Defect Localization and Root Cause Analysis on e-Fuse Read Reliability Failure

Author(s):  
Hung Chin Chen ◽  
Chih Yang Tsai ◽  
Shih Yuan Liu ◽  
Yu Pang Chang ◽  
Jian Chang Lin

Abstract Fault isolation is the most important step for Failure Analysis (FA), and it is closely linked with the success rate of failure mechanism finding. In this paper, we will introduce a case that hard to debug with traditional FA skills. In order to find out its root cause, several advanced techniques such as layout tracing, circuit edit and Infrared Ray–Optical Beam Induced Resistance Change (IR-OBIRCH) analysis had been applied. The circuit edit was performed following layout tracing for depositing probing pads by Focused Ion Beam (FIB). Then, IR-OBIRCH analysis with biasing on the two FIB deposited probing pads and a failure location was detected. Finally, the root cause of inter- metal layer bridge was found in subsequent physical failure analysis.

Author(s):  
Liang Hong ◽  
Jia Li ◽  
Haifeng Wang

Abstract This paper provides an innovative root cause failure analysis method that combines multiple failure analysis (FA) techniques to narrow down and expose the shorting location and allow the material analysis of the shorting defect. It begins with a basic electrical testing to narrow down shorting metal layers, then utilizing mechanical lapping to expose over coat layers. This is followed by optical beam induced resistance change imaging to further narrow down the shorting location. Scanning electron microscopy and optical imaging are used together with focused ion beam milling to slice and view through the potential shorting area until the shorting defect is exposed. Finally, transmission electron microscopy (TEM) sample is prepared, and TEM analysis is carried out to pin point the root cause of the shorting. This method has been demonstrated successfully on Western Digital inter-metal layers shorting FA.


Author(s):  
C.C. Ooi ◽  
K.H. Siek ◽  
K.S. Sim

Abstract Focused ion beam system has been widely used as a critical failure analysis tool as microprocessor technology advances at a ramping speed. It has become an essential step in failure analysis to reveal physical defects post electrical fault isolation. In this highly competitive and challenging environment prevalent today, failure analysis throughput time is of utmost important. Therefore quick, efficient and reliable physical failure analysis technique is needed to avoid potential issues from becoming bigger. This paper will discuss the applications of FIB as a defect localization and root cause determination tool through the passive charge contrast technique and pattern FIB analysis.


2015 ◽  
Vol 2015 (1) ◽  
pp. 000469-000473 ◽  
Author(s):  
J. Gaudestad ◽  
A. Orozco ◽  
I. De Wolf ◽  
T. Wang ◽  
T. Webers ◽  
...  

In this paper we show an efficient workflow that combines Magnetic Field Imaging (MFI) and Dual Beam Plasma Focused Ion Beam (DB-PFIB) for fast and efficient Fault Isolation and root cause analysis in 2.5/3D devices. The work proves MFI is the best method for Electric Fault Isolation (EFI) of short failures in 2.5/3D Through Silicon Via (TSV) triple stacked devices in a true non-destructive way by imaging the current path. To confirm the failing locations and to do Physical Failure Analysis (PFA), a DB-PFIB system was used for cross sectioning and volume analysis of the TSV structures and high resolution imaging of the identified defects. With a DB-PFIB, the fault is exposed and analyzed without any sample prep artifacts seen in mechanical polishing or laser preparation techniques and done in a considerably shorter amount of time than that required when using a traditional Gallium Focused Ion Beam (FIB).


Author(s):  
J. Gaudestad ◽  
A. Orozco ◽  
I. De Wolf ◽  
T. Wang ◽  
T. Webers ◽  
...  

Abstract In this paper we show an efficient workflow that combines Magnetic Field Imaging (MFI) and Dual Beam Plasma Focused Ion Beam (DB-PFIB) for fast and efficient Fault Isolation and root cause analysis in 2.5/3D devices. The work proves MFI is the best method for Electric Fault Isolation (EFI) of short failures in 2.5/3D Through Silicon Via (TSV) triple stacked devices in a true non-destructive way by imaging the current path. To confirm the failing locations and to do Physical Failure Analysis (PFA), a DB-PFIB system was used for cross sectioning and volume analysis of the TSV structures and high resolution imaging of the identified defects. With a DB-PFIB, the fault is exposed and analyzed without any sample prep artifacts seen in mechanical polishing or laser preparation techniques and done in a considerably shorter amount of time than that required when using a traditional Gallium Focused Ion Beam (FIB).


Author(s):  
Yoav Weizman ◽  
Ezra Baruch ◽  
Michael Zimin

Abstract Emission microscopy is usually implemented for static operating conditions of the DUT. Under dynamic operation it is nearly impossible to identify a failure out of the noisy background. In this paper we describe a simple technique that could be used in cases where the temporal location of the failure was identified however the physical location is not known or partially known. The technique was originally introduced to investigate IDDq failures (1) in order to investigate timing related issues with automated tester equipment. Ishii et al (2) improved the technique and coupled an emission microscope to the tester for functional failure analysis of DRAMs and logic LSIs. Using consecutive step-by-step tester halting coupled to a sensitive emission microscope, one is able detect the failure while it occurs. We will describe a failure analysis case in which marginal design and process variations combined to create contention at certain logic states. Since the failure occurred arbitrarily, the use of the traditional LVP, that requires a stable failure, misled the analysts. Furthermore, even if we used advanced tools as PICA, which was actually designed to locate such failures, we believe that there would have been little chance of observing the failure since the failure appeared only below 1.3V where the PICA tool has diminished photon detection sensitivity. For this case the step-by-step halting technique helped to isolate the failure location after a short round of measurements. With the use of logic simulations, the root cause of the failure was clear once the failing gate was known.


Author(s):  
P. Tangyunyong ◽  
A.Y. Liang ◽  
A.W. Righter ◽  
D.L. Barton ◽  
J.M. Soden

Abstract Fluorescent microthermal imaging (FMI) involves coating a sample surface with a thin fluorescent film that, upon exposure to UV light source, emits temperature-dependent fluorescence [1-7]. The principle behind FMI was thoroughly reviewed at the ISTFA in 1994 [8, 9]. In two recent publications [10,11], we identified several factors in film preparation and data processing that dramatically improved the thermal resolution and sensitivity of FMI. These factors include signal averaging, the use of base mixture films, film stabilization and film curing. These findings significantly enhance the capability of FMI as a failure analysis tool. In this paper, we show several examples that use FMI to quickly localize heat-generating defects ("hot spots"). When used with other failure analysis techniques such as focused ion beam (FIB) cross sectioning and scanning electron microscope (SEM) imaging, we demonstrate that FMI is a powerful tool to efficiently identify the root cause of failures in complex ICs. In addition to defect localization, we use a failing IC to determine the sensitivity of FMI (i.e., the lowest power that can be detected) in an ideal situation where the defects are very localized and near the surface.


2018 ◽  
Author(s):  
Sze Yee Tan ◽  
Chiu Soon Wong ◽  
Chea Wee Lo ◽  
Cin Sheng Goh

Abstract In the back-end assembly process, all of the packages will be tested prior to disposition to the customers in order to filter out any device with failure. For a reject unit with an unknown failure mechanism, it will be subjected to a comprehensive failure analysis (FA) to identify the root cause of the failure. Non-destructive verification, following by front-side decapsulation and internal physical inspection is the common way to visualise and identify the physical defect that usually causes the failure of a device during the back-end assembly process. For certain failures, visualization of the defect might not be straight forward after the decapsulation because the defect may be embedded or buried underneath a layer or wedge bond on the die. In this case, a more complicated FA analysis flow which comprises various precision techniques such as parallel lapping, hotspot localisation and focused-ion-beam (FIB) analyses will be needed to thin down the top layer/wedge bond for a precise localisation of the defect prior to precision analysis by FIB. However, the process to thin down the top layer/wedge bond with an exposed die of a partially decapsulated package is a tricky job as artefacts such as crack/scratches on die are likely to be introduced during the process of polishing. Also it is relatively difficult to control the thickness and levelling of the top layer/wedge bond during the thinning process. In this work, we developed a method that allows the analyst to re-cap the partially decapped package, and also to precisely measure and thin down the top layer to an accuracy of less than < 2um without the introduction of artefacts.


Author(s):  
Jim Shearer ◽  
Kim Le ◽  
Xiaoyu Yang ◽  
Monty Cleeves ◽  
Al Meeks

Abstract This article presents a case study to solve an IDDQ leakage problem using a variety of failure analysis techniques on a product. The product is fabricated using a 3-metal-layer 0.25 μm CMOS process with the addition of Matrix's proprietary 3-D memory layers. The failure analysis used both top and backside analytical techniques, including liquid crystal, photon emission microscopy from both front and back, dual-beam focused ion beam cross-sectioning, field emission scanning electron microscopy imaging, parallel-lap/passive voltage contrast, microprobing of parallel-lapped samples, and scanning capacitance microscopy. The article discusses how the application of each of the techniques narrowed down the search for this IDDQ leakage path. This leakage path was eliminated using the two corrective actions: The resist is pre-treated prior to ion implantation to produce a consistent resist sidewall profile; and the Nwell boundaries were adjusted in the next Nwell mask revision.


Author(s):  
Bence Hevesi

Abstract In this paper, different failure analysis (FA) workflows are showed which combines different FA approaches for fast and efficient fault isolation and root cause analysis in system level products. Two case studies will be presented to show the importance of a well-adjusted failure analysis workflow.


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