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1.
In this study we observed significantly improved properties, over a pure copper (Cu) film, for a copper-silver alloy film
made with a pure copper film co-sputtered with a minute amount of either Ag0.3N0.4 or Ag1.2N0.7 on a barrierless Si substrate. In either case, no noticeable interaction between the film␣and the Si substrate was found
after annealing at 600°C for 1 h. The Cu(Ag0.3,N0.4) film was thermally stable after annealing at 400°C for 240 h. The film’s resistivity was ∼2.2 μΩ cm after annealing at 600°C, while its leakage current was found to be lower than that of a pure Cu film by three orders
of magnitude. The adhesion of the Cu(Ag1.2,N0.7) film to the Si substrate was approximately seven times that of a pure Cu film to a silicon substrate. Hence, a Cu film doped
with Ag and N seems to be a better candidate for both barrierless metallization and the making of superior interconnects. 相似文献
2.
This investigation prepares a low-resistivity and self-passivated Cu(In) thin film. The dissociation behaviors of dilute Cu-alloy
thin films, containing 1.5–5at.%In, were prepared on glass substrates by a cosputter deposition, and were subsequently annealed
in the temperature range of 200–600 °C for 10–30 min. Thus, self-passivated Cu thin films in the form In2O3/Cu/SiO2 were obtained by annealing Cu(In) alloy films at an elevated temperature. Structural analysis indicated that only strong
copper diffraction peaks were detected from the as-deposited film, and an In2O3 phase was formed on the surface of the film by annealing the film at an elevated temperature under oxygen ambient. The formation
of In2O3/Cu/SiO2 improved the resistivity, adhesion to SiO2, and passivative capability of the studied film. A dramatic reduction in the resistivity of the film occurred at 500 °C,
and was considered to be associated with preferential indium segregation during annealing, yielding a low resistivity below
2.92 μΩcm. The results of this study can be potentially exploited in the application of thin-film transistor–liquid crystal display
gate electrodes and copper metallization in integrated circuits. 相似文献
3.
Copper (titanium) [Cu(Ti)] films with low titanium (Ti) concentration were found to form thin Ti-rich barrier layers at the
film/substrate interfaces after annealing, which is referred to as self-formation of the barrier layers. This Cu(Ti) alloy
was one of the best candidates for interconnect materials used in next-generation ultra-large-scale integrated (ULSI) devices
that require both very thin barrier layers and low-resistance interconnects. In the present paper, in order to investigate
the influences of annealing ambient on resistivity and microstructure of the Cu alloys, the Cu(7.3at.%Ti) films were prepared
on the SiO2 substrates and annealed at 500°C in ultra-high vacuum (UHV) or argon (Ar) with a small amount of impurity oxygen. After annealing
the film at 500°C in UHV, the resistivity was not reduced below 16 μΩ-cm. Intermetallic compounds of Cu4Ti were observed to form in the films and believed to cause the high resistivity. However, after subsequently annealing in
Ar, these compounds were found to decompose to form surface TiO
x
and interfacial barrier layers, and the resistivity was reduced to 3.0 μΩ-cm. The present experiment suggested that oxygen
reactive to titanium during annealing played an important role for both self-formation of the interfacial barrier layers and
reduction of the interconnect resistivity. 相似文献
4.
In this study, (100)-orientation silicon wafer coated with TiN barrier is catalyzed by a Pd/Sn colloid, which serves as an
activator for electroless copper deposition. After activation, electroless deposition of Cu occurs on the catalytic surface.
The coverage of the Cu deposit reaches 100% and the adsorptive amount of Pd is greatly increased by the conditioning process.
The correlation between deposition rate, resistivity, morphology, crystal structure, and composition of the deposit when varying
the temperature of the plating bath is discussed. The deposition rate of Cu is monitored by both the electrochemical method
and the profilometer (α-step), while the other properties of the deposit are measured by four-point probe, scanning electron
microscopy (SEM), x-ray diffraction (XRD), and Auger electron microscopy (AES). Deposition at 70°C is favorable due to the
higher deposition rate, lower resistivity, less impurities, and more preferred orientation in the crystal structure than that
at lower temperature. Problems regarding adhesion and high resistivity can be greatly mitigated via 400°C thermal annealing.
The resistivity of Cu can be reduced to 2.2 μΩcm. Moreover, trenches of 1 μm and 0.25 μm on patterned wafer have been successfully
filled by electroless deposition of Cu with the aid of surfactant C12. 相似文献
5.
Thermal performance of sputtered insoluble Cu(W) films for advanced barrierless metallization 总被引:1,自引:0,他引:1
The thermal performance of sputtered Cu films with dilute insoluble W (1.3 at.%) on barrierless Si substrates has been studied,
using the analyses of focused ion beam, x-ray diffraction, and electrical resistivity measurement. The role of the Cu(W) film
as a seed layer has been confirmed based on the thermal performance evaluations in both thermal cycling and isothermal annealing
at various temperatures. The electrical resistivity of ∼1.8 μΩ-cm for Cu/Cu(W) film is obtained after thermal annealing at
400°C. Because of the good thermal stability, the Cu(W) seed layer is also considered to act as a diffusion buffer and is
stable up to 490°C for the barrierless Si scheme. The results indicate that the Cu/Cu(W) scheme has potential in advanced
barrierless metallization applications. 相似文献
6.
This study reports the good thermal stability of a sputtered Cu(MoN
x
) seed layer on a barrierless Si substrate. A Cu film with a small amount of MoN
x
was deposited by reactive co-sputtering of Cu and Mo in an Ar/N2 gas mixture. After annealing at 560°C for 1 h, no copper silicide formation was observed at the interface of Cu and Si. Leakage
current and resistivity evaluations reveal the good thermal reliability of Cu with a dilute amount of MoN
x
at temperatures up to 560°C, suggesting its potential application in advanced barrierless metallization. The thermal performance
of Cu(MoN
x
) as a seed layer was evaluated when pure Cu is deposited on top. X-ray diffraction, focused ion beam microscopy, and transmission
electron microscopy results confirm the presence of an ∼10-nm-thick reaction layer formed at the seed layer/Si interface after
annealing at 630°C for 1 h. Although the exact composition and structure of this reaction layer could not be unambiguously
identified due to trace amounts of Mo and N, this reaction layer protects Cu from a detrimental reaction with Si. The Cu(MoN
x
) seed layer is thus considered to act as a diffusion buffer with stability up to 630°C for the barrierless Si scheme. An
electrical resistivity of 2.5 μΩ cm was obtained for the Cu/Cu(MoN
x
) scheme after annealing at 630°C. 相似文献
7.
We report the effect of steam oxidation at 875° C on the electrical resistivity, crystalline quality (measured by ion channeling),
and Al concentration (measured by secondary ion mass spectrometry) in 0.25 μm thick, Si-implanted and recrystallized, Si-on-sapphire
films. After a deep Si implantation (180 keV, 1.4×l015 Si/cm2) at room temperature, and solid-phase epitaxial regrowth from the non-amorphized, 0.03 μm thick surface region, the initially
undoped SOS films become doped p-type, and their resistivity decreases from (1−5)xl014 ficm to 0.5 Ωcm. The doping is due to electrically active Al, released from the A12O3 by the Si implantation, and present in the recrystallized films at a concentration of ≃2×l016 Al/cm3 . After a 75 min steam oxidation at 875 °C, which consumes 0.06 Μm of Si, the resistivity of the recrystallized films increases
to over 40 Ωcm, but the Al concentration is unchanged. The oxidation also uncovers higher quality material below the non-recrystallized
surface layer. A semi-quantitative model is proposed to explain the electrical data, based on the diffusion of oxygen from
the Si/SiO2 interface into the SOS film during oxidation, and the formation of Al-O-Si neutral complexes. Data on the stability of the
high-resistivity films against high-temperature annealing or re-amorphization and annealing is given. 相似文献
8.
An air-fireable, glass-free, electrically conductive thick-film material (96.6% Ag, 1.38% Cu, 0.28% Al, 0.35% Ti, and 1.39%
Sn by weight) and a conventional glass-containing, electrically conductive thick-film materials (96.6% Ag and 3.4% glass frit
by weight), both on alumina substrates, were studied by electrical, mechanical, thermal, and microscopic methods. The volume
electrical resistivity of the glass-free thick film (2.5×10−6 Ω·cm, 30-μm thick) is lower than that of the glass-containing thick film (3.9×10−6 Ω·cm, 19-μm thick), with each film processed at its optimum firing temperature. The optimum firing temperature is 930°C and
850°C for glass-free and glass-containing thick films, respectively, as indicated by the criteria of low resistivity and high
scratch resistance. The glass-free thick film has a higher scratch resistance than the glass-containing thick film, both fired
at their respective optimum temperatures, suggesting that the former has higher bond strength to the alumina substrate. The
formation process of the glass-free and glass-containing thick films is similar. The process involves solid-state diffusion
of silver, which results in a silver network and grain boundaries. However, the sintering of silver particulates in the glass-containing
thick film is enhanced by the viscous flow of glass. 相似文献
9.
Electrically nonconductive thermal pastes have been attained using carbon (carbon black or graphite) as the conductive component
and ceramic (fumed alumina or exfoliated clay) as the nonconductive component. For graphite particles (5 μm), both clay and alumina are effective in breaking up the electrical connectivity, resulting in pastes with electrical resistivity
up to 1013Ω·cm and thermal contact conductance (between copper surfaces of roughness 15 μm) up to 9 × 104 W/m2·°C. For carbon black (30 nm), clay is more effective than alumina, providing a paste with resistivity 1011 Ω·cm and thermal contact conductance 7 × 104 W/m2·°C. Carbon black increases the thermal stability, whereas either graphite or alumina decreases the thermal stability. The
antioxidation effect of carbon black is further increased by the presence of clay up to 1.5 vol.%. The addition of clay (up
to 0.6 vol.%) or alumina (up to 2.5 vol.%) to graphite paste enhances the thermal stability. 相似文献
10.
M. A. Capano J. K. Patterson L. Petry J. S. Solomon 《Journal of Electronic Materials》2003,32(5):458-463
The processing conditions necessary to achieve low resistivity of the C54-TiSi2 phase in contact with 6H-SiC are explored. This study demonstrates that an interlayer of Si between a Ti layer and the 6H-SiC
substrate suppresses the formation of TiC, and that a metallization consisting of either Ti-rich or Si-rich silicide phases
may be chosen. When the Ti-to-Si layer thickness ratio is 1:3, the C54-TiSi2 and TiSi phases are observed following a 600°C/30 min and an 850°C/30 min annealing cycle. When the Ti-to-Si layer thickness
ratio is 1:1, Ti5Si3 and TiSi phases are observed following the same annealing cycle. Time-dependent, in-situ resistance measurements are rationalized
in terms of these microstructural developments. The Ti5Si3/TiSi structure is demonstrated to have a resistivity of 239 μΩ·cm, whereas the TiSi2/TiSi structure has a resistivity of only 23 μΩ·cm. Explanations for different microstructures observed are presented. 相似文献
11.
H. J. Yang S. Lee J. B. Park H. M. Lee E. G. Lee C. M. Lee H. N. Hong S. Mori J. H. Lee J. G. Lee 《Journal of Electronic Materials》2005,34(5):643-646
The behavior of boron in Cu(4.8at.%B)/Ti/SiO2 was investigated as a function of temperature, and its influences on the Cu-Ti interaction, resistivity, and diffusion barrier
properties were also studied. The results showed the formation of a titanium boride layer at the Cu-Ti interface, after heating
the Cu(B)/Ti/SiO2 at 400°C and higher, effectively served as a barrier for the Cu and Ti diffusion, and significantly enhanced the Cu (111)
texture. The resistivity dropped from 16.3 to 2.33 μΩ-cm after heating at 600°C, and continued to decrease up to 800°C. As
a result, the Cu, in the form of B(O)x/Cu/TiB2/Ti(O)x/SiO2 multilayers, obtained by heating the Cu(B)/Ti/SiO2, showed high thermal stability with low resistivity and, thus, can be used as interconnections in advanced integrated circuits.
Since the Cu, in the form of B(O)x/Cu/TiB2/Ti(O)x/SiO2 multilayers, obtained by heating the Cu(B)/Ti/SiO2, showed high thermal stability with low resistivity, it can be used as interconnections in advanced integrated circuits. 相似文献
12.
Kartika Chandra Sahoo Chun-Wei Chang Yuen-Yee Wong Tung-Ling Hsieh Edward Yi Chang Ching-Ting Lee 《Journal of Electronic Materials》2008,37(6):901-904
The thermal stability of the Cu/Cr/Ge/Pd/n+-GaAs contact structure was evaluated. In this structure, a thin 40 nm layer of chromium was deposited as a diffusion barrier
to block copper diffusion into GaAs. After thermal annealing at 350°C, the specific contact resistance of the copper-based
ohmic contact Cu/Cr/Ge/Pd was measured to be (5.1 ± 0.6) × 10−7 Ω cm2. Diffusion behaviors of these films at different annealing temperatures were characterized by metal sheet resistance, X-ray
diffraction data, Auger electron spectroscopy, and transmission electron microscopy. The Cu/Cr/Ge/Pd contact structure was
very stable after 350°C annealing. However, after 400°C annealing, the reaction of copper with the underlying layers started
to occur and formed Cu3Ga, Cu3As, Cu9Ga4, and Ge3Cu phases due to interfacial instability and copper diffusion. 相似文献
13.
The interaction between thin films of hydrogenated amorphous silicon and sputter-deposited chromium has been studied. Following
deposition of the chromium films at room temperature, the films were annealed over a range of times and temperatures below
350°C. It was found that an amorphous silicide was formed only a few nanometers thick with the square of thickness proportional
to the annealing time. The activation energy for the process was 0.55±0.05 eV. The formation process of the silicide was very
reproducible with the value of density derived from the thickness and Cr surface density being close to the value for crystalline
CrSi2 for all films formed at temperatures ≤300°C. The specific resistivity of the amorphous CrSi2 was ≈600 μΩ·cm and independent of annealing temperature. 相似文献
14.
Effect of growth temperature on properties of transparent conducting gallium-doped ZnO films 总被引:1,自引:0,他引:1
A. Kh. Abduev A. K. Akhmedov A. Sh. Asvarov A. A. Abdullaev S. N. Sulyanov 《Semiconductors》2010,44(1):32-36
Transparent conducting gallium-doped ZnO films are deposited on glass substrates by magnetron sputtering of conducting ceramic
targets. The dependences of structural, electric, and optical characteristics of ZnO:Ga films on the substrate temperature
are investigated during the deposition. Stability of resistivity of films is considered during annealing in air. It is found
that the films deposited at the substrate temperature of 250°C have the lowest resistivity of 3.8 × 10−4 Ω cm, while those deposited at 200°C have the highest thermal stability. 相似文献
15.
Alain E. Kaloyeros Aiguo Feng Jonathan Garhart Kenneth C. Brooks Sumanta K. Ghosh Arjun N. Saxena Fred Luehrs 《Journal of Electronic Materials》1990,19(3):271-276
Copper films for potential use in multilevel metallization in ULSIC’s were produced by low temperature (250–350° C) metal-organic
chemical vapor deposition (LTMOCVD) in atmospheres of pure H2 or mixture Ar/H2 from the β-diketonate precursor bis(1,1,1,5,5,5-hexafluoroacetylacetonato) copper(ll), Cu(hfa)2. The films were analyzed by x-ray diffraction (XRD), Rutherford backscattering (RBS), Auger electron spectroscopy (AES),
scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDXS). The results of these studies showed that
the films were uniform, continuous, adherent and highly pure—oxygen and carbon contents were below the detection limits of
AES. Four point resistivity measurements showed that the copper films had very low resistivity, as low as 1.9 μΩcm for the
films deposited in pure hydrogen atmosphere. Our preliminary results seem to indicate that LTMOCVD is a very attractive technique
for copper multilevel metallizations. 相似文献
16.
Kazuhiro Ito Keiji Hamasaka Kazuyuki Kohama Yasuharu Shirai Masanori Murakami 《Journal of Electronic Materials》2014,43(7):2540-2547
Cu(0.5 at.%Mg) alloy films were deposited on glass substrates, and annealed at 200–400 °C in vacuum. The resistivity of the Cu(Mg) films was reduced to about 3.0 μΩcm after annealing at 200 °C for 30 min, and the tensile strength of adhesion of the Cu(Mg) films to the glass substrates was increased to 30–40 and 35–55 MPa after annealing at 250 and 300 °C, respectively. The reduction in resistivity can be explained as reduced impurity scattering and grain-boundary scattering, since Mg segregation to the film surface and Cu(Mg)/glass interface, and consequent Cu grain growth, were observed. Increased adhesion of the Cu(Mg) films to glass substrates after annealing was also explained by the strong segregation of Mg atoms, and the formation of a reaction layer at the interface. Mg atoms were observed to have reacted with the glass substrates and formed a thin crystalline MgO layer at the interface in the samples annealed at 300 °C, while Mg atoms were highly concentrated above the Cu(Mg)/glass interface without oxide formation at the interface in the samples annealed at 250 °C. Thus, the process temperature and time to obtain low-resistivity and high-adhesion Cu alloy films on glass substrates could be reduced to 250 °C and 30 min using Cu(Mg) films. 相似文献
17.
Nadeemullah Mahadik Mulpuri V. Rao Albert V. Davydov 《Journal of Electronic Materials》2006,35(11):2035-2040
The performance of a novel Ge/Cu/Ti metallization scheme on n-type GaN has been investigated for obtaining thermally and electrically
stable low-resistance ohmic contacts. Isochronal (2 min.) anneals in the 600–740°C temperature range and isothermal (690°C)
anneals for 2–10 min. duration were performed in inert atmosphere. For the 690°C isothermal schedule, ohmic behavior was observed
after annealing for 3 min. or longer with a lowest contact resistivity of 9.1 × 10−5 Ωcm2 after the 10 min. anneal for a net donor doping concentration of 9.2 × 1017 cm−Ω3. Mean roughness (Ra) for anneals at 690°C was almost constant at around 5 nm, up to an annealing duration of 10 min., which indicates a good
thermal stability of the contact scheme. 相似文献
18.
In metallization, peeling and oxidation of tungsten silicide are the most serious problems of tungsten rich silicide. In this
study, multilayer-derived silicon rich tungsten silicide with the silicon film on the outermost surface is investigated to
avoid these problems. The dependence of sheet resistance on the annealing conditions is studied. X-ray diffraction results
indicate that silicide formation is nearly completed after 30 min annealing at 750° C. Microstructures of silicide and polycides
are investigated by electron microscopy. Silicide deposited on SiO2 has smaller grains that deposited on poly-Si. A resistivity of 60 μΩ-cm is obtained for multilayer-derived WSi2.3. 相似文献
19.
C. H. Lin J. P. Chu T. Mahalingam T. N. Lin S. F. Wang 《Journal of Electronic Materials》2003,32(11):1235-1239
The thermal annealing behavior of Cu films containing insoluble 2.0 at. % Mo magnetron co-sputtered on Si substrates is discussed
in the present study. The Cu-Mo films were vacuum annealed at temperatures ranging from 200°C to 800°C. X-ray diffraction
(XRD) and scanning electron microscopy (SEM) observations have shown that Cu4Si was formed at 530°C, whereas pure Cu film exhibited Cu4Si growth at 400°C. Twins are observed in focused ion beam (FIB) images of as-deposited and 400°C annealed, pure Cu film,
and these twins result from the intrinsically low stacking-fault energy. Twins appearing in pure Cu film may offer an extra
diffusion channel during annealing for copper silicide formation. In Cu-Mo films, the shallow diffusion profiles for Cu into
Si were observed through secondary ion mass spectroscopy (SIMS) analysis. Higher activation energy obtained through differential
scanning calorimetry (DSC) analysis for the formation of copper silicide further confirms the beneficial effect of Mo on the
thermal stability of Cu film. 相似文献
20.
Thermal stability of Cu(W) and Cu(Mo) films for advanced barrierless Cu metallization: Effects of annealing time 总被引:1,自引:0,他引:1
The current study investigates the effects of insoluble substances (W and Mo) in pure Cu films on the thermal stability, microstructure,
and electrical properties of the films. The results can be used to assess the feasibility of the barrierless Cu film in the
metallization process. The films investigated were deposited using magnetron sputtering onto the barrierless Si (100) substrate
and then annealed between 400°C and 450°C in vacuum for long periods of time. After annealing, the film properties were examined
by x-ray diffraction (XRD), the four-point probe method, leakage current measurements, and focused ion beam (FIB) analysis.
The results indicate that no detectable copper silicide is formed after 48-h annealing of Cu(W) films at 400°C. In contrast,
for the Cu(Mo) film, copper silicide is formed after 18-h annealing at the same temperature and hence electrical properties
are poor. This evidence suggests that the Cu(W) film has better thermal stability during long periods of annealing and is
suitable for an advanced barrierless metallization process. 相似文献