Electrical Faults Captured by In-line E-beam Inspection and Failure Analysis

Author(s):  
Z.G. Song ◽  
G.B. Ang ◽  
H.Y. Li ◽  
V. Sane ◽  
J. Indahwan ◽  
...  

Abstract Fault isolation is a critical step of failure analysis, which is most important for yield improvement for any new microelectronic device manufacturing. Conventionally, electrical faults are isolated by emission microscopy, liquid crystal, LIVA/TIVA and ORBIRCH etc. techniques after final test. As microelectronic devices are becoming more complicated and with multiple metal layers, failure analysis faces more challenges than before. These challenges are even tougher in wafer foundries because little device information is available. This makes yield ramp-up take longer time. Utilizing inline E-beam inspection equipment, the electrical faults can be captured at the source layer rather than after final test. E-beam inspection can be incorporated in the manufacturing line at any critical layer of front end and back-end. This paper describes the in-line E-beam inspection and presents three cases: (1) Gate-oxide issue, (2) Contact issue, and (3) Interconnect issue to demonstrate its application.

Author(s):  
Hua Younan ◽  
Chu Susan ◽  
Gui Dong ◽  
Mo Zhiqiang ◽  
Xing Zhenxiang ◽  
...  

Abstract As device feature size continues to shrink, the reducing gate oxide thickness puts more stringent requirements on gate dielectric quality in terms of defect density and contamination concentration. As a result, analyzing gate oxide integrity and dielectric breakdown failures during wafer fabrication becomes more difficult. Using a traditional FA flow and methods some defects were observed after electrical fault isolation using emission microscopic tools such as EMMI and TIVA. Even with some success with conventional FA the root cause was unclear. In this paper, we will propose an analysis flow for GOI failures to improve FA’s success rate. In this new proposed flow both a chemical method, Wright Etch, and SIMS analysis techniques are employed to identify root cause of the GOI failures after EFA fault isolation. In general, the shape of the defect might provide information as to the root cause of the GOI failure, whether related to PID or contamination. However, Wright Etch results are inadequate to answer the questions of whether the failure is caused by contamination or not. If there is a contaminate another technique is required to determine what the contaminant is and where it comes from. If the failure is confirmed to be due to contamination, SIMS is used to further determine the contamination source at the ppm-ppb level. In this paper, a real case of GOI failure will be discussed and presented. Using the new failure analysis flow, the root cause was identified to be iron contamination introduced from a worn out part made of stainless steel.


2011 ◽  
Vol 58-60 ◽  
pp. 2171-2176 ◽  
Author(s):  
Yuan Chen ◽  
Xiao Wen Zhang

Focused ion beam (FIB) system is a powerful microfabrication tool which uses electronic lenses to focus the ion beam even up to nanometer level. The FIB technology has become one of the most necessary failure analysis and failure mechanism study tools for microelectronic device in the past several years. Bonding failure is one of the most common failure mechanisms for microelectronic devices. But because of the invisibility of the bonding interface, it is difficult to analyze this kind of failure. The paper introduced the basic principles of FIB technology. And two cases for microelectronic devices bonding failure were analyzed successfully by FIB technology in this paper.


Author(s):  
Ng Hui Peng ◽  
Teo Angela ◽  
Ang Ghim Boon ◽  
Yip Kim Hong ◽  
Chang Qing Chen ◽  
...  

Abstract With the rapid development of semiconductor manufacturing technologies, IC devices evolve to smaller feature sizes and higher densities, and thus the task of performing successful failure analysis (FA) is becoming increasingly difficult. Device miniaturization often requires high spatial resolution fault isolation and physical analysis [1]. To cater to the shrinking of devices, extensive process improvements have been conducted at the front-end-of-line (FEOL) structures. As a result, among the numerous types of defects leading to chip failure, FEOL defects are becoming more common for devices of advanced tech nodes [2]. Therefore, it becomes more complexity and difficulty on searching the physical defect. Sample preparation is a key activity in material and failure analysis. In order to image small structures or defects it is often necessary to remove excess material or layers hiding the feature of interest. Removing selected layers to isolate a structure is called delayering. It can be accomplished by chemical etching using liquid or plasma chemistry, or by mechanical means, by polishing off each unwanted layer.


Author(s):  
D.S. Patrick ◽  
L.C. Wagner ◽  
P.T. Nguyen

Abstract Failure isolation and debug of CMOS integrated circuits over the past several years has become increasingly difficult to perform on standard failure analysis functional testers. Due to the increase in pin counts, clock speeds, increased complexity and the large number of power supply pins on current ICS, smaller and less equipped testers are often unable to test these newer devices. To reduce the time of analysis and improve the failure isolation capabilities for failing ICS, failure isolation is now performed using the same production testers used in product development, multiprobe and final test. With these production testers, the test hardware, program and pattern sets are already available and ready for use. By using a special interface that docks the production test head to failure isolation equipment such as the emission microscope, liquid crystal station and E-Beam prober, the analyst can quickly and easily isolate the faillure on an IC. This also enables engineers in design, product engineering and the waferfab yield enhancement groups to utilize this equipment to quickly solve critical design and yield issues. Significant cycle time savings have been achieved with the migration to this method of electrical stimulation for failure isolation.


Author(s):  
Hashim Ismail ◽  
Ang Chung Keow ◽  
Kenny Gan Chye Siong

Abstract An output switching malfunction was reported on a bridge driver IC. The electrical verification testing revealed evidence of an earlier over current condition resulting from an abnormal voltage sense during a switching event. Based on these test results, we developed the hypothesis that a threshold voltage mismatch existed between the sense transistor and the output transistor. This paper describes the failure analysis approach we used to characterize the threshold voltage mismatch as well as our approach to determine the root cause, which was trapped charge on the gate oxide of the sense transistor.


Author(s):  
K.A. Mohammad ◽  
L.J. Liu ◽  
S.F. Liew ◽  
S.F. Chong ◽  
D.G. Lee ◽  
...  

Abstract The paper focuses on the pad contamination defect removal technique. The defect is detected at the outgoing inspection step. The failure analysis results showed that the defect is Fluorine type contamination. The failure analysis indicated many source contributors mainly from Fluorine based processes. The focus is in the present work is in the rework method for the removal of this defect. The combination of wet and dry etch processing in the rework routine is utilized for the removal of the defect and preventive action plans for in-line were introduced and implemented to avoid this event in the future. The reliability of the wafer is verified using various tests including full map electrical, electrical sort, gate oxide breakdown (GOI) and wafer reliability level, passivation quick kill to ensure the integrity of the wafer after undergoing the rework routine. The wafer is monitored closely over a period of time to ensure it has no mushroom defect.


Author(s):  
Michael B. Schmidt ◽  
Noor Jehan Saujauddin

Abstract Scan testing and passive voltage contrast (PVC) techniques have been widely used as failure analysis fault isolation tools. Scan diagnosis can narrow a failure to a given net and passive voltage contrast can give real-time, large-scale electronic information about a sample at various stages of deprocessing. In the highly competitive and challenging environment of today, failure analysis cycle time is very important. By combining scan FA with a much higher sensitivity passive voltage contrast technique, one can quickly find defects that have traditionally posed a great challenge.


Author(s):  
Andrew J. Komrowski ◽  
N. S. Somcio ◽  
Daniel J. D. Sullivan ◽  
Charles R. Silvis ◽  
Luis Curiel ◽  
...  

Abstract The use of flip chip technology inside component packaging, so called flip chip in package (FCIP), is an increasingly common package type in the semiconductor industry because of high pin-counts, performance and reliability. Sample preparation methods and flows which enable physical failure analysis (PFA) of FCIP are thus in demand to characterize defects in die with these package types. As interconnect metallization schemes become more dense and complex, access to the backside silicon of a functional device also becomes important for fault isolation test purposes. To address these requirements, a detailed PFA flow is described which chronicles the sample preparation methods necessary to isolate a physical defect in the die of an organic-substrate FCIP.


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):  
Sebastian Brand ◽  
Matthias Petzold ◽  
Peter Czurratis ◽  
Peter Hoffrogge

Abstract In industrial manufacturing of microelectronic components, non-destructive failure analysis methods are required for either quality control or for providing a rapid fault isolation and defect localization prior to detailed investigations requiring target preparation. Scanning acoustic microscopy (SAM) is a powerful tool enabling the inspection of internal structures in optically opaque materials non-destructively. In addition, depth specific information can be employed for two- and three-dimensional internal imaging without the need of time consuming tomographic scan procedures. The resolution achievable by acoustic microscopy is depending on parameters of both the test equipment and the sample under investigation. However, if applying acoustic microscopy for pure intensity imaging most of its potential remains unused. The aim of the current work was the development of a comprehensive analysis toolbox for extending the application of SAM by employing its full potential. Thus, typical case examples representing different fields of application were considered ranging from high density interconnect flip-chip devices over wafer-bonded components to solder tape connectors of a photovoltaic (PV) solar panel. The progress achieved during this work can be split into three categories: Signal Analysis and Parametric Imaging (SA-PI), Signal Analysis and Defect Evaluation (SA-DE) and Image Processing and Resolution Enhancement (IP-RE). Data acquisition was performed using a commercially available scanning acoustic microscope equipped with several ultrasonic transducers covering the frequency range from 15 MHz to 175 MHz. The acoustic data recorded were subjected to sophisticated algorithms operating in time-, frequency- and spatial domain for performing signal- and image analysis. In all three of the presented applications acoustic microscopy combined with signal- and image processing algorithms proved to be a powerful tool for non-destructive inspection.


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