The mechanism of Pd distribution in the process of FAB formation during Pd-coated Cu wire bonding

Du, Yahong; Liu, Zhiquan; Ji, Hongjun; Li, Mingyu; Wen, Minru

doi:10.1007/s10854-018-9508-z

Cited by 6 publications

(7 citation statements)

References 14 publications

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“…Coating the Cu wire with a pure metal layer which oxidizes slowly at processing temperature can extend shelf life and improve the corrosion resistance, bondability, and reliability of Cu bonding wire [ 91 , 92 ]. The coated pure metal layer comprises of noble metal elements such as Au, Ag, Pt, Pd and other metal elements of high corrosion resistance such as Ni, Co, Cr, and Ti.…”

Section: Cu Bonding Wirementioning

confidence: 99%

“…Among them, Pd shows stable performance and high corrosion resistance under long-term exposure to high temperature and high humidity conditions, and has good ductility, plasticity, and bending capacity, which adds an oxide-free and easily bondable surface for Cu wire [ 93 , 94 ]. Pd coating has excellent adhesion to Cu wire; round and stable FAB can typically be formed in a nitrogen atmosphere for Pd-coated Cu (PCC) wire [ 92 , 95 ]. PCC wire generally presents a much larger stitch bond window and more robust second bond, and shows better performance on Al pads in humidity stress and oxidation environments compared with bare Cu wire.…”

Section: Cu Bonding Wirementioning

confidence: 99%

“…The growth mechanism of Cu-Al IMCs was investigated by Yang et al during the annealing temperature from 50 °C to 70 °C based on the in situ HRTEM, and the results showed that Cu-Al IMCs near and apart from the Cu layer were Cu 9 Al 4 and CuAl 2, respectively. An accurate growth equation of Cu-Al IMCs was also obtained according to the in situ experimental results, which provides theoretical reference for the study of Cu-Al bond reliability [ 92 ]. Moreover, the presence of Pd at the bond interface can slow down the Cu-Al IMCs growth and preserve the bond strength during thermal annealing [ 111 ].…”

Section: Cu Bonding Wirementioning

confidence: 99%

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Research Progress on Bonding Wire for Microelectronic Packaging

et al. 2023

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Wire bonding is still the most popular chip interconnect technology in microelectronic packaging and will not be replaced by other interconnect methods for a long time in the future. Au bonding wire has been a mainstream semiconductor packaging material for many decades due to its unique chemical stability, reliable manufacturing, and operation properties. However, the drastic increasing price of Au bonding wire has motivated the industry to search for alternate bonding materials for use in microelectronic packaging such as Cu and Ag bonding wires. The main benefits of using Cu bonding wire over Au bonding wire are lower material cost, higher electrical and thermal conductivity that enables smaller diameter Cu bonding wire to carry identical current as an Au bonding wire without overheating, and lower reaction rates between Cu and Al that serve to improve the reliability performance in long periods of high temperature storage conditions. However, the high hardness, easy oxidation, and complex bonding process of Cu bonding wire make it not the best alternative for Au bonding wire. Therefore, Ag bonding wire as a new alternative with potential application comes to the packaging market; it has higher thermal conductivity and lower electric resistivity in comparison with Cu bonding wire, which makes it a good candidate for power electronics, and higher elastic modulus and hardness than Au bonding wire, but lower than Cu bonding wire, which makes it easier to bond. This paper begins with a brief introduction about the developing history of bonding wires. Next, manufacturability and reliability of Au, Cu, and Ag bonding wires are introduced. Furthermore, general comparisons on basic performance and applications between the three types of bonding wires are discussed. In the end, developing trends of bonding wire are provided. Hopefully, this review can be regarded as a useful complement to other reviews on wire bonding technology and applications.

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Section: Cu Bonding Wirementioning

confidence: 99%

Section: Cu Bonding Wirementioning

confidence: 99%

Section: Cu Bonding Wirementioning

confidence: 99%

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Research Progress on Bonding Wire for Microelectronic Packaging

et al. 2023

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“…The discharge time of EFO has an effect on the distribution of Pd on FAB. Du et al [ 41 ] analyzed that the density of Pd was greater than that of Cu, so Pd would move downward and solidify with the increase of time during the solidification process of FAB. Therefore, a longer EFO discharge time will lead to a larger Pd coverage on the FAB surface.…”

Section: The Distribution Of Pd In Fab and Bonding Interfacementioning

confidence: 99%

Research Progress of Palladium-Plated Copper Bonding Wire in Microelectronic Packaging

Zhang,

Guo,

Cao

et al. 2023

Micromachines

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Wire-bonding technology is the most commonly used chip interconnection technology in microelectronic packaging. Metal bonding wire is the key material for wire bonding and plays an important role in the reliability of electronic devices. In recent years, palladium-plated copper (PdCu) bonding wire has been widely used because of its low cost, good electrical and thermal conductivity, the fact that it is not easy to oxidize, and its high reliability. Therefore, it is necessary to review its research progress. In this paper, the preparation and application of palladium-plated copper bonding wire are reviewed. Firstly, the preparation methods of electroplating, electroless plating, and direct plating are introduced. Secondly, the factors affecting the distribution of Pd in free air balls and bonding interfaces, the effect of Pd on the formation and growth of intermetallic compounds in PdCu wire, stitch bond, and reliability of PdCu wire are summarized and analyzed in the application process. Finally, its development prospect is prospected. Hopefully, this review can help readers to have a comprehensive understanding of the preparation and application of palladium-plated copper bonding wires, and can accelerate the promotion of its application in more fields in the future.

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“…Du Yahong et al [ 46 , 47 ] conducted wire bonding experiments using PCC wire on Al pads, establishing a model for the distribution of Pd on the FAB during wire bonding. They also investigated the effects of Pd on the Cu-Al interface reaction during ultrasonic welding.…”

Section: Fab Morphologymentioning

confidence: 99%

Copper Wire Bonding: A Review

et al. 2023

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This paper provides a comprehensive review on copper (Cu) wire bonding. Firstly, it introduces the common types of Cu wire available in the market, including bare Cu wire, coated Cu wire, insulated Cu wire, and alloyed Cu wire. For each type, their characteristics and application areas are discussed. Additionally, we provide detailed insights into the impact of Free Air Ball (FAB) morphology on bonding reliability, including its effect on bond strength and formation mechanisms. Next, the reliability of Cu wire bonding is analyzed, with a focus on the impact of intermetallic compounds and corrosion on bonding reliability. Specifically, the formation, growth, and stability of intermetallic compounds at bonding interfaces are discussed, and their effects on bonding strength and reliability are evaluated. The detrimental mechanisms of corrosion on Cu wire bonding and corrosion inhibition methods are also analyzed. Subsequently, the applications of simulation in Cu wire bonding are presented, including finite element analysis and molecular dynamics simulations, which provide important tools for a deeper understanding of the bonding process and failure mechanisms. Finally, the current development status of Cu wire bonding is summarized, and future research directions are discussed.

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The mechanism of Pd distribution in the process of FAB formation during Pd-coated Cu wire bonding

Cited by 6 publications

References 14 publications

Research Progress on Bonding Wire for Microelectronic Packaging

Research Progress on Bonding Wire for Microelectronic Packaging

Research Progress of Palladium-Plated Copper Bonding Wire in Microelectronic Packaging

Copper Wire Bonding: A Review

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