What's "CapModel" and "CapTable" about in .tf files

[hzbhhh]

Dear all,

I'm recently learning to use icc2 and smic180 library for a backend design task. After building the .ndm file from .tf, .db and .lef files, I use it to create library but I find many warnings in the console like these:

Warning: smic18_5lm.tf line 2583, unsupported technology file section 'CapTable'. It will be ignored. (TECH-001)
Warning: smic18_5lm.tf line 2597, unsupported technology file section 'CapTable'. It will be ignored. (TECH-001)
Warning: smic18_5lm.tf line 2611, unsupported technology file section 'CapModel'. It will be ignored. (TECH-001)
Warning: smic18_5lm.tf line 2629, unsupported technology file section 'CapModel'. It will be ignored. (TECH-001)

I find it really hard to solve those warnings as I don't even know what those "CapTable" and "CapModel" are used for in .tf file. So I wonder if anyone has an explanation for them.

Thanks a lot.

Here are some "CapTable" code in .tf file:

CapTable        "poly_C_TOP_GP_14NOM" {
                wireWidthSize                = 5
                wireSpacingSize        = 16
                wireWidth                        = (0.18, 0.36, 0.54, 0.72, 0.9)
                wireSpacing                = (0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4)
                capValue                        = (
                        3.21089e-06, 4.31766e-06, 5.08723e-06, 5.61531e-06, 5.97976e-06, 6.23676e-06, 6.42063e-06, 6.55657e-06, 6.65854e-06, 6.73641e-06, 6.79687e-06, 6.8445e-06, 6.88245e-06, 6.91304e-06, 6.9386e-06, 6.95804e-06,
                        4.19968e-06, 5.33686e-06, 6.15404e-06, 6.73069e-06, 7.13777e-06, 7.43115e-06, 7.64664e-06, 7.8078e-06, 7.9304e-06, 8.02521e-06, 8.09959e-06, 8.15872e-06, 8.20649e-06, 8.24559e-06, 8.276e-06, 8.30207e-06,
                        5.19391e-06, 6.33945e-06, 7.18459e-06, 7.78953e-06, 8.22627e-06, 8.54585e-06, 8.78358e-06, 8.96349e-06, 9.10181e-06, 9.20981e-06, 9.29524e-06, 9.36421e-06, 9.41974e-06, 9.46357e-06, 9.50097e-06, 9.53202e-06,
                        6.17943e-06, 7.33602e-06, 8.19696e-06, 8.82394e-06, 9.28203e-06, 9.62091e-06, 9.87565e-06, 1.00702e-05, 1.02211e-05, 1.03399e-05, 1.04352e-05, 1.05108e-05, 1.05718e-05, 1.06227e-05, 1.06649e-05, 1.07e-05,
                        7.1688e-06, 8.33133e-06, 9.20727e-06, 9.85164e-06, 1.03267e-05, 1.06814e-05, 1.09502e-05, 1.11572e-05, 1.13189e-05, 1.14473e-05, 1.15495e-05, 1.16316e-05, 1.16995e-05, 1.17555e-05, 1.18019e-05, 1.18409e-05
                )
}

 

[FvM]

I'm not in the IC design business, but I can give you an obvious explanation:

Not all information in the technology file can be processed by the IC compiler. Some information is reserved for a post-layout simulation with other tools. The warnings are just normal operation.

 

[ThisIsNotSam]

In this case, captables are one of the files that ICC can take as input when doing timing estimation.

The way to read the capTable is as a matrix. One axis is the wire width, the other is the wire spacing. The capacitance between two wires is found by consulting the table. Notice that the template declares 5 indexes for width and 16 for spacing. that is why the table is 5x16.

I believe the warning you are seeing are because ICC prefers to see this information in another format. The way you converted the files created issues. If you have tluplus files, those are preferred.