激光重熔PBGA钎料球与Au/Ni/Cu焊盘的界面反应

INTERFACIAL REACTION BETWEEN PBGA SOLDER BALL AND Au/Ni/Cu PAD DURING LASER REFLOW

研究了塑料球栅阵列（ＰＢＧＡ）钎料球激光重熔过程中钎料与Ａｕ／Ｎｉ／Ｃｕ焊盘之间的界面反应 结果表明： 界面处金 属间化合物的生成与激光输入能量密切相关． 当激光输入能量较小时，焊盘上的Ａｕ没有完全溶解到钎料中．界面处存在一层连续 的 ＡｕＳｎ２和一些垂直或斜向生长到钎料中的针状 ＡｕＳｎ４化合物． 增大激光输入能量．Ａｕ完全溶解到钎料中，界面处连续的 ＡｕＳｎ２化合物层全部转化为针状 ＡｕＳｎ４相、有部分 ＡｕＳｎ４针从界面处折断并落入钎料中．当激光功率为 １８ Ｗ，激光加热时 间为 ４００ ｍｓ时，ＡｕＳｎ４相在界面处消失、以细小颗粒弥散分布在钎料内部．

Interfacial reaction between plastic ball grid array (PBGA) solder ball and Au/Ni/Cu pad during laser reflow soldering was studied. Results show that the morphology of intermetallic compounds at interface is strongly influenced by laser input energy. When laser input energy was small, a continuous AuSn2 layer and needle-like AuSn4 are found at the interface, With the increase of laser input energy, all the continuous AuSn2 layer converts into needle-like AuSn4, and some needle-like AuSn4 phases break off at the interface and fall into the solder. With the increase of laser input further, all the AuSn4 phases disappear at the interface, distributing evenly inside the solder as small particles.