saam wrote on Mar 6th, 2011, 8:46pm:Can anyone tel me ..Why top metal layer (M8) has low resistance compare to bottom (M1) ???
ThankU
saam
Unique to process as others have stated, but commonly its because they make the top layer thicker.
If its all copper CMP layers, you have very good control over the characteristics of the layer thickness.
The PDR's are fussy so that you can avoid cupping/dishing issues, when doing the CMP planarization of the layers.