IC Interconnect Modeling

1
IC Interconnect Modeling Dr. Paul Van Halen
http//www.ece.pdx.edu/vanhalen

• PROBLEM
• Resistive, capacitive and inductive effects in
  circuit interconnect impose constraints on
  mixed-signal system performance.
• RLC effects in the interconnect cause signal
  coupling and result in signal integrity
  degradation.
• Increasing transistor frequency response can
  result in in-band resonant frequencies due to
  LC interconnect parasitics, which in turn can
  produce undesirable underdamped behavior
  (ringing) and system instability (oscillations).
• Resistive effects cause ohmic drops in the
  interconnect which can affect system accuracy and
  performance.
• Resistive effects also can lead to
  electro-migration and premature field failure.
• GOAL
• Provide circuit designers with accurate RLC
  extraction, modeling and simulation tools,
  enabling them to mitigate the impact of
  interconnect on circuit performance.
• CHALLENGES
• Tools currently available lack accuracy,
  performance. There is no common user interface
  and the absence of a common data format
  necessitates the use of cumbersome glue scripts.

• Data management the amount of data is huge.
  Typically a circuit with fewer than 100,000
  transistors will produce an equivalent resistive
  interconnect network with 5,000,000 to 10,000,000
  resistors.
• To gauge the impact of the interconnect
  parasitics we need to be able to simulate these
  very large systems.
• Use hierarchical or windowing techniques to
  extract parasitic information.
• STATUS
• Use open source tools to provide a common user
  interface and data management
• PostgresQL database for interconnect data and
  simulation results.
• Eclipse for development and deployment of an
  integrated user interface.
• In cooperation with Tektronix (sabbatical
  2004-2005), tools for the management and
  visualization of ohmic drop and electro-migration
  effect in ICs were developed.
• Figures show how circuit bias, layout
  information and parasitic extraction data are
  used to simulate and visualize the ohmic drops in
  one of the voltage supply nets of an integrated
  circuit.

Professor Van Halens research interests are in
the general areas of device physics, modeling and
characterization and how the models impact the
design and simulation of analog ICs. More
recently our interests have shifted towards
system level modeling and simulation. This shift
has been driven by the growing interest in
convergence product mixed-signal ASICs, where
analog interface circuitry is integrated with
high-speed digital signal processing and control
systems in the same IC. Mixed-signal ASICs are
now the fastest growing market segment in most
electronic areas. Personal Communications Systems
are but one of a series of new products which
signal a convergence of technologies and
disciplines communications, computing and audio
and video signal processing. Complex high speed
mixed mode systems need a fast and flexible
evaluation of concepts and feasibility. Taking
advantage of the flexibility and expandability of
Tektronix Analog Design System simulation
platform, circuit simulation, and
measurement. The group of Prof. Van Halen is
currently working on functional simulation models
of nonlinear dynamic systems phase-locked loops,
Sigma-Delta and other digital modulation schemes.
These functional models are characterized through
parameter extraction from transistor level
simulation and data acquired from measurements,
and interfaces with traditional transistor models
in critical areas, allow for accurate and fast
system simulation of large mixed mode systems.

• Selected Publications
• A. Sunardi, G. Boyle, B. Biehl, P. Van Halen,
  "A Novel Approach for Evaluating Electromigration
  Effects in Large Analog Integrated Circuits or
  Reducing the Field Failure Rate of IC's,"
  Tektronix Symposium, 2005.
• B. Willoughby, Y. Fu, P. Van Halen, "Design of
  a Behavioral, SPICE-Compatible Charge-Pump Phase
  Detector Simulation Model," IEEE Transactions on
  Circuits and Systems, 2005.
• P. Van Halen, G. Boyle, "A Noise Source for
  Transient Nonlinear System Simulation," IEEE
  Transactions on Circuits and Systems, 2005.
• P. Van Halen, "Automated Modeling of Interconnect
  Properties for Current and Future IC Tool
  Development for ASIC Designs," Tektronix
  Technical Report, 2003.
• P. Van Halen, "Development of an Interconnect
  Centric Backplane Data Format and API for High
  Speed ASIC Designs," Tektronix Technical Report,
  2002.