Unique Autoclave Stress Induced Failure Mechanism

2005 ◽  
Author(s):  
John Butchko ◽  
Bruce T. Gillette
Keyword(s):  
Corrosion Rate ◽  
Grain Boundary ◽  
Failure Analysis ◽  
Failure Mechanism ◽  
Metal Corrosion ◽  
Corrosion Mechanism ◽  
Reliability Testing ◽  
Process Change ◽  
Transistor Reliability ◽  
Pass Through

Abstract Autoclave Stress failures were encountered at the 96 hour read during transistor reliability testing. A unique metal corrosion mechanism was found during the failure analysis, which was creating a contamination path to the drain source junction, resulting in high Idss and Igss leakage. The Al(Si) top metal was oxidizing along the grain boundaries at a faster rate than at the surface. There was subsurface blistering of the Al(Si), along with the grain boundary corrosion. This blistering was creating a contamination path from the package to the Si surface. Several variations in the metal stack were evaluated to better understand the cause of the failures and to provide a process solution. The prevention of intergranular metal corrosion and subsurface blistering during autoclave testing required a materials change from Al(Si) to Al(Si)(Cu). This change resulted in a reduced corrosion rate and consequently prevented Si contamination due to blistering. The process change resulted in a successful pass through the autoclave testing.

The Application of Novel Failure Analysis Techniques and Defect Modeling in Eliminating Short Poly End-Cap Problem in Submicron CMOS Devices

1996 ◽  
Author(s):  
Y.E. Hong ◽  
M.T.T. We
Keyword(s):  
Failure Analysis ◽  
Failure Mechanism ◽  
Leakage Current ◽  
Packing Density ◽  
Process Change ◽  
Defect Modeling ◽  
Functional Failure ◽  
Analysis Techniques ◽  
Post Process ◽  
First Time

Abstract As transistor dimension shrinks down below submicron to cater for higher speed and higher packing density, it is very important to characterize the shrinkage carefully to avoid unwanted parametric problems. Leakage current across short poly end-cap is a new failure mechanism that falls in this category and was for the first time, uncovered in submicron multilayered CMOS devices. This mechanism was responsible for a systematic yield problem; identified as the 'centre wafer striping' functional failure problem. This paper presents the advanced failure analysis techniques and defect modeling used to narrow down and identify this new mechanism. Post process change by loosening the marginal poly end-cap criteria eliminated the problem completely.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

Case Study in Fault Isolation of a Metal Short for Yield Enhancement

2010 ◽  
Author(s):  
Sarven Ipek ◽  
David Grosjean
Keyword(s):  
Failure Analysis ◽  
Failure Mechanism ◽  
Photon Emission ◽  
Fault Isolation ◽  
Yield Enhancement ◽  
Analysis Technique ◽  
Laser Signal ◽  
Signal Injection ◽  
Microscopy Techniques

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.

Investigation of High Frequency Failures on a 0.35μm CMOS IC

1999 ◽  
Author(s):  
Alan Kennen ◽  
John F. Guravage ◽  
Lauren Foster ◽  
John Kornblum
Keyword(s):  
Failure Analysis ◽  
Failure Mechanism ◽  
Integrated Circuit ◽  
Metal Layer ◽  
Ion Beam ◽  
Stress Test ◽  
Design For Test ◽  
Interface Failure ◽  
Serial Interface ◽  
High Impedance

Abstract Rapidly changing technology highlights the necessity of developing new failure analysis methodologies. This paper will discuss the combination of two techniques, Design for Test (DFT) and Focused Ion Beam (FIB) analysis, as a means for successfully isolating and identifying a series of high impedance failure sites in a 0.35 μm CMOS design. Although DFT was designed for production testing, the failure mechanism discussed in this paper may not have been isolated without this technique. The device of interest is a mixed signal integrated circuit that provides a digital up-convert function and quadrature modulation. The majority of the circuit functions are digital and as such the majority of the die area is digital. For this analysis, Built In Self Test (BIST) circuitry, an evaluation board for bench testing and FIB techniques were used to successfully identify an unusual failure mechanism. Samples were subjected to Highly Accelerated Stress Test (HAST) as part of the device qualification effort. Post-HAST electrical testing at 200MHz indicated that two units were non-functional. Several different functional blocks on the chip failed electrical testing. One part of the circuitry that failed was the serial interface. The failure analysis team decided to look at the serial interface failure mode first because of the simplicity of the test. After thorough analysis the FA team discovered increasing the data setup time at the serial port input allowed the device to work properly. SEM and FIB techniques were performed which identified a high impedance connection between a metal layer and the underlying via layer. The circuit was modified using a FIB edit, after which all vectors were read back correctly, without the additional set-up time.

Failure Analysis on a Counterweight Assembly of an Aeroengine

2011 ◽  
Vol 339 ◽  
pp. 342-348
Author(s):  
Hai Jun Tang ◽  
Hong Yu Yao
Keyword(s):  
Heat Treatment ◽  
Stress Concentration ◽  
Failure Analysis ◽  
Failure Mechanism ◽  
Treatment Process ◽  
Hardness Test ◽  
Heat Treatment Process ◽  
Material Loss ◽  
Structure Strength ◽  
Crucial Part

The paper presents a failure analysis on a counterweight assembly installed on crank shaft which resulted in an in-flight shutdown of a piston aeroengine. The counterweight assembly failure includes counterweight block material loss and fractured washer which is the most crucial part for in-flight shutdown in this type of aeroengine. Macro observation, fractography analysis, metallography analysis and hardness test were conducted on the failed counterweight assembly. The result shows that failure mechanism of counterweight block and washer is fatigue. The washer failure is likely due to inappropriate heat treatment process and continuous impact in flight by slightly tilted roller. Counterweight material loss is attributed to stress concentration, low structure strength and impact came from the tilted roller. Finally some safety suggestion on design and maintenance is given.

Failure of the Crude-Oil Tank Induced by Two Independent Corrosion Processes

2013 ◽  
Vol 577-578 ◽  
pp. 529-532 ◽  
Author(s):  
Jiří Sís ◽  
Bedřich Votava
Keyword(s):  
Corrosion Rate ◽  
Failure Analysis ◽  
Crude Oil ◽  
Weld Joint ◽  
Heat Affected Zone ◽  
Low Cycle Fatigue ◽  
Basic Material ◽  
Cycle Fatigue ◽  
Concrete Base ◽  
Oil Tank

Corrosion processes are frequent reasons of failure of materials in many applications. Results of failure analysis of the crude-oil tank after more than 30 years of service are summarized in this work. The failure was caused by two different and independent corrosion processes – corrosion in crude oil inside the tank and corrosion from concrete base under the tank. Both corrosion processes usually occur equally over the whole surface. In this case, however, both the corrosion processes occurred with distinctly higher corrosion rate in basic material alongside of heat affected zone of weld joint as well. The crack with length about 420 mm was the final result of these processes. The effect of low-cycle fatigue from filling and draining of crude oil is usually significant and was discussed as well.

scholarly journals A Review of the electrochemical corrosion of metals in choline chloride based deep eutectic solvents

2021 ◽  
Author(s):  
Mihael Bučko ◽  
Jelena Bajat
Keyword(s):  
Ionic Liquids ◽  
Corrosion Rate ◽  
Wide Spectrum ◽  
Choline Chloride ◽  
Electrochemical Corrosion ◽  
Deep Eutectic Solvents ◽  
High Viscosity ◽  
Metal Corrosion ◽  
Melting Points ◽  
Separate Class

Deep eutectic solvents (DESs) are a class of mixtures with melting points notably lower than those of their raw constituent components. These liquids have found a tremendously wide spectrum of applications in the last two decades of their research, so their contact and interaction with technical metals and alloys are inevitable. Therefore, the corrosivity of DESs towards metals is an extremely important topic. This review summarizes research efforts collected in the last two decades related to the corrosion rate of various metals in different DESs. Since the DESs are mainly composed of organic raw compounds, and by their physicochemical properties they may be regarded as a separate class of ionic liquids, the literature data about DESs corrosivity has been compared to the data related to the corrosivity of various organic solvents and ionic liquids as well. All the results gained until now show significantly low corrosivity of DESs. This observation is discussed in relation to the chemical composition of DESs. The absence of the oxidizing agents, the inhibitory action of organic ions and molecules, high viscosity and low electrical conductivity have been recognized as the main factors contributing to the low metal corrosion rate in DESs.

Effect of nickel content in the corrosion process of TiC/Cu-Ni composites immersed in synthetic seawater

MRS Advances ◽  
2019 ◽  
Vol 4 (63) ◽  
pp. 3475-3484
Author(s):  
Miguel A. Téllez-Villaseñor ◽  
Carlos A. León Patino ◽  
Ricardo Galván Martínez ◽  
Ena A. Aguilar Reyes
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Nickel Content ◽  
Corrosion Mechanism ◽  
Composite Surface ◽  
Synthetic Seawater ◽  
Ni Content ◽  
The Matrix ◽  
Static Conditions

ABSTRACTThe work presents an electrochemical study of the corrosion behaviour of two TiC/Cu-Ni metal matrix composites with a content of 10 and 20 wt.% Ni immersed in synthetic seawater. The composites were synthesized by a capillary infiltration technique, obtaining dense materials TiC/Cu-10Ni and TiC/Cu-20 Ni with a residual porosity of 1.8 and 1.7%, respectively. The corrosion rate (CR) was evaluated from the techniques of polarization curves (PC), linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Electrochemical measurements were carried out under static conditions, ambient temperature and atmospheric pressure at 24 hours exposure in the electrolytic medium. The corrosion rate is affected by the Ni content in the matrix, with less corrosion in the composite with a higher Ni content. The higher content of Ni in the Cu-Ni alloy provides higher passivation and stability to the corrosion products film that are absorbed on the composite surface. Microscopic examination (SEM) showed a characteristic morphology of a corrosion mechanism of the localized type (pits and crevices) generated by a differential aeration, where the TiC/Cu-10Ni composite showed greater degradation.

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