SPRINTCAD QUARTERLY SUMMARY
July 1 - September 30, 1995
ORGANIZATION:
Stanford University
SUBCONTRACTORS:
none
PRINCIPAL INVESTIGATORS:
Robert W. Dutton, dutton@gloworm.Stanford.EDU, (650) 723-4138
Kincho H. Law, law@cive.Stanford.EDU, (650) 725-3154
Krishna Sa
raswat, saraswat@ee.Stanford.EDU, (650) 725-3610
Peter Pinsky, pinsky@ce.Stanford.EDU
PROJECT LEADER
Edwin C. Kan,
kan@gloworm.Stanford.EDU, (415) 723-9796
TITLE OF EFFORT:
"SPRINT-CAD"---Industry-Networked TCAD using Shared Parallel Computers
RELATED INFORMATION:
The URL for Stanford TCAD projects is:
http://www-tcad.stanford.edu
OBJECTIVE:
First-time capabilities to bridge solid modeling, FEM-based
parallel computation of fabrication processes and electrical analysis
of the resulting IC structures will be developed. Models needed to
represent diffusion, etching, deposition, oxidation and stress analysis
resulting from a sequence of process steps necessary in the creation
of electrical devices will be developed. This effort will provide a
radically new HPC framework for technology-based 3D process/device
modeling as well as realistic benchmarks to test HPC architectures
and software.
APPROACH:
We will build, integrate and test TCAD modules based on an
object-oriented approach that both develops and uses information
models in support of CFI-based standards. The modules and software
engineering methodology will be designed specifically to exploit
parallel computers and library components. The 3D process simulation
modules will utilize HPC platforms and provide new functional
capabilities for "computational prototyping" of the following key
technology fabrication steps:
- deposition/etching module---of special interest are CVD and plasma
assisted processes that result in high aspect ratio structures such as
trenches and filling/planarization of structures for metal
interconnects. Algorithmic work focuses on geometric manipulations and
surface evolution.
- thermal/stress analysis module---that can solve nonlinear
constitutive models for key process steps involving growth of
dielectric layers and impurity redistribution as well as the resulting
stress fields. Advanced formulations for finite elements are being
developed that support: parallel computation, adaptive gridding and
domain decomposition.
PROGRESS:
The 3D geometry/field server will be built based on the
minimal SWR specification,
which can be obtained from the
TCAD group home page
http://www-tcad.stanford.edu/news.html. The applicational
procedural interface (API) of the minimalistic SWR server has
been carefully examined for the 3D situation. Although the API
needs virtually no change for integrating 3D applications, the
moving boundary and validation of the boundary representation
of geometry can not be easily extended from the methods adopted
by FOREST 2D server. These functionalities will be replaced
by the level-set function approach, with the boundary representation
and the parametric representation of the geometry reconstructed
and interchanged at each step. Although this implementation is
much more computationally expensive, it is robust since no topological
check is necessary and it can preserve the accuracy of the surface
moving velocity calculation. After the boundary representation is
obtained, the 3D static volume and surface grid will be provided by
oct-tree based mesher CAMINO.
The quad/Oct-tree adaptive grid has been implemented with level-set
(collision-free) boundary movement to improve computational and memory
efficiency. It has presently been connected with
SPEEDIE,
the physical
etch/deposition simulator within the SprintCAD modules. One of the
major difficulties of the level-set boundary movement is depletion of
materials through multiple interfaces. We have demonstrated the
multi-region etching examples such as vias, contact holes and
self-aligned contacts to validate the software.
For 3D TCAD problems, a suite of iterative solvers and
preconditioners are necessary for reasonable execution time.
The PETSc from GNU General Public Software has a comprehensive
collection of iterative solvers and preconditioners, and will
provide parallel processing capabilities based on MPI in the
future release. Although for domain decomposition partition
data distribution and integration may need to be reorganized,
PETSc will provide a good starting point for initial efforts
on parallelization of
ALAMODE.
Implementation of visco-elastic-thermal oxidation modeling using
finite deformation and level-set function kinematics has been
started in the ALAMODE environment. New operators and integration
schemes are under construction. The geometry/field server interface
needs to be enhanced to accept boundary movement information and feeback
on time steps. A posteriori error estimator
for diffusion and recombination operator has also started implementation
in ALAMODE. Error estimation for boundary movement using level-set
functions is under study.
To accommodate the computational requirements by the Sprint-CAD
tools and by another ARPA project, Computational Prototyping for
21st Century Semiconductor Devices, the
IBM SP1 system has been upgraded to 9076 SP with 16 nodes.
Since IBM stopped supporting SP1 load handler, this upgrade
can also provide more reliable benchmark for parallel algorithms.
RECENT ACCOMPLISHMENTS:
- The 3D geometry/field server will be built based on the minimal SWR
specification. The boundary movement and geometry validation will be
performed using the level-set function method. The 3D static volume
and surface grid will be provided by CAMINO.
- Quad/Oct-tree adaptive grid has been implemented in the
SPEEDIE simulator with level-set (collision-free) boundary movement
to improve computational and memory efficiency. Multi-region etching
examples such as vias, contact holes and self-aligned contacts have
been demonstrated preserving physical accuracy.
- SUPREM-ALAMODE has connected with PETSc from GNU General Public
License. A variety of direct sparse solvers and iterative solvers
are now available for ALAMODE.
- Implementation of visco-elastic-thermal oxidation modeling using
finite deformation and level-set function kinematics has been
started in the ALAMODE environment. A posteriori error estimator
for diffusion and recombination operator has also started implementation
in ALAMODE.
- The IBM SP1 system has been upgraded to 9076 SP with 16 nodes.
FY-`96 PLANS:
- Test 3D Thermal Module and integration of parallel
solver technology.
- Implementation of 3D Oxidation within Thermal Module
and transition into unified capabilities (both diffusion
and oxidation).
- Implementation of complete server for 3D Deposition/Etching
Module, including 3D parallel solver to support flux calculations.
- Benchmark the overall SPRINT-CAD modules in terms of a deep
submicron MOS technology. The Thermal Module will demonstrate 3D
analysis of locally oxidized isolation and shallow junction diffusion
steps. The Deposition/Etching Module will demonstrate first-time
functionality of a 3D server-based architecture and implementation.
TECHNOLOGY TRANSITION:
Modeling philosophy and benchmark of the SUPREM OO7 framework and
SUPREM ALAMODE PDE solver have been presented in the Advanced TCAD Simulation
Platforms Workshop organized by SEMATECH on Aug. 29-31, 1995 in Santa Clara,
CA. Participants includes National Labs, Sematech Tab members, Industrial
users and TCAD developers. We have presented how the Object-Oriented
technology can improve software quality and reliability without speed
penalty. The programming methodology and philosophy have been discussed
in detail and are well received.
The main developer of SUPREM-ALAMODE solver architecture had
worked in Intel for summer intern. The dial-an-operator design
and server-based geometry/field environment of the ALAMODE
implementation have been regarded as great potentials toward
building Intel's next-generation TCAD tools. Option 3 of the
PARASCOPE ARPA project, the follow-on for SprintCAD, has been
started for the first quarter of FY96. The PROPHET process simulation
tool from ATT will be integrated into the SUPREM-OO7 server-based
environment and released to other TCAD users.
Edwin C. Kan
kan@gloworm.stanford.edu
201 AEL, Stanford University, Stanford, CA 94305
Office: (415)723-9796
Fax: (415)725-7731
Date prepared: 10/28/95