why do we need shield ring with in the block ?

[ramprasad]

hi all,

i have a doubt, In fullchip level we have one shield ring , but why do we need a shield ring with in the block ? Is it mandatory, what happens if it is not there ?

Please explain in detail .

Thanks :smile:

 

[yadavvlsi]

Seal ring is put around chip to identify end of chip during dicing. Dicing is process of cutting individual chip from wafer after fabrication. So it is not required at block level.

 

[nav_vlsi]

There is another perspective to your query too

seal ring is normally decouples your Die from wafer substrate, it actually prevent Die from getting infected from any substrate noise.

Reg. block level, it depends on what type of IP is present in your block, if u have a pure Analog Macro, it better to put guard ring.