一种基于Ag-Sn等温凝固的圆片键合技术

研究了用Ag-Sn作为键合中间层的圆片健合。相对于成熟的Au-Sn键合系统(典型键合温度是280℃),该系统可以提供更低成本、更高键合后分离(De-Bonding)温度的圆片级键合方案。使用直径为100mm硅片,盖板硅片上溅射多层金属Ti/Ni/Sn/Au,利用Lift-off工艺来形成图形。基板硅片上溅射Ti/Ni/Au/Ag。硅片制备好后,将盖板和基板叠放在一起送入键合机进行键合。键合过程在N2气氛中进行,键合过程中不需要使用助焊剂。研究了不同键合参数,如键合压力、温度等对键合结果的影响。剪切强度测试表明样品的剪切强度平均在55.17MPa。TMA测试表明键合后分离温度可以控制在500℃左右。He泄漏测试证明封接的气密性极好。

A Ag-Sn Isothermal Solidification Technology For Fluxless Hermetic Wafer Bonding

A new bonding system, Ag-Sn, as the bonding media for wafer level packaging is investigated. Comparing to well developed Au-Sn bonding (typically bonding temperature of 280 ℃), Ag-Sn would provide a lower cost and higher de-bonding temperature wafer-level bonding method. Cap wafer was sputtered with thin films of Ti/Ni/Sn/Au and to form the pattern with the lift-off process. Ti/Ni/Ag was sputtered on substrate wafer. After the metallization the cap wafer and substrate wafer were brought into contact and sent into the bonder. Bonding process was performed in a nitrogen environment and no flux is used. Different bonding parameters such as bonding force and bonding temperature are studied. The average shear strength of 55.17MPa was achieved. TMA indicates the de-bonding temperature is about 500℃. Very good hermeticity was proved by He leakage test.