ILFA design rules for HDI PCBs | ||||
---|---|---|---|---|
A. Plated Thruhole | see figure I. on page 2 | Value | ||
B. Buried Via | ||||
Minimum final diameter | Depending on aspect ratio | ≥100 µm | ||
Drilled diameter | Final diameter + 100 µm | |||
Maximum aspect ratio | Drilled diameter : via depth | ≤ 1:10 | ||
Minimum pad diameter outer layer up to 8 Layers | ≥ Final diameter + 300 µm | |||
Minimum pad diameter inner layer up to 8 Layers | ≥ Final diameter + 350 µm | |||
Minimum pad diameter outer layer > 8 Layers | ≥ Final diameter + 300 µm | |||
Minimum pad diameter inner layer > 8 Layers | ≥ Final diameter + 400 µm | |||
C. Standard Mircovia | see figure II. on page 2 | Value | ||
D. Filled & Capped Mircovia | ||||
E. Copper filled Mircovia | ||||
Minimum diameter as formed | Depending on aspect ratio | ≥ 100 µm | ||
Maximum diameter as formed | ≤ 150 µm | |||
Final diameter | Diameter as formed – (plating x 2) | |||
Minimum capture land | Acc. To IPC-2226 A, Level B | ≥ Diameter as formed+ 175 µm | ||
Minimum target land | Acc. To IPC-2226 A, Level B | ≥ Diameter as formed+ 150 µm | ||
Maximum aspect ratio | Diameter as formed : Via depth | ≤ 1:1 | ||
Filling level copper filled via | 75 % - 90 % | |||
F. Variable depth / skipped Microvia | see figure III. on page 2 | Value | ||
Currently under development | ||||
G. Stacked Microvia | see figure IV. on page 2 | Value | ||
Maximum cycles of stacked vias | 4 | |||
All other values see: C. Standard microvias | ||||
H. Staggered Microvia | see figure V. on page 2 | Value | ||
Minimum staggered microvia pitch | ≥ (Pad a + Pad b)/2 | |||
I. Layout on outer / inner layer | see figure VI & VII. on page 2 | Value | ||
Minimum line / space | ≥ 75 µm / ≥ 75 µm | |||
Minimum distance wall to copper plated thruholes | ≥ 250 µm | |||
Minimum distance wall to copper microvia | ≥ 162,5 µm | |||
Minimum soldermask web | Green soldermask | ≥ 80 µm | ||
Minimum soldermask clearance | ≥ 35 µm | |||
Minimum soldermask overlapping (Soldermask defined pad) | ≥ 35 µm | |||
Your requirements violate our design rules? Please contact us. We will try to find an alternative solution with you. |