金屬間化合物的形成機理
(重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 對255 ℃時Sn-6.5Zn釬料/Cu基板界面反應(yīng)及金屬間化合物的形成與轉(zhuǎn)化進行熱力學(xué)計算與分析，并利用SEM、EDS、XRD研究分析255 ℃不同釬焊時間條件下釬料/Cu基板界面組織與IMC層形態(tài)特征。結(jié)果表明：Sn-6.5Zn釬料/Cu焊點界面緊靠Cu基板側(cè)形成CuZn層；CuZn IMC有與釬料中的Zn原子繼續(xù)反應(yīng)生成Cu5Zn8 IMC的趨勢；在相同釬焊溫度條件下，不同釬焊時間對界面厚度影響不大；隨釬焊時間延長，Sn-6.5Zn釬料/Cu基板焊點界面IMC層的平均厚度增大，界面粗糙度則由于不同釬焊時間IMC在液態(tài)釬料中生長與溶解的差異，呈現(xiàn)先增大而后降低到一個均衡值的變化趨勢。
關(guān)鍵字: Sn-6.5Zn釬料；界面；金屬間化合物；熱力學(xué)；粗糙度
（College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:The interfacial reaction of Sn-Zn solder/Cu substrate soldered at 255 ℃ and the formation and transformation of intermetallic compounds (IMC) were investigated by the thermodynamic calculation and analysis. The interface of the joint produced at 255 ℃ with various soldering times was analyzed by scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results show that CuZn IMC forms preferentially within the Cu substrate. The Cu5Zn8 IMC forms by the reaction of CuZn with Zn atoms diffused from the solder. The effect of the soldering time on the interface thickness at the same soldering temperature is slight. With prolonging soldering time, the interface thickness between Sn-6.5Zn solder and Cu substrate increases, and the interface roughness reaches obviously a maximum value, and then decreases to a stable value, which is due to the non-uniform growth and dissolution of dendrite in liquid solder.
Key words: Sn-6.5Zn solder; interface; intermetallic compound; thermodynamics; roughness
