| 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. |
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