minEndOfStubSpacing

Specifies the minimum spacing between a stub and its neighboring geometry for two types of stubs.

• A minimum stub has a side that is less than or equal to a given length (eosMinLength).
• A maximum stub has a side that is greater than or equal to a given length (eosMaxLength).

The constraint applies when any geometry occurs within a region defined by the minEndOfStubSpacing constraint, the width of the stub (eosWidth), and the side length for maximum stubs (eosMaxLength) and/or minimum stubs (eosMinLength). The following figure shows examples of stubs where c1 and c2 are the stub sides.

The following types of neighboring geometries will trigger the constraint:

• A step pattern with a step distance less than eosJogDistance and a step width less than eosJogWidth
  
  
• A jog pattern with a jog distance less than eosJogDistance and jog width less than eosJogWidth
  
  
• A perpendicular wire (optionally less than a given width)
  
  
• A wire within radial proximity of a stub end corner
  
  

minEndOfStubSpacing Quick Reference

Constraint Type	Layer
Value Types	Value
Database Types	Design, Technology
Scope	design, foundry
Category	Spacing

Value Type

The minEndOfStubSpacing constraint has a Value that represents the minimum distance required between the end of a stub and its neighboring geometry.

Parameters

• eosWidth (Value) is the maximum width of the stub. The constraint applies only when the stub width is less than or equal to the specified eosWidth parameter value.
• eosMaxLength (Value) is the minimum length for one side of a maximum stub. The constraint applies only when one side of the stub is greater than or equal to this value.
• eosMinLength (Value) is the maximum length for one side of a minimum stub. The constraint applies only when one side of the stub is less than or equal to this value.
• eosJogDistance (Value) and eosJogWidth (Value) are optional and specify the step pattern parameters. The step pattern is recognized when 0 < step distance < eosJogDistance and step width < eosJogWidth. A violation occurs if a step pattern is found that is less than minEndOfStubSpacing from the stub end.
• eosJogDistance (Value) and eosJogWidth (Value) are optional and specify the jog pattern parameters. The jog pattern is recognized when 0 < jog distance < eosJogDistance and jog width < eosJogWidth. A violation occurs if a jog pattern is found that is less than minEndOfStubSpacing from the stub end.
• width (Value) is optional and specifies the width of metal within the projection of the stub end that will trigger the constraint. This parameter is checked only if neither a step nor jog pattern is detected.
• eolRadialCheck (BoolValue) is optional and enables radial checking from the stub end corners. This parameter is only checked when width, eosJogDistance, and eosJogWidth are not given.

Examples

The following example for a minimum stub results in a violation whenever any wire is located within minEndOfStubSpacing of the stub end.

set_constraint_parameter -name eosMaxLength -Value 0.28
set_constraint_parameter -name eosWidth -Value 0.24
set_constraint_parameter -name eolRadialCheck -BoolValue true
set_layer_constraint -layer Metal2 -constraint minEndOfStubSpacing -Value 0.20 -hardness hard

The following example for a maximum stub results in a violation if one of the following occurs:

• A jog or step pattern is detected that is within 0.13 of the stub end.
• A less than 0.12 wide wire is detected within 0.13 of the stub end.
  
  

set_constraint_parameter -name eosMaxLength -Value 0.05
set_constraint_parameter -name eosWidth -Value 0.12
set_constraint_parameter -name eosJogDistance -Value 0.12
set_constraint_parameter -name eosJogWidth -Value 0.12
set_constraint_parameter -name width -Value 0.12
set_layer_constraint -layer Metal3 -constraint minEndOfStubSpacing -Value 0.13 -hardness hard

Related Topics

Spacing Constraints

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