A Case Study of Trapped Charge Induced Surface Leakage

Thursday, November 9, 2017: 11:55 AM
Ballroom A (Pasadena Convention Center)
Mr. Xiang-Dong Wang , NXP Semiconductors N.V., Chandler, AZ
Xu Cheng , NXP Semiconductors N.V., Chandler, AZ
Evgueniy Stefanov , NXP Semiconductors N.V., Chandler, AZ
William Godek , NXP Semiconductors N.V., Chandler, AZ


Finding the root cause of charge related device failures has been difficult for a few reasons. In many cases, the leakage is relatively small and tends to spread out over a relatively large area. While diagnostic techniques using laser stimulation, such as OBIRCH, or photoemission are very powerful in identifying localized defects in silicon crystal and backend metal layers, they are found to be not as sensitive in isolating charge induced leakage. Moreover, high resolution physical analysis tools, such as TEM, or FIB/SEM, are often not applicable for visualizing charge related defects. Here we present a case study of dielectric charge induced leakage in a high voltage ESD device. By using atomic force probing (AFP) for detailed electrical characterization of individual devices, experimenting with UV radiation, and SCM 2D dopant profiling analysis, we could show that trapped charges in dielectric layers cause leakage near silicon surface. The FAB fixed the problem by implementing proper measures based on this finding.