Definition

Flip chip mounts a bare die face-down with solder bumps connecting directly to the substrate - no wire bonds. Benefits: shortest possible interconnect (lowest inductance), higher I/O density, better thermal path through the die back. Challenges: requires precise bump placement, underfill for reliability, substrate with matching bump pitch (often 0.15-0.4mm). Used in high-performance processors, RF devices, and space-constrained applications. PCB substrates for flip chip need HDI capability with micro-vias for escape routing from the dense bump array.