Investigation of the effect of indium addition on wettability of Sn‐Ag‐Cu solders

Abstract

Purpose -The purpose of this paper is to investigate the influence of In additions on the wetting properties of the Sn2.86Ag0.40Cu (in wt%) eutecticbased alloys, on a copper substrate, in the presence of a flux. The main goal was to find correlations between the results of the wetting balance (WB) and the sessile drop (SD) method, in relation to the contact angles. Design/methodology/approach -The WB method was applied for the wetting measurements, at 2508C, in an air atmosphere and in the presence of a flux. The SD measurements were conducted at the same temperature, in the presence of the same flux, but in an Ar atmosphere, while the maximum bubble pressure (MBP) and dilatometric measurements were conducted in an Ar þ H 2 atmosphere. The density data from the dilatometric method were used for the determination of the surface tension by means of MBP, and the WB method was used to determine the surface and interfacial tension. Next, the surface tension data from these two methods were compared. The WB data were used to calculate the contact angles and the obtained indirect data were compared with the results of the direct SD measurements of the contact angle. Findings -A higher In content in the alloy resulted in a lower contact angle on the copper, and the WB results agreed well with the results of the SD experiments. It was confirmed that, in liquid In-Sn and the alloys containing In and Sn (Ag-In-Sn, Sn-Ag-Cu-In, Sn-Zn-In), the improvement of the wettability was indicated only by the increase of the contact angle with the increasing In content. Research limitations/implications -Further studies are necessary for the confirmation of practical application, but they should be directed to the soldering of high indium alloys on printed circuit boards, with different finishes and qualities of the solder joint performance. Practical implications -Taking into account the contact angle data from the WB and SD methods, the best results of the SAC-In alloy on copper were obtained for the alloy of the highest In content. It was found that the contact angles from SD after 4 s were higher (non-equilibrium conditions) than the values calculated from WB after 3 s. In contrast, the contact angles from SD after 10 min (equilibrium conditions) were lower than those from WB after 3 s. The comparison suggests that the contact angles from WB are situated within the data from SD, showing the same lowering tendency with the increasing content of In, and they may be well accepted for practical purposes. On the other hand, the sample of the solder in the SD method, after a prolonged time -in order to get the equilibrium contact angle -may be used to study the interfacial phenomena with the Cu substrate. The differential thermal analysis results indicate that the melting temperature decreases with increasing tin concentration. Taking into account the results of this study and the available literature data, alloys containing 8-10 wt% of In can be recommended for practical application. Originality/value -The WB and SD methods were used fo...

Thermophysical properties and wetting behavior on Cu of selected SAC alloys

“…For comparison, viscosity measurements were carried out with the modified capillary (MC) method over the range 563-1,124 K, as described in detail in Gancarz et al (2011). The density of the liquid alloys was also measured with a dilatometric method (Moser et al, 2001) over the range 518-1,186 K, the surface tension with a maximum bubble pressure (MBP) method (Moser et al, 2001) over the range 524-1,177 K and, for comparison, with a wetting balance (WB) method (Miyazaki et al, 1997) at 523 K. The studies of wetting behaviour were conducted with the use of sessile drop (SD) and WB methods according to the procedure described in detail in Moser et al (2011). Copper plates 25 £ 20 £ 0.2 mm were used for wetting angle measurements in the SD method.…”

Physicochemical Properties of Sn-Zn and SAC + Bi Alloys

“…Sn2.56Ag0.27Cu11.45Bi, [35] Sn3.13Ag0.58Cu3.51In, [6] Sn3.04Ag0.41Cu, [16] Sn10Pb, [34] SAC+3%Bi SAC+3%Bi Fig. 5.…”

“…Temperature dependence of density of SAC + 3Bi alloys obtained by two measurement methods (DC, Dl) in this study along with literature data. 6,16,27 A comparison between the calculated results based on Eq. 7 and the measured values for SAC + 3.07Bi and Sn-9Zn is shown in Fig.…”

“…The first group are alloys based on the Sn-Ag-Cu system (SAC) with addition of different metals. [1][2][3][4][5][6] Sn-Zn alloys with additions such as Cu, Ag, In, Sb, and Bi [7][8][9][10][11][12][13] form the second group. Studies of the mechanical and technological properties (wettability, wear, etc.)…”

Physicochemical Properties of Sb-Sn-Zn Alloys

“…4 Eutectic Sn-Zn alloys [5][6][7][8] form the second most interesting group of metallic materials for use in the electronics industry, the first being the triple eutectic Ag-Sn-Cu (SAC) alloys. [9][10][11] The most frequently used solder modifiers for Sn-Zn eutectic are bismuth, indium, and antimony. [12][13][14] Antimony addition is used to improve the mechanical properties and increase the melting temperature range from 472 K to 500 K. 15 Addition of antimony to SAC with composition Sn-3.5Ag-0.7Cu (at.%) increases its tensile strength, 16 with the best results observed for 1 at.% Sb content.…”