How do you avoid antenna DRC violation?

How will you avoid Antenna DRC Violation?..

what is antenna violation & ways to prevent it

hi kumar

aviod antenna violation using Jumpers are a short metal segment inserted onto a long route of another metal layer.
The Magma design system implements a powerful jumper-based antenna solution that
effectively solves the majority of the antenna violations with little impact on the routing congestion. The remainder of the violations can be fixed using diode insertion. Jumpertechniques are the most effective method of avoiding antenna-effect problems

Added after 28 seconds:

vamsi

what are antenna violations

hi vamsi
jumper means u r specifying about the jags in to different layer and comes back to the same layer,,,,,
is it prefer to put the antenna diode or to jag the layers

antenna drc violation

ya correct

what is antenna violation ?

First, antenna violation is always checked only as a areas ratio and is an approximation... in other words, by having an antenna violation does not 100% mean you will have a problem... it's only saying you might have a problem...

Having said this... anytime the metal jumper solves your problem, it's a better solution but, as I said before, sometimes (for the checking rule) is not enough and will ask for the diode...

It's true that the diode will 100% solve your "violation" but watch out that, in certain conditions, the leakage this diode will have could actually kill your circuit... Conclusion... As always, this is a trade of...

antenna violation & ways to prevent it

Hi all,

When the netlist has some tie hi/low net(logic 1/0),the tool will connect these nets to power/ground net directly, and some violations will appear on the power/ground net, is the only way is adding tie cell, but not the diode cell?

antennae violation

I got a clear answer for this question.. Here it is.

During the process of plasma etching, charges accumulate along the metal strips. The longer the strips are, the more charges are accumulated. IF a small transistor gate connected to these long metal strips, the gate oxide can be destroyed (large electric field over a very thin electric) , This is called as Antenna violation.

The ways to prevent is , by making jogging the metal line, which is atleast one metal above the layer to be protected. If we want to remove antenna violation in metal2 then need to jog it in metal3 not in metal1. The reason being while we are etching metal2, metal3 layer is not laid out. So the two pieces of metal2 got disconnected. Only the piece of metal connected to gate have charge to gate. When we laydown metal3, the remaining portion of metal got charge added to metal3. This is called accumulative antenna effect.

Another way of preventing is adding reverse Diodes at the gates.

Thanks to all the people who has contributed for this Topic..

Kumar

process antenna violation

hi kumar,,,
good explantation u have given for the metal jogging for avoiding the violation, but i have lot of confusion at the diode insertion,, how it will helps in avioding anttena effect with a reverse biased diode..

antenna problem diode insertion

Raju,
Basically what you add it's called antenna diode or "leaker". It's a diode with the anode connected to the protected line and the cathode to substrate.

If the voltage on the node drops below teh substrate potential, then the leaker gets forward-biased and clamps the voltage. If the voltage on the node rises above substrate potential then the diode junction will avalanche before the thick oxide is damaged...

So, basically, you use the fact that it has leakage to protect the circuit but, by the other hand, it's kind of dangerous if that leakage (that can be really important if temp is high) can affect your circuit...

what is antenna violations

Thanks alot layoutmaster.. Even I had the same doubt.. Now its clear for me...

Antenna Violation

Layout master can u please explain something about the density rules which we have to take care about..or layer density rules...what is the need ??

Antenna Violation

Hi vlsitech,
Take a look at the topic you created about Metal Density.

There is an explanation by me and later an important clarification (from vasantha) I forgot to mention saying that one of the most important reasons is to get the degree of planarity needed for this submicron processes.

THe deposition of patterned layers upon the wafer inevitably introduces variations in surface height and each layer added to the conductor stack worsens the topography... That's why some "planarization techniques" are used to minimized that effect and, between them you have the Fill with metal dummies and the check of metal coverage.

Re: Antenna Violation

by adding the antenna diodes or by doing the metal hopping you can reduce the antenna violations.

Re: Antenna Violation

chk this

Re: Antenna Violation

hai kumar ,

I ahve a confusion,

u r jogging metal r we need to jog net.

phutane

Re: Antenna Violation

Hi phutanesv,
Can you please elaborate your question?. As far I know all the nets are made by using the metals.

Kumar

Antenna Violation

hi,layoutmaster,
The diode should be reversed connected with the protected metal.
i.e. cathode connected to the protected line and anode connected to the substrate.