Re: When is the good timing for adding the filler cell in As
In principle, after CTS - you want to give CTS as much freedom as possible to place the clock distribution buffers in the optimal places to minimize skew.
in post rout opt. step the following message display, and frocess was terminated....
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ERROR: Cannot place filler cell instance "xofiller!FILL64!1".
Please purge them or fix them first.
***************************************
* Overlap Removal(OV) Engine Terminated
***************************************
WARNING : Assert failed at pdsMain.c(2668)
WARNING : Assert failed at pdsMain.c(2065)
ERROR : pdsPushParams() failed --- parameter stack empty
CGHIER: +++ Checking for HCG and flat CG consistency ... +++
CGHIER: +++ Done with checking HCG and flat CG consistency. +++
CGHIER: Number of errors = 0
Fail to execute command
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so I need to purge filler cell in this stage, and re-do add filler after detail route.
Could you please tell me how to avoid above problem ?
Re: When is the good timing for adding the filler cell in As
1. IO Filler : should be add after IO pads are placed.
2. Core Filler : Core filler is to fill up the void between standard cells, usually in acutal layout, it has power rail, diffusion, and N-well layer. Core filler should be fill up all the core space after CTS, IPO, DRV etc, but before final detailing routing.
In a simple term, core filler are added before detailing routing.