I recommend checking the documentation that came with the PDK for any mention of whether you need to supply this. The rule might be abbreviated "CAP ORDER". If already present, it is likely to be in the rules.C file (or whatever the foundry has called the file containing capacitance rules), which the main rule file includes by reference. It could also be in the main rule file, probably with some sort of IFDEF surrounding it.
Also, the person I checked with before posting this pointed out that the SVRF manual notes that if you are using coplanar layers, and the capacitance rule file was generated by xCalibrate 2010.3 or later, the Cap Order statement should be omitted. (It isn't clear to me whether that is because the capacitance rules will have their own Capacitance Order statement or it is meant to run without an order at all.)
Hope this helps-
Hi Wonyoung. Were you able to resolve your issue? The CAPACITANCE ORDER statement should contain all of your metal layers, in order. You can look at the header of the capacitance rule file for the layer names. If you are using an old rule file, you need to have this statement. If you use a newer rule file, then you don't need it anymore.