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First Workshop for Solder Joint Design
NSF Geometry Center
May 31 - June 2, 1994
Workshop Report
From: Carol Handwerker, NIST
carolh@enh.nist.gov
(301) 975-6158
The dominant product and technological drivers in almost all
commercial electronics systems are cost, performance, and
reliability. While these same drivers are important in
determining what electrical and optical interconnections to use
in a particular design, industry has been hampered from
optimizing interconnection choices because there are no tools to
integrate design/performance with manufacturing and reliability.
As dimensions of microelectronic circuits become smaller and
smaller, the importance of such design tools will continue to
increase.
Two examples that indicate the need for such tools for solder
systems are: fine pitch solder joints and alignment of optical
interconnections. Defects in solder joints are increasing in
number and severity as the pitch becomes smaller. The choices of
component lead and board geometries and assembly processes are
made without being able to evaluate the probability of forming
short or open circuits during assembly or to predict the
reliability of the resulting fine pitch solder joints. Solder is
also being used for alignment of optical devices without a
quantitative understanding of the degree of alignment possible in
the design. Furthermore, the stability of alignment is dependent
on the creep and fatigue of the solder alignment system.
Inspection and repair of individual solder defects are expensive,
labor-intensive operations that can no longer be performed in the
current economic climate and for small size scales in electrical
and optical interconnect systems.
The lack of integrated design, manufacturing, and reliability
modeling was identified as a potential show stopper by industry
in the Semiconductor Industry Association (SIA) Semiconductor
Technology Roadmap. Development of a wide range of system models
for packaging is required to fulfill this need, and extensive and
reliable manufacturing data and standards are needed in order to
allow validation of these system models. While some design and
reliability models are used by industry, there are no
manufacturing models in use.
Over the past five years, several industrial, government, and
academic groups have independently recognized the need for an
integrated design system for solder joints capable of analyzing
specific geometries in terms of manufacturability and
reliability. Each of these groups has a major research program
in solder joint design for performance, manufacturing, and
reliability. These groups and principal investigators include:
Digital Equipment Corporation: Gary Friedman, National Institute
of Standards and Technology (NIST): Carol Handwerker; Marquette
University: Steve Heinrich, University of Colorado - Boulder:
Y.C. Lee, State University of New York - Binghamton: Tim Singler;
Massachusetts Institute of Technology: Julian Szekely, University
of Technology - Loughborough: David Whalley and Sandia National
Laboratories: Fred Yost.
Representatives from these research groups were invited to meet
for a Workshop on Solder Joint Design at the NSF Geometry Center,
Minneapolis, MN, from May 31 to June 2, 1994, sponsored by the
NIST Center for Theoretical and Computational Materials Science.
The purpose of the Workshop was to discuss the modeling
approaches that each has taken and to examine whether these
organizations could join together to create an integrated design
tool for design, manufacturing and reliability for solder joints.
The meeting began on Tuesday afternoon (May 31st) with Ken
Brakke's introduction to the Surface Evolver program and a brief
orientation to the Geometry Center. The participants spent the
rest of the afternoon transferring their simulations to the
Geometry Center computers. On June 1 morning each research group
described its approaches to solder joint design and the types of
modeling/simulations they do. For the remainder of that day and
the following morning, the participants demonstrated the range of
their simulations on the computers at the Geometry Center. Some
researchers using different computational approaches ran their
simulations with identical geometries to get a quantitative
comparison of their models' predictions.
The workshop ended with a general affirmation that the
participants want to work together as a group to generate design
tools for solder in electrical and optical interconnect systems.
In order to publicize the existence of this Working Group on
Solder Joint Design (name may change) in the electronics
community and to solicit collaboration with industry, the
following steps will be taken:
- Produce a workshop report that can be distributed as an
information/publicity document for the group. This
report will include a description of each group's work,
the viewgraphs used in the presentations, and the work
plan of the group.
- Provide an overview of the group's activities on
MOSAIC, including movies of simulations as well as
still shots of the final results.
- Announce to the electronics industry the existence of
the group through regular mail and electronic mail and
tell them how to gain access to the hard copy report
and to the MOSAIC files.
- Present the Working Group's plans and the research
results of each individual organization at a session on
solder joint design for manufacturing and reliability
at an electronics association meeting. This will
require that the group organize the session. An output
of the group will be a set of archival journal papers
to be published together. This will complement the
first information document.
- Hold another workshop at the Geometry Center to which
other industrial partners, such as Ford, Hughes,
Motorola, Texas Instruments, and Aerospace Corporation,
will be invited.
We are grateful to the NSF Geometry Center for its support of
this program. This workshop would not have been possible without
having access to the personnel and facilities of the Geometry
Center. The work of Ken Brakke is central to the program. His
presence at the workshop helped make it a success and his
willingness to continue collaborating with the group will be
essential to fulfilling the group's long-term goals. The
collegial atmosphere of place, with its helpful staff members,
such as Angie Vale, and interesting visiting mathematicians, such
as Rob Kusner and Jean Taylor, makes it a place where
stimulating discussions occur naturally, and where work can get
done. NIST's Center for Theoretical and Comptational Materials
Science has been formed using the NSF Geometry Center as a model
of how to get people to really work together on common modeling
problems.
We will return to the Geometry Center for a week-long workshop in
1995. Some travel funding will be available from NIST and the
Geometry Center. This meeting will include some additional
modelers from industry in addition to those at the first
workshop.
If there is any funding available from the Geometry Center for
travel or lodging and meals, please consider us for such funding.
The NIST Center for Theoretical and Computational Materials
Science will provide some funding for the workshop, but the exact
amount available for the group will not be known until after the
beginning of the next fiscal year.
Thank you again for your assistance. I look forward to our
continuing cooperation.
Participants
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