SPRINTCAD QUARTERLY SUMMARY
April 1 - June 30, 1995
ORGANIZATION:
Stanford University
SUB-CONTRACTORS:
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:
Most of Sprint-CAD research directions have made good
progress within the last quarter, and there are major breakthroughs
on the diffusion and etching/deposition modules. These are summarized
below.
The dial-an-operator finite-element program
ALAMODE
has been successfully implemented for 1-2-3D test problems such as boron
segregation (benchmarked with SUPREM IV) and
five-species kinetic phosphorus diffusion
(benchmarked with PEPPER). Demonstration
examples include 1D and 2D SUPREM mesh and 3D FLOOPS mesh. Diffusion
in poly-silicon by considering the average grain boundary
growth/recombination is under intensive study. This will demonstrate
first-time capabilities in consistent modeling of both front-end and
back-end processes. The layered access to model definition and
program control have been implemented using the tcl scripting language.
The 2D and 3D
SPEEDIE
for physical etching/deposition simulation
has been implemented with a collision-free boundary movement method
based on the level-set function approach. The boundary merge and
cutoff can be simulated in a physical manner. Examples of 2D
overhang structure with PECVD and 3D stringer problems on nonplanar
surfaces have been successfully simulated. This approach is a
first-time demonstration of the 3D geometry/field server that can
be used for accurate physical etching/deposition simulation.
The FOREST 2D geometry/field server now fully supports the minimal
SWR specification and has been under testing to be used by the
newly developed modules (ALAMODE and SPEEDIE) in the procedural
level. The CAMINO 3D geometry/field server can now provide most
of the functions in the minimal SWR specification, but in lack
of the geometry fixing capabilities. An active study of using
the collision free method for 3D geometry fixing is under way.
All of the tools developed have been aiming at the open architecture
of SUPREM OO7, which will contain true plug-and-play capabilities
for all physical simulation modules, geometry/field servers,
graphical visualizers and user control.
The new finite-deformation oxidation model has been demonstrated
for asymptotic elastic and viscous cases. Consideration on thermal
constitution relations and deformation kinematics has been added
to the formulation. The boundary movement will be treated by
the collision-free method summarized above. A quasi-3D
modeling of the LOCOS isolation structure has been developed
based on 2D simulation and physical manipulation of geometry
in the third dimension. This approach has been calibrated with the
experimental results.
RECENT ACCOMPLISHMENTS:
- The minimal SWR specification is accepted for publication and
is available by (ftp).
- The 2D geometry and field server FOREST, which fully support the
minimal SWR specification, is ready for beta release.
- SUPREM-ALAMODE (the dial-an-operator PDE solver) has demonstrated
3D capabilities on contact hole boron diffusion. Currently it
can use geometry and field information from FOREST, SUPREM and
FLOOPS. Dimensionality independence of operators has been demonstrated.
- The physical etching and deposition simulator SPEEDIE has demonstrated
use of the collision-free boundary movement method for both 2D and 3D.
- The new oxidation constitutive model based on finite-deformation
has been successfully demonstrated on asymptotic elastic and viscous
cases. The quasi-3D oxidation modeling for the LOCOS structure
has been calibrated with experimental results.
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:
The proposed minimal SWR specification, which
is fully supported by the FOREST geometry and field server, is released
for beta test at IBM, ATT and Intel. This is not only a release
of ONE OF the proposed standards, but also a fully functional server
supporting the standard, so that the specification is ready for
practical testing purposes. The SUPREM-ALAMODE code has been used
in other Stanford groups as well as in Intel, where one of the
key developers of the dial-an-operator module has been working as
a summer intern. Various defect-related dopant transport effects,
such as the transient enhanced diffusion, have been vigorously
studied using the flexible physical definition and multi-dimension
capability in ALAMODE. At Intel, it will also be tested on heat
conduction during device operation as an entirely different type
of application owing to ALAMODE's tremendous flexibility. The advance
in etching/deposition boundary movement will be included in the future
SPEEDIE release.
Edwin C. Kan
kan@gloworm.stanford.edu
201 AEL, Stanford University, Stanford, CA 94305
Office: (415)723-9796
Fax: (415)725-7731
Date prepared: 7/27/95
