Dishing Effect Query

[masummist]

Can anyone tell me what is dishing effect?

Thanks

 

[Gayathri Jeyaram]

Can anyone tell me what is dishing effect?

Thanks

The metal nets are not perfect a rectangle when seen cross-sectionally but looks like a dish due to CMP https://en.wikipedia.org/wiki/Chemical-mechanical_planarization

This causes shorts between two metal nets and open in a metal net.

Max density and min density will be defined in the lef file for each metal layer to help avoid problems due to dishing.

 

[kenambo]

Hi,

Metal dishing is defined as the difference between the height of the oxide in the spaces
and that of the metal in the trenches.

It is caused by the Chemical Mechanical Planarisation(chemical Mechanical polishing). This CMP is used in IC fabrication to get ahigh level of planarisation..

It imay be reduced by some Dummy Fill techniques effectively..

Thanks

 

[masummist]

Thanks Gayathri and kenambo