回流次数和Ag含量对(Au-20Sn)-xAg/Cu焊接界面组织与剪切强度的影响

摘要

以(Au-20Sn)-xAg(x=0,0.5,1,2)作为焊料,将2块纯铜板进行回流焊接,研究回流次数与焊料中的Ag含量对(Au-20Sn)-Ag/Cu 焊接界面的组织与剪切强度的影响.结果表明:一次回流焊接后,焊接界面组织由(Au,Ag,Cu)5Sn组成,回流次数增加到50次时,界面出现CuAu层,当回流次数增加到100次时,在靠近基板一侧出现Cu3Au层.添加Ag元素可抑制焊接界面金属间化合物层的生长.一次回流焊接的界面剪切强度随焊料中Ag含量增加而逐渐提高,(Au-20Sn)-xAg/Cu(x=0,0.5,1,2)界面的剪切强度分别为92.14,93.59,95.65和98.43 MPa.剪切强度随回流次数增加而降低,降低的幅度随Ag含量增加而减小.%Two pure Cu plates were bonded using(Au-20Sn)-xAg(x=0.5,1,2)as solder.The effects of reflow number and Ag content on the microstructure and shear strength of(Au-20Sn)-Ag/Cu solder joint were studied.The results show that IMC(intermetallic compound)in the joint line is composed of(Au,Ag,Cu)5Sn after one reflow.The CuAu layer appears after 50 reflows.Lastly,Cu3Au layer appears beside the Cu substrate after 100 reflows.The addition of Ag can suppress the growth speed of the IMC.When reflow number is one,the shear strength of solder joint increases with increasing Ag content.The shear strength of(Au-20Sn)-xAg/Cu(x=0,0.5,1,2)are 92.14,93.59 and 98.43 MPa,respectively.The shear strength decreases with increasing reflow number,and the decreasing rate decreases with increasing Ag content.