DESIGN FOR PACKAGEABILITY

University of Tennessee
Microelectronic Systems Research Laboratory
DESIGN FOR PACKAGEABILITY


OBJECTIVE:

Conventional approaches to microelectronic system design, partitioning and physical IC design should be optimized to take full advantage of MCM packaging. The purpose of this project is to assist the system designer in exploring the design space in order to perform this optimization. This goal will be accomplished by identifying the areas of the design cycle which benefit the most by taking full advantage of the new opportunities which MCMs provide.
Overview Paper (InterPack-95)

APPROACH:

The following design space exploration tools and demonstrations are planned:

* Design-for-Packageability Tool: This tool allows the system designer to explore IC and package options at an early stage of the design which may be input at different levels of abstractions including conceptual, behavioral and structural representations. It will partition a design at different levels of abstractions. It differs from other partitioning tools in that it considers salient features of the chosen MCM technology.

* Multi-objective Design Advisor: This information management tool empowers the designer with an efficient way of filtering and visualizing results graphically, permitting trade-off studies to be performed.

* Coordinated IC and MCM Physical Design Tool: This interactive tool will enable the system designer to consider the placement of the ICs on the MCM substrate before completing the IC pin assignment and physical design.

* Application of Design for Packageability: The tools described above are being utilized to analyze and partition an industrial-strength system (SUN MicroSparc CPU) into multiple ICs that will be fabricated and tested as a single MCM.

ACCOMPLISHMENTS:

The Design-for-Packageability Tool is now in place and has been used to analyze the SUN MicroSparc CPU. Our results, which were presented at the 1995 IEEE Multi-Chip Module Conference, indicated that it is seven times more cost-effective to fabricate three smaller dies with area-array bonding on an MCM-D substrate than to produce one large monolithic die. The optimization tool selected the best partition from over 21,000 candidates that were obtained by combining nine functional units (Memory Management Unit, Floating Point Unit, etc.) in all possible combinations.
The multi-objective design advisor (MODA) is operational and can be used to evaluate candidate designs and perform trade-off analysis. It can also filter a large number of designs and present them to the designer in rank order using a variety of criteria.

PLANS:

(1) Synthesize and fabricate via MOSIS the optimum set of MicroSparc CPU dies using area array pads as determined by our newly developed Design-For-Packageability (DFP) tool.
(2) Develop an automated means of coordinating IC and MCM physical design to achieve a global optimum.
(3) Design and fabricate several MCMs via MIDAS.
(4) Utilize our Design-For-Packageability (DFP) tool to consider other CPU and cache scenarious which affect machine architecture and hence performance, power, cost, etc.
(5) Extend the capabilities of the DFP tool to permit partitioning at the behaviorial and structural levels, thereby calibrating the results obtained at the functional level.
(6) Empower system designers with these system design space exploration tools via short courses and software releases.

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dbouldin@utk.edu