Ultrasonically enhanced flux-less bonding with Zn-5Al alloy under ambient condition for high-temperature electronics interconnects

Liu, Canyu; Liu, Allan; Su, Yuezeng; Chen, Yi; Zhou, Zhaoxia; Liu, Changqing

doi:10.1016/j.jmapro.2021.10.065

Cited by 11 publications

(3 citation statements)

References 38 publications

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“…Currently, only soft solders have been applied in electronics packaging, which have melting points below 450 °C. In comparison, the hard solders or brazing alloys have liquidus temperatures above 450 °C, but there has been a very limited attempt intending to apply brazing alloys in electronics assembly due to their high process temperature if using the conventional reflow method [3]. It is desirable if Pb-free interconnection materials with high melting points can be assembled by low-temperature processing technology.…”

Section: Introductionmentioning

confidence: 99%

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Liu,

Zhou,

Liu

2023

IMAPSource Proceedings

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There has been growing interest in wide bandgap (WBG) semiconductors including SiC and GaN due to the increasing demands for electronic devices serving at high temperatures. However, to maximise the potential capacity of WBG devices, new high-temperature interconnection materials and processes are indispensable as the current existing Sn-based solder alloys and bonding processes developed for Si devices are unable to meet the reliability requirements. In the present work, reactive brazing alloys including Cu-15Ag-5P and Incusil (Ag-27.25Cu-12.5In-1.25Ti) with melting points above 600°C have been utilized as the interconnection materials which offer excellent properties under high operation temperature. The self-propagating exothermic reaction (SPER) was applied for the bonding process via an intense rapid local heating and cooling at a millisecond scale. The strong Cu/Cu-15Ag-5P/Cu and Cu/Incusil/Cu sandwich bonded structures have been created with the assistance of SPER, where the nanofoil was applied from the outside of stacked structures as an external heat source and the bonding process was conducted in the ambient atmosphere without using flux. It has been found that the P element in Cu-15Ag-P alloy has the self-flux effect, which is beneficial for the ultra-fast interfacial reaction process. The experiments where the nanofoil was placed inside of stacked structures between two sheets of brazing alloys have also been conducted, which exhibited the well-bonded interface microstructures between nanofoil and brazing alloys. The outlook on the design for practicality and industrial uses for SPER-assisted bonding with brazing alloys has also been discussed, as a potential viable assembly route for the high-temperature and high-power electronics packaging.

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Section: Introductionmentioning

confidence: 99%

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Liu,

Zhou,

Liu

2023

IMAPSource Proceedings

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“…Zn-Al alloys are reasonable candidates as hightemperature solder materials because they have a melting point above 350°C, excellent thermal and electrical conductivity, and good mechanical properties [8,9]. However, Zn-Al solder is easily oxidized and has poor wettability, requiring special processes such as joining with a strong flux or applying ultrasonic waves [10]. Therefore, it is important to consider joining methods that do not require these special processes for Zn-Al solder.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of High-Temperature Solder by Zn Plating Films Containing Al Particles

Kobayashi,

Abiko,

Shohji

2023

KEM

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This study investigated the microstructure and melting point of the Zn–Al composite electroplating film. The cross-sectional microstructure and shear strength of the joints made from the plating films were also evaluated. Zn and Al were confirmed in the plating films from initial microstructure observation. The plating film prepared by a plating bath without cationic surfactant melted near the melting point of Zn and the eutectic point of Zn–Al. When jointed at a joining temperature of 443°C, joining pressure of 5 MPa, and holding time of 5 min, multiple intermetallic compounds, Zn–Al eutectic layers, and unreacted Al particles were observed in the joint layer. From quantitative analysis, the multiple intermetallic compounds were estimated to be Zn–Ni and Zn–Al–Ni intermetallic compounds. The shear strength of the joints increased with increasing joining pressure but was lower than that of Sn–5Sb solder. Fracture after the shear test was observed at the interface between unreacted Al particles and Zn–Al–Ni intermetallic compounds, and inside unreacted Al particles.

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“…Although they are widely used as interconnection materials, they are not suitable for high-temperature applications. High MP solders (e.g., >320 °C), for example, lead-based solder, are harmful to the environment, gold-based solder is high-cost, and bismuth-based solder and zinc-based solder have poor electrical conductivity. − Thus, alternative reliable interconnection materials that can withstand high temperature are urgently needed.…”

Section: Introductionmentioning

confidence: 99%

Robust Cu–Cu Bonding with Multiscale Coralloid Nano-Cu₃Sn Paste for High-Power Electronics Packaging

Guo

Liu

et al. 2022

ACS Appl. Electron. Mater.

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In this work, a multiscale coralloid nano-Cu3Sn composed of a bimodal structure (∼55 and ∼120 nm) has been successfully synthesized to meet low-cost and Pb-free packaging demands for high-power electronic application. Owing to the excellent oxidation resistance of the Cu3Sn intermetallic compounds (IMCs) and the protection of solvent poly(ethylene glycol)-400 (PEG-400) at high temperature, the full-Cu3Sn joints sintered in air have a comparative shear strength with the joints acquired in vacuum when the sintering temperature is no more than 300 °C. The full-Cu3Sn joints acquired at 300 °C in air achieve a high bonding strength of 40.4 MPa, which is superior to those of traditional Sn-based solder joints (19 MPa) and full-Cu6Sn5 joints (17.7 MPa). The electrical resistivity of the sintered Cu3Sn films reaches 29.1 μΩ·cm in air. Cu3.02Sn0.98 is formed at the interface between the Cu substrate and sintered Cu3Sn layer, contributing to the exceptional bonding strength of the full-Cu3Sn joints. The bonding strength of the joints after high-temperature storage (HTS) tests reveals that the prepared full-Cu3Sn joints possess outstanding long-term thermal stability with a shear strength of 47.9 MPa after 800 h of storage at 250 °C. Our work breaks through the synthesis bottleneck of nano-Cu3Sn IMCs and provides the underlying insights needed to guide the design of highly stable full-IMC joints for high-temperature electronic packaging.

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Ultrasonically enhanced flux-less bonding with Zn-5Al alloy under ambient condition for high-temperature electronics interconnects

Cited by 11 publications

References 38 publications

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Fabrication of High-Temperature Solder by Zn Plating Films Containing Al Particles

Robust Cu–Cu Bonding with Multiscale Coralloid Nano-Cu₃Sn Paste for High-Power Electronics Packaging

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Ultrasonically enhanced flux-less bonding with Zn-5Al alloy under ambient condition for high-temperature electronics interconnects

Cited by 11 publications

References 38 publications

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

Fabrication of High-Temperature Solder by Zn Plating Films Containing Al Particles

Robust Cu–Cu Bonding with Multiscale Coralloid Nano-Cu3Sn Paste for High-Power Electronics Packaging

Contact Info

Product

Resources

About

Robust Cu–Cu Bonding with Multiscale Coralloid Nano-Cu₃Sn Paste for High-Power Electronics Packaging