Utilizing Via in Pad (VIPPO) for Fine Pitch BGAs
I am exploring the use of Via in Pad (VIPPO) for the first time and have some questions for those experienced in this technique. I am working with a 0.5mm pitch BGA and a 0.3mm ball, aiming for a 0.25mm pad size. Here are a few queries I have:
- How should VIPPO be specified on the fabrication drawing for the board supplier?
- For a 0.25mm pad, traditionally a minimum 3mil annular ring was required. Does this mean a <4mil drill is needed, or is there something I am overlooking?
- When VIPPO is specified, are the vias filled and plated on one side or both sides of the board?
- How can I indicate to the board supplier which vias should be filled and plated? (I am using Altium for design)
Although some may find this familiar, my extensive experience in PCB design has not previously necessitated the use of VIPPO. Exploring new techniques is always an exciting part of the design process.
