双层基板塑封器件的声扫检查方法研究

Study on Acoustic Scanning Inspection Method of Plastic Encapsulated Devices on Double-Layer Substrates

在对双层基板塑料封装器件进行扫描声学显微镜检查时,对器件结构和声扫设备成像了解不充分,容易导致误判。对ACTEL公司生产的2款双层基板结构的FPGA器件进行化学开封和物理解剖分析,同时从器件检测波形特点、声扫图像特征、同类器件对比验证等多个方面进行综合分析及验证。指出当门限内包含2个及以上主波信号时,应关注器件的封装结构。在充分了解器件结构后,通过门限设置选定与关注界面对应的界面波,再进行声扫即可得出正确的结果。

When scanning acoustic microscope is used to inspect plastic encapsulated devices on double-layer substrates,the understanding of device structure and imaging of the acoustic scanning equipment is insufficient,which is easy to lead to misjudgement.The chemical unpacking and physical anatomy analysis of two kinds of FPGA devices with double-layer substrate structure produced by ACTEL Company are carried out.At the same time,comprehensive analysis and verification are carried out from many aspects,such as the characteristics of device detection waveform,the characteristics of acoustic scanning image,and the comparative verification of similar devices.It is pointed out that when the threshold contains two or more main wave signals,the package structure of the device should be paid attention to.After the device structure is fully understood,the interface wave corresponding to the focus interface is selected through the threshold setting,and then the correct result can be obtained by acoustic scanning.