Issue link: https://iconnect007.uberflip.com/i/1527613
10 DESIGN007 MAGAZINE I OCTOBER 2024 We recently spoke with IPC instructor Kris Moyer about partial HDI, a process that's recently been growing in popularity. Par- tial HDI allows designers to escape route out from tight-pitch BGAs on one layer, where a mechanically drilled plated through-hole is not an option, while avoiding the complexity and expense of sequential lamination cycles. As Kris explains, this process doesn't add much to the cost, and it's fairly straightforward. But there are some competing signal integrity and fabrication requirements to contend with. We asked Kris to walk us through this process. Partial HDI: A Complete Solution Andy Shaughnessy: We've been talking recently about partial HDI. You've been teaching this in your IPC classes. Tell us about it. Kris Moyer: e BGAs are the most problem- atic as far as tight pitch, along with the col- umn grid array (CGA), and the land grid array (LGA). All these packages have been going to smaller pitches. When they first came out, we were at 1.27 mm pitch, and you could easily get a mechanically drilled plated through-hole via between the lands. But as you start get- ting below that pitch to 0.5 mm, 0.4 mm, and Feature Interview by the I-Connect007 Editorial Team