Process Info

Foundry

Lets you select the foundry for which you want to run EM-IR analysis.

Node

Lets you select the process node associated with the foundry.

Layout View

Specifies the library, cell, and view to be opened in ADE.

Results Directory

Output Directory

Specifies the directory in which the EM-IR analysis results will be saved.

Use separate directories for extraction, simulation

Lets you specify if you want to save the results for extraction and simulation in separate directories.

Extraction Output Directory

Specifies the directory in which the extraction results will be saved.

Simulation Output Directory

Specifies the directory in which the simulation results will be saved.

EM Settings

EM Data Source

Specifies the format of EM rules. The following options are available:

• ICT File: Interconnect technology (ICT) file
• ICT-EM: ICT file containing only EM rules
• EM Data File: File that specifies the technology information, such as current density limits, and provides a mapping between the layers for highlighting.
• iRCX-EM: Interoperable interconnect extraction (iRCX) file contains the process and EM model information for EM analysis and is provided by the foundry.

TechFile

Specifies the Quantus technology file.

EM Rule File

Specifies the file containing the EM reliability rules.

EM Temperature

Specifies the temperature, in degree Celsius, at which the EM analysis will be run. The default EM Temperature is set to Tsim (simulation temperature).

Ambient Temperature

Specifies the ambient temperature, in degree Celsius, for EM analysis. The default Ambient Temperature is set to Tsim (simulation temperature).

Delta T

Specifies the maximum rise in temperature, in degree Celsius, caused due to Joule heating. It must be a positive value.

Lifetime

Specifies the lifetime for which the EM analysis will be run. You can specify the value in hours or years.

Design Resistors

Specifies the list of design resistors. For each resistor, you can specify the resistor model name, width, length, and layer name. You can either load an existing design resistor setup, or add design resistor models and save the setup.

Thermal Analysis Settings

Layout Cellview

Specifies the Virtuoso Layout view.

SHE

Enable SHE

Enables self-heating effect (SHE) analysis.

Heat Sink

Specifies that the heat-sink effect should be included in SHE analysis.

Mode

Specifies the mode of SHE analysis. The following options are available:

• Region: Specifies that thermal reports will contain temperature rise of OD region and metal resistors.
• Tiles: Specifies that thermal reports will contain temperature rise of OD region and metal resistors based on the specified tile matrix.
  When you select Tiles, two additional fields, X and Y appear in which you need to specify the x and y coordinates of the tiles.

Parameter File

Specifies the SHE analysis parameter (param.sh) file, which is required for calculating the SHE analysis results with heat-sink effect.

FIT

Enable FIT

Enables failures-in-time (FIT) analysis.

Product Life

Specifies the lifetime of product in hours.

Mode

Specifies the mode of FIT analysis. The following options are available:

• sdc_at_env_T: Calculates SDC at the environment temperature.
• sdc_at_seb_T: Calculates SDC at the statistical EM budgeting (SEB) temperature.

Parameter File

Specifies the SHE analysis parameter (param.sh) file with the FIT information for all segments of metals and vias.

Power Nets

Select from schematic

Lets you select power nets in the schematic.

Net Name

Specifies the name of a power net.

Net Type

Lets you specify a net as a global power or ground net, group and ungroup nets, move nets to a group, and remove a net.

Add Setup

Lets you specify the various extraction settings.

Name

Specifies the name of the extraction run for which you are defining the settings.

Existing DSPF

Specifies that an existing Detailed Standard Parasitic Format (DSPF) file will be used for EM-IR analysis. Click the Browse (...) button to select a DSPF file.

The DSPF file is a third-party netlist file that is used to provide all the parasitic information of the design for performing simulations using the Spectre X simulator.

Existing CCL

Specifies that an existing common command language (CCL) file will be used for EM-IR analysis.

Click the Browse (...) button next to the CCL File field to select a file. The CCL file contains the commands and options that define the extraction run.

Click the Browse (...) button next to the DSPF File field to specify the location of the generated DSPF file.

Custom

Allows to generate a new extraction setup.

Run DSPF Linter

Specifies to run the spfchecker utility on DSPF. The DSPF Linter utility analyzes a DSPF file, reports problems that may cause simulation problems, and creates an EM-IR conf file with recommended mapping statements.

Job Policy

Allows you to set up an extraction job policy and define the methods of how distributed processing jobs are submitted to the local or remote hosts.

Technology

File/Directory

Lets you specify one of the following:

• Technology Library File: Specifies the file to be used for reading the technology data.
• Technology Directory: Specifies the directory that contains the technology file.

Technology Name

Specifies the name of the technology to be used for extraction.

This field appears only when you select a technology library file for reading the technology data.

Corners

Lets you specify the corners and the temperature of the corners at which the extraction will be performed.

This field appears only when you select a technology library file for reading the technology data.

Use temperature coefficient for extracted resistors

Specifies that the temp_coeff value specified in the CCL file will be used for extraction.

If you select this check box, you cannot specify the temperature of the individual corners. The options, Temp and temp_coeff specified in the CCL file, are mutually exclusive.

Temp

Specifies the temperature at which the extraction will be performed. By default, a temperature of 25 degree Celsius is used.

The options, Temp and Use temperature coefficient for extracted resistors, are mutually exclusive.

Input

LVS Source

Lets you specify whether the Layout Versus Schematic (LVS) input data will come from. The following options are available:

• Calibre
• PVS/Pegasus (default value)

LVS Query Output Directory

Specifies the path to the directory in which the input LVS data is stored.

Run Name

Specifies the name of the LVS run.

Type

Type

Specifies the extraction type and the coupling mode. The following extraction options are available:

• RC: Specifies that both parasitic resistors and capacitors will be extracted.
• R only: Specifies that only parasitic resistors will be extracted.

When R only is selected, the simulation time is short. While selecting the extraction mode, consider the type of simulation being run. For example, to run a DC operating point (DCOP) simulation, select R only as the extraction mode because the capacitance values are not required.

The following coupling modes are available:

• coupled: Specifies that coupled capacitance extraction will be performed.
• decoupled: Specifies that decoupled capacitance extraction will be performed.

Output

Format

Specifies the format of extraction output file.

Advanced Settings for Input/Parasitics/Output

Input

Pin Order File

Specifies the file that contains the order of pins to be used during extraction.

The pin order is specified in the DSPF file using the .SUBCKT and .ENDS statements. You can use this option to provide a file with a different pin order that will override the order specified using the default .SUBCKT statement in the DSPF file.

Below are examples of pin orders in the DSPF file before and after specifying the pin order file.

Without the pin order file:

    .SUBCKT top In_001 VDD Out_001  VSS In_002 Out_002 In_003 Out_004 ...

    .ENDS

With the pin order file:

    .SUBCKT top VDD VSS In_001 Out_001 In_002 Out_002 In_003 Out_004 ...

    .ENDS

Blocking Device Cells File

Specifies the file containing the parasitic blocking device cell names, if any. Parasitic extraction for these devices are skipped.

Include Command File

Lets you specify the file with user-customized extract commands.

Parasitics

Via Array Spacing

Specifies the distance that will be used as the maximum distance criteria for grouping vias within the same array. This means that if the distance between vias is less than the specified maximum distance, they are grouped within the same array.

The default value of the via array spacing is 0.35 times the via size for N10, N16, N12, and N20 processes. For other processes, the default is auto, in which case Voltus-XFi sets the via spacing automatically.

Via Array Count

Specifies the number of vias per side allowed in an array (without the per via layer count option).

The default value is 4. For example, if the via array count is set to 2, the number of vias allowed per array side will be 2.

Fracture Via Count

Specifies the number that will be used to divide the pseudo vias into segments during extraction

Output

Resistor Settings

Add parasitic resistor color (mask number)

Enables color-aware EM analysis.

Add subconductor layer name

Includes information about the parasitic resistor models for the subconductor layers. This is used to support different EM rules for poly layers during EM analysis.

Filter

Suppress instance cards (*|I) for C only nets

Specifies that the instance cards and the corresponding dummy resistors for the capacitance-only nets are not printed in the results.

Center resistors

Includes sub-nodes after eliminating resistors with small resistance values.

When this option is selected, the survivor sub-nodes, among a group of sub-nodes that are formed by the filtered resistors, are chosen based on their proximity to the geometric center of the group. This field is specific to process nodes 5nm and below.

Specify minimum resistance per layer

Lets you specify the LVS layer name for which the minimum resistance value for the extracted parasitic resistors is to be applied. If the layer name is not specified, the default value, RH_TN_6 0, is used. This field is specific to process nodes 5nm and below.

Misc

Ground Net Node

Lets you select the reference or ground net node.

Subnode Character

Specifies the subnode identification character. By default, : is specified.

Comment top subckt

Comments out the top sub circuit statements from the DSPF file.

Compress output DSPF File

Generates the DSPF file in a compressed format.

Add Dynamic Analysis/ Add SPGS Analysis/ Add Static Analysis

Lets you specify the various EM analysis settings.

Dynamic Analysis Setup/ SPGS Analysis Setup/ Static Analysis Setup

Name

Specifies the name of the analysis run for which you are defining the settings.

Testbench Tab

Testbench Information

Allows you to select a library, cell, and maestro view to be opened in ADE.

Open

Opens the maestro view in ADE.

Active Setup

Indicates to select the active or current simulation setup in ADE.

Setup State

Indicates to select a previously saved simulation setup in ADE.

Window Tab

Time Window

Specifies the duration of EM-IR analysis. The following options are available:

• Full Transient Time: Specifies that the EM-IR analysis is run over the entire simulation period.
• Custom: You can select the time window of EM-IR analysis and provide the start and stop times.

Power Nets Tab

IR Analysis

Compute maximum IR drop (vmax)

Calculates the maximum IR drop value of each power net.

Compute average IR drop (vavg)

Calculates the average IR drop value of each power net.

EM Analysis

Compute peak EM violation (ipeak)

Calculates the peak current violation value of each power net.

Compute average EM violation (iavg)

Calculates the average current violation value of each power net.

Compute RMS EM violation (irms)

Calculates the root mean square (RMS) current violation value of each power net.

Specify Power Nets

Enable

Allows to select the power net to be included for EM-IR analysis.

Net name

Specifies the power net name.

Voltage Regulator Nets

Allows to select the voltage regulator nets to be included for EM-IR analysis. Click Select nets from schematic to select the nets in the schematic.

In this tab, you can specify the following:

• Analysis - Compute node maximum or average IR drop compared to reference.
• Reference Voltage - Use either maximum voltage of all nodes at each timepoint, average voltage of all nodes at each timepoint, net pin node as reference, or specified voltage value as reference to calculate IR drop.
• Ref-Node - Use specified node of net as reference.
• Vref - Use the specified voltage reference value.

Signal Nets Tab

EM Analysis

Compute peak EM violation (ipeak)

Calculates the peak current violation value of each signal net.

Compute average EM violation (iavg)

Calculates the average current violation value of each signal net.

Compute RMS EM violation (irms)

Calculates the root mean square (RMS) current violation value of each signal net.

EM

Enable

Allows to select the signal net to be included for EM analysis.

Net name

Specifies the signal net name.

IR

Lets you load the table data from a file.

Lets you save the table data to a file.

Enable

Allows to select the signal net on which IR drop analysis is to be performed.

Net name

Specifies the signal net name that is not connected to any voltage source.

Analysis

Specifies to compute node maximum (sigvmax), average (sigvavg), or absolute average (sigvabsavg) IR drop compared to reference.

Ref Voltage

Specifies to use either maximum voltage of all nodes at each timepoint, average voltage of all nodes at each timepoint, net pin node as reference, or specified voltage value as reference to calculate IR drop.

Ref-Node

Allows to use the specified node of net as reference.

Vref(V)

Allows to use the specified voltage reference value.

Select from Schematic

Lets you select signal nets in the schematic.

Solver Tab

Solver Settings

Method

Specifies the solver method with which the EM-IR analysis will be run. The following options are available:

• Direct: When high accuracy is needed, a brute-force simulation of the entire system – circuit plus parasitic resistances and capacitances – can be performed to accurately calculate EM-IR of any net. This approach is called the “one-step” method, where the EM-IR simulation performance and capacity is subject to the limitation of the circuit simulator being used.
• 2-stage: To conduct EM-IR simulation on circuits with much larger power and signal nets, within a shorter time, there is an alternative approach that involves decoupling the nonlinear circuit simulation from the linear RC net analysis. You can iterate the linear RC net analysis by modifying the layout; however, the nonlinear circuit simulation is done only once. This approach is called the “two-step” method. The decoupling of the linear RC nets from the nonlinear circuit is not mathematically equivalent to the original design and certain inaccuracy is introduced but it provides the benefit of simulation performance and capacity.

EMIR Preset

Specifies the options that let you trade off accuracy and performance. These options not only control solver settings, but also enable parasitic optimization after automatically detecting post-layout designs.

The possible values for this option are cx, ax, mx, lx, and vx, with cx being the most accurate mode and vx the highest performing mode.

• Use cx when a golden reference is required.
• Use ax for high-precision analog applications.
• Use mx for most analog applications. This is the default mode.
• Use lx for power management and other relaxed analog application circuits.
• Use vx for custom IC verification.

Advanced Tab

Advanced Analysis Settings

Toggle Frequency

Specifies the frequency of the nets so that the tool can derive the Td (total on-time period) for multiple clock cycles. You can specify frequencies for different nets as shown below:

(NETA, 4.6e9) (NETB, 2.3e9)

Toggle Net Frequency File

Specifies the name of the file that contains the net names and their corresponding frequency values. This file is used to specify the frequency of nets to compute the Td (total on-time period) for multiple clock cycles. This file contains net names separated by commas and the frequency values.

A sample frequency file is shown below:

NETA, 4.6e9

NETB, 2.3e9

Peak

AC Peak Analysis (iacpeak)

Specifies to calculate the current density violations based on the peak AC current for metal lines, vias, and contacts. It is applied to periodic AC or pulsed DC signals.

Dynamic AC Peak

When you set dynamic AC peak to single or multiple peak, it is important to set the Pulse Width Threshold. Td has different values for the single or multiple peak values of dynamic AC peak:

• Single Peak - When dynamic AC peak is single, Td=the time duration of maximum peak.
• Multiple Peak - When dynamic AC peak is multiple peak, Td=sum of time durations of different peaks, Td1+Td2+TdN....

Pulse Width Threshold

Enables pulse-wise EM current calculation for violation visualization. This option defines the current threshold for finding the start of the pulse. Any value below the threshold value is considered as zero.

Multiple Peak Threshold

Specifies the threshold percentage for the peak current above which the Td for a particular peak is added to the final Td. It is used to calculate the pulse width for a given peak.

Average

Use Recovery Factor

Specifies whether or not layer-wise recovery factor is to be used for calculating the average current density.

If the recovery factor is specified, then the average current density calculation is as follows:

iavg=max(|iavgpos|,|iavgneg|)- recovery_factor*min(|iavgpos|,|iavgneg|)

If not specified, then iavg=iavgpos+iavgneg

where iavgpos is the average current in the positive direction and iavgneg is the average current in the negative direction.

Recovery Factor

Calculates the effective DC electromigration in the bipolar current waveforms. This accounts for some 'sweep back recovery' of EM during the negative portion of the current waveform.

The following equation shows how the recovery factor is used by the software while calculating the total average EM current:

I (avg) = max( I+, I- ) - (recovery factor)* min( I+, I-)

where I+ is the average of I in the positive direction and I- is the average of I in the negative direction

Average Absolute Current (iavgabs)

Specifies to calculate the current density violations based on the average value of absolute current.

Miscellaneous

Options File

Specifies a file containing additional options for the EMIR run.

ECO File

Enables what-if analysis and applies the changes defined in the ECO file.

ECO

Net Name

Specifies the name of the net for which conversion between pins, tap nodes, and subnodes are to be done.

Conversion Type

Species the type of conversion. The possible options are:

• Pins to Subnodes
• Pins to Taps
• Subnodes to Taps
• Subnodes to Pins
• Taps to Pins
• Taps to Subnodes

Include

Specifies the tap/pin/node to be included.

Exclude

Specifies the tap/pin/node to be excluded.

DSPF Layer

Specifies the name of the DSPF layer on which conversion is performed.