Innovus 出现了负数的Cell Delay

coyboy912 · 发表于 2022-8-31 09:56:47

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请教一下大家，Innovus出现了负数的Cell Delay让我百思不得其解，而且生成sdf中多个地方都出现了，这就导致Innovus出来的结果不好。用spef和pt算就没问题。
库是比较老的库，innovus 20和15版本都是如此。Transition Time和Cap都在合理的范围里面（Table）。而且还有一个现象，ss corner下，负数是最负的，ff corner反而逼近于正数方向，大小是反常规的。

innovus 5> reportDelayCalculation -from xx/FE_OFC9534_n1039/H01 -to xx/FE_OFC9534_n1039/N01
The report is generated with view func_rc_max. Use option -view <view_name> to report it for other views. Run the report_analysis_view command to list views.
**WARN: (IMPDC-3245): The RC data is not in memory or the RC data in memory is for a different RC corner. RC data is being read.
Type 'man IMPDC-3245' for more detail.
###############################################################
#  Generated by:    Cadence Innovus
#  OS:             Linux x86_64
#  Generated on:
#  Design:
#  Command:          reportDelayCalculation -from xx/FE_OFC9534_n1039/H01 -to xx/FE_OFC9534_n1039/N01
###############################################################

From pin : xx/FE_OFC9534_n1039/H01
To Pin    : xx/FE_OFC9534_n1039/N01
Cell    : F
Library : xx_5V_MAX
Arc sense  : positive unate
Delay type : cell delay

-------------------------------------------------------------
RC Summary for net xx/FE_OFN9563_n1039
-------------------------------------------------------------
Number of capacitance : 71
Net capacitance    : 0.215809 pF
Total capacitance    : 0.224331 pF
Number of resistance  : 70
Total resistance    : 70.142197 Ohm
-------------------------------------------------------------
   Rise       Fall
-------------------------------------------------------------
Input transition time  : 0.286700 ns 0.222300 ns
Cell delay          : -1.438200 ns -0.372800 ns
Output transition time : 1.640400 ns 1.194200 ns
-------------------------------------------------------------