scholarly journals Material Properties of Zr–Cu–Ni–Al Thin Films as Diffusion Barrier Layer

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 540 ◽  
Author(s):  
Po-Hsien Sung ◽  
Tei-Chen Chen

Due to the rapid increase in current density encountered in new chips, the phenomena of thermomigration and electromigration in the solder bump become a serious reliability issue. Currently, Ni or TiN, as a barrier layer, is widely academically studied and industrially accepted to inhibit rapid copper diffusion in interconnect structures. Unfortunately, these barrier layers are polycrystalline and provide inadequate protection because grain boundaries may presumably serve as fast diffusion paths for copper and could react to form Cu–Sn intermetallic compounds (IMCs). Amorphous metallic films, however, have the potential to be the most effective barrier layer for Cu metallization due to the absence of grain boundaries and immiscibility with copper. In this article, the diffusion properties, the strength of the interface between polycrystalline and amorphous ZrCuNiAl thin film, and the effects of quenching rate on the internal microstructures of amorphous metal films were individually investigated by molecular dynamics (MD) simulation. Moreover, experimental data of the diffusion process for three different cases, i.e., without barrier layer, with an Ni barrier layer, and with a Zr53Cu30Ni9Al8 thin film metallic glass (TFMG) barrier layer, were individually depicted. The simulation results show that, for ZrCuNiAl alloy, more than 99% of the amorphous phase at a quenching rate between 0.25 K/ps and 25 K/ps can be obtained, indicating that this alloy has superior glass-forming ability. The simulation of diffusion behavior indicated that a higher amorphous ratio resulted in better barrier performance. Moreover, a very small and uniformly distributed strain appears in the ZrCuNiAl layer in the simulation of the interfacial tension test; however, almost all the voids are initiated and propagated in the Cu layer. These phenomena indicate that the strength of the ZrCuNiAl/Cu interface and ZrCuNiAl layer is greater than polycrystalline Cu. Experimental results show that the Zr53Cu30Ni9Al8 TFMG layer exhibits a superior barrier effect. Almost no IMCs appear in this TFMG barrier layer even after aging at 125 °C for 500 h.

1995 ◽  
Vol 391 ◽  
Author(s):  
S. Kordic ◽  
R.A.M. Wolters ◽  
R.A. Augur ◽  
A.G. Dirks

AbstractThe influence of a TiW barrier layer on the stress-voiding behavior of AlCu and AlSiCu interconnects is investigated. The results are compared to the same alloys deposited on SiO2- In both cases, AlCu exhibits a notably better voiding behavior compared to AlSiCu. In the case in which the alloys are directly deposited on the TiW barrier without breaking vacuum between TiW and Al(Si)Cu depositions, a significant improvement of the voiding behavior of both alloys is observed. Compared to AlCu, AlSiCu shows worse voiding behavior due to the presence of Si precipitates, which introduce significant extra dislocations and defects in the Al grains. These dislocations and defects are diffusion paths which assist stress relaxation and void formation. In the presence of a TiW barrier part of the Si content of the AlSiCu is consumed during the anneal by the Al-TiW interface, which results in a decreased number of dislocations and defects within the Al grains, and an improved voiding behavior compared to AlSiCu on SiO2-Furthermore, W and Ti diffuse into the grain boundaries of both alloys. The presence of W and Ti in the grain boundaries reduces the amount of Cu depletion from within the grains, which makes both alloys more resistant to stress voiding. The above is supported by Auger and TEM results. The electromigration results of the alloys in question are presented. These show that also with respect to electromigration AlCu is the preferred alloy both on TiW and SiO2.


APL Materials ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 013001 ◽  
Author(s):  
Chia-Chi Yu ◽  
Hsin-jay Wu ◽  
Matthias T. Agne ◽  
Ian T. Witting ◽  
Ping-Yuan Deng ◽  
...  

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1087
Author(s):  
Po-Hsien Sung ◽  
Tei-Chen Chen

It is well-known that Cu–Sn intermetallic compounds are easily produced during reflow process and result in poor reliability of solder bump. Recently, amorphous metallic films have been considered to be the most effective barrier layer because of the absence of grain boundaries and immiscibility with copper. Since Cu–Ag alloys are characterized by their lower electrical resistivity and superior glass-forming ability, they are appropriate to be used as the diffusion barrier layers. In this study, molecular dynamics simulation was performed to investigate the effects of composition ratio and quenching rate on the internal microstructure, diffusion properties, and the strength of the interface between polycrystalline Cu and Cu–Ag barrier layers. The results showed that Cu40Ag60 and Cu60Ag40 present more than 95% of the amorphous at quenching rate between 0.25 and 25 K/ps, indicating a good glass-forming ability. Diffusion simulation showed that a better barrier performance can be achieved with higher amorphous ratio. For the sample of Cu20Ag80 with quenching rate of 25 K/ps, a void is initially generated in amorphous Cu–Ag layer during the tensile test. This indicates the strength of amorphous Cu–Ag is weaker than Cu–Ag/Cu interface and the polycrystalline Cu layer.


2009 ◽  
Vol 203 (24) ◽  
pp. 3692-3700 ◽  
Author(s):  
Z. Abdel Hamid ◽  
A. Abdel Aal ◽  
Ali Shaaban ◽  
H.B. Hassan

1994 ◽  
Vol 343 ◽  
Author(s):  
A.J. Kellock ◽  
J.E.E. Baglin ◽  
K.R. Coffey ◽  
J.K. Howard ◽  
M.A. Parker ◽  
...  

ABSTRACTThermal interdiffusion mechanisms and kinetics have been studied for Ta-Permalloy (Ni80Fe20), Ta-Ni and Ta-Fe thin film couples, in the temperature range 300°C - 600°C. Interaction modes identified for the Ta-NiFe system include: fast diffusion of Ta into grain boundaries of NiFe, and nucleation and growth of Ni3Ta, with consequent depletion of Ni in the remaining NiFe, and eventual segregation of Fe.


2001 ◽  
Vol 388 (1-2) ◽  
pp. 27-33 ◽  
Author(s):  
Kai-Min Yin ◽  
Li Chang ◽  
Fu-Rong Chen ◽  
Ji-Jung Kai ◽  
Cheng-Cheng Chiang ◽  
...  

1992 ◽  
Vol 7 (8) ◽  
pp. 1976-1979 ◽  
Author(s):  
T.C. Hufnagel ◽  
S. Brennan ◽  
A.P. Payne ◽  
B.M. Clemens

We have observed a rapid amorphization reaction at ambient temperature in the Gd/Co system by employing grazing incidence x-ray scattering. We find that a 135 Å crystalline Gd film is amorphized in less than 30 min by deposition of Co. We postulate that the rapidity of the reaction is due to surface diffusion of Co atoms after deposition to fast diffusion sites such as grain boundaries in the Gd film. Once the interfacial region has been amorphized these fast diffusion paths are sealed off from the surface, rapid diffusion of Co into the Gd crystalline layer is prevented, and the amorphization reaction stops.


1987 ◽  
Vol 2 (5) ◽  
pp. 697-703 ◽  
Author(s):  
Chin-An Chang

Thin-film interactions have been increasingly important to various aspects of electronic technologies, including devices and packaging. Extensive outdiffusion and alloy formation, for example, can be detrimental to the yield and reliability of the parts fabricated. Understanding such interactions, and their dependence on various factors, continues to be a challenge to thin-film scientists. Several aspects related to thin-film interactions are described in this paper: a review of the ambient effects that provides an understanding of the basic reaction mechanisms at the interface; an illustration of concerns upon choosing a diffusion barrier layer, and reaction across such a layer; and the effect of undesired outdiffusion on the solder spread related to joining.


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