Static Fault Isolation on the Functional Failure Analysis

Author(s):  
C.Q. Chen ◽  
Z.H. Mai ◽  
G.B. Ang ◽  
B.H. Liu ◽  
P.T. Ng ◽  
...  

Abstract As the technology keeps scaling down and IC design becomes more and more complex, failure analysis becomes much more challenging, especially for static fault isolation. For semiconductor foundry FA, it will become even more challenging due to lack of enough information. Static fault isolation is the major global fault isolation methodology in foundry FA and it is difficult to access and trigger the failing signal detected by scan and BIST test, which is widely applied in modern IC design. Because, in most of the time, the normal two pin bias (Vdd and Vss) can only get the comparable IV result between bad unit and the reference unit for function related fail. There are two possibilities from reverse engineering perspective. Firstly, the defect location may not be accessed by the DC bias. Secondly, even if the defect can be accessed, but the defect induced current or voltage change is too small to be differentiated from the overall signal. So it will be concealed in the overall current. However, it is still possible for us to do global fault isolation for the second situation. In this paper, a unit with Iddoff failure was analyzed. Although, no significant IV difference was observed between failed and reference units, a distinct Photon Emission (EMMI) spot was successfully observed in the failed unit. Layout analysis and process analysis on this EMMI spot further confirmed the reality of the emission spot.

Author(s):  
C.Q. Chen ◽  
P.T. Ng ◽  
G.B. Ang ◽  
Francis Rivai ◽  
S.L. Ting ◽  
...  

Abstract As semiconductor technology keeps scaling down, failure analysis and device characterizations become more and more challenging. Global fault isolation without detailed circuit information comprises the majority of foundry EFA cases. Certain suspected areas can be isolated, but further narrow-down of transistor and device performance is very important with regards to process monitoring and failure analysis. A nanoprobing methodology is widely applied in advanced failure analysis, especially during device level electrical characterization. It is useful to verify device performance and to prove the problematic structure electrically. But sometimes the EFA spot coverage is too big to do nanoprobing analysis. Then further narrow-down is quite critical to identify the suspected structure before nanoprobing is employed. That means there is a gap between global fault isolation and localized device analysis. Under these kinds of situation, PVC and AFP current image are offen options to identify the suspected structure, but they still have their limitation for many soft defect or marginal fails. As in this case, PVC and AFP current image failed to identify the defect in the spot range. To overcome the shortage of PVC and AFP current image analysis, laser was innovatively applied in our current image analysis in this paper. As is known to all, proper wavelength laser can induce the photovoltaic effect in the device. The photovoltaic effect induced photo current can bring with it some information of the device. If this kind of information was properly interpreted, it can give us some clue of the device performance.


Author(s):  
Sarven Ipek ◽  
David Grosjean

Abstract The application of an individual failure analysis technique rarely provides the failure mechanism. More typically, the results of numerous techniques need to be combined and considered to locate and verify the correct failure mechanism. This paper describes a particular case in which different microscopy techniques (photon emission, laser signal injection, and current imaging) gave clues to the problem, which then needed to be combined with manual probing and a thorough understanding of the circuit to locate the defect. By combining probing of that circuit block with the mapping and emission results, the authors were able to understand the photon emission spots and the laser signal injection microscopy (LSIM) signatures to be effects of the defect. It also helped them narrow down the search for the defect so that LSIM on a small part of the circuit could lead to the actual defect.


Author(s):  
Steve Ferrier ◽  
Kevin D. Martin ◽  
Donald Schulte

Abstract Application of a formal Failure Analysis metaprocess to a stubborn yield loss problem provided a framework that ultimately facilitated a solution. Absence of results from conventional failure analysis techniques such as PEM (Photon Emission Microscopy) and liquid crystal microthermography frustrated early attempts to analyze this low-level supply leakage failure mode. Subsequently, a reorganized analysis team attacked the problem using a specific toplevel metaprocess.(1,a) Using the metaprocess, analysts generated a specific unique step-by-step analysis process in real time. Along the way, this approach encouraged the creative identification of secondary failure effects that provided repeated breakthroughs in the analysis flow. Analysis proceeded steadily toward the failure cause in spite of its character as a three-way interaction among factors in the IC design, mask generation, and wafer manufacturing processes. The metaprocess also provided the formal structure that, at the conclusion of the analysis, permitted a one-sheet summary of the failure's cause-effect relationships and the analysis flow leading to discovery of the anomaly. As with every application of this metaprocess, the resulting analysis flow simply represented an effective version of good failure analysis. The formal and flexible codification of the analysis decision-making process, however, provided several specific benefits, not least of which was the ability to proceed with high confidence that the problem could and would be solved. This paper describes the application of the metaprocess, and also the key measurements and causeeffect relationships in the 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):  
C.Q. Chen ◽  
P.T. Ng ◽  
G.B. Ang ◽  
Francis Rivai ◽  
A.C.T. Quah ◽  
...  

Abstract As semiconductor technology keeps scaling down, failure analysis and device characterizations become more and more challenging. Global fault isolation without detailed circuit information comprises the majority of foundry EFA cases. Certain suspected areas can be isolated, but further narrow-down of transistor and device performance is very important with regards to process monitoring and failure analysis. A nanoprobing methodology is widely applied in advanced failure analysis, especially during device level electrical characterization. It is useful to verify device performance and to prove the problematic structure electrically, especially for implantation related problems [1] [2]. Implantation related defects, or invisible defects, are the most challenging defect types for the application of fault isolation in all of the failure analysis jobs. The key challenge for these kinds of analyses is to make the defect visible. Sometimes, it is difficult or even impossible to visualize the defective point. Then, sufficient electrical evidence and theory analysis are important to bring the issue to resolution. For these kinds of analyses, a nanoprobing system is a necessary tool to conduct the detailed analysis. Combined with the device physics and electrical theory analysis, nanoprobing can bring out the perfect failure mechanism and problematic process step. There are two popular nanoprobing systems in our lab, one is SEM based and the other is AFM based. Both systems have their advantages and disadvantages in the electrical characterization and fault isolation field. In this paper, an implantation related issue was analyzed. Gross leakage was observed on the failed units as compared with good units. Global fault isolation, TIVA and EMMI failed to find the exclusive hotspot. With the GDS and process analysis, the nanoprobing was employed to the performance check on some of the suspected structures. Finally, the defective location was successfully isolated by nanoprobing. Combined with device physics and electrical analysis, the problematic process was successfully isolated.


Author(s):  
M. Boostandoost ◽  
X. Ycaza ◽  
R. Leihkauf ◽  
U. Kerst ◽  
C. Boit

Abstract In this study, the challenges to transfer the microelectronics failure analysis techniques to the photovoltaic industry have been discussed. The main focus of this study was the PHEMOS as a tool with strong technological research capacity developed for microelectronics failure analysis, and OBIC (Optical Beam Induced Current) as a non-destructive technique for detecting and localizing various defects in semiconductor devices. This failure analysis tool was a high resolution optical infrared photon emission microscope used mainly in microelectronics for qualitative analysis and localization of semiconductor defects. Such failure analysis equipment was designed to meet requirements for modern microelectronic devices. Characterization of current photovoltaic device often requires quantitative analysis and should provide information about the electrical and material properties of the solar cell. Therefore, in addition to the demand for further data processing of the obtained results we had to study the corresponding operating regime of solar cells to allow for a correct interpretation of measurement results. In this paper, some of the related problems we faced during this study, e.g. large amount of data processing, the spatial misalignment of the images obtained as EL (Electroluminescence) and IR-LBIC (Infrared Light Beam Induced Current), the implemented laser wavelength, its profile and power density for IR-LBIC measurement. These topics have been discussed in detailed to facilitate a reliable transfer of these techniques from microelectronics to the photovoltaic world.


Author(s):  
Jessica Yang ◽  
Omprakash Rengaraj ◽  
Puneet Gupta ◽  
Rudolf Schlangen

Abstract Static Random-Access Memory (SRAM) failure analysis (FA) is important during chip-level reliability evaluation and yield improvement. Single-bit, paired-bit, and quad-bit failures—whose defect should be at the failing bit-cell locations—can be directly sent for Physical Failure Analysis (PFA). For one or multiple row/column failures with too large of a suspected circuit area, more detailed fault isolation is required before PFA. Currently, Photon Emission Microscopy (PEM) is the most commonly used Electrical Failure Analysis (EFA) technique for this kind of fail [1]. Soft-Defect Localization / Dynamic Laser Stimulation (SDL/DLS) can also be applied on soft (Vmin) row/column fails for further isolation [2]. However, some failures do not have abnormal emission spots or DLS sensitivity and require different localization techniques. Laser Voltage Imaging (LVI) and Laser Voltage Probing (LVP) are widely established for logic EFA, [3] but require periodic activation via ATE which may not be possible using MBIST hardware and test-patterns optimized for fast production testing. This paper discusses the test setup challenges to enable LVI & LVP on SRAM fails and includes two case studies on <14 nm advanced process silicon.


Author(s):  
Keonil Kim ◽  
Sungjin Kim ◽  
Kunjae Lee ◽  
Kyeongju Jin ◽  
Yunwoo Lee ◽  
...  

Abstract In most of the non-destructive electrical fault isolation cases, techniques such as DLS, Photon Emission, LIT, OBIRCH indicate a fault location directly. But relying on just one of these techniques for marginal failure mechanism is not enough for better fault localization. When Failure Analysis (FA) engineers encounter high NDF (No Defect Found) rates, by using only one of the techniques, they may need to consider the relationship between the responded locations by different techniques and fail phenomenon for better defect isolation. This paper talks about how a responded DLS location does not always indicate a fault location and how LVP data collected using DLS location can pin point the real defect location.


Author(s):  
Soon Lim ◽  
Jian Hua Bi ◽  
Lian Choo Goh ◽  
Soh Ping Neo ◽  
Sudhindra Tatti

Abstract The progress of modern day integrated circuit fabrication technology and packaging has made fault isolation using conventional emission microscopy via the top of the integrated circuit more difficult, if not impossible. This is primarily due to the use of increased levels and density of metal-interconnect, and the advent of new packaging technology, e.g. flip-chip, ball-grid array and lead-on-chip, etc. Backside photon emission microscopy, i.e. performing photon emission microscopy through the bulk of the silicon via the back of the integrated circuit is a solution to this problem. This paper outlines the failure analysis of sub-micron silicon integrated circuits using backside photon emission microscopy. Sample preparation, practical difficulties encountered and case histories will be discussed.


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