Research on soldering AlN ceramics with Cu substrate using Sn-Ag-Ti solder

Abstract

Purpose This study aims to solder AlN ceramics with a Cu substrate using an active type Sn-Ag-Ti solder. Soldering was performed with power ultrasound. The Sn3.5Ag2Ti alloy was first studied. Design/methodology/approach It was found to contain a Sn matrix, where both Ag phase – ɛ-Ag3Sn – and Ti phases ɛ-Ti6Sn5 and Ti2Sn3 – were identified. Ti contained in these phases is distributed to the interface with ceramic material. A reaction layer was thus formed. This layer varies in thickness from 0.5 to 3.5 µm and ensures the wettability of an active solder on the surfaces of ceramic materials. Findings X-ray diffraction analysis proved the presence of new NTi and AlTi2 phases on the fractured surface. Sn plays the main role in bond formation when soldering the Cu substrate with Sn-Ag-Ti solder. The Cu3Sn and Cu6Sn5 phases, which grow in direction from the phase interface to solder matrix, were found in all cases within the solder/Cu substrate interface. The combination of AlN ceramics/Cu joint maintained a shear strength of 29.5 MPa, whereas the Cu/Cu joint showed a somewhat higher shear strength of 39.5 MPa. Originality/value The present study was oriented towards soldering of AlN ceramics with a Cu substrate by the aid of ultrasound, and the fluxless soldering method was applied. Soldering alloy type Sn-Ag-Ti was analysed, and the interactions between the solder and ceramic and/or Cu substrate were studied. The shear strength of fabricated soldered joints was measured.

Characterization of Sn–Sb–Ti Solder Alloy and the Study of Its Use for the Ultrasonic Soldering Process of SiC Ceramics with a Cu–SiC Metal–Ceramic Composite

“…Based on the previous studies [14,22], it was supposed that the active Ti element will be concentrated in the boundary with the ceramic SiC material, where it will form new phases. The interaction of titanium was observed in the solder/SiC ceramics boundary (Figure 18 and Table 7), whereby a higher amount of Ti was precipitated in this boundary.…”

“…Titanium is the most frequently used element that is added to soldering alloys, but other active metals are also used. The performance of solders alloyed with titanium is documented in many studies [10][11][12][13][14][15][16][17]. Titanium allows wetting and soldering of Ti, Al, Si, glass, and different types of ceramics owing to the activation of soldered surfaces [18,19].…”

“…Subsequently, these substrates with molten solder were placed on each other and the joint was formed. We have reported this procedure of soldered joint fabrication in another study [14]. The schematic representation of this process is shown in Figure 4.…”

Characterization of Soldering Alloy Type Bi-Ag-Ti and the Study of Ultrasonic Soldering of Silicon and Copper

“…From the planar distribution (Figure 15b) it is obvious that Ti significantly contributes to bond formation, together with silver (Figure 15d). Based on the previous studies [21,25], it was assumed that the active element, Ti, will concentrate in the boundary with the silicon, where it will form the new phases. Thus, the presence of a new phase, TiSi2, was proved.…”

“…They attained an average shear strength of 45.3 MPa. In our previous work [21], we also carried out research on the soldering of AlN ceramics with Sn-Ag-Ti based solder. The effect of Ti in the joint boundary was clearly proved.…”