Re: metal density violation
Background:
The thickness of dielectric layers vary due to the different patterns of metal on successive metal layers. These variations will impact yield.
Insert metal fill to increase metal layers's metal density, and make the topology of all the metal layers more uniform, therefore reduce the thickness variations.
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Reason:
Depends on the design, metal pattern may not distribute enough in some region duing routing phase. Therefore, metal dendity violations occur.
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Impact:
Insert metal fill may affect both timing & sinal integrity.
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