Turbo-generator life management and service technology

CADless laser assisted methodologies for failure analysis and device reliability

Defect isolation and failure analysis is a key factor that drive development and manufacturing yield improvements in semiconductor packaging industry. From a manufacturing point of view, ensuring adequate package reliability is becoming more challenging due to increasing packaging complexity and a more pronounced impact from material physical property mismatch among packaging materials and components. The task of isolating defects and finding root cause is further complicated by ever shrinking feature sizes within the device and/or package, already approaching the nanometer range in contemporary semiconductor packages. Conventional failure analysis techniques such as physical cross sectioning or micro-cutting using focused ion beams(FIB) are sometimes no longer sufficient to find these defects. Both physical cross section and FIB are only capable of exposing the defect in two dimensions (x and y directions), which makes pinpointing the defect in depth, i.e., the z direction, extremely difficult when dealing defects with micron and submicron size. Additional complications are many times introduced during conventional sample preparation, which can introduce undesirable artifacts associated with the module and/or device depackaging. These artifacts may mask the true defects, or lead to misinterpretation of the true cause of failure. In this work, it has been determined that a three-dimensional failure analysis method is critical for finding some defects in silicon packages. For example, xenon difluoride (XeF2) has excellent selectivity to silicon and provides efficient material removal by chemical reaction, generating gaseous by-products that can be readily exhausted [1]. Furthermore, XeF2 has very little reaction with non-silicon materials, such as SiO2, and the metals and polymers commonly used in semiconductor devices and packages. This paper reports the application of XeF2 as an effective failure analysis technique to reveal defects in silicon packages. The mechanism of selective reaction between XeF2 and Si is discussed and key design features of the failure analysis tool are presented. The paper also highlights a few case studies which advantageously utilize XeF2 etching to expose defects. XeF2 was especially effective in detecting the source of electrical leakage in 3D packages having Through Silicon Via (TSV) structures. Due to its high etching selectivity to silicon, the leakage area in electrically failing samples was found to be due to damage of the TSV liner (passivation layer material) and further analysis reveals a three dimensional view of the TSV defect. With the addition of XeF2 etching, further characterization of defects by traditional methods such as FIB micro cutting also becomes more practical. The work suggests that a wider application of Si removal via XeF2 can be achieved by combining mechanical milling of bulk silicon followed by a final, low stress, silicon removal by XeF2 etching.

This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 539, Areas 25 and 26 Railroad Tracks, as identified in the Federal Facility Agreement and Consent Order (FFACO). A modification to the FFACOwas approved in May 2010 to transfer the two Railroad Tracks corrective action sites (CASs) from CAU 114 into CAU539. The two CASs are located in Areas 25 and 26 of the Nevada Test Site: • 25-99-21, Area 25 Railroad Tracks • 26-99-05, Area 26 Railroad Tracks This plan provides the methodology for field activities needed to gather the necessary information for closing the two CASs. There is sufficient information and process knowledge from historical documentation and investigations of similar sites regarding the expected nature and extent of potential contaminants to recommend closure of the CAU 539 Railroad Tracks CASs using the SAFER process. Additional information will be obtained by conducting a field investigation before selecting the appropriate corrective action for each CAS. The results of the field investigation should support a defensible recommendation that no further corrective action is necessary. If it is determined that complete clean closure cannot be accomplished during the SAFER, then a hold point will have been reached and the Nevada Division of Environmental Protection (NDEP) will be consulted to determine whether the remaining contamination will be closed under the alternative corrective action of closure in place with use restrictions. This will be presented in a closure report that will be prepared and submitted to the NDEP for review and approval. The sites will be investigated based on the data quality objectives (DQOs) developed on December 14, 2009, by representatives of U.S.Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office; Navarro Nevada Environmental Services, LLC (NNES); and National Security Technologies, LLC. The DQO process has been used to identify and define the type, amount, and quality of data needed to determine and implement appropriate corrective actions for each Railroad Tracks CAS in CAU 539. The following text summarizes the SAFER activities that will support the closure of CAU 539: • Perform site preparation activities (e.g., utilities clearances, radiological surveys). • Collect in situ dose measurements. • Collect environmental samples from designated target populations (e.g., lead bricks) to confirm or disprove the presence of contaminants of concern (COCs) as necessary to supplement existing information. • If no COCs are present at a CAS, establish no further action as the corrective action. • If COCs exist, collect environmental samples from designated target populations (e.g., clean soil adjacent to contaminated soil) and submit for laboratory analyses to define the extent of COC contamination. If a COC is present at a CAS, NNES will consult NDEP to determine the path forward, then either: • Establish clean closure as the corrective action. The material to be remediated will be removed, disposed of as waste, and verification samples will be collected from remaining soil, or • Establish closure in place as the corrective action and implement the appropriate use restrictions.

This case series highlights the challenges in eye banking and the importance of a quality assurance program. Three cases triggered corrective and preventive actions (CAPAs) to improve the processes. Case 1 emphasized training to prevent retrieval failures. Case 2 stressed the need for blood samples and comprehensive documentation. In Case 3, mishandling led to policy revisions and staff training. CAPA involved identifying concerns, root cause analysis, action plans, implementation, checks, and closure. Errors can occur in man, machinery, process, and policies. Continuous CAPA ensures continuous quality improvement and safe corneal tissue transplantation, benefiting patients in need.

Results from an engineering investigation, including findings, root cause and corrective action of an ETF40B compressor incident, are presented in this paper. Vericor’s ETF40B is used to power US NAVY Landing Craft Air Cushion (LCAC) vehicles that have undergone the Service Life Extension Program (SLEP). This paper discusses the initial review of an engine incident, the results of the engineering investigation that led to identifying root cause and the successful validation testing providing fleet corrective action. This paper will present the history of the investigation, the metallurgical analysis findings, the results of finite element stress analysis and investigative testing performed on the vane. The paper will conclude with the testing conducted to verify the design solution and how the final field and production compressor changes were incorporated.

Failure modes and effects analysis (FMEA) is a popular reliability tool in petroleum engineering. In FMEA, potential failure modes or corrective actions are evaluated, each assigned a Risk Priority Number (RPN) score, and prioritized for decision making. FMEA is also known as Failure Modes, Effects, and Criticality Analysis (FMECA), while focuses on failure modes prioritization. Despite of the popularity of FMEA and FMECA, it is not clear, how potential failure modes and corrective actions could be represented systematically, for effective decision making. In this paper, two new representations (i.e., a tree representation and a vector representation), for potential failure modes and corrective actions, are proposed. The tree representation for a potential failure mode allows its root cause(s), effect(s) and corrective action(s), together with their severity, occurrence and detection rating(s), to be represented as a three-layer tree model. The tree representation for a corrective action with similar contents is outlined too. The RPN model, together with its score, is represented as a node of the tree model. These tree models can also be represented as their associated equivalence layered-vector representations. In this paper, the usefulness of the proposed approaches is illustrated with benchmark FMEA worksheets pertaining to petroleum engineering.

Cost-effective fault diagnosis of a multi-component dynamic system under corrective maintenance

Root cause failure analysis of lithium-ion batteries provides important feedback for cell design, manufacture, and use. As batteries are being produced with larger form factors and higher energy densities, failure analysis techniques must be adapted to characteristics of the specific batteries. This paper will discuss the significance of melted copper in lithium-ion battery cells that have experienced thermal runaway and how the interpretation of such evidence has evolved over time. Specialized testing techniques that may prove helpful in determining the root cause of battery failures will also be described.

Improved reliability in small multichip ball grid arrays

Photon Emission Microscopy (PEM) is a popular technique for microelectronics failure analysis by detecting the photon emission from a defective circuit, when a failing device is electrically exercised at certain voltage. The photon emission contains physical location information, photon emission spectral information and photon emission intensity information. People often use the physical location information to localize a defective circuit and guide the follow-up physical failure analysis to find the defects. However, this procedure does not always work. Sometimes, it shows no defect found (NDF). In this paper, we propose a new computer vision-based analysis of the photon emission intensity for identifying the root cause of the excessively high IDDQ at elevated Vdds. The procedure includes collecting photon emissions at different Vdds and a follow-up photon emission intensity analysis with computer vision techniques. The procedure was applied on a case of microprocessor chip. After analyzing the dependencies of photon emission intensity on Vdd for 4 types of circuits, it was concluded that the SRAM circuit leakage is the root cause of the excessively high IDDQ at elevated Vdd.

The Root cause analysis, called the Tripod Beta, is an approach to the analysis of incidents using the Tripod theory of Accident causation and the hazard and effect management Process (HEMP). This approach was adopted few years ago to stem the increasing rates of serious HSE incidents in SPDC and the advantages can be seen. The pattern of previous incident investigation has been the same-the discovery that an incident happens always puts an end to the investigation, as if there is no need to look further-no need to see that such incidents are the effects of other causes. The root cause (Tripod Beta) tool is a tree approach to the analysis of accidents and incidents. The method will lead you to take both short term immediate corrective actions, as well as finding the underlying root causes (latent failures) hidden in the way we do our work that will cause similar problems in the future. The Tripod Beta promotes thorough incident investigation with clear, concise and consistent reporting. This paper presents the SPDC experience using this tripod Beta method in carrying out incident investigation/analysis and the incident trends (since adopting the method) and advantages will be highlighted

Root Cause Analysis of Product Service Failure Using Computer Experimentation Technique

This paper describes a new LIT technique named External trigger Synchronous LIT (ESLIT). LIT is widely used in device analysis from initial investigation to fault isolation. This technique uses a “lock-in function” to reduce thermal spreading from the heat source. Conventional LIT analysis is usually performed under limited set-up conditions with some probes without ATE. However, in the case of ESLIT, ATE can be used to reproduce the failure state of the DUT during the LIT analysis. And the “lock-in function” is used to identify specific hotspots that correspond to IDDQ failure states. In our experiment, the results of ESLIT perfectly agreed with IDDQ fault diagnosis candidates. On the other hand, PEM and OBIRCH detected not only logic-related points, but also non-logic-related points that did not match the fault diagnostic results. We also confirmed that ESLIT is available nondestructively. We think that ESLIT is a useful technique for IDDQ failure analysis since it can identify the true root cause even in the case of multiple failure.

Maintenance is performed to restore a system's inherent reliability. However, reliability is not enough: a maintenance task must “pay for itself‘ in dollars or readiness. This applies to all types of maintenance: corrective, preventive, and alterative. We can reduce corrective maintenance costs through preventive and alterative maintenance. We can reduce preventive maintenance costs by eliminating inapplicable and ineffecitve tasks. We must weigh alterative maintenance costs against the value of improved readiness and cost‐avoidance of future corrective maintenance.The U. S. Navy is improving alterative maintenance by engineering for reduced maintenance (ERM). This process corrects the root cause of some high‐cost items by replacing the system, component, or coating with an improved design or material. It overcomes the limit of preventive maintenance: higher levels of inherent reliability require design improvement.The U. S. Navy is improving preventive maintenance through condition‐based maintenance (CBM). The Navy's CBM initiative encompasses three parallel efforts: rules (improving maintenance requirements and plans), tools (using computer and diagnostic technology to facilitate maintenance decision‐making), and schools (educating all levels of maintenance decision‐makers in reliability and condition‐based maintenance engineering principles).This paper addresses how the U. S. Navy surface ship community plans to avoid inapplicable and ineffective maintenance and reduce maintenance costs without sacrificing reliability.

The range of industrial applications requiring adjustable speed drives (ASD) is continuously increasing. Although generally highly reliable, a breakdown of an electrical machine has to be prevented under any circumstance for certain applications like safety-critical devices or industrial systems with many drives installed. To increase efficiency and return-on-investment the drives are operated at or near their rated values. High dynamics, overload and the fast switching of the inverter cause additional stress for the different drive components. One of the major causes for drive breakdown is insulation deterioration. Before an actual breakdown of the insulation system occurs, the machine's high-frequency behavior is altered. Therefore monitoring of the drive's hf-behavior can be employed to evaluate the insulation condition. However, other drive components like cabling, grounding or the inverter may change the drive's hf-behavior as well. The possibility to separate the different influences of the machine's hf-behavior is thus essential and will be shown by experimental results.