August_EDFA_Digital

edfas.org ELECTRONIC DEV ICE FA I LURE ANALYSIS | VOLUME 24 NO . 3 32 HIGH SPEED X-RAY TOMOGRAPHY WITH SUBMICRON RESOLUTION FOR FA AND REVERSE ENGINEERING OF PACKAGES, PCBs, AND 300 mmWAFERS S.H. Lau 1 , Sheraz Gul 1 , Jeff Gelb 1 , Tianzhu Qin 1 , Guibin Zan 2 , Katie Matusik 1 , David Vine 1 , Sylvia Lewis 1 , and Wenbing Yun 1 1 Sigray Inc., Concord, California 2 Stanford University, Stanford, California shlau@sigray.com EDFAAO (2022) 3:32-38 1537-0755/$19.00 ©ASM International ® INTRODUCTION The advancement in consumer electronics and high- performance requirements for emergingapplications such as the internet of things (IOT), self-driving cars, artificial intelligence (AI), and 5G have propelled new heteroge- neous integration packages. Further, the combined con- tinuingminiaturization (higher IOdensity and decreasing pitches), newmaterials, andmaterial integration schemes lead to new reliability challenges. X-ray imaging has been one of the primary nondestructive analysis methods for electronic packages and printed circuit boards (PCBs) for over threedecades. Real time x-ray imaging and computed tomography have now become key workhorses in non- destructive imaging, driven by developments in 3D x-ray microscopy [1-2] through improved resolution and through- put. [3-4] However, the continually shrinking features and growth of heterogeneous packaging and wafer-level packaging drive urgent demand for even higher resolu- tion but on larger samples, including larger packages and on wafers. Currently, gaps in nondestructive 2D and 3D imaging in failure analysis exist due to lack of resolution for submicron defects typically found in most cracks or voids inmicrobumps less than 30microns in diameter. To increase time efficiency and minimize potential destruc- tion of the feature, such failures should ideally be imaged in the intact sample. The larger form factors of samples including modern heterogeneous packages, PCBs, and whole wafers adds yet another layer of difficulty, and submicron defects on such samples are far beyond the Fig. 1 Innovations in the novel 3D x-ray tool for rapid high-resolution tomography of large electronic packages and PCB.