Zynq SOC Low-Voltage and Temperature-Dependent L2 Cache Failure Diagnosis and Defect Localization Case Study

Author(s):  
Haonan Bai ◽  
Lan Yin Lee ◽  
Yang Jing ◽  
Peter Floyd Salinas ◽  
Kok Keng Chua

Abstract Failure analysis and defect localization on 28nm All Programmable Zynq System-on-Chip (SoC) device is extremely challenging. While conventional FPGA, which only consists of the Programmable Logic, has greater ease and flexibility in pattern generation during fault isolation, the all programmable SoC device integrates a dual ARM Cortex-A9 cores with Programmable Logic (PL) in a single chip. The cache data access in-between processor and PL is more complex and test methodology has lesser degree of control on cache data flow and stack sequence. This paper introduced an advanced fault isolation test methodology combining Software Development Kit (SDK) with scan based diagnostic test for cache failures. It successfully pinpoint to failure locations with physical defects found. As conventional physical failure analysis approaches using SEM based passive voltage contrast could not observe any abnormalities, current imaging and nano-probing measurement using AFP played critical roles in detecting nano-ampere leakages prior subsequent TEM analysis. The findings were then feedback to the foundry for process improvement. Furthermore, a new screening methodology is innovated where an extreme low-voltage test at high temperature in Automatic Test to detect and eliminate the process marginal leakage failure.

Author(s):  
Kevin Gearhardt ◽  
Chris Schuermyer ◽  
Ruifeng Guo

Abstract This paper presents an iterative diagnosis test generation framework to improve logic fault diagnosis resolution. Industrial examples are presented in this paper on how additional targeted pattern generation can be used to improve defect localization before physical failure analysis of a die. This enables failure analysts to be more effective by reducing the dependence on the more expensive physical fault isolation techniques.


Author(s):  
M.K. Dawood ◽  
C. Chen ◽  
P.K. Tan ◽  
S. James ◽  
P.S. Limin ◽  
...  

Abstract In this work, we present two case studies on the utilization of advanced nanoprobing on 20nm logic devices at contact layer to identify the root cause of scan logic failures. In both cases, conventional failure analysis followed by inspection of passive voltage contrast (PVC) failed to identify any abnormality in the devices. Technology advancement makes identifying failure mechanisms increasingly more challenging using conventional methods of physical failure analysis (PFA). Almost all PFA cases for 20nm technology node devices and beyond require Transmission Electron Microscopy (TEM) analysis. Before TEM analysis can be performed, fault isolation is required to correctly determine the precise failing location. Isolated transistor probing was performed on the suspected logic NMOS and PMOS transistors to identify the failing transistors for TEM analysis. In this paper, nanoprobing was used to isolate the failing transistor of a logic cell. Nanoprobing revealed anomalies between the drain and bulk junction which was found to be due to contact gouging of different severities.


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.


Author(s):  
S.H. Goh ◽  
B.L. Yeoh ◽  
G.F. You ◽  
W.H. Hung ◽  
Jeffrey Lam ◽  
...  

Abstract Backside frequency mapping on modulating active in transistors is well established for defect localization on broken scan chains. Recent experiments have proven the existence of frequency signals from passive structures modulations. In this paper, we demonstrate the effectiveness of this technique on a 65 nm technology node device failure. A resistive leaky path leading to a functional failure which, otherwise cannot be isolated using dynamic emission microscopy, is localized in this work to guide follow on failure analysis.


Author(s):  
Seth J. Prejean ◽  
Joseph Shannon

Abstract This paper describes improvements in backside deprocessing of CMOS (Complimentary Metal Oxide Semiconductor) SOI (Silicon On Insulator) integrated circuits. The deprocessing techniques described here have been adapted from a previous research publication on backside deprocessing of bulk CMOS integrated circuits [1]. The focus of these improvements was to provide a repeatable and reliable methodology of deprocessing CMOS devices from the backside. We describe a repeatable and efficient technique to deprocess flip chip packaged devices and unpackaged die from the backside. While this technique has been demonstrated on SOI and bulk devices, this paper will focus on the latest SOI technology. The technique is useful for quick and easy access to the transistor level while preserving the metal interconnects for further analysis. It is also useful for deprocessing already thinned or polished die without removing them from the package. Removing a thin die from a package is very difficult and could potentially damage the device. This is especially beneficial when performing physical failure analysis of samples that have been back thinned for the purpose of fault isolation and defect localization techniques such as: LIVA (Laser Induced Voltage Alteration), TIVA (Thermally Induce Voltage Alteration), SDL [2] (Soft Defect Localization), and TRE (Time Resolved Emission) analysis. An important fundamental advantage of deprocessing SOI devices is that the BOX (Buried Oxide) layer acts as a chemical etch stop when etching the backside or bulk silicon. This leaves the transistor active silicon intact for analysis. Further delayering allows for the inspection of the active silicon, gate oxide, silicide, spacers, and poly. After deprocessing the transistor level, the metal layers are still intact and, in most cases, still electrically connected to the outside world. This can provide additional failure analysis opportunities.


Author(s):  
Hui Peng Ng ◽  
Angela Teo ◽  
Ghim Boon Ang ◽  
Alfred Quah ◽  
N. Dayanand ◽  
...  

Abstract This paper discussed on how the importance of failure analysis to identify the root cause and mechanism that resulted in the MEMS failure. The defect seen was either directly on the MEMS caps or the CMOS integrated chip in wafer fabrication. Two case studies were highlighted in the discussion to demonstrate how the FA procedures that the analysts had adopted in order to narrow down to the defect site successfully on MEMS cap as well as on CMOS chip on MEMS package units. Besides the use of electrical fault isolation tool/technique such as TIVA for defect localization, a new physical deprocessing approach based on the cutting method was performed on the MEMS package unit in order to separate the MEMS from the Si Cap. This approach would definitely help to prevent the introduction of particles and artifacts during the PFA that could mislead the FA analyst into wrong data interpretation. Other FA tool such as SEM inspection to observe the physical defect and Auger analysis to identify the elements in the defect during the course of analysis were also documented in this paper.


Author(s):  
Philippe Perdu ◽  
Romain Desplats

Abstract IDDQ testing detects a majority of faults in logic ICs. To improve defect coverage with very short test patterns, IDDQ testing has been integrated in fault simulators embedded with automatic test pattern generation (ATPG) algorithms. Nevertheless, for failure analysis purposes, this progress has not eliminated the complex task of fault isolation at the silicon level of ICs. Defect localization is facilitated with IDDQ testing because the defect is detected as soon as it is activated inside the device. At the failed vector, abnormal IDDQ current is measured and accurate localization of the corresponding defect inside the chip can be performed. Thermally related techniques or emission microscopy can be used for this localization process. Very powerful tools like electron beam testers can also be used to deeply analyze faulty devices by internal contactless testing. In this paper, we will present an application of IDDQ testing for fault detection and some key issues regarding localization of the corresponding defect: • Appropriate techniques, • Switching from electrical testing to fault localization, • Modifying the test pattern to shorten the localization process, • Constructing a localization method based on an IDDQ diagnostic.


2021 ◽  
Author(s):  
Kuang-Tse Ho ◽  
Cheng-Che Li

Abstract This research summarizes a variety of physical failure modes of GaAs-based oxide-confined VCSELs and their root causes. Standard failure analysis procedure, which includes defect fault isolation by PEM or IR-OBIRCH and physical inspection by TEM analysis are also presented in detail.


Author(s):  
Chia Ling Kong ◽  
Mohammed R. Islam

Abstract Fault Isolation / Failure Analysis (FI/FA) of increasingly complex embedded memory in microprocessors is becoming more difficult due to process scaling and presence of subtle defects. As physical failure analysis (PFA) is destructive and involves expensive and time-consuming processes, fault diagnosis needs to be as precise as possible to ensure successful physical defect sighting. This paper introduces a cache Fault Isolation methodology that focuses on exhaustive data collection to derive concrete hypothesis of physical fault location and to overcome the existing FA/FI challenges. The methodology involves a novel application of existing DFT techniques in combination with circuit analysis, pattern hacking, defect localization and PFA tools. Some of the techniques, for example pattern modification or circuit simulation, are applied repeatedly in order to obtain higher-level of isolation – from cell/logic level to transistor/gate level, and finally down to physical structure/layer level. This multi-level FI approach is the key to localize the failing area to greater precision, which had proven itself in Intel Itanium® II processor yield improvement process.


Author(s):  
Christian Schmidt ◽  
Frank Altmann ◽  
David P. Vallett

Abstract Lock-in thermography and magnetic current imaging are emerging as the two image-based fault isolation methods most capable of meeting the challenges of short and open defect localization in thick, opaque assemblies. Such devices are rapidly becoming prevalent as 3D integration begins to ramp up production. This paper expands on previously published work with a qualitative comparison of the techniques on single chip and stacked die packages with known designed-in or FIB created defects.


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