Failure Analysis of a Qualification Unit Injector for a Satellite Thruster

Author(s):  
M. Lipschutz ◽  
R. Brannam ◽  
T. Nguyentat

Abstract This article details the results of a failure analysis performed on a Qualification Unit injector for a military satellite thrusters and explains that the failure was initially detected due to a shift in performance during qualification testing. Failure analysis involved non-destructive evaluation on the injector using micro-focus X-ray and scanning electron microscopy. Serial cross-sectional metallography was then performed, with each cross-section documented by optical microscopy and SEM. The failure analysis resulted in three main conclusions: (1) the root cause of the failure was attributed to multiple detonations in or around the damaged orifice; these detonations were likely caused by fuel and/or combustion products condensing in the orifice between pulses and then igniting during a subsequent pulse; (2) multiple damage mechanisms were identified in addition to the ZOT detonations; and (3) the material and platelet manufacturing process met all design parameters.

Author(s):  
Srinath Rajaram ◽  
Denise Barrientos ◽  
Nadia Ahmad ◽  
Robert Carpenter ◽  
Eric Barbian

Abstract Failure Analysis labs involved in customer returns always face a greater challenge, demand from customer for a faster turnaround time to identify the root cause of the failure. Unfortunately, root cause identification in failure analysis is often performed incompletely or rushing into destructive techniques, leading to poor understanding of the failure mechanism and root-cause, customer dissatisfaction. Scanning Acoustic Tomography (SAT), also called Scanning Acoustic Microscope (SAM) has been adopted by several Failure Analysis labs because it provides reliable non-destructive imaging of package cracks and delamination. The SAM is a vital tool in the effort to analyze molded packages. This paper provides a review of non-destructive testing method used to evaluate Integrated Circuit (IC) package. The case studies discussed in this paper identifies different types of defects and the capabilities of B-Scan (cross-sectional tomography) method employed for defect detection beyond delamination.


Author(s):  
Christian Schmidt ◽  
Michél Simon ◽  
Frank Altmann ◽  
Antoine Nowodzinski

Abstract The paper will present an approach for non-destructive localization of thermal active defects at multi chip devices combining the Lock-in Thermography and following local X-Ray inspection. In combination of both methods inner defects in inter chip connections of complex device built ups can be found in a non-destructive way before opening the device. The methods were demonstrated at defective flip chip devices with a high ohmic daisy chain with lots of chip to chip contacts. Subsequently, cross section analysis at located high ohmic contacts was performed in order to find the root cause of the failure.


Author(s):  
Tsan-Chang Chuang ◽  
Cha-Ming Shen ◽  
Shi-Chen Lin ◽  
Chen-May Huang ◽  
Jin-Hong Chou ◽  
...  

Abstract Scanning capacitance microscopy (SCM) is a 2-D carrier and/or dopant concentration profiling technique under development that utilizes the excellent spatial resolution of scanning probe microscopy. However, PV-SCM has limited capability to achieve the goal due to inherent "plane" trait. On top of that, deeper concentration profile just like deep N-well is also one of restrictions to use. For representing above contents more clearly, this paper presents a few cases that demonstrate the alternated and optimized application of PV-SCM and X-SCM. The case studies concern Joint Test Action Group failure and stand-by failure. These cases illustrate that the correct selection from either plane-view or cross-sectional SCM analysis according to the surrounding of defect could help to exactly and rapidly diagnose the failure mechanism. Alternating and optimizing PV-SCM and X-SCM techniques to navigate various implant issue could provide corrective actions that suit local circumstance of defects and identify the root cause.


SPE Journal ◽  
2013 ◽  
Vol 18 (06) ◽  
pp. 1217-1228 ◽  
Author(s):  
Hascakir Berna ◽  
Cynthia M. Ross ◽  
Louis M. Castanier ◽  
Anthony R. Kovscek

Summary In-situ combustion (ISC) is a successful method with great potential for thermal enhanced oil recovery. Field applications of ISC are limited, however, because the process is complex and not well-understood. A significant open question for ISC is the formation of coke or "fuel" in correct quantities that is sufficiently reactive to sustain combustion. We study ISC from a laboratory perspective in 1 m long combustion tubes that allow the monitoring of the progress of the combustion front by use of X-ray computed tomography (CT) and temperature profiles. Two crude oils—12°API (986 kg/m3) and 9°API (1007 kg/m3)—are studied. Cross-sectional images of oil movement and banking in situ are obtained through the appropriate analysis of the spatially and temporally varying CT numbers. Combustion-tube runs are quenched before front breakthrough at the production end, thereby permitting a post-mortem analysis of combustion products and, in particular, the fuel (coke and coke-like residues) just downstream of the combustion front. Fuel is analyzed with both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). XPS and SEM results are used to identify the shape, texture, and elemental composition of fuel in the X-ray CT images. The SEM and XPS results aid efforts to differentiate among combustion-tube results with significant and negligible amounts of clay minerals. Initial results indicate that clays increase the surface area of fuel deposits formed, and this aids combustion. In addition, comparisons are made of coke-like residues formed during experiments under an inert nitrogen atmosphere and from in-situ combustion. Study results contribute to an improved mechanistic understanding of ISC, fuel formation, and the role of mineral substrates in either aiding or impeding combustion. CT imaging permits inference of the width and movement of the fuel zone in situ.


2013 ◽  
Vol 2013 (1) ◽  
pp. 000303-000311
Author(s):  
Terence Q. Collier ◽  
Indira Gubeljic

Contaminated and corroded aluminum bond pads can lead to a number of reliability failures. Poor wirebondability, false failures at electrical probe due to high contact resistance, opens on RDL layers due to incomplete sputter, and various early life failures during JEDEC testing can all be attributed to excess oxidation and corrosion on aluminum bond pads. Understanding what layers exist on the bond pad surface is critical. Oxides, hydrates, xyfluorides and various soups of materials can be confirmed from combinations of Auger, SIMMS and FTIR but there is a chance the die can be damaged and the spot sizes can be problematic picking up information outside the bond pad target. Layer analysis of the pad can also be difficult since sputtering rates vary based on the contaminants on the pad and any thermal processing. How does one evaluate bond pads without a destructive test? Is there a process for accurate bond pad evaluation while minimizing die damage? Sure. The cycle time and costs of these tests can also be a concern particularly for a customer wanting a quick response from failure analysis. A better method is to bond the die with a gold stud bump followed by selectively etching away the gold. Etching the gold highlights the intermetallics and shows how much of the gold alloyed with aluminum versus blocked oxides. Voiding can be demonstrated, that might be misconstrued as Kirkendall voiding, by cross sectional analysis.


2015 ◽  
Vol 2015 (1) ◽  
pp. 000675-000684
Author(s):  
Rama Hegde ◽  
Anne Anderson ◽  
Sam Subramanian ◽  
Andrew Mawer ◽  
Ed Hall ◽  
...  

In-process failures were experienced during printed circuit board (PCB) SMT assembly of a 16 Quad Flat No Leads (QFN) device. The failures appeared to be solderability related with QFN unit I/O pads not soldering robustly and sometimes leading to QFN detachment following board mounting. When assembly did take place on affected QFN units, the resulting solder joint was observed to be weak. This paper reports on very systematic analyses of the QFN device I/O pads using optical inspections, AES surface, AES depth profiling, SEM/EDX, SIMS, FIB and TEM cross-sectional measurements to determine the root cause of the failure and the failure mechanism. The detached QFN units, suspect and good unsoldered units, passing and failing units obtained from customers were examined. The industry standard surface mount solderability testing was performed on good and suspect parts, and all were observed to pass as evidenced by >95% coverage of the I/O pads. Optical inspections and a wide variety of physical analysis of the pads on fresh parts showed no anomalies with only the expected Au over Pd over Ni found. AES analysis was performed including depth profiling to look for any issues in the NiPdAu over base Cu plating layers that could be contributing the solderability failures. The AES depth profiling indicated AuPd film on the Ni under layer for the I/O pads as expected. No unexpected elements or oxide layers were observed at any layer. Then, one failing and one passing units were compared by doing FIB cross-section, FIB planar section and TEM cross-section analysis. The cross-sectional analysis showed rough Ni surface for the failing units, while the Ni surface was relatively smooth for the passing unit. Further, finer Cu grains and Ni grains were observed on the passing units. Additionally, the lead frame fabrication process mapping showed rough Cu, Ni “texturing” and use of low electro chemical polishing (ECP) current on the bad units compared to that of the good units. All affected bad units were confirmed coming from a second source Cu supplier with the rough Cu. The weak and irregular NiSn IMC formation on the bad units caused IMC separation and possible spalling during board solder reflow primarily due to the rough base Cu and irregular grain sizes and resulting lower ECP lead frame plating current. A possible final factor was marginally low Pd thickness. In conclusion, the 16 QFN device solderability failure root cause summary and the lessons learned from a wide variety of analysis techniques will be discussed.


2011 ◽  
Vol 2011 (1) ◽  
pp. 001078-001083 ◽  
Author(s):  
K. Fahey ◽  
R. Estrada ◽  
L. Mirkarimi ◽  
R. Katkar ◽  
D. Buckminster ◽  
...  

This paper describes the utilization of non-destructive imaging using 3D x-ray microscopy for package development and failure analysis. Four case studies are discussed to explain our methodology and its impact on our advanced packaging development effort. Identifying and locating failures embedded deep inside the package, such as a solder fatigue failure within a flip chip package, without the need for physical cross-sectioning is of substantial benefit because it preserves the package for further analysis. Also of utility is the ability to reveal the structural details of the package while producing superior quality 2D and volumetric images. The technique could be used not only for analysis of defects and failures, but also to characterize geometries and morphologies during the process and package development stage.


2016 ◽  
Vol 33 (2) ◽  
pp. 94-101
Author(s):  
Kamil Janeczek ◽  
Aneta Arazna ◽  
Konrad Futera ◽  
Grazyna Koziol

Purpose The aim of this paper is to present non-destructive and destructive methods of failure analysis of epoxy moulded IC packages on the example of power MOSFETs in SOT-227 package. Design/methodology/approach A power MOSFET in SOT-227 package was examined twice using X-ray inspection, at first as the whole component to check if it is damaged and then after removing the upper part of package by mechanical grinding. The purpose of the second X-ray inspection was to prepare images for estimation of the total number and approximate location of voids in soft solder layers. Finally, power MOSFETs were subjected to decapsulation process using a concentrated sulphuric acid to verify existence of damage areas noticed during X-ray analysis and to observe other possible failures such as cracks in aluminium metallization or wires deformation. Findings X-ray analysis was revealed to be adequate technique to detect damage (e.g. meltings) in power MOSFETs in SOT-227 package, but only when tested components were analysed in the side view. This type of analysis combined with a graphic software is also suitable for voids estimation in soft solder layers. Moreover, it was found that a single acid (concentrated sulphuric acid) at elevated temperature can be successfully used for decapsulation of power MOSFETs in SOT-227 package without damage of aluminium metallization and aluminium wires. Such decapsulation process enables analysis of defects in wire, die and package materials. Research limitations/implications Further investigations are required to examine if the presented methods of failures analysis can be used for other types of components (e.g. high power resistors) in similar packages. Practical/implications The described methods of failure analysis can find application in electronic industry to select components which are free of damage and in effect which allow to produce high reliable devices. Apart from it, the presented method is applicable to evaluate reasons of improper work of tested electronic devices and to identify faked components. Originality/value This paper contains valuable information for research and technical staff involved in the assessment of electronic devices who needs practical methods of failure analysis of epoxy moulded IC packages.


Author(s):  
Akira Mizoguchi ◽  
Minoru Sugawara ◽  
Masahide Nakamura ◽  
Koichiro Takeuchi

Abstract We have been paying attention to the development of the nondestructive physical analysis (NDPA) technology. We think that NDPA is a technology which doesn't depend on the worker's capability or experience. There are many NDPA techniques, and analysis using X-ray imaging is one of the principal techniques. Due to the progress of the image analysis using computers in recent years, X-ray imaging have been evolving from two dimensional images to three dimensional imaging. We have been applying X-ray CT imaging to actual failure analysis and reliability evaluation since 2008. At ISTFA 2009, we reported on the effectiveness of X-ray Computed Tomography (CT) images in the failure analysis. [1] We confirmed that the X-ray CT image had various applications, for example, screening for counterfeit parts, the detection of the defect of the multi-layers printed wiring boards (multi-layers PWB), the structure confirmation of caulking contacts, and the detection of cracks or voids of the solder joint. This paper discusses the effectiveness of X-ray CT imaging in failure analysis and discusses the effectiveness of applying X-ray CT imaging to the propagation of cracks occurring at solder joints during temperature cycling test.


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