Product Documentation
Voltus-Fi Custom Power Integrity Solution XL User Guide
Product Version IC23.1, August 2023

14

Statistical ElectroMigration Budgeting

Statistical ElectroMigration Budgeting (SEB) enables you to meet the ElectroMigration (EM) reliability targets by performing a statistical interconnect EM analysis based on the current modeling and thermal analysis of the design. This feature leverages the statistical nature of EM reliability to compute the level of the EM risk for all design rule violations. SEB analysis requires fixing of only those violations that add significant risk. This reduces the design verification time and improves performance while ensuring that the design meets its chip-level reliability goals.

Failures in Time (FIT) is a factor to represent the chip failure rate. Following is the definition of FIT:

1 FIT  = One failure per 10^9 product hours

= One failure in 1000 products through 10^6 hours

= One failure in 105 products through 10^4 hours

= or any other combination between products and hours as long as the product of the two is 10^9

Voltus-Fi will calculate the FIT value for each resistor of metal and via. The tool will follow the foundry EM definition to calculate FIT. This flow is supported in Voltus-Fi and involves the following tasks:

  1. Calculating the FIT for each resistor of metals and vias.
  2. Applying FIT reduction using the calculation.
  3. Adding all the reduced FIT values to get the total block/chip FIT.
  4. Generating a report with all the FIT information in a text format.

The following flowchart depicts the high-level flow for SEB in Voltus-Fi:

Related Topics

FIT Reduction Method

This section details the FIT reduction methods used for metal and via resistors.

Metal FIT Reduction

Metal FIT Reduction Example 1

Metal FIT Reduction Example 2

VIA FIT Reduction

VIA FIT Reduction Example

Related Topics

Inputs for the SEB Flow

For running the SEB relaxation flow, you need to provide the SEB parameter file with FIT calculations.

Following is a sample of the SEB parameter file:

FIT_TABLE 72 5 (LAYER:V, MTF_HOUR:V, SIGMA:V, Ea:V, EXP_N:V r:V) 
FIELD             MTF_HOUR    SIGMA        Ea        EXP_N     r
LAYER
M12               1.73e5      0.22         0.8        1          1
VIA11             1.73e5      0.22         0.8        1          1
M11               1.73e5      0.22         0.8        1          1
VIA10             1.73e5      0.22         0.8        1          1
M10               1.73e5      0.22         0.8        1          1
VIA9              1.73e5      0.22         0.8        1          1
M9                1.73e5      0.22         0.9        1          1
VIA8              1.73e5      0.22         0.9        1          1
M8                1.73e5      0.22         0.9        1          1

Where,

Related Topics

SEB Flow emirutil Command Option

The following option is specified in the EMIR control file using the emirutil command for the SEB flow:

Keyword Option Set Explanation Default Value

emirutil

 
sebParamFile=”paramfilepath”

Specifies the self-heating effect (SHE) analysis parameter file, which is required for calculating the SHE analysis results.

For the SEB flow, this file should include the FIT information for all segments of metals and vias.

Example:

emirutil sebParamFile=[../Techfile/ICTEM/seb.ircx]

none

 

print_em_report=[ [net=[all_nets | all_power | all_signal | netname] type=[fit] filename=output_file_name]

Generates the EM report with the SHE for the SEB flow. You can specify the following:

  • filename: creates a report with the specified filename.
  • net: creates a report for the specified nets - all power nets (all_power), all signal nets (all_signal), all nets (all_nets), or a net (netname).
  • type - creates a report for the SEB flow (FIT).

Example: 

emirutil 
print_em_report=[net=all_nets
type=fit filename=
fit_woshe.rpt]

none

Related Topics

Sample EMIR Configuration File

Following is a sample EMIR configuration file with specifications for the SEB flow:

net name=[XTOP.*] analysis=[iavg imax irms iacpeak vavg vmax]
emirutil auto_detect_geounit=[false]
solver method=[direct | iterated]       
emirutil techfile=[../../../../Techfile/RCE_qrc/qrcTechFile]  >>  provide qrcTechfile path 
emirutil EMOnlyICTFile=[../../../../Techfile/ICTEM/drawn_color.ictem] >> provide ICTEM file (if any) 
emirutil Tj=<value>
emirutil Tambient=<value>
emirutil ProductLife=<value>        >> default value=5 years 
emirutil autorun=[true]
emirutil report=[text |HTML]
emirutil idirn=[true |false]
emirutil splitACDCRules=[true|false]
emirutil extendedreport=[true|false]
emirutil optimisticEMRuleSelection=[true|false]
emirutil simpleSingleViaDefinition=[true |false]
emirutil redundantNonCDRules=[true |false]
emirutil dbu=<value>
emirutil powerRailRules=[on|off]
emirutil sebParamFile="./test_SEB_n7_1p12m.ircx"  >> provide the SEB param file path 
emirutil print_em_report=[net=all_nets type=fit filename=fit_woshe.rpt]   >> the reporting option to print the FIT report

Related Topics

SEB GUI Variable

The option for the SEB flow can also be specified in the GUI in the Variables form that opens on the EM tab of the IR/EM Results form.

Variable Name Option Set

sebParamFile

Specifies the SHE analysis parameter file, which is required for calculating the SHE analysis results.

For the SEB flow, this file should include the FIT information for all segments of metals and vias.

Example:

sebParamFile ./test_SEB_n7_1p12m.ircx

Related Topics

SEB Report

The SEB flow generates a report with the total reduced FIT for all resistors.

Following is a sample SEB FIT Results file:

Where,

Related Topics


Return to top
 ⠀
X