to have a strong (111) preferred orientation. The roughness of the films was observed below 10 nm, which was smooth enough and acceptable for metal direct bonding. Ag-to-Ag direct bonding was then performed to satisfy the requirement of TSV interconnections. The ultra-thin nanotwinned Ag films with (111) preferred orientation will have many potential applications in interconnects and 3D IC packaging.

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“…Chuang et al reported that the (002) Ti adhesive layer not only enhances the bonding strength between a metallic film and Si substrate but also alleviates the lattice mismatch, allowing the epitaxial growth of nanotwinned Ag films on Si substrates, which in turn decreases the thickness of the transition layer [26]. Lai also reported that a thicker transition layer tends to have poorer thermal stability due to the tendency of grain growth of the random grains to replace the Ag nanotwinned structure, especially at high temperatures [27]. The above studies aimed to decrease the thickness of the transition layer and optimize high-density nanotwinned films with a strong (111) surface orientation, but few studies have considered the optimization of nanotwinned films in the sputtering process.…”

Section: Introductionmentioning

confidence: 99%

Sputtering of Ultra-thin Cu Nano-twinned Films on Si Wafers for Application in Advanced 3D-IC Packaging

Yang,

Chuang

2023

Proceedings of the 9th World Congress on Mechanical, Chemical, and Material Engineering

View full text Add to dashboard Cite

The nanotwinned structure has been attracting a great deal of attention due to its excellent mechanical and electrical properties. In this study, ultra-thin nanotwinned Cu (nt-Cu) films with a thickness of 1.5 um were fabricated by DC magnetron sputtering with moderate substrate bias. Within these films, an equiaxed-grain transition layer only 100-400 nm thick was formed between the nanotwinned region and Si substrate and observed by focused ion beam (FIB). The XRD and EBSD analyses indicated that the as-deposited nanotwinned films had a strong (111) preferred orientation. The surface roughness of the films, as measured with an atomic force microscope (AFM), was below 10 nm, which was sufficiently smooth for chip bonding at low temperature with minor pressure. Direct bonding of Si chips sputtered with such ultra-thin nt-Cu films with (111) preferred orientation has been evidenced to yield a sound interface, and this bonding method can be applied for the manufacturing of 3D-IC packages.

show abstract

Thermal stability of grain structure for Ag nanotwinned films sputtered with substrate bias

Cited by 7 publications

References 27 publications

Ultra-Thin Cu Nano-Twinned Films Sputtered On Si Wafers for Low Temperature Hybrid Bonding Of Advanced 3D-IC Packages

Ultra-Thin Cu Nano-Twinned Films Sputtered On Si Wafers for Low Temperature Hybrid Bonding Of Advanced 3D-IC Packages

Sputtering of Ultra-thin Ag Nano-twinned Films on Si Wafers for the Applications in TSV Interconnection of 3D-IC Advanced Packages Copper Solvent Extraction

Sputtering of Ultra-thin Cu Nano-twinned Films on Si Wafers for Application in Advanced 3D-IC Packaging

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