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Sentaurus Interconnect
1. Getting Started

1.1 Overview
1.2 Working With This Module
1.3 File Types
1.4 Linear Solvers
1.5 Starting Sentaurus Interconnect

Objectives

To introduce the features of Sentaurus Interconnect.
To demonstrate how to run Sentaurus Interconnect.

1.1 Overview

Sentaurus Interconnect is an advanced 1D, 2D, and 3D simulator suitable for IC interconnect reliability analysis. It features modern software architecture and state-of-the-art models to address current and future interconnect technologies, and it is capable of mechanical, thermal, and electrical analyses.

Sentaurus Interconnect shares with Sentaurus Process capabilities for process simulation such as etching and deposition, and an interface to Sentaurus Structure Editor. Meshing is performed by default with Sentaurus Mesh. Sentaurus Interconnect also uses the Alagator scripting language that allows you to implement and solve your own nonmechanics partial differential equations.

1.2 Working With This Module

In this module, you are guided through several examples that showcase different modes in which Sentaurus Interconnect can be used.

In the context of these examples, the most widely used Sentaurus Interconnect commands are introduced for creating a model, defining the material properties, setting the boundary conditions, and solving the problems.

This module discusses only keywords and options used in the given examples. As Sentaurus Interconnect shares a common "foundation" with Sentaurus Process, refer to the Sentaurus Process module for more information about meshing, process simulation, Advanced Calibration, and the Alagator scripting language. Refer to the Sentaurus™ Interconnect User Guide.

All the examples are given as packaged Sentaurus Workbench projects. After creating a local copy, the files can be opened with Sentaurus Workbench.

1.3 File Types

The main file types used in Sentaurus Interconnect are:

Command file (*.cmd)
This is the main input file for Sentaurus Interconnect. It contains all the process steps and can be edited. It is referred to as the command file or input file.
Log file (*.log and *.out)
Sentaurus Interconnect generates a .log file when it is run from the command line and an .out file when it is run from Sentaurus Workbench. Both files contain information about each processing step, and the models and values of physical parameters used in it. The amount of information written to the log file is controlled by the info argument, which is available in nearly all commands. The global default information level (0) can be changed with pdbSet InfoDefault <n>. Allowed values of InfoDefault are 0, 1, and 2 with higher values indicating more verbose output. Any value higher than 2 will be interpreted as 2.
TDR boundary file (*_bnd.tdr)
This file stores the boundaries of the structure without the bulk mesh or fields. It can be used as the structure file for the meshing engine Sentaurus Mesh and can be loaded into Sentaurus Visual for viewing. The name of a TDR boundary file can be specified with the tdr argument of the init command of Sentaurus Interconnect, and then the loaded boundary will be meshed.
TDR grid and doping file (*_sis.tdr)
TDR files can be used to split and restart a simulation. Such restart files are saved using the struct tdr=<c> command because restarting requires interface data, parameter and command settings, mesh ordering information, as well as the bulk grid and data. If either !pdb or !interfaces is specified in the struct command, the TDR file will not be suitable for restarting. The TDR file can be loaded into Sentaurus Interconnect using the init command, but the results of the subsequent simulation steps might differ in a simulation with splits and a restart, compared to a simulation of the entire flow in one attempt. TDR files store the following types of information:
- Geometry of the device and the grid.
- Distribution of doping and other datasets in the device.
- The internal structure of the mesh in Sentaurus Interconnect required to restore the simulation mesh to the same state in memory that is present at the time of saving the file. Restart files store coordinates and field values without scaling to prevent round-off errors.
- By default, Sentaurus Interconnect stores all changes to the parameter database made after the initial loading of the database and all commands that create objects later referenced, such as refinement boxes and masks in the TDR file. A TDR file can be either reloaded into Sentaurus Interconnect to continue the simulation or loaded into Sentaurus Visual for viewing.
  The parameter settings stored in a TDR file can be viewed using
  pdbBrowser -nopdb -tdr <tdrfile> (see Sentaurus™ Interconnect User Guide, "Viewing Parameters Stored in TDR Files" for details).
For information about the TDR format, see the Sentaurus™ Data Explorer User Guide.
XGRAPH file (*.plx)
This file saves the 1D distributions of the doping concentration or other fields in a specified 1D cross section. This file can be viewed by loading it into Inspect.

1.4 Linear Solvers

The Parallel Direct Solver (PARDISO) is the default solver for 1D and 2D simulations in Sentaurus Interconnect.

To activate PARDISO for 3D simulations for thermal and electrical equations (compute) and mechanics (Flow), use:

math compute dim=3 pardiso
math Flow    dim=3 pardiso

To activate PARDISO multithreading with, for example, four threads, use:

math numThreadsPardiso=4

The Iterative Linear Solver (ILS) is the default solver for 3D simulations in Sentaurus Interconnect as well as for cases that involve diffusion of species in two dimensions.

To activate ILS for 2D simulations for thermal and electrical equations (compute) and mechanics (Flow), use:

math compute dim=2 ils
math Flow    dim=2 ils

In the case of poor convergence, you can improve the quality of the preconditioning of the matrices by reducing the ILS.ilut.tau parameter, for example, from 2x10^–3 (the default value for the 3D compute command) to 2x10^–4, or even a smaller value.

The generalized minimal residual (GMRES) iterative solver stores a given number m of backvectors. If the solution does not converge within m iterations, GMRES restarts. Higher values of m improve convergence but increase memory use. You set m in Sentaurus Interconnect by changing the parameter ILS.gmres.restart.

Recommended values are between the default value of 100 to 150 for the 3D compute command:

pdbSet Math compute 3D ILS.ilut.tau 5e-5
pdbSet Math compute 3D ILS.gmres.restart 150
pdbSet Math compute 3D ILS.maxit 300
pdbSet Math compute 3D ILS.tolrel 1e-9
pdbSet Math compute 3D ILS.refine.residual 10

To run ILS in parallel on multiple threads, use:

math numThreadsILS=4

1.5 Starting Sentaurus Interconnect

You can run Sentaurus Interconnect in either interactive mode or batch mode. In interactive mode, an entire process flow can be simulated by entering commands line-by-line as standard input. To start Sentaurus Interconnect in interactive mode, type the following on the command line:

> sinterconnect

Sentaurus Interconnect displays version and host information, followed by the Sentaurus Interconnect command prompt:

****************************************************************************
***                        Sentaurus Interconnect                        ***
***                          Version N-2017.09                           ***
***                         (1.0, x86_64, Linux)                         ***
***                                                                      ***
***                       Copyright (C) 1993-2002                        ***
***          The board of regents of the University of Florida           ***
***                       Copyright (C) 1994-2017                        ***
***                            Synopsys, Inc.                            ***
***                                                                      ***
***  This software and the associated documentation are confidential     ***
***  and proprietary to Synopsys, Inc.  Your use or disclosure of this   ***
***  software is subject to the terms and conditions of a written        ***
***  license agreement between you, or your company, and Synopsys, Inc.  ***
****************************************************************************

Compiled Wed Jul  5 20:25:34 PDT 2017 on tcadprod32

      Started at: Thu Jul  6 14:28:23 2017 (CEST)
       User name: letay
       Host name: device3
             PID: 20566
    Architecture: x86_64
Operating system: Linux rel. 2.6.32-642.13.1.el6.x86_64 ver. #1 SMP Wed Nov 23\
 16:03:01 EST 2016

------------------------------------------------------------------------------
Checking syntax of n1_sis.cmd:
TBB Warning: failed to destroy task scheduler TLS: Invalid argument

Syntax check complete.
------------------------------------------------------------------------------

Starting Tcl interpreter with inputfile: n1_sis.cmd
       sinterconnect: Checked Out

Loading models file:\
 /u/isedist/sentaurus/tcad/N-2017.09-L1/lib/sinterconnect-0.0.0/TclLib/SINTERCO\
NNECT.models... done.

You now can enter Sentaurus Interconnect commands at the prompt:

sinterconnect>

This is a flexible way of working with Sentaurus Interconnect to test individual process steps or short sequences, but it is inconvenient for long process flows. It is more useful to compile the command sequence in a command file, which can be run in batch mode or inside Sentaurus Workbench.

To run Sentaurus Interconnect in batch mode, load a command file when starting Sentaurus Interconnect, for example:

> sinterconnect input.cmd