Crosstalk b/w two different metal layers

[mahanthesh]

crosstalk between metal layers

Hi,

Crosstalk between two nets, is it possible to happen between two different metal layers of signal routing i.e metal 2 & metal 3?


Thanks in advance
Mahanthesh

 

[albred]

Yes. Metal 2 and metal 3 nets are routed in different directions in general, but some time they are routed in the same direction for special case, which may causes crosstalk problem.

 

[mahanthesh]

Thanks Albred,

Metal 2 & 3 will be perpendicular to each other. Suppose in metal 2 & metal 4 there can be crosstalk right?

I also wanted to know the whether crosstalk is more between same metal layers or in different metal layers with spacing is same for different cases.

 

[eng_Semi]

Hi,

I don't get ur last phrase but I'll answer u from what I got:

The coupling capacitance between two path on the same metal layer is much larger than the coupling capacitance between two paths on different metal layers, and the last is larger than the crossing capacitance between two paths on different metal layers.

 

[Shohdy]

Hi,

I think the coupling capacitance mainly depends on the distance between the paths.
So we can not say that the coupling is larger or smaller in a certain case without mentioning an average distance between the two paths.

In the case of two diffrent metal layers, the perpendicular distance is fixed in each technology, while in the case of same metal layers the distance depends on the design.

Regards,
Shohdy

 

[shankarmit]

The cross talk between same metal sounds more than two different metals..

suppose you do non preferrable routing.. then you might have cross talk between metal2 and metal 3 when they are in same direction.. between metal2 and metal4 cross talk does not sounds better as they are far away..


Regards
Shankar

 

[albred]

Hi,
The key issue about crosstalk discussed here is the coupled capacitance.
For capacitance between two nets in the same layer or different layers, it also depend on given process. The picture uploaded will show it.
You should check you process technical file for your solution.