23.2
Failure Analysis of Embedded Non-Volatile Memory with Nano- and Micro-Probing Techniques
Failure Analysis of Embedded Non-Volatile Memory with Nano- and Micro-Probing Techniques
Wednesday, November 4, 2015
Exhibit Hall D (Oregon Convention Center )
Summary:
While embedded NVM provides much needed integrated solution for miniaturization and faster data retrieving, it creates some unique challenges for failure analysis. Nano-probing techniques, such as atomic force probe (AFP) used in this study, allow us to access individual devices at contact or via levels and characterize the details as much as possible before a decision can be made for physical analysis. However, for it to be applied to NVM, it is not trivial to develop a deprocessing procedure to achieve planar surface throughout the array, as most NVM arrays are very large, up to a few millimeters across. In this paper, we report the application of AFP to characterize each individual bit at contact level, or individual column at via1 level. By applying program/erase cycle to each individual bit, we were able to capture each individual's failure characteristics. Based on the information, further diagnostic and physical analysis techniques, such as optical beam induced resistance change (OBIRCH) and FIB x-section, were used to find the failure mechanisms. In case-1, it is found that silicide residual could cause column to column leakage by creating electrical path between active areas of adjacent columns. In case-2, it is found that single bit failures due to low erase current can be recovered with repeated program/erase cycle.
While embedded NVM provides much needed integrated solution for miniaturization and faster data retrieving, it creates some unique challenges for failure analysis. Nano-probing techniques, such as atomic force probe (AFP) used in this study, allow us to access individual devices at contact or via levels and characterize the details as much as possible before a decision can be made for physical analysis. However, for it to be applied to NVM, it is not trivial to develop a deprocessing procedure to achieve planar surface throughout the array, as most NVM arrays are very large, up to a few millimeters across. In this paper, we report the application of AFP to characterize each individual bit at contact level, or individual column at via1 level. By applying program/erase cycle to each individual bit, we were able to capture each individual's failure characteristics. Based on the information, further diagnostic and physical analysis techniques, such as optical beam induced resistance change (OBIRCH) and FIB x-section, were used to find the failure mechanisms. In case-1, it is found that silicide residual could cause column to column leakage by creating electrical path between active areas of adjacent columns. In case-2, it is found that single bit failures due to low erase current can be recovered with repeated program/erase cycle.