The 1995 Software Release Features Strengthened and Expanded Virtual Wafer Fab

A fourth VWF integration layer has been added to the previous three VWF layer structure, as indicated in the diagram. This new layer is called the Production Tools. Architecturally, it is the outer most layer, enveloping the Automation Tools. The Production Tools allow remote usage of the Response Surface Models (RSM) generated by the Automation Tools. The Production Tools may be run on either a UNIX workstation or a PC running MS WINDOWS. Calibrated RSM's, generated by the VWF Automation tools may be used for a variety of applications by engineers in the manufacturing and design areas. The goal is to bring processing technology issues closer to both design and to manufacturing. Studies of SPICE model parameters trading off against technological and layout variations can be performed in an interactive environment.


The Production Tools consist of the following modules:

  • Yield Analysis - study the effects of process variations directly on final yield distribution
  • Failure Analysis - Study the most likely cause of parametric failures
  • Model Calibration - Allow the fitting of simulated data to measured data in an automated environment
  • Process Synthesis - Interactive technological parameter analysis

New ATHENA Features

  • New Implant Moments Control - Ion Implantation moments may now be user specified allowing improved calibration facilities of implanted profiles
  • Wet and Dry point defect parameters - Point defect parameters may be specified separately for both wet and dry oxidizing ambients
  • 4 new materials AlGaAs, InGaAs, SiGe and InP, have been added to the data structures of Flash. Graded composition fractions of compound materials allow linearly graded layers of materials to be deposited
  • Adaptive meshing allows a grid to be refined automatically as a function of advancing diffusion front or during ion implantation
  • Oxidation is now available as part of the new physical two stream polysilicon diffusion model
  • Enhanced triple point oxidation control
  • Parameters controlling the details of an oxidation profile at a 'triple point' have been added allowing more user control. This further enhances the SALICIDE capabilities, allowing correct salicide birds beak profile simulation
  • Silicidation has been enhanced with extra dissolution control parameters
  • Secondary recoil has been included for use within Monte Carlo Ion implantation. Dynamic amorphisation has been added as part of Monte Carlo ion implantation
  • A damage threshold parameter may now be specified for use with ion implantation damage models
  • The C-interpreter capability has been added for use with Athena. Users may now access both diffusion, activation and segregation models
  • Chemical and Divergence parameters have been added to the RIE model within ELITE
  • Chemical Mechanical Polishing models have been added. A hard and a soft pad models now allow the simulation of this important new planarisation process
  • Optical lithography may now be performed using annular sources


New ATLAS Features

  • Six Equation Solver - allows fully coupled solutions for potential, electron and hole concentrations, electron and hole temperatures, and lattice temperature. Users may arbitrarily choose which subset of equations is used
  • DEVICE3D - ATLAS based 3D device simulation for silicon MOS and bipolar. Syntactically and behaviorally analogous with ATLAS based SPISCES. Can be used for simulation of SEU, narrow channel effects, latchup etc
  • THERMAL3D - ATLAS based 3D thermal simulation for arbitrary packaging structures. Quickly calculates temperature distribution on arbitrary structure with user defined heat sources and sinks
  • INTERCONNECT3D - ATLAS based 3D interconnect simulation for extraction of interconnect parasitics. Features an interface to IC layout, including GDSII format. Outputs a SPICE sub-circuit
  • Curve Tracer - Automatic curve tracing based on dynamic load line techniques. Automatically chooses direction and size of steps to trace out complex "IV" characteristics such as single and double snapback
  • Enhanced Energy Balance Model - Fermi statistics, GaAs-like mobility model, energy dependent relaxation times, static projection for carrier temperatures
  • GIGA enhancements - static projection for initial guesses, self consistent coupled solutions with carrier temperatures
  • LUMINOUS enhancements - spatial response extraction, minimum power specification to limit number of rays, understands optical characteristics of metal regions, time dependence put into general photogeneration C interpreter function
  • TFT enhancements - user specifiable number of discrete mid-gap states, output of trap state densities versus energy, C interpreter functions for state densities versus energy
  • Improved numerical methods - Gummel, Block and Newton, more intuitive CLIMIT parameters
  • Improved syntax - SYMBOLIC statement no longer necessary, automatic SOLVE INIT, better default behavior, improved syntax for specifying which equations are solved
  • Improved handling of touching electrodes/metal regions and electrodes with the same name. Handles run-time output and log file output as though a single electrode
  • New trap assisted tunneling model - based on Hurkx et. al., accounts for tunneling via trap transitions using an analytic approximation that modifies the lifetimes in the standard SRH model
  • Improved models for EPROMs - uses potential gradients in insulators to determine which electrodes collect hot carriers and tunneling currents
  • Improved run-time output - multiple levels of verbosity, more consistent error messages, better printing of mesh, region and electrode summaries,improvements in the output from MODELS PRINT
  • New examples - 117 examples divided into 21 applications areas


Interactive Tools


  • New statistic plots include histograms, pie charts, lines graphs and star plots
  • X11 Font Support - The on screen and printed presentation of TonyPlot plots is now much clearer using X11 scalable fonts
  • Read compressed or zipped files - This enables TonyPlot user to gzip or compress plot structures to save disk space, some time is taken to decompress the files when loading
  • Spot height labeling on 2D plots - press a key at any location in a 2D contour plot to add automatic spot height labels to the plot
  • Improved axis control - including mirroring, labeling, tick subdivisions and more


  • Utmost support - Ability to run Utmost in batch mode and select the required technology. This allows the generation of optimized SPICE Models
  • Optolith support - Eight new popups have been created to support the Optolith syntax under the ATHENA commands menu
  • Sensitivity analysis - DeckBuild can now support limited sensitivity analysis from within the Optimizer option
  • Much improved mask handling - Mask bias, misalignment and delta CD information may now be entered in the MASK statement to study these effects
  • Better run-time control of running simulator - The "stop now" feature allows the currently executing simulation to be halted without killing or quitting the simulator
  • Batch mode on non-X displays - DeckBuild may now be run in a non-X environment while in batch mode. This enables batch jobs to be executed remotely on non X displays or while a user is logged off
  • Many more command line options - The command line options have been expanded to include new features such as Non-X mode and selecting a simulator version
  • Environment variable substitution - If a local variable is not found for a substitution the DeckBuild will now search for an Environment variable which matches


Parameter Extraction

  • S parameter and H parameters - Adds the capability to extract the real and imaginary parts of S and H parameters from log files
  • Junction capacitance - This will calculate the junction capacitance of a specified P/N junction with any region as a function of applied bias to that region
  • Junction breakdown - Using the Selberherr impact ionization model this will calculate the electron or hole ionization integral of any region as a function of the applied bias to that region
  • User defined voltage range for 1D Vt extractions - This allows specification of the bias range used for the gate voltage sweep and substrate bias
  • 2D Max and Min concentration - The peak or minimum concentration of any dopant or solution quantity may now be extracted for a whole 2D structure or for a specified area of the structure. The actual coordinates of the maximum or minimum values may also be retrieved
  • Improved curve extractions - This allows multiple instances of the same value to be found along on IV curve
  • Variable substitution - Variable substitution may now be used for numeric values in extract statements
  • QUICKBIP tuning parameters - This enables the QUICKBIP 1D device simulator tuning parameters to be set as required on the command line


  • High accuracy cutlines - this enables mask cutlines to be defined with great accuracy even when the layout section loaded is large
  • Improved GDSII support - MaskViews now supports full GDSII - level 6 including hierarchy and rotation within the GDSII structure
  • Support for unnamed electrodes - MaskViews now has more intelligence when exporting cutlines and can thus warn of possible problems when used in subsequent simulations


  • Join Structure - This allows two structures to be together according to user preferences
  • Stretch Structures - Allows a structure to be stretched based on a cutline or area to use as the stretch information
  • Localized mesh control in semiconductor - Meshing can be controlled within rectangular local regions of any semiconductor
  • Change region attributes without remesh - It is now possible to alter all region attributes without remeshing the structure
  • Ability to abort more user requests - Many of DevEdit's tasks such can now be aborted at the users request
  • Improved handling of regions with complex geometrics - Regions with complex shapes are now handled efficiently within DevEdit


TonyPlot 3D

  • All new product for interactive 3D visualization
  • Interactive real-time scaling, rotation and translation
  • Numerous visualization techniques, including materials, region separation, contours, 3d vector fields, isolines and isosurfaces
  • Arbitrary cutting and slicing planes, positioned interactively with the mouse and pointer
  • Full support of all major graphics accelerator hardware


Production Tools

  • Calibration
  • Yield analysis
  • Failure Analysis
  • Interactive Spice Model parameter analysis


Automation Tools

VWF Visualizer

  • Utmost integration - The VWF Visualizer is now capable of seamlessly taking the VWF concept out of the TCAD domain and into characterization. The Visualizer can join together several sets of device test output thus providing the required input to the characterization stage. Support is also provided for storage of Utmost library elements within the VWF split fragment library
  • Support for Production Tools - The Visualizer can provide raw data points, RSM models and supporting information to the VWF Production Tools
  • Ability to add new splits as required - The Visualizer's split editor has been greatly enhanced. It is now possible to add extra split variables to an existing experiment
  • Ability to edit split fragments - It is now possible to edit split fragments individually and via the library object. This facility provides great flexibility in designing the experiment as subtle differences in flow can be introduced into each branch as required
  • User data import - user data can now be imported from file. This will allow the user a practical route to performing calibration to measured data
  • Directory creation allowed most places - The Visualizer's previously rigid directory structure has been relaxed somewhat allowing directories to be created in most locations
  • D-optimal designs - A D-optimal filter has been added which allows an optimum subset for RSM models to be selected from a larger number of experimental runs



  • Lower CPU usage - NetView internals have been improved greatly, reducing the CPU requirement of this tool by a considerable amount
  • Flexible timeout system - Machines can now set a time out internal based on 15 minute increments. This provides more control over the machine resources that will be used to run VWF jobs
  • Ability to view more jobs - The VWF job queue window can now be expanded to allow more of the queued, running or allocated jobs to be viewed



  • Utmost Support - The VWF netmanager is now able to capture and store a variety of Utmost specific data set from a simmgr in the VWF
  • lFast Netmgr - Simmgr Communications - The communication link between the simulation runtime agent (simmgr) and the database storage agent (netmgr) has been drastically improved. This should reduce job crashes and maximize throughput of information to and from the VWF database.



  • Utmost support - The Simmgr now has the ability to run Utmost in batch mode and automatically load the log files created from previous Atlas tests
  • S Parameter files saved to database - Log files converted into S parameter format using the Atlas Utmost statement are now saved to the database for later extraction when executing an Utmost test
  • Remote Pause (For Backups) - When a pause message is sent by the administration program, VWF Admin, all Simmgrs will now pause the current process to enable safe backup to be executed with no simulations accessing the database
  • Improved Extract Support - Support for new extract features including continuation lines for extract syntax