Co-sputtered Cu(Ti) thin alloy film for formation of Cu diffusion and chip-level bonding

Lin, Ping; Chen, Hao; Hsieh, Hsien Chien; Tseng, Tsan Hsien; Lee, Hsin Yi; Wu, Albert T.

doi:10.1016/j.matchemphys.2018.01.043

Cited by 9 publications

(7 citation statements)

References 15 publications

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“…All annealed Ti-Cu coatings show more obvious particles on their surfaces compared to as-deposited Ti-Cu coatings. Noncontiguous hillocks or islands are probably formed at 300 • C, and then grow up and form continuous hillocks or islands with clear boundaries after annealing at 400-500 • C. A similar phenomenon has been reported by Po Chen Lin, who found that annealing Cu (Ti) coatings with copper content of 62 at.% at 400 • C results in the formation of islands followed by their growth to form continuous Cu-rich layers [34]. Figure 7 shows the surface morphology and the corresponding root mean squared surface roughness (R q ) for the as-deposited and annealed Ti-Cu coatings deposited on Si substrates.…”

Section: Surface Morphologysupporting

confidence: 76%

“…Using kinetic calculations, it has previously been reported that the diffusion of Ti is faster than that of Cu [34]. Tsukimoto et al reported that the Ti atoms diffused to the coating-SiO 2 interfaces and surface of Cu (Ti) coatings form a self-formed supersaturated Ti diffusion barrier after aging treatment at 400 • C [25].…”

Section: Surface Chemistry and Structural Analyses Of Ti-cu Coatingsmentioning

confidence: 99%

“…It has been reported that the resistivity values of TiO compounds is 2.6 × 10 −6 Ω•m [42], which is close to that of the as-deposited Ti-Cu coating. The formation of non-stoichiometric titanium oxides such as TiO or Ti 3 O is the main factor influencing the resistivity of the Ti-Cu coatings annealed at 500 • C. It has also been shown that the Ti atoms segregate on the surfaces and lead to a decrease in the resistivity for the Cu (Ti) coatings annealed at 400 • C [34]. Besides, the annealing process can reduce the non-equilibrium defects and metastable structure, resulting in the increase of the conductivity of free electrons and decrease of the resistivity [43,44].…”

Section: Electrical Resistivity Of Ti-cu Coatingsmentioning

confidence: 99%

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Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Qin

et al. 2020

Coatings

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Titanium-copper (Ti–Cu) coatings have attracted extensive attention in the surface modification of industrial and biomedical materials due to their excellent physical and chemical properties and biocompatibility. Here, Ti–Cu coatings are fabricated using a combination of high-power pulsed magnetron sputtering (HPPMS; also known as high power impulse magnetron sputtering (HiPIMS)) and DC magnetron sputtering followed by vacuum annealing at varied temperatures (300, 400, and 500 °C). X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) data showed that Ti, Cu, and CuTi3 are mainly formed in the coatings before annealing, while Ti3O, Cu2O, and CuTi3 are the main compounds present in the annealed coatings. The cross-sectional TEM micrographs and corresponding EDS results provided evidence that Ti is mainly present on the surface and interfaces of the silicon substrate and the Ti–Cu coatings annealed at 500 °C, while the bulk of the coatings is enriched with Cu. The resistivity of the coatings decreased with increasing the annealing temperature from 300 to 500 °C. Based on self-corrosion current density data, the Ti–Cu coating annealed at 300 °C showed similar corrosion performance compared to the as-deposited Ti–Cu coating, while the corrosion rate increased for the Ti–Cu coatings annealed at 400 and 500 °C. Stable release of copper ions in PBS (cumulative released concentration of 0.8–1.0 μM) for up to 30 days was achieved for all the annealed coatings. Altogether, the results demonstrate that vacuum annealing is a simple and viable approach to tune the Cu diffusion and microstructure of the Ti–Cu coatings, thereby modulating their electrical resistivity, corrosion performance, and Cu ion release behavior.

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Section: Surface Morphologysupporting

confidence: 76%

Section: Surface Chemistry and Structural Analyses Of Ti-cu Coatingsmentioning

confidence: 99%

Section: Electrical Resistivity Of Ti-cu Coatingsmentioning

confidence: 99%

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Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Qin

et al. 2020

Coatings

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“…The self-formed barrier layer offers low electrical resistivity, resistance to Cu diffusion, resistance to electromigration and compatibility with conformal deposition techniques [16][17][18][19][20][21]. A self-formed barrier scheme is achieved by doping with diffusion barrier elements as well as their nitrides and carbides, such as Ti, Zr, Mn and WN [22][23][24][25][26][27][28]. All these doped elements have low-concentration solutes in Cu, which are supposed to segregate at the interface as a diffusion layer during annealing [16,29].…”

Section: Introductionmentioning

confidence: 99%

Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization

et al. 2022

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The barrier properties and diffusion behavior of Cu(Re) alloy films were studied. The films were deposited onto barrierless SiO2/Si by magnetron sputtering. X-ray diffraction patterns and electric resistivity results proved that the Cu(Re) alloy films without a barrier layer were thermally stable up to 550 °C. Transmission electron microscopy images and energy-dispersive spectrometry employing scanning transmission electron microscopy provided evidence for a self-formed Re-enriched diffusion layer between the Cu(Re) alloy and SiO2/Si substrate. Furthermore, the chemical states of Re atoms at the Cu(Re)/SiO2 interface were analyzed by X-ray photoemission spectroscopy. The self-formed diffusion layer was found to be composed of Re metal, ReO and ReO3. At 650 °C, the Cu(Re) layer was completely destroyed due to atom diffusion. The low electrical resistivity in combination with the high thermal stability suggests that the Cu(Re) alloy could be the ultimate Cu interconnect diffusion barrier.

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“…Moreover, self-forming Cu alloy films are normally deposited by sputtering. [27][28][29][30] During sputtering, free radicals and ultraviolet irradiation generated from vacuum plasma are readily to damage porous SiOCH dielectric materials, subsequently degrading their bonding or dielectric properties. 31,32 Thus, the use of a deposition method that eliminates the plasma damage of p-SiOCH substrates is essential for the implementation of sputter deposition to Cu interconnect fabrication.…”

mentioning

confidence: 99%

Reliability Enhancement of Copper/Porous SiOCH Metallization Systems Using Nitrogen Stuffing and Bias-Filter Sputter Deposited Mn₂O₃ Barrier

Fang¹,

Yu²,

Chen³

et al. 2019

ECS J. Solid State Sci. Technol.

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A robust ultrathin barrier to retard Cu diffusion is needed for fabricating state-of-the-art Cu interconnects associated with porous dielectric materials. Gas stuffing of grain boundaries is widely used to strengthen conventional polycrystalline TiN and TaN barriers. Alternatively, a self-formed MnOx layer derived typically from sputter-deposited Cu(Mn) alloy film is a viable barrier. However, vacuum plasma generated during Cu(Mn) deposition tends to damage porous dielectric materials. Thus, this study combines the two approaches, proposing a strategy to enhance reliability of copper/porous carbon-doped organosilica (p-SiOCH) metallization systems using nitrogen stuffed p-SiOCH and bias-filter sputter deposited Mn2O3. An ultrathin (1–4 nm) Mn2O3 film, deposited by reactive sputtering with a biased-filter mechanism on nitrogen-stuffed p-SiOCH (p-SiOCH(N)), was proposed as a barrier layer to prevent Cu from diffusion. Electrical properties of the samples were evaluated by capacitance-voltage and current density-electric field measurements. The bias-filter mechanism eliminated plasma damage of the p-SiOCH(N) layers. Furthermore, stabilization annealing converted Mn2O3 to Mn2O3-x(N) (manganese sub-oxynitride), giving the highest barrier performance for the Cu metallization layer, while maintaining the pristine dielectric properties of the p-SiOCH(N) layers. The Cu/Mn2O3-x(N)/p-SiOCH(N) structure also exhibited extremely low leakage currents after reliability tests, indicting their applicability to Cu metallization.

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Co-sputtered Cu(Ti) thin alloy film for formation of Cu diffusion and chip-level bonding

Cited by 9 publications

References 15 publications

Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization

Reliability Enhancement of Copper/Porous SiOCH Metallization Systems Using Nitrogen Stuffing and Bias-Filter Sputter Deposited Mn₂O₃ Barrier

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Co-sputtered Cu(Ti) thin alloy film for formation of Cu diffusion and chip-level bonding

Cited by 9 publications

References 15 publications

Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization

Reliability Enhancement of Copper/Porous SiOCH Metallization Systems Using Nitrogen Stuffing and Bias-Filter Sputter Deposited Mn2O3 Barrier

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Reliability Enhancement of Copper/Porous SiOCH Metallization Systems Using Nitrogen Stuffing and Bias-Filter Sputter Deposited Mn₂O₃ Barrier