The Silent Killer Inside Your Board

Imagine baking a cake where the filling expands five times faster than the crust. That's exactly what happens inside your PCB every time it hits a reflow oven. The copper barrels, the resin, the glass fibres, and the solder balls all want to grow at different speeds when heated. Most of the time it works out. Sometimes — usually under your most expensive BGA it doesn't.

This article unpacks three terms that are usually discussed separately but should always be discussed together: CTE (Coefficient of Thermal Expansion), Tg (Glass Transition Temperature), and Via-in-Pad (VIP). Get these right and your boards survive thousands of thermal cycles. Get them wrong and you'll be staring at a dead BGA wondering why "the design was fine."

Why this matters

The cheap part of solving these problems is the design phase. …

— Article from E-Cad Bridge —