月壤侵彻环境下控制器温循与振动可靠性评估优化  

Reliability Evaluation and Optimization of Temperature Cycle and Vibration for the Controller in Lunar Soil Encroachment Environment

作　　者：师航波 盖瑞 李逵 刘曦[1] 葛坚定 马荟 Shi Hangbo;Gai Rui;Li Kui;Liu Xi;Ge Jianding;Ma Hui(Xi'an Microelectronics Research Institute,Xi'an 710000,China)

机构地区：[1]西安微电子技术研究所,西安710000

出　　处：《半导体技术》2023年第11期1045-1052,共8页Semiconductor Technology

摘　　要：相较于传统航天器,月壤探测器所经历的环境具有高冲击量级和结构小型化的特点,为提高月壤探测器在侵彻环境下的可靠性,需对其内部的控制器结构进行加固灌封设计。以控制器内部关键薄弱部位——超尺寸无引线封装(LCC)器件和堆叠组装(PoP)器件为研究对象,建立温循条件下的热应力有限元模型,重点关注焊点的应力和寿命。结果表明PoP器件的焊点应力和应变都很小,其寿命循环次数远超过200次,满足热学条件下的可靠性要求。对有一定风险的LCC器件进行工艺方案优化设计,对比不同灌封胶对其焊点的影响。经过分析可知:在热学温循条件中不同灌封胶直接影响LCC器件的焊点应力和寿命;在力学随机振动条件下,不同灌封胶对焊点应力影响很小,但相比无灌封胶情况,其焊点应力可大幅度减小。最终选用DB9002灌封胶,LCC器件在热学条件下的焊点最大应力约为53.1 MPa,焊点寿命为4515次,力学条件下的焊点最大应力约为7.16 MPa,其温循条件和振动条件下的可靠性均得到明显改善。Compared with traditional spacecraft,the lunar soil probe is subjected to an environment with high impact level and small structural size.To improve the reliability of the lunar soil probe in the encroachment environment,the internal controller structure needs to be reinforced and sealed.With the oversized leadless chip carrier(LCC)device and package on package(PoP)device which are critical weak points inside the controller as the research objects,a thermal stress finite element model was established under temperature cycling conditions,focusing on the stress and lifetime of the solder joints.The results show that the stress and strain of solder joints of the PoP device are very small,and its lifetime cycle far exceeds 200 times,meeting the reliability requirements under thermal conditions.For the LCC device with certain risks,the process scheme was designed and optimized,and the influence of different potting adhesives on its solder joints was compared.The analysis reveals that different potting adhesives directly affect the stress and lifetime of solder joints of the LCC device under thermal temperature cycling conditions.Under mechanical random vibration condition,the influence of different potting adhesives on solder joint stress was minimal.However,compared with the absence of potting adhesive,the stress on solder joints can be significantly reduced.Finally,the DB9002 potting adhesive was selected,and the LCC device achieves a maximum solder joint stress of about 53.1 MPa and a lifetime of 4515 times under thermal conditions,and a maximum solder joint stress of about 7.16 MPa under mechanical conditions improving the reliability under both temperature cycling and vibration conditions.

关 键 词：月壤探测器 超尺寸器件 灌封胶 可靠性评估 温循条件 振动条件 

分 类 号：TN406[电子电信—微电子学与固体电子学]