8.0 Antenna Ratio Rules

An antenna includes all conducting structures on the same layer and the same electrical node that connect to an active area only via layers below it.

ANTENNA RATIO RULES

RULE NO.

DESCRIPTION

LAYOUT RULE

Layer

Poly2, Metal1 to MetalTop

ANT.1

Maximum ratio of Poly2 perimeter area to related gate oxide area

200

ANT.2 (1)

Maximum ratio of Metal1 perimeter area to related gate oxide area

400

ANT.3 (1)

Maximum ratio of Metal2 perimeter area to related gate oxide area

400

ANT.4 (1)

Maximum ratio of Metal3 perimeter area to related gate oxide area

400

ANT.5 (1)

Maximum ratio of Metal4 perimeter area to related gate oxide area

400

ANT.6 (1)

Maximum ratio of Metal5 perimeter area to related gate oxide area

400

ANT.7 (1)

Maximum ratio of MetalTop perimeter area to related gate oxide area

400

ANT.8

Maximum ratio of contact area to related gate oxide area

10

ANT.9 (1)

Maximum ratio of Via1 area to related gate oxide area

20

ANT.10 (1)

Maximum ratio of Via2 area to related gate oxide area

20

ANT.11 (1)

Maximum ratio of Via3 area to related gate oxide area

20

ANT.12 (1)

Maximum ratio of Via4 area to related gate oxide area

20

ANT.13 (1)

Maximum ratio of Via5 area to related gate oxide area

20

ANT.14

If MIM is between Metaln and Metal (n+1), Then:

Maximum ratio of each of the metal layer (Metal (n+1) to MetalTop) perimeter

area to related MIM area (For example, If MIM is between Metal2 and

Metal3, then need to check ANT.14 for M3, M4, … MetalTop to its related MIM)

400

ANT.15

If MIM is between Metaln and Metal (n+1), then:

Maximum ratio of each of Via (Vian to most top Via) area to related MIM

area (For example, If MIM is between Metal2 and Metal3, then need to

check ANT.15 for V2, V3, … most top Via to its related MIM)

20

Note

  1. Possible repairs to metal antenna nodes, which have a high via count or antenna ratio.

    1. Add an NCOMP/Substrate diode for NMOS gate, PCOMP/Nwell diode for PMOS gate.

    2. Break the metal close to the gate and jog the metal to an upper metal level.

Remedy for Antenna Rule violations:

  1. Connecting antenna diode

RULE NO.

DESCRIPTION

LAYOUT RULE

ANT.16

If any of the above antenna ratio rules fails then the antenna diodes

shall be connected in a reverse bias mode between the metal line

failing antenna ratio (connected to gate poly or MIM cap top plate)

and the substrate underneath.

For DRC check if Metaln or Vian fails antenna ratio then it shall

check whether this Metaln or Vian is directly connected to COMP

through lower level metals, vias and contacts or not?

Case (a): Connection to COMP is not present: Flag error

Case (b): Connection to COMP is present: Then:

  1. For Thin gate case: (COMP AND Poly2 NOT DUALGATE):

Treat Gate area = (thin gate area +

MF* (COMP area directly connection that node))

This comp area contained the protection diode and any other

drain or source junction connected to this node.

MF: stand for multiplying factor, for this case MF=2

  1. For Thick gate case (COMP AND Poly2 AND

DUALGATE) Treat Gate area = (Thick gate area +

MF* (COMP area directly connection that node))

This comp area contained the protection diode and any other

drain or source junction connected to this node.

MF: stand for multiplying factor, for this case MF=15

  1. For MIM Cap case:

Treat MIM area = (FuseTop area + MF* (COMP area directly

connection that node))(For MIM option-A process)

Treat MIM area = (FuseTop area + MF* (COMP area directly

connection that node))(For MIM option-B process)

This comp area contained the protection diode and any other

drain or source junction connected to this node.

MF: stand for multiplying factor, for this case MF=15

And check back the validity of antenna ratios as specified in

rules ANT.1 to ANT.15.

(2) Other Possible repairs if the Antenna ratio violate the design rule is break the metal close to the gate and jog the metal to an upper metal level.

ANTENNA RATIO RULES

ANTENNA RATIO RULES

Example:

Illustration on the above antenna ratio calculation: (Terms on the right hand side of the equations below (eg. Metal3) refer to the layout areas of the corresponding structures in the diagram above.)

\[ \begin{align}\begin{aligned}Antenna_ratio (Metal_3) = Metal_3/(Poly_{2A} + Poly_{2B} + Poly_{2C})\\Antenna_ratio (M2A) = Metal_{2A}/(Poly_{2A} + Poly_{2B})\\Antenna_ratio (M2B) = Metal_{2B}/Poly_{2C}\end{aligned}\end{align} \]

Poly2/Metal Perimeter Area calculation

Area calculation
\[Poly2/Metal Perimeter Area = 2 [(t X z) + (t X y)]\]

Where

y: Poly2/Metal length

z: Poly2/Metal width

t: Poly2/Metal thickness

Poly2

Metal1

Metal2

Metal3

Metal4

Metal5

MetalTop (6K Å)

MetalTop.1 (9K Å)

MetalTop.2 (11K Å)

MetalTop.3 (30K Å)

t(um)

0.2um

0.54um

0.54um

0.54um

0.54um

0.54um

0.69um

0.99um

1.19um

3.035um