How to maintain plane flow with VIAs under a BGA

By Bas Driessen

 

For one of our customers, we received a question about how to maintain plane flow with VIAs under a BGA when repositioning those VIAs. Especially with a fine VIA grid, it can take time to center the VIAs neatly between others. The challenge is that even the slightest movement of a VIA can cause the plane to be cut between two VIAs. From a design perspective, this is undesirable as it restricts plane flow.

 

So, is there a way to make the VIAs snap to the BGA grid, allowing them to be moved around under the BGA without cutting the plane?

 

Absolutely. To demonstrate this, we’ve created a video showing how to align the VIA grid with the BGA grid anywhere on the board.

 

 

In short, the proper way to achieve this is to set the VIA grid offset to the X and Y coordinates of the BGA. Then, use the pitch or half-pitch of the BGA as your VIA grid spacing. 
Once configured, moving a VIA will cause it to snap to the BGA grid.

 

To learn more feel free to contact us.