Novel Non-Destructive Physical Bitmap Verification Technique on SRAM and NOR Flash

In this paper, several optical fault isolation techniques (PEM, EOFM, OBIRCH) were evaluated to non-destructively verify the physical coordinate of SRAM and NOR Flash bitmap. PEM and EOFM are effective for SRAM bitmapping, while OBIRCH and PEM are effective for NOR Flash bitmapping. The physical bitmapping techniques presented provide an alternative to the conventional physical bitmap verification technique using FIB circuit edit and laser induced damage.

I. Introduction

Bitmaps from the electrical test have been essential to characterize and localize memory failure. The characterization data of the fail Device Under Test (DUT) helps to narrow down the potential cause of the failure and to proceed with further fault isolation in Failure Analysis [1]. In NXP, memory bitmap is available for a wide range of products with SRAM and NOR Flash. To enable the Failure Analysis of a DUT with memory failure, the bitmap data of each product is verified physically in silicon.