Searching for new Sn-Ag-Cu based lead free solders with low melting temperature using a thermodynamic modeling method

AIM Solders是一家总部位于加拿大的公司，主要生产电子行业的锡铅和无铅焊料组装材料，对无铅焊料的开发有着浓厚的兴趣。焊料在材料工业中发挥着重要作用，特别是在电子封装应用中[1，2]。铅是锡基钎料中传统的合金元素，但对人体健康有害。因此，在世界上最重要的市场（美国，中国，欧盟和日本），禁止使用含铅焊料的新法律已经实施。因此，发展无铅焊料势在必行。目前商业化的无铅焊料主要基于Sn和几种合金元素（Ag、Cu、Bi、Ni、Zn和Sb等）。Sn-Ag-Cu合金（如SAC 305）是最常用的无铅焊料。然而，与Sb-Pb焊料相比，Sn-Ag-Cu基合金的主要问题是其相对较高的第一熔化温度（称为共晶温度）。AIM焊料需要我们小组的帮助来解决这个问题，并找到具有较低共晶温度的Sn-Ag-Cu-X-Y多元合金的成分。 本计画将在未来五个月内，以有效且可操作的方式，寻找并设计新的低共晶温度的锡银铜基焊料。

AIM Solders is a Montreal-based company leading the global manufacturing of tin-lead and lead-free solders assembly materials for the electronics industry, which has a strong interest for the lead-free solders development. Solders play an important role in the materials industry especially in the electronic packaging applications [1, 2]. Lead (Pb) is the traditional alloying element in Sn-based solders, but is harmful to human health. So in the most important markets of the world (USA, China, EU, and Japan), new laws banning the use of Pb containing solders have been imposed. Therefore, the requirement of development lead-free solders is imperative. Current commercial lead-free solders are mainly based on Sn with several alloying elements (Ag, Cu, Bi, Ni, Zn, and Sb etc.). Sn-Ag-Cu alloys (like SAC305) are the most used lead-free solders. However, the main problem of Sn-Ag-Cu-based alloys is its relatively high first melting temperature (called eutectic temperature) in comparison with Sb-Pb solders. AIM Solders requires the assistance from our group to solve this problem and find compositions of Sn-Ag-Cu-X-Y multicomponent alloys with lower eutectic temperatures. The present project will be aimed at searching and designing new Sn-Ag-Cu-based solders with low eutectic temperature in an effective and operable way within a period of 5 months.