Multi-Chip Packages
“Multi-Chip Packages” or MCP is a terminology used within
National Semiconductor Corp. Outsiders refer to the same
type of packaging as “Few-Chip Packages” or FCP (pro-
posed by MCC) or low-end Multi-Chip Modules (MCM).
MCP refers to a packaging configuration containing at most
five (5) chips, connected via wirebonds to a multilayer circuit
board, and protected by either a molded encapsulant or a
low-cost ceramic package. In the simplest case, dies can be
attached to a die paddle without a substrate, and inter-die
communication is achieved through die-to-die wirebonding.
It is as if all the chips were integrated into one single die and
packaged as such, since the same form factor and footprint
are kept to facilitate subsequent board assembly operations.
Thus, this quasi-integration of functions is transparent to the
end-user who only sees the end-product as one single pack-
age. MCPs can also incorporate the use of passive compo-
nents.
A key feature of MCP is the use of standard packages as a
vehicle for low-end MCM applications. This allows the end
user to readily incorporate MCP solutions since the test,
handling, and mounting equipment already exist in the in-
dustry.
Being one version of the MCMs, MCPs benefit from the
same advantages that MCMs offer, namely:
Improved Performance: closer positioning of the dies
on the substrate and shorter interconnection lengths
should enhance system speed dramatically.
Higher Integration Density: substituting several pack-
ages for one slightly larger but single package, should ei-
ther free board real estate for other use or help reduce
the board size.
Lower Power Consumption: smaller drivers are
needed resulting in lower power consumption.
Mixed Signal Applications: MCP allows the integration
of chips made from different technologies in one pack-
age.
Lower Cost: cost savings result from fewer packages
with a fewer number of leads, a simplified board layout,
and the feasibility of mixed technologies in the same
package. Smaller risks are associated with MCPs com-
pared to MCMs since existing package and board as-
sembly equipment and technologies are used. For in-
stance, the same CAD design software for board layout
can be extended to MCP substrate design, standard
pick-and-place tooling can be used for die placement, the
same leadframe outline can be applied eliminating the
needs for new molds or trim and form tooling, and test
sockets and even shipping containers for MCPs fitting the
form factor of single chip packages can be readily de-
ployed.
Time-to-Market: inserting several dies into the same
package allows much faster introduction of the product
into the market compared to integrating all the desired
functions on a new single chip. The latter can still be
achieved provided that the product needs and volume
forecasted are warranted. Thus, MCP finds a special
niche in packaging, acting as transitory stage between
product needs and chip integration. The timely introduc-
tion is most important since the highest profit margins are
always achieved in the early stages of the product life
cycle.
Aside from offering products in MCP configuration, Na-
tional Semiconductor will also work with customers to
design and manufacture their requirements using this
technology.
Four types of MCPs are currently offered by NSC. The type
numbers increase with the complexity of the package, and is
summarized in
Figure 1
.
Type 1: Multiple dies with die-to-leadframe bonding. No
substrate.
Type 2: Multiple dies with die-to-die bonding. No sub-
strate.
Type 3: Multiple dies with jumper chip. No substrate.
Type 4: Multiple dies on substrate.
April 2000
Multi-Chip Packages
© 2000 National Semiconductor Corporation MS011801 www.national.com
MCP Types
Type 1: Multiple Dies, No Substrate Die-to-L/F Wire Bonding
MS011801-1
Type 2: Multiple Dies, No Substrate Die-to-Die Wire Bonding
MS011801-2
Type 3: Multiple Dies, Jumper Chip
MS011801-3
Type 4: Multiple Dies on Substrate
MS011801-4
FIGURE 1. Schematic of the four types of MCPs offered by NSC. The MCPs can be obtained in a variety of packages.
Multi-Chip Packages
www.national.com 2
MCP Types (Continued)
The MCP can be configured in the following eight classes of
form factors with the relevant pin count:
1. Molded plastic thru-hole packages.
2. Molded plastic surface mount packages.
3. Molded thin packages.
4. Molded PGAs and LGAs.
5. Cavity packages (non-hermetic).
6. Ceramic thru-hole packages.
7. Ceramic surface mount packages.
8. Ceramic PGAs.
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Multi-Chip Packages
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