Ultrafast air bonding between SiC ceramic and SnAgTi alloy under the action of ultrasounds

Abstract

With the aim of overcoming the limitations of traditional soldering ceramic methods for power device packaging, a simple but ultrafast bonding technology is reported. The effect and mechanism of ultrasonic action on the interfacial bonding and microstructure is investigated and thoroughly discussed. An ultrafast interfacial bond between SiC ceramics and SnAgTi active solder has been successfully achieved through a reaction at the interface at a low temperature of 250 °C in the extremely short time. High-resolution transmission electron microscopy (HRTEM) revealed that a silica layer on the surface of SiC reacted with Ti from the SnAgTi active solder to form a nanometer-thickness amorphous titania layer at the interface under the ultrasonic action, which creates an exceptional interfacial structure and facilitates bonding between the two dissimilar crystals. A discontinuous titania layer at the interface was identified within 0.1 s. With further increasing ultrasonic action time to 1 s, a continuous titania layer with a thickness of 7.6 ± 0.5 nm formed at the interface. A new interfacial reaction mechanism was revealed and it was found that ultrasound accelerated the reaction of liquid active solder/ceramic. Our finding demonstrated that ultrasound could be an effective approach for joining ceramics which is difficult to wet by a liquid metal at low temperature. The combined impact of ultrasonic cavitation and streaming dominated the mechanism and kinetics of the rapid interfacial reaction.

Ceramic-to-metal bonding using rare-earth containing Sn–Bi solder

“…As illustrated in Fig. 1 , the active solder facilitates the direct bonding to glass substrates through the following process [ 17 , 20 – 22 ]: (i) At the start of the soldering process, RE elements freely diffuse within the molten solder; (ii) Upon reaching the glass interface, the RE elements form covalent bonds with exposed oxygen atoms on the glass surface, allowing the absorption and accumulation of RE elements from the solder; (3) As the soldering time increases, more RE elements diffuse towards the glass interface, initiating a reaction between the RE elements and SiO 2 . This reaction ultimately forms a thin interfacial layer, resulting in strong bonding between the glass and the solder.…”

Evolution behavior of cavitation bubble in pure Sn liquid medium with narrow gap under low-amplitude ultrasound

“…Based on the vibration decay of the large-area flat metal substrates, the cavitation bubbles accompanied by the nucleation, oscillation and collapse [3] , [4] processes could present two modes, including transient cavitation and steady cavitation [4] , [5] , [6] , in the liquid metal. Meanwhile, the cavitation bubbles could form micro-jet and acoustic streaming [7] , [8] near the substrate wall, resulting in the breaking the oxide film [9] , [10] on the metal substrate surface and the discharge of gas in the liquid solder [11] . Therefore, it is essential to analyze the shape evolution and the migration of the cavitation bubble in the narrow-gap soldering seam, in order to improve the soldering process and the mechanical properties of the joints.…”

Study of Wettability and Solderability of SiC Ceramics with Ni by Use of Sn-Sb-Ti Solder by Heating with Electron Beam in Vacuum

“…Wu et al [ 21 ] investigated the microstructural evolution of SiC joints that were soldered using Zn-Al filler metals with the assistance of ultrasound. Their other works [ 22 ] studied these joints using Sn-Zn-Al and Sn-Ag-Ti solder alloys [ 23 ]. In their works, the authors claim that ultrasonic cavitation-induced heterogeneous nucleation was the refinement mechanism of the bond layer of the joints, and that ultrasonic action improved the shear strength of these joints.…”