# ![](media/image1.wmf) NEWS FLASH OCTOBER 2002

# ![](media/image2.jpeg){width="2.376388888888889in" height="0.20833333333333334in"}

## Latchup/Latent Damage

![](media/image3.wmf)

### 

### *[Latent Damage From Single-Event Latchup](#latent-damage-from-single-event-latchup)* Refutes the myth of using latchable parts in spacecraft without serious consequences...

### [*Study of Catastrophic Latchup in the DSP2100 Signal Processor Chip for MLS*](#study-of-catastrophic-latchup-in-the-dsp2100-signal-processor-chip-for-mls) Unveils a proposed mitigation strategy to reduce risk of latchup that causes immediate device destruction...

### [*Latchup Test Considerations for Analog-to-Digital Converters*](#latchup-test-considerations-for-analog-to-digital-converters) Illustrates key test factors---effective ion range, current limiting, temperature, and circuit behavior during latchup...

### [*Radiation Damage and Single-Event Effect Results for Candidate Spacecraft Electronics*](#radiation-damage-and-single-event-effect-results-for-candidate-spacecraft-electronics) Presents data on SEE, Co-60 TID, and proton-induced damage on spacecraft electronics devices...

## 

## Tin Whiskers

### [*Tin Whisker Observations on Pure Tin-Plated Ceramic Chip Capacitors*](#tin-whisker-observations-on-pure-tin-plated-ceramic-chip-capacitors) Proves that MLCCs are not immune to tin whisker formation and highlights the confounding nature of tin whiskers...

### [*Tin Whiskers: Attributes and Mitigation*](#_Tin_Whiskers:_) Analyzes problematic issues of tin whisker formation on passive components, summarizes recent experiments, and discusses practical recommendations...

### [*Effects of Conformal Coat on Tin Whisker Growth*](#effects-of-conformal-coat-on-tin-whisker-growth) Measures protective effects of Uralane coating on initiation/growth of tin whiskers, its ability to prevent or inhibit emergence of tin whiskers, and its ability to prevent shorting...

### [*Tin Whiskers: Revisiting an Old Problem*](#_Tin_Whiskers:__1) Describes tin whisker characteristics and formation and suggests strategies to reduce tin whisker risk on space flight hardware...

![](media/image4.png){width="1.25in" height="1.5416666666666667in"}

## Other Topics

### [*Overview of Ball Grid Array and Chip Scale Packaging Technology*](#overview-of-ball-grid-array-and-chip-scale-packaging-technology) Presents a synopsis and pros and cons for designing, manufacturing, and testing printed wire assemblies populated with BGAs and CSPs...

### [*Destructive Physical Analysis (DPA) Statistics, July Through September 2002*](#destructive-physical-analysis-dpa-statistics-july-through-september-2002) Shows recent DPA statistics by sample quantity, job type, part number, and project...

# ![](media/image5.jpeg){width="2.622916666666667in" height="0.21805555555555556in"}

***[Virtual Conference on Plastic Encapsulated Microcircuits (PEMs) for
Use in Space](#_Virtual_Conference_on)*** December 5, 2002, using Web-Ex
at your computer station or in an e-room; for details, contact Dory
Josephson, 301.286.7927 or <Philomin.D.Josephson.1@gsfc.nasa.gov>.

**Latchup/Latent Damage**

### Latent Damage From Single-Event Latchup

Heidi N. Becker, Tetsuo F. Miyahira, and Allan H. Johnston, NASA
JPL/California Institute of Technology

This research illuminates the serious consequences resulting from flying
latchable parts. Becker et al. detected evidence of melting, voiding,
and fracturing of metallization; insulator/dielectric cracking; and
globules of metal that could potentially cause short circuits in
microcircuits that had suffered an SEL event. A full description of the
characteristic physical signatures of latent damage is included, along
with key parameters of these types of events. By using scanning electron
microscopy and energy dispersive spectroscopy to detect and characterize
latent damage in microcircuits that have suffered SEL, the research
highlights the need for greater caution. Projects need to look for
evidence of latent damage after the SEL test and ensure that current
densities during latchup were low enough that damage to metallization
and dielectrics is improbable.

To view the full-length article, go to
<http://nppp.jpl.nasa.gov/docs/Latent_Damage.pdf>.

### Study of Catastrophic Latchup in the DSP2100 Signal Processor Chip for MLS

Heidi N. Becker, Allan H. Johnston, and Tetsuo F. Miyahira, NASA
JPL/California Institute of Technology

This report summarizes the results of a series of tests to characterize
catastrophic radiation-induced latchup in the DSP2100, which is used in
three different applications on MLS. Latchup has been observed by JPL as
well as by two other test organizations (Aerospace Corporation and ESA)
in heavy-ion tests of DSP2100 devices. Tests were done on devices from
the same date code used in MLS. Those results were reported in an
internal JPL Test Report in April 2001. Heavy-ion data from these
reports were used to calculate expected latchup rates for MLS. The
estimated rates were 0.102 per year from heavy ions, and 1.7 per
"design-case flare." Those rates apply to each part. Three DSP2100
devices are used on MLS, increasing the latchup probability by three.

To view the full-length article, go to
<http://nppp.jpl.nasa.gov/docs/MLSLatchup-Cf2.pdf>.

### Latchup Test Considerations for Analog-to-Digital Converters

Allan H. Johnston and Tetsuo F. Miyahira, NASA JPL/California Institute
of Technology

Many CMOS circuits are sensitive to latchup from heavy ions, and latchup
is one of the major considerations when CMOS devices are evaluated for
space applications. Radiation-induced latchup has been studied for many
years, but it remains a difficult problem in actual circuits because
latchup sensitivity inherently depends on the layout and distribution of
contacts, power, and ground within complex circuits. The gain of the
parasitic bipolar transistors that form potential latchup paths is
nearly always high enough so that latchup can potentially occur.
However, the key factor in latchup sensitivity is the external
resistance across the base-emitter junctions of the two parasitic
transistors, not the transistor gain.

To view the full-length article, go to
<http://nepp.nasa.gov/index_nasa.cfm/478/BC46BBB1-3E90-42D5-982DDBDFC641DB28/>.

### Radiation Damage and Single-Event Effect Results for Candidate Spacecraft Electronics

Martha V. O'Bryan, Raytheon ITSS, Kenneth A. LaBel, NASA GSFC, Robert A.
Reed, NASA GSFC, James W. Howard, Jr., Jackson & Tull Chartered
Engineers, Ray L. Ladbury, Orbital Sciences Corporation, Janet L. Barth,
NASA GSFC, Scott D. Kniffin, Orbital Sciences Corporation, Christina M.
Seidlick, Raytheon ITSS, Paul W. Marshall, Consultant, Cheryl J.
Marshall, Consultant, Hak S. Kim, Jackson & Tull Chartered Engineers,
Donald K. Hawkins, NASA GSFC, Anthony B. Sanders, NASA GSFC, Martin A.
Carts, Raytheon ITSS, James D. Forney, Jackson & Tull Chartered
Engineers, David R. Roth, Applied Physics Laboratory, James D. Kinnison,
Applied Physics Laboratory, Elbert Nhan, Applied Physics Laboratory, and
Kusum Sahu, QSS Group, Inc.

We present data on the vulnerability of a variety of candidate
spacecraft electronics to proton and heavy-ion induced single-event
effects and proton-induced damage. We also present data on the
susceptibility of parts to functional degradation resulting from total
ionizing dose at low dose rates (0.003--4.52 rads (Si)/s). Devices
tested include optoelectronics, digital, analog, linear bipolar, hybrid
devices, Analog-to-Digital Converters (ADCs), Digital-to-Analog
Converters (DACs), and DC-DC converters, among others.

To view the full-length article, go to
<http://radhome.gsfc.nasa.gov/radhome/papers/nsrec00_W21.pdf> or

[http://nepp.nasa.gov/DocUploads/7EE2C982-FBCC-4931-BFCCB4FCB78B2560/nsrec01_W15.pdf.](http://nepp.nasa.gov/DocUploads/7EE2C982-FBCC-4931-BFCCB4FCB78B2560/nsrec01_W15.pdf. )

#### Tin Whiskers

### Tin Whisker Observations on Pure Tin-Plated Ceramic Chip Capacitors

Jay Brusse, QSS Group, Inc.

Tin whiskers pose a risk of intermittent short circuits in terrestrial
applications and potentially catastrophic metal vapor arcs in space
(vacuum) environments. Research on whiskering and mitigation practices
has historically produced highly variable results. These variations and
recurring observations of whisker-induced failures are central to the
high reliability community's reluctance to adopt lead-free finish
alternatives, especially pure tin, until clear evidence exists that the
factors affecting whisker growth are understood and can be controlled.
This paper highlights the variability of previous claims using recent
observations of greater than 200-µm-long whiskers on pure tin-plated
ceramic chip capacitors as a classic example of the confounding nature
of this phenomenon.

For more information, contact: Jay Brusse, Senior Components Engineer,
QSS Group, Inc. at NASA Goddard Space Flight Center, Bldg. 22, Room 036,
Greenbelt, MD 20771, <Jay.A.Brusse.1@gsfc.nasa.gov>. This paper was
presented at the Electronics Finishing II Session and published in the
official proceedings of AESF SUR/FIN 2002, June 24-27, sponsored by the
American Electroplaters and Surface Finishers Society, Orlando, FL.
Posted with permission of the AESF.

To view the full-length article, go to
<http://nepp.nasa.gov/whiskers/references/tech_papers/brusse_2002_sur_fin_paper.pdf>.

### Tin Whiskers: Attributes and Mitigation

Jay A. Brusse, QSS Group, Inc., Gary J. Ewell, The Aerospace
Corporation, and Jocelyn P. Siplon, The Aerospace Corporation

The movement to eliminate lead (Pb), especially active in Japan and the
European Union, has resulted in an increasing use of pure tin (Sn)
coatings on leads and other external and internal surfaces of
capacitors, resistors, and other passive components. This paper
discusses the issues of tin whisker growth with respect to passive
components. It also presents both a critical analysis of existing
published documents on tin whisker nucleation and growth and a summary
of very recent experiments that provide further understanding of the
potential means of whisker formation mitigation. Many of the proposed
mechanisms for mitigation, including control of the immediate
underplating material, use of conformal coating, regulating the
thickness of the tin coating, use of matte tin electroplating, and
annealing or fusing of the tin layer, are inadequate. They are likely to
reduce the incidence of nucleation or growth but do not provide an
absolute guarantee of lack of whisker formation.

To view the full-length article, go to
<http://nepp.nasa.gov/index_nasa.cfm/478/5A676ED4-A9EF-4F3E-975B05515589AF7F/>.

### Effects of Conformal Coat on Tin Whisker Growth

Jong S. Kadesch, Orbital Sciences Corporation/NASA GSFC, and Henning
Leidecker, NASA GSFC

A whisker from a tin plated part was blamed for the loss of a commercial
spacecraft in 1998. Although pure tin finishes are prohibited by NASA,
tin plated parts, such as hybrids, relays, and commercial-off-the-shelf
(COTS) parts, were discovered to have been installed in NASA spacecraft.
Invariably, the assumption is that a conformal coat will prevent the
growth of, or short circuits caused by, tin whiskers. This study
measures the effect a Uralane coating has on the initiation and growth
of tin whiskers, on the ability of this coating to prevent a tin whisker
from emerging from the coating, and on the ability to prevent shorting.

To view the full-length article, go to
<http://nepp.nasa.gov/whisker/article/kadesch.PDF>.

### Tin Whiskers: Revisiting an Old Problem

Jay Brusse, QSS Group, Inc.

Recent events have reminded the space community of the potential risks
associated with the use of pure tin-plated finishes on electronic
components and assemblies. Pure tin finishes are susceptible to the
spontaneous growth of single crystal structures known as tin whiskers.
Tin whiskers are capable of causing electrical failures ranging from
parametric deviations to catastrophic short circuits. Although the tin
whisker phenomenon has been documented for decades and is reasonably
well understood, it is still a reliability hazard that warrants special
attention.

This article does not provide a complete explanation of the tin whisker
growth mechanism; numerous (often contradictory) publications have
attempted this task. The intent is to provide a comprehensive
explanation of generally accepted understandings of tin whiskers along
with some suggestions for how to reduce the risk of tin whiskers on
space flight hardware. In addition, Goddard Space Flight Center is
maintaining a Tin Whisker Information Homepage to provide regular
updates to facts and findings as they become available.

To view the full-length article, go to
<http://nepp.nasa.gov/index_nasa.cfm/478/2B1FC8E9-4AF1-4F2F-837213A632C25CE9/>.

## Other Topics

### Overview of Ball Grid Array and Chip Scale Packaging Technology

### for Space Flight Missions

Reza Ghaffarian, NASA JPL/California Institute of Technology

This document provides an overview for designing, manufacturing, and
testing printed wiring assemblies populated with ball grid arrays (BGAs)
and chip scale packages (CSPs). NASA Headquarters, Code AE, has funded
JPL for the last several years to investigate the use of BGAs and CSPs
for potential space flight missions. Within the last 2 years, a few
types of BGAs have been qualified for NASA missions including X-2000 and
Mars Exploration Rover, and are currently being qualified for Mars05.

The full-length article is currently being updated; upon completion, it
will be posted on the NEPP Web site at
[http://nepp.nasa.gov](http://nepp.nasa.gov/).

### Destructive Physical Analysis (DPA) Statistics, July Through September 2002

Darryl Lakins, NASA GSFC

DPAs in the table below were conducted at the GSFC Parts Analysis Lab.

  ------------ ---------- ---------------------------- ----------------------
  **Sample**   **Job**    **Part**                     **Project**

  **Qty.**     **Type**   **Number**                   

  2            DPA        5962-9163901MFA              ASTROE2

  2            DPA        ADDAC87D-DB1-V/88SB          ASTROE2

  3            DPA        JANTXV2N222A                 ASTROE2

  3            DPA        JANTXV2N2907A                ASTROE2

  3            DPA        5962-8984106LA               HST

  5            DPA        CND2047-DAF/20               ST-5

  3            DPA        5962-8874801UA               ASTROE2

  2            DPA        JANTXV2N2905A                ASTROE2

  3            DPA        M38510/13503BPA              ASTROE2

  2            DPA        5962-9164001MFA              ASTROE2

  2            DPA        5962H9215314QNC              ASTROE2

  3            DPA        M8340110H1001FA              ASTROE2

  3            DPA        M8340110H1002GA              ASTROE2

  3            DPA        OP-221AZ/883Q                ASTROE2

  1            DPA        7389-2030-09                 MLA

  2            DPA        M39016/29-057M               ASTROE2

  2            DPA        5962\--88762016A             ASTROE2

  5            DPA        HMC220MS8                    ST-5

  5            DPA        RF2422                       ST-5

  3            DPA        H0705CPX2R00F10              ST-5

  1            DPA        5962-0150802QYC              ST-5

  12           DPA        66099-103                    SWIFT

  3            DPA        M38510/14103BEA              ASTROE2

  3            DPA        5962-7705301XA               ASTROE2

  5            DPA        CDR35BX334AKUS               SWIFT

  5            DPA        CDR35BX334AKUS               SWIFT

  5            DPA        CDR32BX333AKUS               SWIFT

  5            DPA        CDR32BX333AKUS               SWIFT

  5            DPA        CDRBX333AKUS                 SWIFT

  2            DPA        CD4047BKMSR                  SWIFT

  5            DPA        OP296GS                      SWIFT

  3            DPA        JANTXV2N3741                 HST

  5            DPA        CDR35BX474AKUS               SWIFT

  3            DPA        5962-015-803QYC              AKTEL

  3            DPA        JANXV1N5550                  HST

  3            DPA        MAX4503EVK                   SWIFT

  5            DPA        MAX4503EUK                   SWIFT

                                                       

  5            DPA        JANTXVIN5331B-1              HST

  3            DPA        JANTXVIN962B-1               HST

  5            DPA        AMP03BH/883                  ASTROE2

  2            DPA        MN6400S/BCH                  ASTROE2

  5            DPA        JANTXV1N914                  ASTROE2

  5            DPA        JM38510/12802BGA             ASTROE2

  5            DPA        5692-8757103XA               ASTROE2

  5            DPA        AD648TQ/883B D/C0145A        ASTROE2

  5            DPA        AD648TQ/883B D/C0145B        ASTROE2

  1            DPA        5962-9320901MPA              ASTROE2

  5            DPA        JM38510/11301BEA             ASTROE2

  5            DPA        5962-8954401GA               ASTROE2

  5            DPA        M38510/11202BPA              ASTROE2

  2            DPA        5962-8757103XA               ASTROE2

  3            DPA        JANTX1N1202A                 ASTROE2

  3            DPA        DAC349-12                    ASTROE2

  3            DPA        M3840110H2261FA              ASTROE2 ACHE

  3            DPA        MCM2668-1M/1.6894MHZ         ASTROE2 ACHE

  2            DPA        CR-101/U-12M00000            ASTROE2 ACHE

  3            DPA        HS9-6617RH-Q                 ASTROE2

  2            DPA        9409-007-02BF                ASTROE2

  2            DPA        9201-043-02B                 ASTROE2

  1            DPA        9409-002-02B-09911A          ASTROE2

  3            DPA        M38510/13503BPA              ASTROE2

  1            DPA        9409-002-02B-0114A           ASTROE2

  2            DPA        9203-023-02B                 ASTROE2

  2            DPA        9201-052-02B                 ASTROE2

  2            DPA        9204-026-02B                 ASTROE2

  3            DPA        5962H9584501QYC              ASTROE2 CAP/CDP

  2            DPA        787RPFB                      ASTROE2CAP

  3            DPA        HCST85KMSR                   ASTROE2 ACHE

  3            DPA        B767747-013                  SWIFT

  2            DPA        5962-8953402MXA              HST

  5            DPA        87016C5002FC                 ST-5

  2            DPA        JANTXV2N5794                 HST WFC3

  3            DPA        M8340110H1003JB              ASTROE2 ACHE

  2            DPA        66099-415                    SWIFT

  2            DPA        JANTXV1N4099-1               HST

  2            DPA        JANTXV1N4103-1               HST

  5            DPA        87016C2002FC                 ST-5

  5            DPA        CDR33BX104AKUS               ST-5

  5            DPA        JANTXV1N5807                 HST WFC3

  2            DPA        M6106/38-004                 HST

  3            DPA        5962-8605305A                HST

  3            DPA        AD549SH/883B                 HST

  3            DPA        JANTXV1N4467                 ASTRO-E2 ACHE

  3            DPA        RF2667                       ST-5

  3            DPA        TPS9103PWR                   ST-5

  5            DPA        OP420GS9940                  SWIFT

  1            DPA        KM48C8000B5-6                SWIFT
  ------------ ---------- ---------------------------- ----------------------

For further information, contact Darryl Lakins, Code 562 Branch Head, at
301.286.6631 or <dlakins@pop500.gsfc.nasa.gov>.

**Special Events**

*Workshop on Thermal Packaging of High Flux Military and Commercial
Electronics*

October 7-10, 2002, Grand Ballroom, Stamp Student Union, University of
Maryland, College Park, MD

For details, contact Dr. Michael Ohadi, <ohadi@eng.umd.edu,>
301.405.5263, or see Web site
[http://www.s2ts.umd.edu/registration.htm](http://http://www.s2ts.umd.edu/registration.htm)

*CALCE Technical Review and Planning Meeting*

October 8-10, 2002, Grand Ballroom, Stamp Student Union, University of
Maryland, College Park, MD

For details, contact Joan Yuan, <joanyuan@eng.umd.edu>, 301.405.1905, or
see Web site [http://www.calce.umd.edu](http://www.calce.umd.edu/)

##### International Test Conference

October 8-10, 2002, Baltimore Convention Center Baltimore, MD

For details, contact Jill Sibert, <j.sibert@advantest.com>, 610.758.8190

*Optoelectronics Packaging and Microoptoelectromechanical Systems
(MOEMS)*

October 8-11, 2002, Bethlehem, PA

For details, contact Rajeshuni Ramesham,
<rajeshuni.ramesham@jpl.nasa.gov>, 818.354.7190, or see Web site
[www.imaps.org](http://www.imaps.org/)

##### World Space Congress 2002

October 10-19, 2002, George R. Brown Convention Center, Houston, TX

For details, contact World Space Congress, <www.aiaa.org/wsc2002>,
800.639.2422, or see Web site [www.aiaa.org](http://www.aiaa.org/)

*IMAPS Advanced Technology Workshop (Optoelectronics Packaging)*

October 11-14, 2002, Radisson Hotel, Bethlehem, PA

For details, contact Bill Heffner, <wheffner@agere.com>, 202.548.4001,
or see Web site
[www.imaps.org/callfor/atw2001opto.htm](http://www.imaps.org/callfor/atw2001opto.htm)

###### Virtual Conference on Plastic Encapsulated Microcircuits (PEMs) for Use in Space

December 5, 2002, using Web-Ex at your computer station or in an e-room

For details, contact Dory Josephson,
<Philomin.D.Josephson.1@gsfc.nasa.gov>, 301.286.7927

**Coming Soon**

## Articles are being accepted for the December 2002 issue of EEE Links.

## Guidelines for EEE Links Article Submission

## 

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

## 

## December 2002 -- Plastics

## Article submission deadline is November 15, 2002.

Submitting articles for EEE Links is a great means by which 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 Jeanne Beatty at <jbeatty@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
    Beatty's e-mail address above).

-   [Biography (to be supplied when requested):]{.underline} 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.

[]{#_Virtual_Conference_on .anchor}