基于差分信号的硅通孔无损缺陷判断与定位

Nondestructive Defect Detection and Localization of Through Silicon Via Based on Differential Signal

硅通孔(Through Silicon Vias,TSV)技术是三维集成电路的核心技术之一.在TSV加工过程中由于填充不均匀、化学机械剖光不彻底等,会造成过孔的开路、短路等缺陷,进而影响系统性能.高效精准的无损检测方法有利于剔除有缺陷裸片,降低缺陷对系统性能的影响.通过分析差分信号激励时地—信号—信号—地(Ground-Signal-Signal-Ground,GSSG)型TSV的电特性,提炼出缺陷无损检测及定位方法,即利用存在缺陷时差模和共模S参数的特点来判断缺陷类型;利用差模S参数及其对频率的数值导数随缺陷位置变化的特点对缺陷进行定位.此外,还对比了输入分别为单端信号和差分信号时的缺陷判断方法,结果表明基于差分信号的缺陷判断方法在判断对地短路缺陷方面比单端信号更有优势.

Through silicon vias(TSV)technology is one of the core technologies of three-dimensional integrated circuit(3D IC).In the manufacturing process of TSV,many factors including nonuniform filling,incompletely chemical mechanical polishing lead to short defect and open defect,which will affect the performance of the system.Thus,efficient and accurate noninvasive defect analysis method is beneficial to eliminate defective dies and reduce the influence of defects on system performance.This paper proposed the methods of defects nondestructive testing and locating by analyzing the electrical characteristics of ground-signal-signal-ground(GSSG)when differential signal is excited.The defect type can be determined according to the characteristics of difference mode and common mode S-parameters.Besides,according to variation of the differential mode S parameters and their numerical derivative with respect to frequency with defect locations,the defects can be located.Furthermore,the methods of single signal and differential signal are compared,and the results show that the differential signal method is more advantageous than single signal method when judging the short defect between signal and ground channels.