Problem Updating vtType Parameter When Swapping NMOS and PMOS in SKILL Code

Hello Cadence Community,

I’m working on a SKILL procedure to swap device cellNames between nmos and pmos while preserving and updating the vtType parameter.

I'm using IC23.1 version

Goal:

• If the device is nmos, store its parameter "vtType" in variable p, change cellName to pmos, and set vtType to pmodel.
• If the device is pmos, store its parameter "vtType" in variable n, change cellName to nmos, and set vtType to nmodel.

Code:

procedure(paratest()
  let((cv a b c d e p n pmodel nmodel newMaster newcdf)
    cv = geGetEditCellView()
    foreach(inst cv~>instances
      a = inst~>cellName
      b = inst~>libName
      c = inst~>viewName
      when(a == "nmos"
        foreach(param cdfGetInstCDF(inst)~>parameters
          when(param~>name == "vtType"
            p = param~>value
            printf("Current value of %s vtType value is %s\n" a p)
            pmodel = if(p == "nvt"
                       then
                         "pvt"
                       else
                         if(p == "nhvt"
                           then
                             "phvt"
                           else
                             if(p == "nulvt"
                               then
                                 "pulvt"
                               else
                                 p
                              )
                          )
                      )
           )
         )
        newMaster = dbOpenCellViewByType(b "pmos" c)
        when(newMaster
          inst~>master = newMaster
          d = inst~>cellName
          when(d == "pmos"
            newcdf = cdfGetInstCDF(inst)
            foreach(param newcdf~>parameters
              when(param~>name == "vtType"
                param~>value = pmodel
                printf("set vtType for %s to: %s\n" d pmodel)
               )
             )
           )
         )
       )
      when(a == "pmos"
        foreach(param cdfGetInstCDF(inst)~>parameters
          when(param~>name == "vtType"
            n = param~>value
            printf("Current value of %s vtType value is %s\n" a n)
            nmodel = if(n == "pvt"
                       then
                         "nvt"
                       else
                         if(n == "phvt"
                           then
                             "uhvt"
                           else
                             if(n == "pulvt"
                               then
                                 "nulvt"
                               else
                                 n
                              )
                          )
                      )
           )
         )
        newMaster = dbOpenCellViewByType(b "nmos" c)
        newcdf = cdfGetInstCDF(inst)
        when(newMaster
          inst~>master = newMaster
          e = inst~>cellName
          when(e == "nmos"
            foreach(param newcdf~>parameters
              when(param~>name == "vtType"
                param~>value = nmodel
                printf("set vtType for %s to: %s\n" e nmodel)
               )
             )
           )
         )
       )
     )
   )
 )

Observed Behavior:

• Output in ciw:
  paratest()
  Current value of nmos vtType value is nvt
  set vtType for pmos to: pvt
  Current value of pmos vtType value is pvt
  set vtType for nmos to: nvt
  Current value of pmos vtType value is pvt
  set vtType for nmos to:nvt
  Current value of nmos vtType value is nvt
  set vtType for pmos to: pvt
   
  Layout output:
  Only cellNames were changing..but vtType parameter is setting "Invalid Model"
  FYI, "Invalid Model" is also included in the list of vtType parameters.

Question:

• Why is the vtType assignment failing and defaulting to "Invalid Model"?
• Is there a better approach to update instance parameters after changing the master?

Any guidance or best practices would be greatly appreciated!