multiple drill holes on a single padstack

Hi Masa

Each throughole padstack can only contain one drill size,  this is because the drill size will map to a Tool in a physical drilling machine that will drill the board.

When doing a HDI based board it is possible to select different vias with different drill sizes for a given layer pair and then generate a seperate drill file for each of the
layer pairs.

It looks to me in your picture what your referencing is a board that uses blind and burried vias ?, Maybe you can clarify that.

Best Regards.

Hi Masa

Each throughole padstack can only contain one drill size,  this is because the drill size will map to a Tool in a physical drilling machine that will drill the board.

When doing a HDI based board it is possible to select different vias with different drill sizes for a given layer pair and then generate a seperate drill file for each of the
layer pairs.

It looks to me in your picture what your referencing is a board that uses blind and burried vias ?, Maybe you can clarify that.

Best Regards.

thank u for ur response.

 sorry for confusion.

yes, i am talking about blind vias

regards

masa

today cadence visited us and i directly asked this question to them.

they suggested i create a structure of two different padstacks as a symbol.

creating a structure works somehow.

i did not have time to discuss further with cadence but i wonder how to replace the two padstacks with the symbol created.

regards

masa

Look at the command Route - Structures - Replace Via with Structure...

Hi MasaMasa it's interesting they suggested a via structure to you, certainly it is possible to use via structures but there is alot of baggage associated with this. Normally doing blind and burried vias one would have a choice of vias to use for a given layer pair
setup in advance, that way you could easily just change the via you wish to use, similar to how it can be done if doing a standard board.

When doing BB Vias in Cadence the via is based on a standard throughole via you have defined and that means one drill size only.
the difference with BB vias is your standard via gets modified so it only will span the layers of interest and in addition to this a drill file for that layer pair can be created.

Even with via structures you're still looking at using a standard via with one drill size for that via, not multiple selectable drill sizes unless something has changed that I am not aware of with respect to tooling assignments. The via structure does have advantages in certain areas though such as including etch. Can be useful for things like diffpairs, fanouts etc.

I think probably the easiest solution for you is to just create a set of vias with different drill sizes you wish to use. The vias could be the same physical size too with just a different drill. Changing the via on the fly is simple too.

Best Regards.

Hi Masa.

I think the best solution is to just create some vias of the same size with different drill sizes. When doing your design it will be very easy to change the via to the size you wish to use. If you go the structure road your adding complexity. Now structures can be useful for things like a standard diff pair arrangement with return path vias included. Structures can also include etch too so all in all pretty handy depending on your application.

The thing to keep in mind is only one drill size per padstack regardless of it is a structure or not.

All the best.