扇出型晶圆级封装可靠性问题与思考

Pondering on the reliability of fan-out wafer-level packaging

半导体先进制程工艺逐步趋于极限,继续沿摩尔定律发展的脚步放缓,而扇出型晶圆级封装(Fan-out Wafer Level Packaging,FOWLP)通过晶圆重构的方式突破了传统扇入封装的I/O引出端的数量限制,并利用多层再布线(Redistribution Layer,RDL)等技术,缩小引脚间距,减薄封装厚度,降低高频信号传输损耗,从而进一步提升芯片集成度。近年来已在消费电子、高性能计算等领域逐渐发展成为具有代表性的先进封装技术,是接续摩尔定律的关键技术。但FOWLP的可靠性问题随着其结构精密和生产流程复杂而日益突出。结合FOWLP近期技术发展和应用的现状,总结了发展趋势;从FOWLP结构的工艺缺陷和失效模式出发,阐述了FOWLP的工艺流程和重点工艺环节;根据不同失效类型,系统归纳了引发失效的物理效应和物理模型;最后,介绍了提升FOWLP结构可靠性的工艺调整和优化设计方法。

Advanced semiconductor manufacturing is approaching its physical limit,making Moore's law not sustainable.Fan-out Wafer Level Packaging(FOWLP)could break through the limitation on the number of I/O outlet terminals of traditional fan-in packaging through wafer reconstruction.Furthermore,the redistribution layer(RDL)technique could be used to reduce pin spacing,package thickness and transmission loss of high frequency signals.In recent years,it has gradually developed to become a representative high-end packaging technology in consumer electronics,high performance computing and many other fields,which is a critical technology to continue Moore􀆳s law.However,the reliability of FOWLP gradually becomes prominent due to its complex structure and production process.The development trend of FOWLP is summarized based on its recent technological development and application status.The process flow and key process of FOWLP structure are described according to the process defects and failure modes of FOWLP structure.For each type of failure,the physical effects and models of failure are summarized systematically.Finally,the process adjustment and optimal design methods are introduced to improve the reliability of FOWLP structure.