Electromigration Test on Void Formation and Failure Mechanism of FCBGA Lead-Free Solder Joints

Jen, Ming Hwa R.; Liu, Lee-Cheng; Lai, Yi‐Shao

doi:10.1109/tcapt.2008.2004579

Cited by 11 publications

(2 citation statements)

References 39 publications

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“…Prevention of the growth of IMCs continues to be a critical limitation for improving the performance of integrated circuits. Thin film metallic glasses (TFMGs) are regarded as excellent diffusion barriers in integrated circuit applications [15]. In particular, refractory metal nitrides, deposited by reactive sputtering, were shown to be promising diffusion barriers.…”

Section: Introductionmentioning

confidence: 99%

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

Sung

Chen

2020

Crystals

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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.

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Section: Introductionmentioning

confidence: 99%

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

Sung

Chen

2020

Crystals

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“…On the contrary, amorphous barrier layers exhibit superior behavior. These kinds of thin film metallic glasses (TFMGs) have been examined and regarded as the promising diffusion barriers in integrated circuits applications [17][18][19][20][21][22] because of the absence of grain boundaries and immiscibility with copper [23][24][25]. Amorphous coatings also can be utilized for the purpose of corrosion resistance [26,27].…”

Section: Introductionmentioning

confidence: 99%

Performance of Cu–Ag Thin Films as Diffusion Barrier Layer

Sung

Chen

2020

Coatings

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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.

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