Straight Talk from the Line: Why I’m Dead-Set on 3D SPI for Fine-Pitch, and 2D Just Doesn’t Cut It

A couple days ago something happened on the line, and it really stung. A batch of 0.4mm QFP boards looked fine to the naked eye right off the printer, but two hours later every single one failed functional test. We cracked open the parts and looked — man, the leads just never got any solder […]