Chemical-Mechanical-Polishing (CMP), first used as a planarization technology in the manufacture of multi-level metal interconnects for high-density Integrated Circuits (IC), is readily adapted as an enabling technology in MicroElectroMechanical Systems (MEMS) fabrication, particularly polysilicon surface micromachining. The authors have demonstrated that CMP enhances the design and manufacturability of MEMS devices by eliminating several photolithographic definition and film etch issues generated by severe topography. In addition, CMP planarization readily allows multi-level polysilicon structures comprised of 4- or more levels of polysilicon, eliminates design compromise generated by non-planar topography, and provides an avenue for integrating different process technologies. A recent investigation has also shown that CMP is a valuable tool for assuring acceptable optical flatness of micro-optical components such as micromirrors. Examples of these enhancements include: an extension of polysilicon surface-micromachining fabrication to a 5-level technology, a method of monolithic integration of electronics and MEMS, and optically flat micromirrors.
The declining state of the Russian military and precarious Russian economic condition will give the US considerable advantages at the START III bargaining table. Taking the US-RF asymmetries into account, this paper discusses a menu of START III measures the US could ask for, and measures it could offer in return, in attempting to negotiate an equitable treaty. Measures the US might seek in a START III treaty include: further reductions in deployed strategic nuclear warheads, irreversibility of reductions through warhead dismantlement; beginning to bring theater nuclear weapons under mutual control, and increased transparency into the Russian nuclear weapons complex. The US may, however, wish to apply its bargaining advantages to attempting to achieve the first steps toward two long-range goals that would enhance US security: bringing theater nuclear weapons into the US-RF arms control arena, and increasing transparency into the Russian nuclear weapons complex. In exchange for measures relating to these objectives, the US might consider offering to Russia: Further strategic weapons reductions approaching levels at which the Russians believe they could maintain a degree of parity with the US; Measures to decrease the large disparities in potential deliver-system uploading capabilities that appear likely under current START II/START III scenarios; and Financial assistance in achieving START II/START III reductions as rapidly as is technically possible.
This paper presents an overview of the issues associated with applying a domain-decomposition message-passing paradigm to the parallel implementation of both explicit and semi-implicit projection algorithms. The use of an element-based domain decomposition with an efficient solution strategy for the pressure field is shown to yield a scalable, parallel solution method capable of treating complex flow problems where high-resolution grids are required. In addition, the use of an SSOR or Jacobi preconditioned conjugate gradient solver with an A-conjugate projection reduces the computational time for the solution of the pressure field, and yields parallel efficiencies above 80% for computations with O(250) elements per processor. The parallel projection solver is verified using a series of 2-D and 3-D benchmarks designed to evaluate time-accurate flow solution methods. Finally, the extension of the projection algorithm to reacting flows is demonstrated for a time-dependent vortex-shedding problem.
The ability to make in-situ performance measurements of MEMS operating at high speeds has been demonstrated using a new image analysis system. Significant improvements in performance and reliability have directly resulted from the use of this system.
Despite evidence of significant management contributions to the causes of major accidents, recent events at Millstone Nuclear Power Station in the US and Ontario Hydro in Canada might lead one to conclude that the significance of safety culture, and the role of management in developing and maintaining an appropriate safety culture, is either not being understood or not being taken serious as integral to the safe operation of some complex, high-reliability operations. It is the purpose of this paper to address four aspects of management that are particularly important to safety culture, and to illustrate how development of an appropriate safety culture is more a matter of common sense than rocket science.
Emergent technologies often suffer from a lack of an installed manufacturing base and an obvious dominant manufacturing technique. Firms which base their search for competitive advantage on emergent disruptive technologies must make hard production choices and endure major manufacturing discontinuities. The authors as well as many other firms, are now facing these challenges with the embrace of microsystems technologies. They add to the literature by providing a set of criteria for firms investing in emergent disruptive technologies. Sandia has long been associated as a pioneer in the development of new manufacturing techniques. Microsystems is just the current in a long line of manufacturing technologies that have been considered for mission critical system applications. The authors as well as others, have had to make the hard choice of investing in specific microsystems manufacturing techniques. Important considerations in the technique choice include: the existing internal manufacturing bases, commonality with existing commercial manufacturing infrastructure, current and projected critical performance characteristics, learning curves, the promise to add new but un-thought-of functionally to existing systems, and the anticipated ability to qualify devices built from the technique for mission critical applications.
For many modern day portable electronic applications, low power high speed devices have become very desirable. Very high values of f{sub T} and f{sub MAX} have been reported with InGaAs/InP heterojunction bipolar transistors (HBTs), but only under high bias and high current level operating conditions. An InGaAs/InP ultra-lowpower HBT with f{sub MAX} greater than 10 GHz operating at less than 20 {micro}A has been reported for the first time in this work. The results are obtained on a 2.5 x 5 {micro}m{sup 2} device, corresponding to less than 150 A/cm{sup 2} of current density. These are the lowest current levels at which f{sub MAX} {ge} 10 GHz has been reported.
In the past, most defense microelectronics components were packaged in ceramic, hermetic enclosures. PEMs are not hermetic because the plastic molding compounds are permeable to moisture. This lack of hermeticity creates an unknown liability, especially with respect to corrosion of the metallization features. This potential liability must be addressed to ensure long-term reliability of these systems is maintained under conditions of long-term dormant storage. However, the corrosion process is difficult to monitor because it occurs under the encapsulating plastic and is therefore not visible. The authors have developed techniques that allow them to study corrosion of Al bondpads and traces under relevant atmospheric corrosion conditions. The cornerstone of this capability is the ATC 2.6, a microelectronic test device designed at Sandia National Laboratories. Corrosion tests were performed by exposing test chips to aggressive environments. The electrical response of the ATC indicated an increase in bondpad resistance with exposure time. Note that the change in resistance is not uniform from one bondpad to another. This illustrates the stochastic nature of the corrosion process. The change in resistance correlated with visual observation of corrosion of the bondpads on the unencapsulated test chips.
Multispectral image analysis of magnetic resonance imaging (MRI) data has been performed using an empirically-derived clustering algorithm. This algorithm groups image pixels into distinct classes which exhibit similar response in the T{sub 2} 1st and 2nd-echo, and T{sub 1} (with ad without gadolinium) MRI images. The grouping is performed in an n-dimensional mathematical space; the n-dimensional volumes bounding each class define each specific tissue type. The classification results are rendered again in real-space by colored-coding each grouped class of pixels (associated with differing tissue types). This classification method is especially well suited for class volumes with complex boundary shapes, and is also expected to robustly detect abnormal tissue classes. The classification process is demonstrated using a three dimensional data set of MRI scans of a human brain tumor.
Researchers at the National Wind Technology Center have identified a need to acquire data on the rotor of an operating wind turbine at precisely the same time as other data is acquired on the ground or on a non-rotating part of the wind turbine. The researchers will analyze that combined data with statistical and correlation techniques to clearly establish phase information and loading paths and insights into the structural loading of wind turbines. A data acquisition unit has been developed to acquire the data from the rotating system at precise universal times specified by the user. The unit utilizes commercial data acquisition hardware, spread-spectrum radio modems, and a Global Positioning Satellite receiver as well as a custom-built programmable logic device. A prototype of the system is now operational, and initial field deployment is anticipated this summer.
A specialized hyperspectral imager has been developed that preprocesses the spectra from an image before the light reaches the detectors. This "optical computer" does not allow the flexibility of digital post-processing. However, the processing is done in real time and the system can examine = 2 x 10{sup 6} scene pixels/sec. Therefore, outdoors it could search for pollutants, vegetation types, minerals, or man-made objects. On a high- speed production line it could identify defects in sheet products like plastic wrap or film, or on painted or plastic parts. ISIS is a line scan imager. A spectrally dispersed slit image is projected on a Spatial Light Modulator. The SLM is programmed to take the inner product of the spectral intensity vector and a spectral basis vector. The SLM directs the positive and negative parts of the inner product to different linear detector arrays so the signal difference equals the inner product. We envision a system with one telescope and =4 SLMS.
Engineered Surety Using the Risk Equation (EnSURE) is a new approach being developed by Sandia National Laboratories for determining and mitigating risk. The EnSURE approach is based on the risk equation, which can be defined by the following equation: R = (Pa)(1-Pe)(C). Where R is risk, Pa is the likelihood of attack, Pe is the system effectiveness and C is the consequence. EnSURE considers each of the components of risk to help in assessing surety (e.g. security, safety, environmental) and providing for the most cost-effective ways to reduce risk. EnSURE is intended to help in evaluating and reducing the risk from either man-caused or natural events. It will help the decision-makers identify possible targets, evaluate the consequences of an event, assess the risk based on the threat and the existing conditions and then help in the application of mitigating measures. EnSURE is in the development stages. It builds on existing and ongoing development activities at Sandia, as well as the considerable work done in the fields of consequence analysis, risk analysis and intelligence. The components of EnSURE include consequences, constraints, threat, target/goal identification, facility/process characterization, evaluation and analysis, system improvement, and decision making. This paper provides a brief description of EnSURE.
This contribution describes three interoperability scenarios for the ATM Security Message Exchange (SME) protocol. These scenarios include network-wide signaling support for the Security Services Information Element, partial signaling support wherethe SSIE is only supported in private or workgroup ATM networks, and the case where the SSIE is nonsupported by any network elements (exceptthosethat implement security services). Explanatory text is proposed for inclusion infection 2.3 of the ATM Security Specification, Version 1.0.
Department of Energy and Defense Programs systems are becoming increasingly reliant on the use of optical technologies that must perform under a range of ionizing radiation environments. In particular, the radiation response of materials under consideration for applications in direct optical initiation (D.O.I.) schemes must be well characterized. In this report, transient radiation effects observed in a KD*P crystal are characterized. Under gamma exposure with 2 MeV photons in a 20--30 nsec pulse, the authors observe induced absorption at 1.06 {micro}m that causes a peak decrease in overall sample transmittance of only 10%. This induced loss is seen to recover fully within the first 30 {micro}sec.
Department of Energy and Defense Programs systems are becoming increasingly reliant on the use of optical technologies that must perform under a range of ionizing radiation environments. In particular, the radiation response of materials under consideration for applications in direct optical initiation (D.O.I.) schemes must be well characterized. In this report, transient radiation effects observed in Schott filter glass S-7010 are characterized. Under gamma exposure with 2 MeV photons in a 20--30 nsec pulse, the authors observe strong initial induced fluorescence in the red region of the spectrum followed by significant induced absorption over the same spectral region. Peak induced absorption coefficients of 0.113 cm{sup {minus}1} and 0.088 cm{sup {minus}1} were calculated at 800 nm and 660 nm respectively.
From July 29 to 31, 1997, the Surety Assessment Center at Sandia National Laboratories hosted the second international symposium on High Consequence Operations Safety, HCOSSII. The two and one-half day symposium allowed participants to share strategies, methodologies, and experiences in high consequence engineering and system design. The symposium addressed organizational influences on high consequence safety, assessment and analysis processes, lessons-learned from high consequence events, human factors in safety, and software safety. A special session at the end of the symposium featured a presentation by Federal Nuclear Center--All Russian Research Institute of Experimental Physics and Sandia National Laboratories personnel on their joint efforts to establish the International Surety Center for Energy Intensive and High Consequence Systems and Infrastructures.
Often the drilling of an oil well is followed by a logging process to characterize the region immediately surrounding the well bore. The electromagnetic (EM) induction tool, which provides the formation resistivity, is among the most frequently run logs. A preliminary study has been conducted to analyze the feasibility of three dimensional (3D) electromagnetic (EM) imaging from a single borehole. The logging tool consists of a vertical magnetic dipole source and multiple 3 component magnetic field receivers offset at different distances from the source. Synthetic data calculated with a 3D finite difference code demonstrate that the phase of the horizontal magnetic fields provides the critical information on the three dimensionality of the medium. A 3D inversion algorithm is then employed to demonstrate the plausibility of 3D inversion using 3 component magnetic field data. Finally, problems associated with introducing biased noise into the horizontal components of the field through misalignment of the logging tool is discussed.
The United States conducted over 100 atmospheric nuclear tests at the Nevada Test Site from 1951 through 1962. Some of the earliest tests caused unexpected damage, primarily broken glass and cracked plaster, in Las Vegas and other surrounding communities. To address this problem, Sandia initiated a program to monitor and predict the pressure waves around NTS. Infrasound recording systems were developed, then field for all tests beginning with Operation Buster in October 1951. Investigators soon discovered that near-surface temperature inversions and wind profiles caused the damaging pressures in Las Vegas. A typical test was recorded at about a dozen stations from the Control Point on NTS to as far away as Pasadena, CA. In addition, some tests in the South Pacific were monitored, as well as numerous chemical explosions. Strip charts recorded signals in the frequency band from 0.05 to 30 Hz, and the paper tapes were achieved at Sandia in the early 1970s. The NTS events ranged in yield from below 1 ton to 74 kilotons; source altitudes varied from near ground level (including some cratering experiments) to as high as 11 km. The resulting data contain a wealth of information on the source function, yield scaling and regional propagation of infrasound signals from atmospheric explosions. The renewed interest in infrasonic monitoring for CTBT verification has prompted the authors to exhume some of the archived records. The authors plan to digitize the signals from several tests and evaluate their applicability to CTBT issues. In addition, they will collect any existing parametric measurements for these records (arrival times, amplitudes, etc.). All data will be converted to CSS database format and made available to the research community. If appropriate, the resulting information could also be included in the Knowledge Base under development for CTBT monitoring.
The US Department of Energy is funding the development of the Multi-spectral Thermal Imager (MTI), a satellite-based multi-spectral (MS) thermal imaging sensor scheduled for launch in October 1999. MTI is a research and development (R and D) platform to test the applicability of multispectral and thermal imaging technology for detecting and monitoring signs of proliferation of weapons of mass destruction. During its three-year mission, MTI will periodically record images of participating government, industrial and natural sites in fifteen visible and infrared spectral bands to provide a variety of image data associated with weapons production activities. The MTI satellite will have spatial resolution in the visible bands that is five times better than LANDSAT TM in each dimension and will have five thermal bands. In this work, the authors quantify the separability between specific materials and the natural background by applying Receiver Operating Curve (ROC) analysis to the residual errors from a linear unmixing. The authors apply the ROC analysis to quantify performance of the MTI. They describe the MTI imager and simulate its data by filtering HYDICE hyperspectral imagery both spatially and spectrally and by introducing atmospheric effects corresponding to the MTI satellite altitude. They compare and contrast the individual effects on performance of spectral resolution, spatial resolution, atmospheric corrections, and varying atmospheric conditions.
A new failure analysis technique has been developed for backside and frontside localization of open and shorted interconnections on ICs. This scanning optical microscopy technique takes advantage of the interactions between IC defects and localized heating using a focused infrared laser ({lambda} = 1,340 nm). Images are produced by monitoring the voltage changes across a constant current supply used to power the IC as the laser beam is scanned across the sample. The method utilizes the Seebeck Effect to localize open interconnections and Thermally-Induced Voltage Alteration (TIVA) to detects shorts. The interaction physics describing the signal generation process and several examples demonstrating the localization of opens and shorts are described. Operational guidelines and limitations are also discussed.
The near eutectic 60Sn-40Pb alloy is the most commonly used solder for electrical interconnections in electronic packages. This alloy has a number of processing advantages (suitable melting point of 183 C and good wetting behavior). However, under conditions of cyclic strain and temperature (thermomechanical fatigue), the microstructure of this alloy undergoes a heterogeneous coarsening and failure process that makes the prediction of solder joint lifetime complex. A viscoplastic constitutive model for solder with an internal state variable that tracks microstructural evolution is currently under development. This constitutive model was implemented in to several finite element codes. With this computational capability, the thermomechanical response of solder interconnects, including microstructural evolution, can be predicted. This capability was applied to predict the thermomechanical response of a ball grid array (BGA) solder interconnect. BGAs with both homogeneous and heterogeneous initial microstructures were evaluated. In this paper, the constitutive model used to describe the solder will first be briefly discussed. The results of computational studies to determine the thermomechanical response of BGA solder interconnects will then be presented.
Radiation detectors have been included in several remote monitoring field trial systems to date. The present study considers detectors at Embalse, Argentina, and Oarai, Japan. At Embalse four gamma detectors have been operating in the instrumentation tubes of spent fuel storage silos for up to three years. Except for minor fluctuations, three of the detectors have operated normally. One of the detectors appears never to have operated correctly. At Oarai two gamma detectors have been monitoring a spent-fuel transfer hatch for over 18 months. These detectors have operated normally throughout the period, although one shows occasional noise spikes.
Materials Protection, Control and Accounting (MPC and A) equipment upgrades are complete at the Institute of Theoretical and Experimental Physics (ITEP), a site that has significant quantities of weapons-potential nuclear materials. Cooperative work was initiated at this Moscow facility as a part of the US-Russian program to upgrade MPC and A systems. An initial site visit and assessment were conducted in September 1996 to establish communication between ITEP, the US Department of Energy (DOE), and participating US National Laboratories. Subsequently, an agreement was reached to develop two master plans for MPC and A upgrades. Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL) assisted in developing a plan for Material Control and Accounting (MC and A) upgrades, and Sandia National Laboratories (SNL) assisted in developing a plan for Physical Protection System (PPS) upgrades. The MC and A plan included MC and A training, a mass measurement program, nondestructive assay instrumentation, item identification (bar coding), physical inventory taking, portal and hand-held nuclear material monitors, and a nuclear materials accounting system. The PPS plan included basic PPS design training, Central Alarm Station (CAS) relocation and equipment upgrades, a site and critical-building access control system, intrusion detection, alarm assessment, and guard force communications.
The US Department of Energy (DOE) and the Russian Special Scientific and Production State Enterprise Eleron have teamed to lead a project to enhance the overall security of Russian Ministry of Atomic Energy (MINATOM) transportation of Special Nuclear Material (SNM) shipments. The effort is called the Railcar Transportation Security Project and is part of the overall DOE Material Protection, Control, and Accounting (MPC and A) program addressing the enhancement of nuclear material control, accounting, and physical protection for Russian SNM. The goal of this MPC and A project is to significantly increase the security of Russian MINATOM highly enriched SNM rail shipments. To accomplish this, the MPC and A Railcar Transportation Security program will provide an enhanced, yet cost effective, railcar transportation security system. The system incorporates a balance between the traditional detection, communications, delay, and response security elements to significantly improve the security of MINATOM SNM shipments. The strategy of this program is to use rapid upgrades to implement mature security technologies as quickly as possible. The rapid upgrades emphasize rapidly deployable delay elements, enhanced radio communications, and intrusion detection and surveillance. Upgraded railcars have begun operation during FY98. Subsequent upgrades will build upon the rapid upgrades and eventually be integrated into a final deployed system configuration. This paper provides an overview of the program, with a summary of performance of the deployed railcars.
A combined engineering and geochemistry approach is recommended for the stabilization of waste in decommissioned tanks and contaminated soils at the AX Tank Farm, Hanford, WA. A two-part strategy of desiccation and gettering is proposed for treatment of the in-tank residual wastes. Dry portland cement and/or fly ash are suggested as an effective and low-cost desiccant for wicking excess moisture from the upper waste layer. Getters work by either ion exchange or phase precipitation to reduce radionuclide concentrations in solution. The authors recommend the use of specific natural and man-made compounds, appropriately proportioned to the unique inventory of each tank. A filler design consisting of multilayered cementitous grout with interlayered sealant horizons should serve to maintain tank integrity and minimize fluid transport to the residual waste form. External tank soil contamination is best mitigated by placement of grouted skirts under and around each tank, together with installation of a cone-shaped permeable reactive barrier beneath the entire tank farm. Actinide release rates are calculated from four tank closure scenarios ranging from no action to a comprehensive stabilization treatment plan (desiccant/getters/grouting/RCRA cap). Although preliminary, these calculations indicate significant reductions in the potential for actinide transport as compared to the no-treatment option.
