Application of Fast Laser Deprocessing Techniques in Physical Failure Analysis on SRAM Memory of Advance Technology

Abstract

With technology scaling of semiconductor devices and further growth of the integrated circuit (IC) design and function complexity, it is necessary to increase the number of transistors in IC’s chip, layer stacks, and process steps. The last few metal layers of Back End Of Line (BEOL) are usually very thick metal lines (>4μm thickness) and protected with hard Silicon Dioxide (SiO2) material that is formed from (TetraEthyl OrthoSilicate) TEOS as Inter-Metal Dielectric (IMD). In order to perform physical failure analysis (PFA) on the logic or memory, the top thick metal layers must be removed. It is time-consuming to deprocess those thick metal and IMD layers using conventional PFA workflows. In this paper, the Fast Laser Deprocessing Technique (FLDT) is proposed to remove the BEOL thick and stubborn metal layers for memory PFA. The proposed FLDT is a cost-effective and quick way to deprocess a sample for defect identification in PFA.

Sample Preparation for Deprocessing of 3D Multi-Die Stacked Package

“…Since it is challenging to isolate failure locations in 3D packages, a large ROI is preferred and the large ROI has to be preferably as intact as possible. Other techniques such as plasma FIB deprocessing [10], broad ion beam milling [11], fast laser deprocessing using green 532 nm laser [12] and microwave-induced plasma (MIP) [13] have some limitations. Xe Plasma FIB deprocessing is limited to a localized area about 100 µm x 100 µm.…”

Chip Recombination Method in Planar Deprocessing – A Solution for Failure Analysis on Chip Edge Defects

“…Often times, FA requires PFIB in physical FA deprocessing for complex and large defective chip edge fails to ensure AOI's planarity and uniformity [4]. Because of the chip edge effect, regular finger deprocessing becomes inefficient in keeping the chip edge AOI uniform [5,6,7]. For analysis labs with no PFIB capability, this type of failure most likely will either be not analyzed or end up damaged (over-polished) during finger deprocessing.…”