Metals used for core rings/power strapes in floorplanning?

[JesseKing]

floorplan question

when floorplanning, which metals should be use for core rings and power strapes? top two layer or bottom two layer?
or others ? and what are the advantages and disadvantages of the these stratagems?

regards

 

[coolrak]

Re: floorplan question

Hi JesseKing,

Normally the top layers are used for core rings and power straps. It done to reduce

the resistance of the power nets(since top metals have more width it will have less

resistance). The bottom layer (1st layer) is totally used for placing the standard cells.

I hope it helps

 

[semi_jl]

floorplan question

But I think we should use different levels met in vertical and horizontal direction, it will be convenient for later routing.
I think so, but if there is something wrong, pls correct it. Thank you!

 

[JesseKing]

Re: floorplan question

Hi JesseKing,

Normally the top layers are used for core rings and power straps. It done to reduce

the resistance of the power nets(since top metals have more width it will have less

resistance). The bottom layer (1st layer) is totally used for placing the standard cells.

I hope it helps

I always use the top 2 layers for core ring and power straps. but in some design, i found that the top layer was always preserved, why? what is the advantages?

 

[coolrak]

Re: floorplan question

How many layers in the design(for the one which has the top layers preserved)

 

[ls000rhb]

floorplan question

top layer have min cap which relax the power supply swing's effect for function cell!!! i often use different layer for the horizonal and vertical rings!!!