Solder Paste & Stencil Design

Aperture reduction: 10–20% for fine-pitch ICs and BGAs to control paste volume
Stencil thickness: 0.12mm for standard 0402+ work; 0.10mm for fine-pitch QFN/BGA
Avoid stencil bridges between adjacent fine-pitch pads — ensure 0.05mm minimum web
For QFN exposed pads: use windowed/segmented aperture to prevent outgassing bridging