SPRINTCAD QUARTERLY SUMMARY

ORGANIZATION:

SUBCONTRACTORS:

PRINCIPAL INVESTIGATORS:

PROJECT LEADER

TITLE OF EFFORT:

RELATED INFORMATION:

OBJECTIVE:

APPROACH:

1. 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.
2. 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:

A new constitutive model for oxidation that considers finite deformation as well as visco-elasticity has been derived. The finite element formulation is thermodynamically consistent and numerically stable. This constitutive model has been tested in the FEAP (finite element analysis program) environment and the elastic and viscous behaviors in the asymptotic limit have been verified for correctness and stability.

An object-oriented information model has been implemented to support FEM formulation and solution of general systems of PDEs. Abstract classes of field element integration and interpolation, operators for field-dependent constitutive models, recombination models, and diffusion, direct and iterative sparse linear solvers and flexible time-stepping schemes have been implemented and validated with a Poisson solver and several 2D nonlinear diffusion examples including segregation effects. Hooks to Suprem IV structure files have been provided for both validation and benchmarking purposes.

Physical modeling of etching/deposition based on Hamilton-Jacobi equations has been demonstrated in 2D SPEEDIE. The surface evolution based on the string model has been connected to the server-based SUPREM OO7 architecture. A minimal SWR specification for the surface mesh server has been defined from our experience with an integrated example containing all process modeling steps. 2D Modeling of anisotropic etch for deep trench technology has been successfully demonstrated. Calibration with SEM measurements has been performed to determine various parameters (such as sticking coefficients). 3D SPEEDIE implementation and demonstration examples have been examined.

RECENT ACCOMPLISHMENTS:

• Quasi-3D modeling for SRAM devices and oxidation has been prototyped.
• The SUPREM OO7 heterogeneous tool integration environment has been demonstrated with the minimal SWR specification with FOREST as the geometry and field servers.
• The 3D meshing program CAMINO has demonstrated anisotropic gridding capabilities. The algorithm will be presented in SISDEP 95.
• The new oxidation constitutive model based on finite-deformation has been successfully demonstrated on asymptotic elastic and viscous cases.
• The dial-an-operator finite-element program has been successfully implemented for 2D static and transient problems. This module has been added to the OO7 environment.
• The etch/depo tool SPEEDIE has been used for modeling deep trench technology and add to the OO7 environment.

FY-`95 PLANS:

• Solid modeling functionality will be improved to support integration across tools for both 2D and 3D---manipulation of SUPREM (2D) data in the 3D information model will be demonstrated.
• The 2D implementation of the Dial-an-Operator code will be completed, interfaced to FOREST and a 3D field server, and benchmarked against existing impurity redistribution models in Suprem IV and PEPPER. The combined 2D/3D version will be parallelized based on static domain decomposition.
• The new constitutive oxidation model will use the finite element representation in dial-an-operator and hence the integration and parallelization efforts can be minimized.
• A 3D extension for SPEEDIE will be implemented with a selected 3D surface mesh server. Efficient methods for parallelization will be investigated and implemented.

TECHNOLOGY TRANSITION:

The object-oriented PDE solver has direct relevance in creating a new module for process simulation that can be linked into the SUPREM OO7 architecture being developed under partial support from SRC. This architecture and the incorporation of other existing 2D tools such as SUPREM and SPEEDIE has been demonstrated at the International Electron Devices Meeting (IEDM) as discussed below. This demonstration and through industrial interactions in preparation for an SRC industrial review to be held in February, 1995 the path for technology transition for the Dial-an-Operator module will be discussed.

SIGNIFICANT EVENTS:

STANFORD DEMONSTRATES NEW SERVER-BASED ARCHITECTURE FOR SUPREM.

At the International Electron Devices Meeting (IEDM) held in San Francisco during December, 1994 the Stanford SPRINT-CAD group demonstrated the first prototype version of the Dial-an-Operator module working in the context of a new architecture for the well-known SUPREM process simulation tool. The agent-based process simulation environment, now called OO7 to reflect the object-oriented approach, supports a heterogeneous integration of tools. Shown at the demonstration was inter-operability between the established SUPREM 4GS and SPEEDIE tools along with the Dial-an-Operator module being developed under the SPRINT-CAD project. In addition to the use of tool agents for control, the demonstration included the use of FOREST as an integrated server to support both geometry and gridding operations in support of OO7.

Date prepared: 1/27/95