What does metal stack option 8m5x2y2z mean ?

[Mina Louis]

what does something like 8m5x2y2z mean? I already know that 8m means 8 metal layers, what about the x y z ?

 

[yadavvlsi]

This means that 8 metal layers with thickness x. 2 metal layers with thickness y and 2 metal layers with thickness z. Total of 12 metal layers. Usually y and z are some integer multiple of x

 

[birdy123]

Hi yadav and Mina

First of all the mentioned stack is wrong.. I will explain you later... but beofre that the noraml nomenculature is

8m5x2y2z-

8m ->>> total 8 metal


5x ->>> 5 metal of x thickness. Mx
2y ->>> 2 metal of y thickness. My
2z ->>> 2 metal of z thickness. Mz
apart of this there will be Metal 1 also . M1 (that's by default included in the metal stack)

So total metals will be 1+5+2+2=10.

So the correct metal stact is 10m5x2y2z.. or may be some thing like 8m5x2y or 8m5x2z.

For more detail, you can cehck the design manual of corresponding Foundry. Above one is with respect to TSMC foundry nomenculature.

I hope it will help you. Let me know in case of any confusion.

 

[Mina Louis]

Thanks so much birdy and yadav
and yes you're right, it's 10m5x2y2z, I wrote it wrong

 

[design_oriented]

5x means not just width but metals M2,M3,M4,M5,M6 have the design rules of Mx (spacing, area, etc.) which is specified under the Mx section in the DRM. Similarly 2y will have M7 and M8 rules as My. This is based on TSMC rules. This nomenclature may be different for different foundries.