Книги2 / 1993 P._Lloyd,__C._C._McAndrew,__M._J._McLennan,__S._N
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Appendix: The Simulator Library
Silvaco's process and device simulators can be classified into four groups: a 2-D process simulation system called ATHENA; a 2-D device simulation system called ATLAS; a 3-D device simulation system called THUNDER; and 'Other Tools' (see Figure AI). The industrial use of S-TCAD focuses on 2-D process and device simulation using ATHENA and ATLAS. These systems are designed to make full use of the capabilities provided by The MASTER Framework.
The Simulator Library
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ATHENA |
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ATLAS |
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Process Simulation |
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Device Simulation |
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OPTOLITH |
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SPISCES |
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BLAZE |
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ELITE |
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GIGA |
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SSUPREM4 |
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LUMINOUS |
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SILICIDE |
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TFT |
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PREDICT2 |
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MIXEDMODE |
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THUNDER |
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OTHER TOOLS |
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Device Simulation |
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DEVICE3D |
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INTERCONNECT3D |
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FLASH |
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THERMAL3D |
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Device Simulation |
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S-MINIMOS |
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Figure A1.
Al.l. The ATHENA 2-D Process Simulation System
ATHENA is a framework based system for 2-D process simulation. It integrates a set of process simulation tools that provide comprehensive capabilities for 2-D process simulation. The individual tools are OPTOLITH, ELITE, and SSUPREM4.
OPTOLITH is a 2-D lithography simulator. It simulates aerial image formation and photoresist exposure and development. OPTOLITH is available in two versions, one planar and one nonplanar. ELITE is a general purpose 2-D topography simulator that simulates a wide range of deposition and etch processes used in modern IC technologies. These processes include dry
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etching, wet etching, APCVD, LPCVD, ion milling, metalization and reflow. SSUPREM4 incorporates a range of advanced physical models for diffusion, implantation, and oxidation. SILICIDE is an add-on module for SSUPREM4 that provides unique capabilities for modeling silicide
A1.2. The ATLAS 2-D Device Simulation System
ATLAS is a framework based system for 2-D device simulation. The ATLAS framework can contain either or both of two primary device simulators, SPISCES and BLAZE, and any combination of four products, GIGA, LUMINOUS, TFf and MIXEDMODE that work in conjunction with either SPISCES or BLAZE.
SPISCES simulates structures encountered in silicon technologies. It maintains backwards compatibility with earlier stand-alone versions of SPISCES. BLAZE handles arbitrary semiconductors, and graded and abrupt heterojunctions. GIGA adds the ability to simulate lattice heating and heatsinks. LUMINOUS adds optoelectronic interactions and very sophisticated ray tracing. TFT adds the features required to simulate devices based on charge conduction in polycystalline and amorphous materials. MIXEDMODE is a circuit simulator that allows numerically-simulated ATLAS devices to be used instead of conventional circuit models for some devices.
A1.3. The THUNDER 3-D Device Simulation System
THUNDER is a framework based system for 3-D device simulation. The THUNDER framework is populated by any combination of three products, DEVICE3D, INTERCONNECT3D, and THERMAL3D. DEVICE3D provides capabilities for the full bipolar simulation of silicon devices. INTERCONNECT3D calculates the capacitances and resistances associated with interconnect structures. THERMAL3D calculates the temperature distribution in 3D thermal environments that can include regions of semiconductor, insulator and heatsink, with user-defined thermal sources in specified regions.
Al.4. Other Tools
The other simulators offered by Silvaco are two I-D process simulators, SSUPREM3 and FLASH, and a 2-D device simulator, S-MINIMOS.
SSUPREM3 is a mature, well-calibrated tool for simulating ion implantation, oxidation and diffusion in silicon structures. FLASH is a process simulator for general materials. It has sophisticated models for ion implantation, and incorporates a dial-an-operator mechanism that is very convenient for developing sophisticated kinteic diffusion-reaction models.
S-MINIMOS is an enhanced version of MINIMOS 4.0, which was developed at the Technical University of Vienna. S-MINIMOS is integrated with
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DeckBuild and TonyPlot for stand-alone operation. More importantly, it is very tightly integrated into the VIrtual Wafer Fab. It can therefore play an important role in simulation-based design and experimentation of MOS based technologies.
TECHNOLOGY CAD SYSTEMS |
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Edited by F. Fasching, S. Halama, S. Se1berherr - |
September 1993 |
CAESAR: The Virtual IC Factory as an Integrated TCAD User Environment
V. Axelrad, Y. Granik, and R. Jewell
Technology Modeling Associates, 3950 Fabian Way, Palo Alto, CA 94303, USA
Abstract
TMA's Virtual IC Factory (CAESAR) is seen as a new enabling technology. CAESAR provides a higher level of user-system interaction than previously possible, especially effective in managing large-scale simulated experiments. CAESAR offers a hierarchic approach to specifying a simulation flow. Its open architecture design allows the utilization of heterogeneous simulators, standard or user-defined post-processing tools and extractors. CAESAR supports large-scale simulations by creating and managing intermediate simulation results. This includes automatic and transparent maintenance of data dependencies, incremental simulation support and visual access to simulation results via icons representing wafer data.
Rather than an incremental improvement over previously chosen approaches, CAESAR represents a qualitatively different complete environment to use TCAD with benefits for both the novice and the experienced so-called "power user". The novice user benefits from the ease-of-use and encapsulation features of the system, allowing to conceal complex physics, numerics, simulator syntax and data interfacing details in pre-tested library modules. The experienced user can concentrate on the engineering goal of the simulation study and run large simulated splits without worrying about massive amounts of simulator input files, data files and complex dependencies between them.
Several major semiconductor companies have been involved in the specifications for CAESAR and its daily development. This assures the practical relevance of the tool, its robustness and suitability to fulfill real engineering needs.
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Synopsis
1.Introduction
2.CAESAR: Scope of the Tool
3.Hierarchy of the Process Recipe
4.Wafer Flow as a Result. of the Simulation Flow
5.Running Splits, Incremental Simulation, Data Management
6.The Run-Sheet Interface
7.Visualization with Michelangelo and STUDIO Viz
8.Post-Processing and Extraction of Results
9.Summary
L Introduction
Traditionally, Technology Computer-Aided Design CTCAD) has been centered around complex numerical simulation tools. These tools are highly sophisticated with respect to the physical phenomena being described and the numerical methods used to this purpose. Consequently, the use of such simulation tools requires a high level of user expertise and experience. Characteristic to applications of TCAD tools was thus the use of input languages to control the complex multitude of physical models and numerical methods available to the user. Since the main emphasis of development work in TCAD was on the simulators themseleves, tool integration was weak. Inter-tool communication as well as storage and maintenance of simulation results required a significant amount of user involvement and responsibility. This approach was indeed justified at the time, as it offered maximum flexibility for the user and did not impede experimentation with numerical methods and physical models.
As process and device simulation is moving out of predominantly research and development environments into more production-oriented engineering groups, the way engineers use TCAD is changing rapidly. Cost pressures from semiconductor manufacturing dictate the use of simulation as an at least partial replacement for actual fab experiments - split runs. Instead of single process steps and/or device simulation problems, the semiconductor engineer needs to model an entire process flow as well as subsequent electrical test procedures for a set of control parameter values, resulting in massive amounts of inter-dependent individual simulations and data. Use of previously developed process/device simulation modules becomes mandatory, requiring support of process module libraries and electrical test procedure libraries for use within an organization across its R&D and manufacturing departments. All this necessitates an unprecedented level of tool integration as well as automated data handling and storage.
With process and device simulation tools rapidly advancing towards maturity, it became feasible to satisfy the needs of both the traditional R&D-oriented TCAD users and newer requirements of manufacturing engineers. The new integrated user environment CAESAR models the relevant aspects of a real semiconductor factory in a tightly integrated and highly intuitive graphical tool set.
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Figure 1. Full View of CAESAR main window, module and step editors and the Work Sheet Dialog.
2.CAESAR: Scope of the Tool
The basic idea behind the virtual factory concept such as CAESAR's is to emulate the workings of an actual semiconductor fab as closely as possible and necessary. The goal is to obtain relevant data such as electrical product performance, processing time, cost, etc. under varying processing conditions. As a result the number of actual physical experiments can be reduced, resulting in drastic cost savings and improved time-to-market. The "classical" TCAD part of this task is process and device simulation, which is currently the scope of CAESAR:
