Low Temperature Bonding of Alumina/Alumina and Alumina/Copper in Air Using Sn3.5Ag4Ti(Ce,Ga) Filler

Abstract

Sn3.5Ag4Ti(Ce,Ga) active filler was used for joining alumina with alumina and alumina with copper at 250°C in air. The joining process was done without flux and without the need for pre-metallization of alumina or a protective atmosphere. After mechanical activation of the bonding surfaces of alumina and copper, the filler showed good wetting on both alumina and copper and led to a strong bond between alumina and copper. Through tensile testing, a bonding strength of 23.7 MPa was found in the alumina/copper joint region. The shear strengths for alumina/alumina, copper/copper and alumina/copper joints were 13.5, 14.3, and 10.2 MPa, respectively. The affinity of cerium for oxygen protects titanium from oxidation, giving rise to the reaction of titanium with alumina at such a low temperature. Electron probe microanalyzer (EPMA) elemental mapping revealed that titanium segregates effectively at the alumina/solder interfaces. After aging tests at 200°C and 150°C, a double layer of Cu 3 Sn and Cu 6 Sn 5 intermetallic compound was formed at the solder/ copper interfaces. With an increase of aging periods, the amount of brittle compound in the joints increased and resulted in decreases in the shear strengths of the alumina/copper joints.

Active soldering of ZnS–SiO2 sputtering targets to copper backing plates using an Sn3.5Ag4Ti(Ce, Ga) filler metal

“…EPMA elemental mapping, shown in Fig. 9(b and c), indicates the segregation enrichment of Ti and Ce at the ZnS-SiO 2 /solder interface, which was also observed in prior studies of ITO/Cu and alumina/Cu joints with the active solder Sn3.5Ag4Ti(Ce, Ga) (Chang et al, 2003b;Chang et al, 2007).…”

Effects of titanium on active bonding between Sn3.5Ag4Ti(Ce,Ga) alloy filler and alumina

“…conducted research on it. Chang [10] only took some simple observation of the interface microstructure and performed tests on the mechanical properties of the joints. Koleňák [11] only performed tests on the mechanical strength of the joints fabricated by ultrasonic activation in air, did not analyze the micro interface.…”

Study of Direct Bonding of Ceramic and Metallic Materials with Zn4Al Solder

“…A nano-crystalline α-Al 2 O 3 layer (2 nm thick) was formed in the Sn-Zn-Al/sapphire boundary during soldering in the air at a temperature of 230°C. The shear strength of joints measured 43 to 48 MPa, which is a relatively high value when compared to other Al 2 O 3 ceramic joints fabricated with active Sn solders and the addition of Ti and/or lanthanides [3,4,5].…”