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Description / Abstract:
Foreword
The developments over the past 8–10 years reflected in this
document have resulted in a variety of new materials, structures,
and interconnect methodologies. This ‘‘smorgasbord'' of MCM
technology is shown in Figure F–1. The selection of the elements
that make up a structure to meet the systems level needs initially
appears to be a difficult problem in the current environment.
However, the choices available should be viewed as part of the
beauty of this technology.
Initially, system requirements should be developed on a
hierarchal basis. A simple high-level breakdown of a system is
shown in Figure F–2. System requirements for cost, reliability and
performance must be clearly understood in the context of the
application and system environment. In this way, requirements are
logically developed and an understanding of their
interrelationships can be inferred or modeled.
The complexity of an MCM structure demands the development of
requirements for the structure from system level considerations.
The next step is to work with system partitioning concepts that
make sense in terms of system cost and performance. For example,
the designer should question whether it makes sense to use single
chip packaging, manufacture a single module an a 10.2 cm [4 in]
substrate, or four modules on a 5.1 cm [2 in] substrate. Perhaps
the answer is the latter when cost is compared to performance
requirements for the system. This process of system partitioning
may require an iteration or two following the initial technology
selection in order to develop accurate costs as the process of
developing a module-based system progresses.
Following the development of system requirements and
partitioning, a specific module can be synthesized which meets the
systems needs through a balancing of module attributes related to
cost, performance, and reliability. At this point, IPC-MC-790 can
become a useful tool in understanding the various module options
and the relationship of these attributes to a potential structure.
this is done through the use of comparisons of interconnect and
substrate properties, manufacturing costs and other criteria for
MCM-L, MCM-D, and MCM-C as defined in section 1 of the document.
Table F–1 shows these various module attributes and their relative
weights for these general categories.
The selection of a general category is initially made through
comparing system requirements to module attributes. This should be
done in a quantitative fashion