Solid-state reaction in an Au wire connection with an Al-Cu pad during aging

Jang, Guh-Yaw; Duh, Jenq‐Gong; Takahashi, Hideyuki; Su, David

doi:10.1007/bf02692453

Cited by 13 publications

(5 citation statements)

References 19 publications

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“…In general, the growth behavior of intermediate phase should follow the parabolic rate law during solid-state reaction. [16][17][18][19][20][21] However, an intermediate phase can be reacted back to one of its parent phases due to the supply limitation, which primarily acted as source for the growth of the phase. [22][23][24] In the Sn-3.0Ag-0.5Cu joints, the Ni(V) layer and solders were regarded as the source for the growth of (Cu 1Ày ,Ni y ) 6 Sn 5 IMC during aging.…”

Section: Imc Growth Kinetics During Aging Treatmentmentioning

confidence: 99%

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elemental redistribution and interfacial reaction mechanism for the flip chip Sn-3.0Ag-(0.5 or 1.5)Cu solder bump with Al/Ni(V)/Cu under-Bump metallization during aging

Jang

Duh

2006

J. Electron. Mater.

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In flip chip technology, Al/Ni(V)/Cu under-bump metallization (UBM) is currently applicable for Pb-free solder, and Sn-Ag-Cu solder is a promising candidate to replace the conventional Sn-Pb solder. In this study, Sn-3.0Ag-(0.5 or 1.5)Cu solder bumps with Al/Ni(V)/Cu UBM after assembly and aging at 150°C were employed to investigate the elemental redistribution and reaction mechanism between solders and UBMs. During assembly, the Cu layer in the Sn-3.0Ag-0.5Cu joint was completely dissolved into solders, while Ni(V) layer was dissolved and reacted with solders to form (Cu 1Ày ,Ni y ) 6 Sn 5 intermetallic compound (IMC). The (Cu 1Ày ,Ni y ) 6 Sn 5 IMC gradually grew with the rate constant of 4.63 3 10 À8 cm/sec 0.5 before 500 h aging had passed. After 500 h aging, the (Cu 1Ày ,Ni y ) 6 Sn 5 IMC dissolved with aging time. In contrast, for the Sn-3.0Ag-1.5Cu joint, only fractions of Cu layer were dissolved during assembly, and the remaining Cu layer reacted with solders to form Cu 6 Sn 5 IMC. It was revealed that Ni in the Ni(V) layer was incorporated into the Cu 6 Sn 5 IMC through slow solid-state diffusion, with most of the Ni(V) layer preserved. During the period of 2,000 h aging, the growth rate constant of (Cu 1Ày ,Ni y ) 6 Sn 5 IMC was down to 1.74 3 10 À8 cm/sec 0.5 in the Sn-3.0Ag-1.5Cu joints. On the basis of metallurgical interaction, IMC morphology evolution, growth behavior of IMC, and Sn-Ag-Cu ternary isotherm, the interfacial reaction mechanism between Sn-3.0Ag-(0.5 or 1.5)Cu solder bump and Al/Ni(V)/Cu UBM was discussed and proposed.

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Section: Imc Growth Kinetics During Aging Treatmentmentioning

confidence: 99%

“…In general, the growth rate of an intermediate phase during the interdiffusion of metals with volume diffusion predominated follows the parabolic rate law: [16][17][18][19][20][21] x À x 0 ¼ kt 1=2…”

Section: Imc Growth Kinetics During Aging Treatmentmentioning

confidence: 99%

elemental redistribution and interfacial reaction mechanism for the flip chip Sn-3.0Ag-(0.5 or 1.5)Cu solder bump with Al/Ni(V)/Cu under-Bump metallization during aging

Jang

Duh

2006

J. Electron. Mater.

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“…However, this bonding system can easily lead to formation of Au-Al intermetallic compounds (IMCs). [1][2][3][4][5][6] Such IMCs are associated with Kirkendall voids, detrimentally affecting the reliability of components, especially in high-power devices and fine-pitch electronic applications. The use of Cu wire for thermosonic ball bonding presents several advantages over the use of Au wire, including significant cost saving, higher electrical and thermal conductivity for faster die functionality, and better mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Growth of Intermetallic Compounds in Thermosonic Copper Wire Bonding on Aluminum Metallization

Liu

Silberschmidt

et al. 2009

Journal of Elec Materi

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Interface evolution caused by thermal aging under different temperatures and durations was investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that approximately 30-nm-thick and discontinuous Cu-Al intermetallic compounds (IMCs) were present in the initial bonds before aging. Cu-Al IMCs grew under thermal aging with increasing aging time. The growth kinetics of the Cu-Al IMCs was correlated to the diffusion process during aging; their combined activation energy was estimated to be 1.01 eV. Initially, Al-rich Cu-Al IMCs formed in the as-bonded state and early stage of aging treatment. Cu 9 Al 4 was identified by selected-area electron diffraction (SAD) as the only type of Cu-Al IMC present after thermal aging at 250°C for 100 h; this is attributed to the relatively short supply of aluminum to the interfacial reaction.

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“…Since IMC II had not formed uniformly after aging at 270 ˚C for 30 min, its thickness could not be measured. The growth rate of an intermediate phase during the interdiffusion of metals follows a parabolic rate law which can be described with an empirical equation [4,12]: (1) where d is the thickness of the intermediate phase layer, d 0 its initial thickness, D is the layer growth coefficient and t is the aging time.…”

Section: Methodsmentioning

confidence: 99%

Effect of isothermal aging on the growth behavior of Cu/Al intermetallic compounds

Mokhtari

Kim

Nishikawa

et al. 2014

2014 International Conference on Electronics Packaging (ICEP)

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This research focuses on the formation and growth behavior of Cu/Al intermetallic compounds (IMCs). In order to investigate IMC growth after 30, 60 and 120 min of aging at 270, 300 and 330 ˚C, cross-section of Al, Cu and Cu/Al IMCs were examined by scanning electron microscopy (SEM). The results showed that the consumption of the Al layer is more rapid than that of Cu layer, and that after 120 min at 330 ˚C the Al layer is entirely consumed. The formation of three distinct Cu/Al IMC layers was observed. Scanning transmission electron microscopy (STEM)/energy-dispersive X-ray spectroscopy (EDS) was used to identify the three IMC layers formed at the interface. These were CuAl, Cu 3 Al 2 and Cu 9 Al 4 . Also, the activation energies of Cu/Al IMC growth were obtained from an Arrhenius plot.

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Solid-state reaction in an Au wire connection with an Al-Cu pad during aging

Cited by 13 publications

References 19 publications

elemental redistribution and interfacial reaction mechanism for the flip chip Sn-3.0Ag-(0.5 or 1.5)Cu solder bump with Al/Ni(V)/Cu under-Bump metallization during aging

elemental redistribution and interfacial reaction mechanism for the flip chip Sn-3.0Ag-(0.5 or 1.5)Cu solder bump with Al/Ni(V)/Cu under-Bump metallization during aging

Growth of Intermetallic Compounds in Thermosonic Copper Wire Bonding on Aluminum Metallization

Effect of isothermal aging on the growth behavior of Cu/Al intermetallic compounds

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