大尺寸LCCC封装器件装联研究

Study on Solder Interconnection in Large Size LCCC Package Devices

LCCC器件具有小型化、高密度和高散热性能等特点,在军工领域中被广泛应用。但因其与FR-4印制板间存在较大CTE差异,在宇航产品真空、高低温循环的特殊环境条件下,会导致器件焊点的长期可靠性下降或失效,使其在宇航产品中的使用受到制约。以大尺寸LCCC44封装器件为研究对象,对其焊点进行可靠性理论计算和试验分析,在此基础上提出了一种LCCC器件新型植球装联方法,可以有效提高器件的装联可靠性:

Because of its small size,good electrical properties and thermal conductivity,the Leadless Ceramic Chip Carrier（LCCC） package is widely used in the military.However,due to the big mismatch of the coefficient of thermal expansion between LCCC and FR-4 printed circuit board（PCB） substrate,the creepfatigue damage of solder joints is prone to take place and lead the further failure of product as a result of the long service of high vacuum thermal stress space environment.An improved solder interconnection procedure has been proposed,the large 44 pins sized device with dimension of 16.5 mmx16.5 mm was selected and employed to study the large LCCC package issue.Some research has been done through the theoretical calculation analysis,indicating that the increased height between LCCC and PCB can improve the yield rate of devices significantly.Therefore,present a reballing method which can significantly improve the reliability of the solder joint and reduce the average failure rate of devices.