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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Contamination control in hybrid microcircuit modules

The influence of chemical and particulate contamination upon the reliability and service life of hybrid microelectronic systems is documented. Several coating systems used include the parylene and Dow Corning silicone (DC90-711). These passivating coatings have potential for decreasing the degradation caused by particulate contaminants in hybrid systems as well as the possible deleterious effect of trapping chemical contaminants which have long term degrading influences upon the performance of the system. The reliability of a representative hybrid microcircuit is enhanced by the coating process.

Kinser, D. L.↗
NASA NTRS1981

X-ray topography study of complex silicon microcircuits

The correlation between the yield of silicon microcircuits wafers versus defects observed in X-ray topographs produced by a high speed curved wafer X-ray topographic camera was investigated. Most of the topographs were made after final wafer probe. Results indicated that most high volume silicon wafer processing does not need X-ray topography as a routine process control. It is further indicated that in changing any existing process or developing a new process the technique can be of significant benefit.

Parker, D. L.↗
NASA NTRS1980

Accelerated life testing effects on CMOS microcircuit characteristics

The 250 C, 200C and 125C accelerated tests are described. The wear-out distributions from the 250 and 200 C tests were used to estimate the activation energy between the two test temperatures. The duration of the 125 C test was not sufficient to bring the test devices into the wear-out region. It was estimated that, for the most complex of the three devices types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment is assessed. Guidlines for the development of accelerated life-test conditions are proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life-test characteristics of CMOS microcircuits is described.

Source record↗
NASA NTRS1983

Microcircuit radiation effects databank

This databank is the collation of radiation test data submitted by many testers and serves as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. It contains radiation sensitivity results from ground tests and is divided into two sections. Section A lists total dose damage information, and section B lists single event upset cross sections, I.E., the probability of a soft error (bit flip) or of a hard error (latchup).

Source record↗
NASA NTRS1983

Microcircuit radiation effects databank

Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single event upset cross sections, i.e., the probability of a soft error (bit flip) or of a hard error (latchup) are presented.

Source record↗
NASA NTRS1984

Dose rate effects in MOS microcircuits

Three read/write random access memories, AM91L24, HM1-6514, and MWS 5114, were subjected to total dose irradiation at three dose rates, with electrical testing after each increment of dosage. Annealing measurements were performed after the radiation tests were completed. The AM91L24 showed a strong dose rate effect and substantial post-irradiation annealing of radiation-induced damage. The dose rate effect was that a lower dose rate produced less net damage than an eqivalent total dose applied at a higher rate. The HM1-6514 showed essentially no dose rate effect and no annealing damage, and the MWS 5114 exhibited a moderate effect with some annealing. It was concluded that dose rate is an important parameter in radiation test procedures for MOS microcircuits and that annealing measurements may be important evaluation aids for such tests.

Cleveland, D. G.↗
NASA NTRS1984

Total dose effects in the 54HC family of microcircuits

Motorola and National Semiconductor 54HC00 and 54HC74 microcircuits were evaluated using CO-60 to determine their total dose radiation hardness. The devices were found to be radiation soft failing parametrically between 5 and 10 K rads and functionally between 20 and 40 K rads. The failures were bias dependent, relatively insensitive to dose rate, and only annealed moderately when left unbiased at room temperature.

Ropiak, S.↗
NASA NTRS1994

Radiation-Protected Protocols For Self-Testing Of Microcircuits

Ionizing radiation need not trigger unintended self-testing. Protocols installed in certain microcircuits permitting functional self-testing do not consider possibility of inadvertent triggering by protons or energetic heavy ions in space or satellite orbit. Recommended devices be rendered immune to so-called single event effects of energetic ions in cosmic rays, flares, or trapped-charge belts surrounding Earth and some other planets. Proposed pair of stimuli be applied to device in specified manner to start self-test. Protocol can require two or more stimuli at single node, or pair of stimuli at two nodes, or some more complicated combination.

Nichols, Donald K.↗
NASA NTRS1997

Critical concerns, solutions and guidelines for use of plastic encapsulated microcircuits for space flight applications

Some of the concerns and risk mitigation procedures for using plastic encapsulated microcircuits (PEMs) for space applications are discussed. Despite their advantages, PEMs cannot be implemented in all space applications by replacing military parts numbers with their commercial counterparts in product designs and part lists. The technical and procurement concerns are summarized, and suggestions for high reliability procurements are given. The ability to withstand deleterious environmental effects and to meet mission critical reliability is the key to the successful use of PEMs for space applications.

Virmani, Nick↗
NASA NTRS2000

Different Approaches for Ensuring Performance/Reliability of Plastic Encapsulated Microcircuits (PEMs) in Space Applications

Engineers within the commercial and aerospace industries are using trade-off and risk analysis to aid in reducing spacecraft system cost while increasing performance and maintaining high reliability. In many cases, Commercial Off-The-Shelf (COTS) components, which include Plastic Encapsulated Microcircuits (PEMs), are candidate packaging technologies for spacecrafts due to their lower cost, lower weight and enhanced functionality. Establishing and implementing a parts program that effectively and reliably makes use of these potentially less reliable, but state-of-the-art devices, has become a significant portion of the job for the parts engineer. Assembling a reliable high performance electronic system, which includes COTS components, requires that the end user assume a risk. To minimize the risk involved, companies have developed methodologies by which they use accelerated stress testing to assess the product and reduce the risk involved to the total system. Currently, there are no industry standard procedures for accomplishing this risk mitigation. This paper will present the approaches for reducing the risk of using PEMs devices in space flight systems as developed by two independent Laboratories. The JPL procedure involves primarily a tailored screening with accelerated stress philosophy while the APL procedure is primarily, a lot qualification procedure. Both Laboratories successfully have reduced the risk of using the particular devices for their respective systems and mission requirements.

Gerke, R. David↗
NASA NTRS2002

Instructions for Plastic Encapsulated Microcircuit(PEM) Selection, Screening and Qualification.

The use of Plastic Encapsulated Microcircuits (PEMs) is permitted on NASA Goddard Space Flight Center (GSFC) spaceflight applications, provided each use is thoroughly evaluated for thermal, mechanical, and radiation implications of the specific application and found to meet mission requirements. PEMs shall be selected for their functional advantage and availability, not for cost saving; the steps necessary to ensure reliability usually negate any initial apparent cost advantage. A PEM shall not be substituted for a form, fit and functional equivalent, high reliability, hermetic device in spaceflight applications. Due to the rapid change in wafer-level designs typical of commercial parts and the unknown traceability between packaging lots and wafer lots, lot specific testing is required for PEMs, unless specifically excepted by the Mission Assurance Requirements (MAR) for the project. Lot specific qualification, screening, radiation hardness assurance analysis and/or testing, shall be consistent with the required reliability level as defined in the MAR. Developers proposing to use PEMs shall address the following items in their Performance Assurance Implementation Plan: source selection (manufacturers and distributors), storage conditions for all stages of use, packing, shipping and handling, electrostatic discharge (ESD), screening and qualification testing, derating, radiation hardness assurance, test house selection and control, data collection and retention.

King, Terry↗
NASA NTRS1997

Morphological evidence for local microcircuits in rat vestibular maculae

Previous studies suggested that intramacular, unmyelinated segments of vestibular afferent nerve fibers and their large afferent endings (calyces) on type I hair cells branch. Many of the branches (processes) contain vesicles and are presynaptic to type II hair cells, other processes, intramacular nerve fibers, and calyces. This study used serial section transmission electron microscopy and three-dimensional reconstruction methods to document the origins and distributions of presynaptic processes of afferents in the medial part of the adult rat utricular macula. The ultrastructural research focused on presynaptic processes whose origin and termination could be observed in a single micrograph. Results showed that calyces had 1) vesiculated, spine-like processes that invaginated type I cells and 2) other, elongate processes that ended on type II cells pre- as well as postsynaptically. Intramacular, unmyelinated segments of afferent nerve fibers gave origin to branches that were presynaptic to type II cells, calyces, calyceal processes, and other nerve fibers in the macula. Synapses with type II cells occurred opposite subsynaptic cisternae (C synapses); all other synapses were asymmetric. Vesicles were pleomorphic but were differentially distributed according to process origin. Small, clear-centered vesicles, approximately 40-60 nm in diameter, predominated in processes originating from afferent nerve fibers and basal parts of calyces. Larger vesicles approximately 70-120 nm in diameter having approximately 40-80 nm electron-opaque cores were dominant in processes originating from the necks of calyces. Results are interpreted to indicate the existence of a complex system of intrinsic feedforward (postsynaptic)-feedback (presynaptic) connections in a network of direct and local microcircuits. The morphological findings support the concept that maculae dynamically preprocess linear acceleratory information before its transmission to the central nervous system.

NASA Center ARC↗
NASA NTRS2006

Reliability Evaluation of Au/Al Wire Bonds in Commercial Microcircuits

The slide presentation provides an overview of research related to problems in quality evaluation in the mechanisms of wire bond degradation. Case studies presented examine the evaluation of reliability of hermetic and plastic microcircuits with suspected poor wire bonding. The authors conclude that in the cases when destructive physical analysis (DPA) or design evaluation indicate possible problems with wire bonding, a wire bond qualification testing may be required. This test should include high temperature storage (175 degrees C to 200 decrees C) of the parts with periodic measurements of contact resistances followed by internal examination and wire pull or ball sear testing.

Teverovsky, Alexander↗