EEE Links Volume 10, No. 2, April
2004![](media/image1.png){width="6.791666666666667in"
height="1.6145833333333333in"}

**NEPP's University Partners and Collaborators**

##### Table of Contents

[***Letter From the Editor***](#section-2)

# FEATURE CONTENT

[**NEPP's University Partners and
Collaborators**](#nepps-university-partners-and-collaborators)

[**AUBURN UNIVERSITY**](#auburn-university)

[Center for Advanced Vehicle Electronics
(CAVE)](#center-for-advanced-vehicle-electronics-cave)

[Center for Space Power and Advanced Electronics
(CSPAE)](#center-for-space-power-and-advanced-electronics-cspae)

*NEPP Task Work with Auburn University CAVE & CSPAE:*

[Evaluation of 3-D Multi-Chip
Modules](#evaluation-of-3-d-multi-chip-modules)

[Lead-Free Solder Alloy
Characterization](#lead-free-solder-alloy-characterization)

**Auburn University**

[RF Devices and Integrated Circuits
Laboratory](#task-lead-guofu-niu-auburn-university)

# [GEORGIA INSTITUTE of TECHNOLOGY](#Georg_Tech)

[High Frequency Systems Laboratory](#Georg_Tech)

*NEPP Task Work with Auburn University and Georgia Institute of
Technology:*

[Radiation Effects on SiGe Microelectronics---Mixed-Signal Technology
and Hardening
Efforts](#radiation-effects-on-sige-microelectronicsmixed-signal-technology-and-hardening-efforts)

# 

# [CASE WESTERN RESERVE UNIVERSITY](#_Ohio_Aerospace_Institute/Case)

# 

# [UNIVERSITY of MARYLAND, CALCE](#computer-aided-life-cycle-engineering-center-calce)

*NEPP Task Work with Case Western Reserve and University of Maryland:*

> [Evaluation of High-Temperature Packaging Module for Implementation of
> SiC Wide-Bandgap
> Microsystems](#evaluation-of-high-temperature-packaging-module-for-implementation-of-sic-wide-bandgap-microsystems)

[**Institute for Space and Defense Electronics (ISDE) at Vanderbilt
University**](#institute-for-space-and-defense-electronics-isde-at-vanderbilt-university)

*NEPP Task Work with Vanderbilt University:*

[Space Computational Radiation Interaction Performance Tools
(SCRIPT)](#SCRIPT)

[Analog Single-Event Transients](#task-lead-ken-label-nasa-gsfc)

**STANDARDS CORNER**

[Proposed Changes to MIL-STD-883E](#standards-corner)

**RECENT FINDINGS**

[**Fiber Optic Epoxy to Alleviate Core Cracking During
Termination**](#foepoxy)

New Publications on NEPP.NASA.GOV

1\. [Optical Assemblies for Space Environments: Characterization of W.
L. Gore Flexlite with Diamond AVIMS](#fo_webex)

2\. [Effect of Vacuum on High-Temperature Degradation of Gold/Aluminum
Wire Bonds in PEMs](#vacuum_wb)

3\. [Level I, II, and III Requirements Compared for
Microcircuits](#LevelI_II_III)

4\. [President's Vision on Space Exploration, February 12,
2004](#President_vision)

5\. [U.S. Air Force Position on Tin Usage](#Airforce_tin)

6\. [Package Qualification Testing Results Performed on the Five Part
Types in the NEPP/NEPAG PEMs Study](#Package_qual)

[**Upcoming Events**](#upcoming_events)

[**Guidelines for *EEE Links* Article Submission**](#section-31)

# 

# Letter From the Editor

Jeannette Plante, *EEE Links* Editor

Dynamic Range Corporation/NASA GSFC

301-286-7437

jfplante@pop500.gsfc.nasa.gov

Welcome to the April 2004 issue of *EEE Links*. This issue highlights
some of the NEPP Program's university partners and collaborators and
describes ways in which these relationships are mutually beneficial. The
focus is on who these partners are, work they do for the NEPP program,
and expertise and resources available to other NASA projects.

Many thanks go out to everyone who contributed to this issue especially
Jeanne Ilg who did much of the research. Please send questions,
suggestions, and comments about the newsletter and its topics to my
e-mail address cited above, or contact me by telephone Monday through
Friday between 8:30 a.m. and 5:30 p.m. EST.

**FEATURE CONTENT**

# NEPP's University Partners and Collaborators

This issue of *EEE Links* highlights some of the NEPP Program's
university partners and collaborators and describes ways in which these
relationships are mutually beneficial. The focus is on who these
partners are, work they do with and for NEPP, and what they can do for
other NASA projects in terms of their expertise and facilities. Each
article includes the following information:

-   The FY04 NEPP task, task lead, and collaborating university.

-   Work that is being done (or planned) that involves the university
    partner.

-   Special skills, knowledge, or facility that the university partner
    brings to the team.

-   Ways in which the partnership extends beyond support of NEPP.

-   Capabilities the university offers of potential interest to NASA
    projects/*EEE Links* readership.

-   Points of contact.

# Auburn University

Auburn University is in the town of Auburn, Alabama, which is 50 miles
northeast of the city of Montgomery and 35 miles west of the
Alabama/Georgia state line. The Samuel Ginn College of Engineering at
Auburn University has been offering engineering courses since 1872 and
consistently ranks in the Nation's top 20 engineering programs by
numbers graduated. The Department of Electrical Engineering hosts
several electronics design, reliability, and packaging research centers.
Auburn is also host to a NASA-sponsored technology transfer research
center for space power and advanced electronics products.

[Back to Table of Contents](#table-of-contents)

## **Center for Advanced Vehicle Electronics (CAVE)**

######### Task Lead: Mark Strickland, NASA MSFC

Mark Strickland of NASA Marshall Space Flight Center (MSFC) is NEPP's
point of contact for work supported by CAVE at Auburn University. Dr.
Jeff Suhling is Mr. Strickland's counterpart at CAVE. CAVE's objective
is to develop and implement new technologies for packaging and
manufacturing electronics with emphasis on harsh environments,
reliability, and cost. It is organized using a consortium model in which
organizations are able to jointly invest, through a membership fee, in a
broad number of research projects. The members jointly choose the
projects of interest each year, and all members are then provided access
to all data, results, and findings. Short descriptions and points of
contact for current projects can be found at
<http://cave.auburn.edu/projects_viewer.cgi>.

The NEPP Program supports a membership in the CAVE consortium, which
allows engineers at the NASA Centers access to the data generated. NASA
MSFC, NASA Johnson Space Center (JSC), NASA Jet Propulsion Laboratory
(JPL), and NASA Goddard Space Flight Center (GSFC) have participated in
the semi-annual meetings in which input is provided about NASA's
interests in proposed tasks.

The current CAVE projects encompass topics of interest to numerous NEPP
tasks. These are component reliability, lead-free connector finishes,
lead-free soldering and tin whisker studies, a flip-chip-on-laminate
study, and high-temperature electronics.

CAVE is developing finite element models and failure models, and
correlating them with empirical data in most of these project areas.

CAVE has access to an Experimental and Computational Mechanics
Laboratory and a Laboratory for Electronics Assembly and Packaging.
Their facilities and staff are capable of fabricating prototypes of
advanced electronics packaging and circuit card assemblies. This
capability is supported by a thin-film processing laboratory, a
thick-film hybrid laboratory, a surface-mount assembly line with
fine-pitch flip-chip capability, a process characterization laboratory,
an electronics packaging laboratory, and an environmental test
laboratory with failure analysis capability. CAVE is supported by 10
faculty members, 6 staff members, and 37 graduate students.

The NEPP Program leverages the cost of additional task work with the
cost of CAVE membership in order to obtain additional support in the
areas of area-array packaging design guidelines, technology readiness of
3-D multi-chip modules, and physical characterization of lead-free
solder alloys. The CAVE Center recently supported a NEPP WebEx
presentation on lead-free solder work, which can be found by clicking on
the link in the event schedule on page at
<http://nepp.nasa.gov/index_nasa.cfm/978/>

[Back to Table of Contents](#table-of-contents)

## **Center for Space Power and Advanced Electronics (CSPAE)**

*Task Lead: Harry Brandhorst, Auburn University*

Auburn University also hosts the Center for Space Power and Advanced
Electronics (CSPAE), which is a technology research, development, and
transfer organization established by NASA in the 1980s. Their work
extends beyond NEPP's areas of interest and has broad applicability to
many NASA missions. The current foci of CSPAE research are:

-   Chemical and biological air purification systems for individuals and
    structures.

-   Electrochemical capacitor technology for actuation applications.

-   Advanced packaging research: Packaging with silicon carbide for
    power electronics, low-temperature material properties, and
    ultra-high-reliability electronics.

-   Electric propulsion technologies: Pulsed inductive thruster and
    pulsed plasma thruster.

-   Multi-directional composite flywheel rotor.

-   Hybrid robotic vehicle technology.

-   Modular power systems.

-   Solar array technology.

###### Points of Contact

MSFC: Mark Strickland, NASA MSFC, Electronic Packaging ED16,
<mark.strickland@nasa.gov>,

256.544.7432.

CAVE Director: Dr. Jeff Suhling, Auburn University, Mechanical
Engineering Professor, <jsuhling@eng.auburn.edu>,

334.844.3332.

CSPAE Director: Dr. Harry Brandhorst, Auburn University,
<brandhh@auburn.edu>,

334.844.5899.

SiC Power Electronics: Dr. Wayne Johnson, IT Peak of Excellence
Director, <johnson@eng.auburn.edu>,

334.844.1880.

[Back to Table of Contents](#table-of-contents)

*NEPP Task Work with Auburn University:*

# Evaluation of 3-D Multi-Chip Modules

*Task Lead: Dr. R. Wayne Johnson, Auburn University*

![](media/image2.jpeg){width="2.6277777777777778in"
height="1.8763888888888889in"}

*Surface-Mount Assembly Line at Auburn University*

The task will provide a comprehensive review and analysis of the current
state-of-the-art and forward-looking research in the area of 3-D
multi-chip modules (MCMs). Multi-chip modules are electronic packages
containing two or more semiconductor chips. Traditional multi-chip
modules are fabricated in a planar, 2-D format. To increase functional
density, 3-D modules have been developed that exploit the third
dimension (up, out of the plane of the PC board) by stacking substrates,
stacking die, and burying die inside the PC board (embedding). This task
seeks to evaluate the various approaches and their applicability to NASA
projects for both performance and reliability.

Auburn University has been working with multi-chip module technology
since 1984. Dr. R. Wayne Johnson has published one book, three book
chapters, and numerous papers in this area. He also helped initiate and
organize the IMAPS Multi-chip Module Conference, which was held annually
in Denver, Colorado, during the 1990s. Auburn University researchers
have designed and fabricated multi-chip modules based on MCM-D, MCM-C,
and MCM-L substrate technologies, and continue to do research in 3-D
packaging technologies. The Microelectronics Laboratory and the
Laboratory for Electronics Assembly and Packaging at Auburn University
have complete facilities to fabricate 3-D multi-chip modules.

###### Point of Contact

R. Wayne Johnson

Ginn Professor of Electrical Engineering

Director, Laboratory for Electronics Assembly & Packaging

Auburn University

162 Broun Hall/ECE Department

Auburn, AL 36849-5201

334.844.1880 (ph.)

334.844.1898 (fax)

[johnson@eng.auburn.edu](mailto:Johnson@eng.auburn.edu)

[Back to Table of Contents](#table-of-contents)

# Lead-Free Solder Alloy Characterization

# *Task Lead: Dr. R. Wayne Johnson, Auburn University*

![](media/image3.jpeg){width="2.78125in" height="2.238888888888889in"}

*Micro-Mechanical Material Tester at Auburn University*

The electronics industry is rapidly moving to eliminate lead in solders
used for assembly. Tin-silver-copper alloys have been selected by the
industry as the replacement for eutectic tin-lead. However, there is
significant variation in the compositions being used. The goal of this
task is to determine the mechanical properties of Sn-Ag-Cu solder alloys
over the range of compositions being used as Sn-Pb replacements. The
database developed will provide the following:

1.  Insight into the effect of alloy composition ratios on mechanical
    properties. This is important because the composition of the
    Sn-Ag-Cu alloy used is currently not specified and varies throughout
    the industry.

2.  The data necessary to perform finite element modeling of electronic
    assemblies with lead-free solder alloys. With the elimination of
    Sn/Pb solder, the 40^+^-year reliability database for electronic
    assembly reliability is invalid. Modeling can complement the
    necessary experimental testing that will be required to qualify NASA
    assemblies with Sn-Ag-Cu solder.

Auburn University has extensive experience in measuring material
properties and modeling electronic assemblies. A key consideration in
properly measuring electronic assembly material properties is to prepare
test specimens of comparable size and processing history to the actual
use condition of the material. For example, the cooling rate
significantly impacts the grain structure of the solder alloy, which in
turn affects the mechanical properties. Thus, test samples must be
cooled at a rate equal to the cooling rate of a real production solder
joint. Similarly, solder joints are very small, and the mechanical
properties of large, cast samples will not be the same as actual solder
joints. Auburn researchers have developed sample preparation techniques
that approach the characteristics of actual solder joints. Auburn also
has a micro-mechanical tester suitable for tensile, fatigue, and creep
measurement of these small samples. The mechanical testing can be
performed as a function of controlled ambient temperature to obtain the
temperature dependent properties of the alloy.

Auburn University has complete facilities for measuring electronic
packaging material properties, finite element modeling, assembly of
reliability test vehicles, environmental reliability testing and failure
analysis. This allows closed-loop correlation between modeling
predictions and actual experimental results for electronic assemblies.

###### Point of Contact

R. Wayne Johnson

Ginn Professor of Electrical Engineering

Director, Laboratory for Electronics Assembly & Packaging

Auburn University

162 Broun Hall/ECE Department

Auburn, AL 36849-5201

334.844.1880 (ph.)

334.844.1898 (fax)

[johnson@eng.auburn.edu](mailto:Johnson@eng.auburn.edu)

# 

[Back to Table of Contents](#table-of-contents)

# 

## **AUBURN UNIVERSITY**

## 

## **RF Devices and Integrated Circuits Laboratory**

######### Task Lead: Guofu Niu, Auburn University

Silicon-Germanium (SiGe) technology is the driving force behind the
explosion in low-cost, lightweight, personal communications devices like
digital wireless handsets, wireless networking devices, direct broadcast
satellites, automobile collision avoidance systems, PDAs, and emerging
ultra-wide-band (UWB) products for wireless video streaming. SiGe
extends the life of wireless phone batteries, and allows smaller and
more durable communication devices. Products combining the capabilities
of cellular phones, global position data, and internet access in one
package, are being designed using SiGe technology. These multifunction,
low-cost, mobile client devices capable of communicating over voice and
data networks represent a key element of the future of computing.

The heart of SiGe technology is a SiGe heterojunction bipolar transistor
(HBT), which offers advantages over both conventional silicon bipolar
and silicon CMOS for implementation of communications circuits. SiGe
research at Auburn includes the design, optimization, and testing of
state-of-the-art SiGe heterojunction bipolar transistors and integrated
circuits. Auburn works closely with IBM, a world leader of SiGe
technology since 1982, and the first company to broadly manufacture SiGe
technology.

A SiGe HBT is similar to a conventional Si bipolar transistor except for
the base. SiGe, a material with narrower bandgap than Si, is used as the
base material. Ge composition is typically graded across the base to
create an accelerating electric field, for minority carriers moving
across the base, with a typical magnitude of 30 - 50 kV/cm.

Auburn's SiGe research covers a wide range of topics, from fundamental
material physics and semiconductor physics to RF integrated circuit
design and testing:

-   SiGe HBT TCAD.

-   Design of HBTs with 60 GHz -- 2,000 GHz cutoff frequencies.

-   Low-noise engineering.

-   High-linearity engineering.

-   RF and microwave characterization of advanced SiGe devices.

-   Design and optimization of low-noise amplifiers.

-   Space applications of SiGe HBTs.

-   RF and microwave device modeling.

Auburn University's research facilities have all of the Cadence IC
design software, Synopsys TCAD software, and ISE TCAD software. Auburn
University has acquired and/or developed hardware and RF
characterization systems to support research including the following:

-   Automatic probes stations.

-   DC I-V semiconductor parameter analyzers (HP4155, HP4156).

-   Microwave probe station (Cascade Microtech).

-   A 8510C vector network analyzer (VNA).

-   Small-signal S-parameter test system (45 MHz to 50 GHz).

-   Low-frequency noise test system.

-   Power-added efficiency test system (45 MHz to 50 GHz).

-   2-26 GHz intermodulation distortion measurement system.

-   RF pulse I-V analyzer for RF power amplifier design (100 ns pulse).

###### Point of Contact

Guofu Niu, Auburn University

200 Broun Hall

Auburn, AL 36849

1856. ph

334-844-1888 fx

g.niu@ieee.org

[Back to Table of Contents](#table-of-contents)

# Georgia Institute of Technology

[]{#Georg_Tech .anchor}

**High Frequency Systems Laboratory**

Dr. John Cressler's SiGe research team, located within the new
High-Frequency Systems Laboratory of the Georgia Electronic Design
Center (GEDC) located in the Technology Square Research Building (TSRB)
at Georgia Tech, has exhaustive measurement capabilities for SiGe HBT
devices and circuits, ranging from DC to mm-wave (110 GHz), fA to A, and
15ºK to 500ºC. These facilities include 1) specialized equipment for DC
and AC characterization across very wide temperature ranges (500ºC down
to 15ºK), and 2) measurement systems for devices and circuits dedicated
to high-sensitivity DC, low-frequency noise, S-parameters, broadband
noise, phase noise, single-tone and two-tone load-pull for linearity,
and cryogenic temperatures.

Cressler's research team has substantial experience in SiGe HBT digital,
RF, and analog circuit design using the Cadence design environment, and
has worked extensively with industrial design kits for the design,
layout, macro placement, ground-rule checking, and tape-out for SiGe HBT
devices and circuits. There is a large cluster of high-end Sun
workstations dedicated to device simulation and modeling using TCAD
tools (semiconductor device computer aided design) from ISE and Synopsys
for 1D, 2D, and full 3D simulation of SiGe HBTs. Comprehensive IC
fabrication and packaging facilities are available at Georgia Tech to
support this program, as needed.

*Point of Contact:*

Dr. John D. Cressler

School of Electrical and Computer Engineering

404-894-5161

cressler@ece.gatech.edu

[Back to Table of Contents](#table-of-contents)

*NEPP Task Work with Auburn University and Georgia Institute of
Technology:*

## **Radiation Effects on SiGe Microelectronics---Mixed-Signal Technology and Hardening Efforts**

######### Task Lead: Robert Reed, NASA GSFC

Silicon-Germanium (SiGe) based technology is widely recognized for its
tremendous potential to impact the high-speed microelectronic industry
by monolithic incorporation of low-power complementary logic with
extremely-high-speed SiGe heterojunction bipolar transistor (HBT) logic.
This BiCMOS approach exploits the maturity of the silicon fabrication
industry; large-scale integration and high yields are possible.
Consequently, the satellite industry stands to benefit from insertion of
both commercial off-the-shelf (COTS) and custom designs. This is
especially true in signal processing and data-handling applications in
which RF elements are combined with high-bandwidth routing of digital
signals along with lower-bandwidth processing. A variety of studies have
examined the ionizing dose, displacement damage, and single-event
characteristics for devices fabricated in IBM SiGe HBTs.

Accessibility to SiGe through an increasing number of manufacturers
(IBM, TI, and Jazz Semiconductor, for example) adds to the importance of
understanding its intrinsic radiation characteristics, and in particular
the single-event effect (SEE) characteristics of the high-bandwidth
HBT-based circuits.

The task description is to provide radiation assessment of emerging
technologies, like SiGe for high-speed communication, RF, mixed-signal,
and system-on-a-chip applications. The goals of this work are to:

-   Develop models for radiation sensitivity of SiGe microelectronics.

-   Develop radiation test protocols and performance prediction
    techniques of SiGe devices.

-   Determine radiation hardening approaches for single-event upsets
    (SEUs) in SiGe.

-   Develop guidelines to SiGe technology insertion into NASA flight
    projects.

-   Evaluate competing technologies to SiGe (when applicable).

GSFC is currently partnering with the Defense Threat Reduction Agency
(DTRA), National Security Agency (NSA), and Defense Advanced Research
Projects Agency (DARPA), as well as relying the expertise at Georgia
Institute of Technology (GT) and Auburn University (AU).

GSFC's university partners play key roles in the collaboration. GT
provides access to emerging high-speed technologies, radiation effects
testing and characterization of SiGe devices, and circuit-level
radiation response modeling. AU provides detailed device modeling to
simulate device and circuit-level response to radiation exposure.

*Point of Contact*

Robert Reed, NASA GSFC, <Robert.A.Reed@nasa.gov>, 301.286.2153

[Back to Table of Contents](#table-of-contents)

# Case Western Reserve University

Case Western Reserve is among the Nation's leading research institutions
in education, research, service, and experiential learning. It was
founded in 1826 and shaped by the merger of the Case Institute of
Technology and Western Reserve University. Case is located in Cleveland,
Ohio. The Micro-fabrication Laboratory specializes in microsensors and
other micro- and nanotechnology development and production. NASA GRC has
demonstrated 500 ^o^C to 600 ^o^C operable SiC chemical gas sensors, SiC
pressure sensors, a SiC accelerometer, SiC electronics, and
high-temperature device packaging technology, with many direct and
indirect contributions from Case Western.

The Case facility has capability in the following areas:

-   Design/modeling, fabrication, testing, and calibration of
    microsensors and microactuators for harsh environments.

-   Advanced micromachining techniques: bulk micromachining, wafer
    bonding, surface micromachining, micromolding, and plating.

-   Silicon carbide: single crystalline and polycrystalline deposition
    by AP-CVD, and related device fabrication processes.

-   Titanium nickel shape memory alloy: sputter deposition processes
    with control of film composition and related device fabrication
    processes.

-   Advanced interface electronics: design and verification of
    state-of-the-art integrated circuits for sensor/actuator signal
    conditioning and processing, as well as wireless data links.

-   Advanced materials analysis: high-resolution scanning electron
    microscopy, high-resolution transmission electron microscopy, X-ray
    diffraction, Auger electron spectroscopy, X-ray photoelectron
    spectroscopy, secondary ion mass spectroscopy, Rutherford
    back-scattering spectroscopy, and nuclear reaction analysis.

Case is one of the key university partners of GRC's Glennan Microsystems
Initiative (GMI), which focuses on SiC in microsystems used in harsh
environments. Case also supplies technical leadership in the area of
microgravity research. See also Case's involvement with the University
of Maryland CALCE task below, Evaluation of High-Temperature Packaging
Module for Implementation of Wide-Bandgap Microsystems.

*Point of Contact*

Professor C. C. Liu, Wallace R. Persons Professor of Sensor Technology
and Control, Electronics Design Center, Bingham Building, Case Western
Reserve University, Cleveland, OH 44146

[Back to Table of Contents](#table-of-contents)

# University of Maryland

# Computer Aided Life Cycle Engineering Center (CALCE)

The University of Maryland at College Park (UMCP) has a history of
partnership and collaboration with the NASA Goddard Space Flight Center
and other research institutions in the Baltimore-Washington area. A
number of UMCP laboratories and technology centers participate in
building flight hardware; a current project is on a low-temperature
electronics effort through the Johns Hopkins Applied Physics Laboratory.
The Computer-Aided Life Cycle Engineering Center (CALCE), hosted by the
A. James Clark School of Engineering, is operated as an
academic-Government-industry consortium exposing their collaborative
efforts to a worldwide audience. The consortium model enables members to
pool their yearly dues to maximize research on a variety of different
topics.

CALCE's broad focus is on the areas of thermo-mechanical and mechanical
fatigue modeling and the application of the physics-of-failure method
for assessing and enhancing reliability, determining materials'
constitutive properties at elevated temperatures, and characterizing
materials compatibility and degradation for high-temperature
electronics. Their facilities encompass a range of environmental testing
equipment including temperature, temperature cycling, thermal shock,
temperature-humidity, altitude, high g-force, shock, vibration, and
industrial gas exposure testing equipment, some of which can be used to
examine devices at high temperatures.

Among the projects that CALCE has worked on for NASA is the study of the
expected lifetime of electronic assemblies in NASA systems, such as the
Space Shuttle Robot Arm and the Mars Sojourner, based on models of the
fatigue susceptibility of solder joints in thermal and mechanical
(g-force and vibration) environments expected in space travel. CALCE
leads a tin whiskers working group, which is investigating thin,
single-crystal whisker growth in lead-free solders in long-term space
mission environments. CALCE has also produced research on failure modes
in plastic encapsulated microcircuits (PEMs) in the temperature range of
150 °C to 200 °C, and in modeling packaging for SiC MEMS sensors using
finite element analysis (FEA) for operation at 500 °C.

# *Point of Contact*

Dr. Patrick McCluskey, Department of Mechanical Engineering, Glenn L.
Martin Hall, University of Maryland, College Park, MD 20742

[Back to Table of Contents](#table-of-contents)

*NEPP Task Work with Case Western Reserve and the University of
Maryland:*

## **Evaluation of High-Temperature Packaging Module for Implementation of SiC Wide Bandgap Microsystems**

*Task Lead: Dr. Liang-yu Chen, OAI/NASA, NASA GRC*

The purpose of NASA Glenn Research Center's collaborations with Case
Western Reserve and the University of Maryland is to bring focused
expertise to the problem of evaluating and enhancing the reliability of
packaging and interconnection structures for SiC microsystems for use in
high-temperature applications, such as propulsion systems and inner
solar planetary exploration. Dr. C. C. Liu at Case Western Reserve is
working with NASA GRC researching high-temperature SiC microsystems and
packaging under various NASA programs, including the current NEPP task,
for which it is designing and fabricating thick-film materials and
components for testing.

The CALCE Center is creating models to assess the reliability of
packaging components and materials for SiC MEMS sensors and associated
electronics through the study of interconnect fatigue related to
die-attach and wire bonds. This modeling is based on an understanding of
fundamental thermo-mechanical and electrical degradation mechanisms.
University of Maryland is also conducting measurements of the mechanical
properties of related material systems at elevated temperatures.

[Back to Table of Contents](#table-of-contents)

# Institute for Space and Defense Electronics (ISDE) at Vanderbilt University

# 

# The ISDE is a non-profit company with close ties to Vanderbilt University's Electrical Engineering and Computer Science Department. Vanderbilt University and ISDE are located in suburban Nashville, Tennessee. The ISDE is involved in support of the DoD in radiation effects for strategic applications. They have also created, with DoD and NASA, a consortium to build new models of radiation effects on different electronic technologies. ISDE's close ties with Vanderbilt allow it to make highly skilled labor and advanced computing and laboratory facilities available to industry and government at an affordable cost.

# 

# ISDE's major programs are organized into the following subject areas: Design and test of radiation-tolerant integrated circuits and semiconductor devices, development of simulation tools for analyzing the effects of radiation on integrated circuits and semiconductor devices, test methods and plans for predicting the survival of electronics in radiation environments, and basic physical mechanisms of radiation damage in semiconductor devices and materials.

# 

*NEPP Task Work with ISDE:*[]{#SCRIPT .anchor}

**Space Computational Radiation Interaction Performance Tools (SCRIPT)**

*Task Lead: Ken LaBel, NASA GSFC*

NASA GSFC and the DoD have engaged ISDE to support the development of
new radiation effects models for microelectronics. The current tools are
being found inadequate for some new technologies, so a need has been
identified to position NASA and DoD for using new models. The first task
will be an attempt to identify the gaps between what the current models
are able to do, what newer models are promising, and what new
capabilities are needed. New approaches include the use of the GEANT4
tool for simulating the passage of particles through matter. (More on
GEANT4 can be found at
[**http://wwwasd.web.cern.ch/wwwasd/geant4/geant4.html**](http://wwwasd.web.cern.ch/wwwasd/geant4/geant4.html).)
The figure below shows the structure of the NASA/DoD/ISDE effort being
supported by NEPP.

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![](media/image4.png){width="5.034722222222222in"
height="3.3979166666666667in"}

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# Analog Single-Event Transients (ASET)

# *Task Lead: Ken LaBel, NASA GSFC*

Commercially available linear bipolar and CMOS devices are often
susceptible to single energetic particle induced transients. ASET task
efforts are to support DOD-funded modeling for developing appropriate
ground-based radiation test methods and determine improved ASET
tolerance. The focus of the ASET task is single-event models,
single-event effects (SEE), and dose and damage modeling and testing.
GSFC provides the testing for the ASET modeling until the models are
aligned with the testing; Vanderbilt's models are improved by GSFC's
validation data. Although Vanderbilt has unique multiprocessing
capability that allows them to do simulations for the modeling, their
major asset is the collective knowledge of the researchers there,
several of whom are world experts in various areas.

# *Point of Contact*

Ken LaBel, 301.286.9936, <Kenneth.A.LaBel.1@gsfc.nasa.gov>.

[Back to Table of Contents](#table-of-contents)

### 

### Standards Corner

### 

### Proposed Changes to MIL-STD-883E

*Jeannette Plante, Dynamic Range Corp./NASA GSFC*

Changes that will be incorporated into MIL-STD-883, the highly used
guideline for high-reliability testing of microcircuits, will form the
new F revision. This revision is expected to be fully coordinated and
implemented by the end of 2004.

The following are the more significant changes expected to be approved:

-   Increase in the number of industry standards invoked, such as ASTM,
    EIA, IPC, and JEDEC.

-   Temperature-related test conditions changed to improve hybrid
    testing.

-   New wording is added to update the seal test method to accommodate
    new laser technologies used for leak detection.

-   Allowance of "equivalent" materials for dye penetrant test because
    standard materials are becoming harder to obtain.

-   Criteria for trimmed and scratched resistors was clarified.

-   Several changes were made in the Scanning Electron Microscope
    section with respect to step coverage, planar oxide interconnect
    technologies, sample sizes, metallization coverage, and differing of
    current density to MIL-PRF-38535.

-   Changes were made regarding PIND testing, including disallowing
    batch or bulk testing, defining a maximum percentage failure for the
    lot, and adding a new equation for determining the right test
    frequency condition for the package height.

A new test method for resistance to solder heat was intended to be added
to address surface-mount packages in a method similar to that found in
MIL-STD-202. This change is not expected to be ready for inclusion in
Revision F. A summary of the changes and a copy of the proposed F
revision can be found at
<http://www.dscc.dla.mil/Programs/MilSpec/initialdrafts.asp> (type
ctrl+F and type in "MIL-STD-883" to jump directly to the two related
links).

[Back to Table of Contents](#table-of-contents)

### Recent Findings

Fiber Optic Epoxy to Alleviate Core Cracking During Termination

[]{#foepoxy .anchor}*Melanie Ott and Patricia Friedberg, NASA GSFC and
Barry Siroka, Fiber Optics Center, New Bedford, MA*

One of the approved epoxies typically used for space flight 100/140
micron optical fiber terminations is the [Tra-Bond
F253](http://www.tra-con.com/pdf/tpb/F253.pdf). This epoxy is approved
for space flight missions because it passes the ASTM-595-93 vacuum
outgassing test and is proven to be adequate to withstand harsh
environmental testing in space flight configuration testing. In the
past, this epoxy has been used for termination with the [Johanson
R2550](http://www.johansonfiber.com/p_fc.html) and the R2547 FC type
space flight approved connectors. The cure schedule specified by Tra-Con
for the F253 is 100 ºC for 15 minutes, and at NASA Goddard Space Flight
Center, the heat is applied for an additional 45 minutes, followed by a
cool-down time of 30 minutes before removal from the oven.

Another epoxy that has passed the ASTM-595-93 test is the AngstromBond
AB9119 with a Total Mass Loss (TML) of 0.64 % and a Collected Volatile
Condensable Materials (CVCM) of 0.00%\[1\]. The cure schedule for this
epoxy was 30 minutes at 120 °C for outgas testing, while the
vendor-recommended minimum schedule is 100 ºC for 15 minutes, 120 ºC for
10 minutes, or 150 ºC for 5 minutes. Another epoxy tested was the
Angstrom Bond AB9112, but it did not pass outgas testing with a TML of
4.33% and a CVCM of 1.34%. This epoxy is therefore not approved for
flight use.\[1\]

During termination of optical fiber assemblies at NASA GSFC, unexplained
core cracking occurred while heat curing the Tra-Bond F253. This
occurred more often when this epoxy had been used to terminate to other
types of connectors (ST and other FC types, for example). Although this
problem has existed for several years, it was not studied in great depth
since most of the space flight manufacturing is done at very small
volumes where yield is less of an issue. For industry, however, core
cracking of multimode fiber during the cure cycle of the epoxy has been
a common problem and is much more of an issue due to the high volume of
manufacturing.

Imidizole cured epoxies, such as the TraBond F253 and the AngstromBond
AB9119, can shrink from 3% to 7% during cure depending upon the mass.
This shrinkage, coupled with the high temperatures required for curing
(100 °C to 150 °C), applies stress on the glass and may cause core
cracking in multimode fiber. Single-mode fiber can easily withstand the
stress because it is strongly compressed. Using an amine-curing system
alleviates the issues of core cracking. An example of an amine-cured
epoxy is the AB9112.

Years ago, the U.S. Navy originally wanted to approve a popular
imidizole epoxy, but they could not accept the failure rate experienced
with that system. For this reason, only amine cure systems are approved
to MIL-PRF-24792A, the specification for two-part optical fiber epoxies.
However, some of the amine-cure systems do not pass the vacuum
outgassing requirements of ASTM E-595-93, as was seen with the testing
results for the AB9112.

The AngstromBond AB9320 was developed to solve the problems previously
mentioned. It has the low stress of the amine system but it yields the
properties of the imidizoles. The manufacturer specifies the following
options for cure schedules: 80 ºC for 30 to 120 minutes, 90 ºC for 15 to
60 minutes, or 100 ºC for 10 to30 minutes. Two of these cure schedules
were used for vacuum outgassing testing. The results of testing the
AB9320 to the ASTM-595-93 are in Table 1.

# Table 1: Outgassing Test Results for AngstromBond AB9320

  ----------------------------- -------------- --------------- -----------
  **Cure Schedule**             **TML**        **CVCM**        **Pass**

  A: 25 Degrees C for 7         1.39%          0.00%           No
  days^\*^                                                     

  B: 100 degrees C for 30       1.13%          0.00%           No
  minutes                                                      

  C: 80 degrees C for 2 hours   0.85%          0.00%           Yes
  ----------------------------- -------------- --------------- -----------

\* This cure schedule is NOT recommended by the manufacturer and is not
considered an adequate cure.

In order for the AB9320 to pass the outgassing test, a cure schedule of
80 ºC for 2 hours must be used. The lower cure temperature is more
advantageous for termination of assemblies that are not rated for
temperatures as high as 100 °C. Many acrylate coatings are rated for 85
°C, making this an important reason to choose a lower cure temperature
epoxy. Industry users state that this epoxy works well with multimode
and single-mode optical fiber and does not cause core cracking.

Although outgassing test results for a space environment are favorable
using cure schedule C for the AB9320, and industry reports success with
termination yield, it is important to verify that a terminated optical
fiber assembly system functions reliably. To validate a terminated
system, it is highly recommended to test the entire assembly for thermal
effects.\[2-3\]

For more information, please visit the Web sites
[misspiggy.gsfc.nasa.gov/photonics](http://misspiggy.gsfc.nasa.gov/photonics/)
and [nepp.nasa.gov/photonics](http://nepp.nasa.gov/photonics).

*References*

1.  M. Bettencourt, M. Ott, "[Fiber Optic Epoxy Outgassing Study for
    Space Flight
    Applications,](http://misspiggy.gsfc.nasa.gov/tva/meldoc/epoxyoutgas.pdf)"
    NASA Electronic Parts and Packaging Program Publication for the
    Electronic Packaging Project, October 4, 2001.
    <http://nepp.nasa.gov/photonics>

2.  M. Ott, P. Friedberg, "[Technology Validation of Optical Fiber
    Cables for Space Flight
    Environments](http://misspiggy.gsfc.nasa.gov/tva/meldoc/cotsfospie2000.pdf),"
    International Society for Optical Engineering, SPIE Conference on
    Optical Devices for Fiber Communication II, Proceedings Vol. 4216,
    November 8, 2000, Boston.

3.  M. Ott, "[Fiber Optic Cable Assemblies for Space Flight II: Thermal
    and Radiation
    Effects](http://misspiggy.gsfc.nasa.gov/tva/meldoc/spiecable98.pdf),"
    International Society for Optical Engineering, Conference on
    Photonics for Space Environments VI, SPIE Proceedings Vol. 3440,
    1998.

> [Back to Table of Contents](#table-of-contents)

New Publications on nepp.nasa.gov

The following publications have recently been uploaded to the NEPP Web
site. Use the following path to find these new documents:

1.  []{#fo_webex .anchor}Optical Assemblies for Space Environments:
    Characterization of W. L. Gore Flexlite with Diamond AVIMS: Audio
    and slide WebEx presentation by Melanie Ott. Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/552FB40C-9D97-45FC-86571C33E7437F44/>

2.  []{#vacuum_wb .anchor}Effect of Vacuum on High-Temperature
    Degradation of Gold/Aluminum Wire Bonds in PEMs: Technical paper by
    Alexander Teverovsky on exploration the wirebond failure mode in
    PEMs. Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/E894E6FE-9D6A-4F91-8D14D2B7A0B3D88F/>

3.  []{#LevelI_II_III .anchor}Level I , II, and III Requirements
    Compared for Microcircuits: Table by Dave Peters comparing the
    difference in requirements defined by the NPSL for microcircuits.
    Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/52BF276D-2DE4-460D-A870A9187B2B4EAE/>

4.  []{#President_vision .anchor}President's Vision on Space
    Exploration, February 12, 2004: John Marburger, III's speech on the
    President's vision for space exploration. Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/F08A6A33-0A3F-41E0-BF4714F9D4D422C5/>

5.  []{#Airforce_tin .anchor}U.S. Air Force Position on Tin Usage: The
    USAF's policy on procuring electronic parts with pure tin plating.
    Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/DBAF7291-ED91-4647-956269FD751EA53D/>[]{#Package_qual
    .anchor}

6.  Package Qualification Testing Results Performed on the Five Part
    Types in the NEPP/NEPAG PEMs Study: A report by Dave Gerke on the
    results of the packaging tests performed on the five candidate parts
    included in the NEPP/NEPAG PEMs Evaluation. Link:
    <http://nepp.nasa.gov/index_nasa.cfm/477/9A39144C-F325-4AB6-A80C873FC394156B/>

[Back to Table of Contents](#table-of-contents)

## **Upcoming Events**

[]{#upcoming_events .anchor}

For calendar updates on the NEPP Web site, go to
<http://nepp.nasa.gov/index_nasa.cfm/485/>

*International Reliability Physics Symposium (IEEE)*

April 25-29, 2004, Hyatt Regency Phoenix at Civic Plaza, Phoenix, AZ

For details, contact Carole D. Graas, <graas@us.ibm.com>, 802.769.1214,
or see event Web site
[http://www.irps.org/](http://http://www.irps.org/)

*Announcement and Call for Papers, Ceramic Interconnect Technology: The
Next Generation II*

April 27-28, 2004, Hyatt Regency Denver, Denver, CO

For details, contact IMAPS, <imaps@imaps.org>, 202.548.4001, or see
event Web site [http://www.imaps.org](http://http://www.imaps.org)

*Fourteenth Biennial Single Event Effects Symposium*

April 27-29, 2004, Manhattan Beach Marriott, Manhattan Beach, CA

For details, contact Donna Cochran, <dcochran@pop700.gsfc.nasa.gov>,
301.286.8258, or see event Web site
[http://radhome.gsfc.nasa.gov/radhome/SEE/seesym.htm](http://http://radhome.gsfc.nasa.gov/radhome/SEE/seesym.htm)

*ISCAS 2004: IEEE International Symposium on Circuits and Systems*

May 23-26, 2004, Sheraton Vancouver Wall Center Hotel

For details, contact ISCAS, <organizers@iscas2004.org>, 256.536.1304, or
see event Web site
[http://www.iscas2004.com/](http://http://www.iscas2004.com/)

*2004 41st Design Automation Conference*

June 7-11, 2004, San Diego, CA

For details, contact Kevin Lepine, <kevin@mpassociates.com>,
303.530.4562, or see event Web site
[http://www.dac.com/41st/index.html](http://http://www.dac.com/41st/index.html)

*Magnetics 2004, Advancements in Magnetic Applications, Technology, and
Materials*

June 9-10, 2004, Denver Marriott Tech Center, Denver, CO

For details, contact Jeremy Martin, <Jeremym@infowebcom.com>,
720.528.3770, extension 118, or see event Web site
[http://www.magneticsmagazine.com](http://www.magneticsmagazine.com/)

*Engineering of Reconfigurable Systems and Algorithms (ERSA '04)*

June 21-24, 2004, Las Vegas, NV

For details, contact Dr. Toomas P. Plaks, <plakst@sbu.ac.uk>,
+44(0)20.7815.7495, or see event Web site
[http://www.scism.lsbu.ac.uk/ERA/ersa04/ersa04.html](http://http://www.scism.lsbu.ac.uk/ERA/ersa04/ersa04.html)

*IMAPS Topical Workshop and Exhibition on Flip Chip Technologies*

June 21-24, 2004, Marriott Hotel, Austin, TX

For details, contact Ted Tessier, <tessiert@statsus.com>, 480.222.1735,
or see event Web site
[http://www.imaps.org/abstracts.htm](http://http://www.imaps.org/abstracts.htm)

*National Space & Missile Materials Symposium*

June 21-25, 2004, Doubletree Hotel Seattle Airport, Seattle, WA

For details, contact Michelle Kubal, <mkubal@anteon.com>, 937.254.7950,
ext. 1168, or see event Web site
[http://www.usasymposium.com/nsmms/default.htm](http://http://www.usasymposium.com/nsmms/default.htm)

*Call for Papers, 2004 Electrostatics Society of America Annual Meeting*

June 23-25, 2004, Rochester, NY

For details, contact Kelly Robinson, <kelly.robinson@kodak.com>,
585.477.4951, or see event Web site
<http://www.electrostatics.org/Announcements/20049620Call-For-Papers.htm>

*Call for Papers, 7th MAPLD International Conference*

September 8-10, 2004, Ronald Reagan Building and International Trade
Center, Washington, DC

For details, contact Rich Katz, <mapld2004@klabs.org>, 301.286.9705, or
see event Web site
[http://klabs.org/mapld04/admin/cfp.html](http://http://klabs.org/mapld04/admin/cfp.html)

## **Guidelines for *EEE Links* Article Submission**

## 

## *EEE Links* is a quarterly publication. The next publication date and focus will be:

## 

## July 2004/Focus on Working Groups Supported by the NEPP Program. Article submission deadline is June 11, 2004.

Submitting articles for *EEE Links* is a great way to transfer
information and knowledge inside and outside of the NASA community.

*EEE Links* supports the NASA Electronic Parts and Packaging Program
(NEPP), and the information presented in this newsletter augments
electronic parts, packaging, and radiation technologies.

*EEE Links* publishes many types of articles relevant to electronic
parts, packaging, and radiation. Primary consideration is given to
articles that relate specifically to the NEPP Program, but we also
consider articles outside of the NEPP Program that address electronic
parts, packaging, or radiation issues.

Article submissions can cover current efforts, referencing status and
completion date. Articles can be informal and be from one paragraph to
three pages in length on the following subjects:

-   Current events within the NEPP Program and projects.

-   Parts.

-   Packaging.

-   Radiation.

-   Reliability issues concerning NEPP.

-   New/emerging technology.

-   Space flight hardware.

-   Quality assurance issues.

To submit an article, please send it in a text-only format, preferably
Microsoft Word, to Jeannette Plante at jfplante@pop500.gsfc.nasa.gov.
Please provide the following information with your article submission:

-   [Abstract:]{.underline} This two- to four-sentence paragraph
    summarizes the key points to capture the reader's attention.

-   [Contact Information:]{.underline} The author must include his or
    her business address, phone, fax, and e-mail address.

-   [Notes and References:]{.underline} Most articles require some
    references, and some contain incidental information best treated as
    notes. Use brackets for references and superscripts for notes, then
    list the two groups separately at the end of the article. These
    should be numbered in the order in which they appear in the article,
    not alphabetically.

-   [Additional Reading:]{.underline} Our readers appreciate pointers to
    relevant books and articles. List these at the end of the article in
    the same format as the references.

-   [Copyright:]{.underline} The author is responsible for obtaining any
    copyright releases or other releases necessary for their article.
    The releases should be forwarded to the *EEE Links* Editor (see
    Jeanne Ilg's e-mail address above).

-   [Biography]{.underline} (to be supplied when requested): This should
    be between 50 and 75 words outlining the author's job, background,
    professional accomplishments, and other pertinent accolades or areas
    of interest. Accompanying photographs might be requested also; these
    should either be in .gif or .jpg format if possible.

**Letters to the Editor**

Please limit letters to 250 words. Include your name, phone number, and
e-mail address. Names are withheld from publication upon request. We
reserve the right to edit for style, length, and content.

[Back to Table of Contents](#table-of-contents)