How floating dummy metal fill affects coupling capacitance?

[starinspace]

I know that there are two kinds of metal fill viz, grounded dummy metal fill and floating dummy metal fill.
By using grounded dummy metal fill the de-coupling cap increases on the signals and thus induces a delay factor in near-by signals. I don't understand how floating dummy metal fill will affect the coupling capacitance or induce cross talk. Can someone please help me figure out this? :thinker::-x

 

[artmalik]

Any metal fill will increase the capacitance of the signals. it is parallel plate capacitor... if it is grounded the resistance is zero to the parallel plate... if it is floating that means it is parallel plate connected with a high resistance path. Still there is additional cap added to the signals....though the effect is less.

 

[starinspace]

Can you please explain in detail? I am really not understanding. Can you please provide a diagram pertaining to this? :roll: :-(