Fat wire via enclosure rule the fat wire via

Fat Wire Via Enclosure Rule
The fat wire via enclosure rule specifies the minimum amount of fat metal overlap over a via
for the metal layer either above or below the via. The minimum overlap requirement depends
on the width of the fat metal enclosing the via, the spacing of nearby metal, and the parallel
length of the nearby metal, as specified in a table.
This is the syntax of the rule:
DesignRule {
layer1 = "MetalX"
layer2 = "ViaX"
fatWireViaEncTblSize = 4
fatWireViaEncWidthThresholdTbl = (W1, W2, W3, W4)
fatWireViaEncParallelLengthThresholdTbl = (L1, L2, L3, L4)
fatWireViaEncMaxSpacingThresholdTbl = (S1, S2, S3, S4)
fatWireViaEnclosureTbl = (E1, E2, E3, E4)
fatWireViaArrayExcludedTbl = (0, 0, 0, 1)
}
Figure 2-62 shows how the minimum enclosure depends on the rule attributes.

Chapter 2: Routing Design Rules
Via Enclosure Rules 2-82
IC Compiler Technology File and Routing Rules Reference Manual D-2010.03-SP2
IC Compiler Technology File and Routing Rules Reference Manual Version D-2010.03-SP2
Figure 2-62 Fat Wire Via Enclosure Rule
Here is an example of the rule:
DesignRule {
layer1 = "Mx"
layer2 = "VIAx"
fatWireViaEncTblSize = 4
fatWireViaEncWidthThresholdTbl = (0.055, 0.060, 0.075, 0.170)
fatWireViaEncParallelLengthThresholdTbl = (0.12, 0.12, 0.14, 0.14)
fatWireViaEncMaxSpacingThresholdTbl = (0.062, 0.068, 0.090, 0.134)
fatWireViaEnclosureTbl = (0.008, 0.009, 0.012, 0.015)
fatWireViaArrayExcludedTbl = (0, 0, 1, 0)
}
In this example, if the fat wire width W is greater than 0.055 but less than or equal to 0.060,
the parallel length L of the nearby metal is greater than or equal to 0.12, and the spacing S
to the nearby metal is less than 0.062, then the minimum enclosure E is 0.008. The last
attribute,
fatWireViaArrayExcludedTbl
, is set to 1 to waive the rule for a double via for the
corresponding set of values for W, L, S, and E.
S
n
E
n
W
n
L
n

Chapter 2: Routing Design Rules
Via Enclosure Rules 2-83
IC Compiler Technology File and Routing Rules Reference Manual Version D-2010.03-SP2
Concave Metal Corner Via Enclosure Rule
The concave metal corner via enclosure rule specifies a minimum allowed distance between
a concave metal corner and a via enclosed by the metal. In Figure 2-63 , the rule prohibits
any concave metal corner within a rectangular exclusion area surrounding the via by a
distance D. The rule does not apply to two vias enclosed by the same metal segments when
the spacing between the vias is no more than S
0
, the
minCutSpacing
value specified in the
ContactCode
section of the technology file.
Figure 2-63 Concave Metal Corner to Via Enclosure Rule
Here is an example of the syntax used for this rule:
DesignRule {
layer1 = "M2"
layer2 = "V1"
concaveMetalToCutMinDist = 0.30
}
In this example, any concave metal corner must be at least 0.30 distance units away from a
single enclosed via.
Note:
This rule is supported only by Zroute.
Violation
DesignRule {
layer1 = "M2"
layer2 = "V1"
concaveMetalToCutMinDist = D
}
D
Violation
No violation
D
Double via with spacing <= S
0
No violation
D
S
0

Chapter 2: Routing Design Rules
Jog Wire Rules 2-84
IC Compiler Technology File and Routing Rules Reference Manual D-2010.03-SP2
IC Compiler Technology File and Routing Rules Reference Manual Version D-2010.03-SP2
Jog Wire Rules