Stencil design uses a 10 to 20% aperture reduction for fine-pitch ICs and BGAs, 0.12 mm thickness for standard work (0.10 mm for fine-pitch QFN/BGA), a 0.05 mm minimum web between apertures, and windowed apertures on QFN exposed pads to prevent bridging.
- 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