基于剪切力学行为下的BGA板级封装可靠性
发布时间：2018-08-04 17:45
【摘要】：焊点作为连接芯片与基板的介质,在电子封装中扮演着至关重要的角色,在微电子产品的正常工作中,焊点在高温和负载的交互作用下,一方面起到传输物理信号的作用,同时还提供着机械保护和热传导的作用。焊点内各材料的热膨胀系数不匹配,极易在体钎料/IMC界面处产生结构缺陷并诱发热疲劳裂纹的萌生及扩展,最终导致焊点以剪切断裂的形式失效。因此,研究焊点的剪切力学行为显得尤为迫切。采用试验的方法对Sn-3.0Ag-0.5Cu、Sn-0.3Ag-0.7Cu、Sn-0.3Ag-0.7Cu-0.07La和Sn-0.3Ag-0.7Cu-0.07La-0.05Ce焊点施加剪切载荷,旨在研究加载速率(0.01mm/s、0.05 mm/s、0.5 mm/s、1 mm/s和2 mm/s)、焊点尺寸(500μm、700μm和900μm)、焊盘成分(Cu/SAC/Cu和Ni/SAC/Ni板级结构)和回流组装顺序(Cu/SAC/Ni和Ni/SAC/Cu板级结构)以及时效处理(160℃下时效0天、10天、20天、30天和40天)对BGA板级结构焊点力学性能的影响规律,研究表明:四种单界面焊点的剪切强度和至断位移均大于板级结构中的焊点,板级结构中添加稀土元素的低银焊点剪切力学性能得到了很大的改善,基本与高银焊点的剪切强度相当,尤其是Cu/SAC0307-0.07La-0.05Ce/Cu焊点的剪切强度表现更为突出。单板结构中焊点断裂在体钎料上,而板级结构中焊点断裂在体钎料/IMC的界面处。板级结构中剪切断裂与实际工况更为相近,断口形貌充分反应出其断裂机理。在Cu/SAC/Cu板级结构中,高银焊点的剪切强度随着加载速率的增加呈现先增加后降低的变化趋势,另外三种焊点剪切强度持续增加。至断位移均随加载速率的增加而降低,但高银焊点降幅较大。加载速率由低速向高速转变时,高银焊点的断裂位置由体钎料/IMC处向IMC转变;低银焊点的断裂位置则由体钎料向体钎料/IMC处转变;加入稀土元素的低银焊点的断裂位置仅是在体钎料上向IMC方向上发生了一定的偏移。随着焊点尺寸的减小,焊点的剪切强度逐渐增加,至断位移逐渐减小,剪切应变则呈现先增加后降低的变化趋势,断裂位置向体钎料转移。Ni/SAC/Ni板级结构焊点的剪切强度和至断位移均大于Cu/SAC/Cu板级结构焊点。Cu/SAC/Cu板级结构焊点断裂在体钎料/IMC界面处,Ni/SAC/Ni板级结构焊点断裂位置均发生在体钎料上。Cu/SAC/Ni结构中的剪切强度和至断位移均低于Ni/SAC/Cu板级结构。对于Cu/SAC/Ni板级结构焊点均断在Cu/SAC侧;对于Ni/SAC/Cu板级结构焊点基本断在Ni/SAC侧。Cu/SAC/Cu和Ni/SAC/Ni板级结构焊点的剪切强度和至断位移均随时效时间的延长而降低,但Cu/SAC/Cu焊点的下降速率大于Ni/SAC/Ni焊点。在时效初期两种结构中焊点的剪切强度均出现了大幅降低。此外,在两种结构中,加入稀土元素的低银焊点的抗时效能力优于高银焊点,表现出良好的剪切力学性能,尤其是Ni/SAC0307-0.07La-0.05Ce/Ni焊点的力学行为表现更为明显。
[Abstract]:Solder joint, as the medium connecting chip and substrate, plays an important role in electronic packaging. In the normal operation of microelectronic products, solder joint plays the role of transmitting physical signal under the interaction of high temperature and load. It also provides mechanical protection and heat conduction. Because of the mismatch of thermal expansion coefficient in solder joints, structural defects can easily occur at the interface of solder / IMC, and the initiation and propagation of thermal fatigue cracks will lead to the failure of solder joints in the form of shear fracture. Therefore, it is urgent to study the shear mechanical behavior of solder joints. Shear loads were applied to Sn-3.0 Ag-0.5CuN Sn-0.3Ag-0.7CuN Sn-0.3Ag-0.7Cu-0.07La and Sn-0.3Ag-0.7Cu-0.07La-0.05Ce solder joints. The aim of this study was to study loading rate (0.01mm / s 0.05mm / s) 0.5 mm / s (1 mm/s and 2 mm/s), solder joint size (500 渭 m, 700 渭 m and 900 渭 m), pad composition (Cu/SAC/Cu and Ni/SAC/Ni plate-grade structure), reflow assembly sequence (Cu/SAC/Ni and Ni/SAC/Cu plate-grade structure) and aging treatment (160 鈩，
本文编号：2164630
[Abstract]:Solder joint, as the medium connecting chip and substrate, plays an important role in electronic packaging. In the normal operation of microelectronic products, solder joint plays the role of transmitting physical signal under the interaction of high temperature and load. It also provides mechanical protection and heat conduction. Because of the mismatch of thermal expansion coefficient in solder joints, structural defects can easily occur at the interface of solder / IMC, and the initiation and propagation of thermal fatigue cracks will lead to the failure of solder joints in the form of shear fracture. Therefore, it is urgent to study the shear mechanical behavior of solder joints. Shear loads were applied to Sn-3.0 Ag-0.5CuN Sn-0.3Ag-0.7CuN Sn-0.3Ag-0.7Cu-0.07La and Sn-0.3Ag-0.7Cu-0.07La-0.05Ce solder joints. The aim of this study was to study loading rate (0.01mm / s 0.05mm / s) 0.5 mm / s (1 mm/s and 2 mm/s), solder joint size (500 渭 m, 700 渭 m and 900 渭 m), pad composition (Cu/SAC/Cu and Ni/SAC/Ni plate-grade structure), reflow assembly sequence (Cu/SAC/Ni and Ni/SAC/Cu plate-grade structure) and aging treatment (160 鈩，
本文编号：2164630
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