低成本高可靠堆叠芯片封装技术

A Low Cost and High Reliable Stack Chips Packaging Technology

为了提供高密度存储解决方案,特别是工作站和PC服务器,研讨了堆叠芯片封装(SCP)技术。SCP封装技术的主要特点为:在模塑塑料封装内部SCP包含多个双存储芯片和引线框架;芯片挑选通过丝焊技术选择完成,形成单个芯片存储容量2倍或4倍的封装;采用在引线框架表面电镀金属焊料的方法,使多个引线框架与整体实现电连接;与别的堆叠封装相比,SCP封装既可靠又有成本竞争力,原因在于SCP封装主要采用了模塑塑料封装技术以及金属焊料互连方法。作为电互连方法,广泛地评定Ag/Sn无钎剂钎焊点和Ag高压机械焊点,并成功地提供可靠的电传导路径而无任何信号衰减。温度循环试验和高压蒸煮试验证明,沿焊点不会产生任何微裂纹。

In an attempt to provide a high density memory solution,especially for workstation and PC server,a stack chips package(referred to as“SCP”are as follows:SCP contains a plurality of both memory chips and lead frames within a molded plastic package,chip selection is made through the wire bonding option,resulting in the package with a memory capacity twice or four times that of monolithic chip;plural lead frames are electrically interconnected all at once,using metal solders electroplated on the lead frame surface,and SCP is found reliable and cost competitive when compared to other stack packages because it basically adopts the molded plastic packaging technology as well as the metal solder interconnection method.As electrical interconnection methods,both fluxless soldering joint of Ag/Sn and high pressure mechanical joint of Ag were evaluated extensively and they successfully provided a reliable electrical conduction path without any signal degradation.Temperature cycle test and pressure cooker test were proved not to produce any micro cracks across the joint.