Within Circuti Data we will probably not discuss etchback, but we may do that in one of the IPC task groups D-33AA (automotive addendum) or D-33AM (medical addendum). If you are interested I can give you access to one of these IPC taskgroups.
The reason for not discussing a specific parameter is that Circuit Data is a "language" - we describe parameters. The users will then add values. Example: CD have a parameter called layers. The user add number of layers.
So, for etchback, what we should do is to add etchback to the parameter "holes" and describe what is etchback. Then we can add variants: positive etchback and negative etchback. But we will never add the value. That is not our task. In your example we could also link etchback to a type of laminate.
example: polyimide laminate generates a special hole treatment. We add the link and user can select if needed or not. CD should not add a requirement, only the option for the user to do it.
writing this from my cottage terrasse lounge, I hope I managed to explain how it works 😀
The only time a customer require etchback is "Positive Etchback". So, like this:
Holes / plated / Positive etchback /boolean
Description: True to indicate Positive Etchback is required per IPC6010 series.
We only need the selection Positive Etchback because that is the only variant a customer can specify - negative etchback is a part of standard processing. Positive etchback is only allowed when specified.