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Holes, Pads & Clearances
| Hole Size | Mechanically drilled holes (finished size) 0.15mm to 6.0mm. Laser drilled microvia's down to 0.05mm. |
|---|---|
| Hole Size Tolerance | Plated +/ - 0.05mm |
| Hole Positional Tolerance | +/ - 0.075mm |
| Pads | Pads require 0.075mm annular ring (diameter of pad is 0.15mm greater than diameter of the drilled hole). |
| Clearances | Clearances in copper planes should leave a 0.25mm annular around the drilled hole |
For Calculations
Drilled Hole = finished hole size + plating allowance + any applicable tolerance
Example
Finished hole size = 0.4mm with AUNIC finish (No Tolerance)
= 0.4+ 0.1 = 0.5mm Drilled Hole Size
Finished hole size = 0.4mm, Tolerance of + 0.1mm/ -0mm with AUNIC finish
= 0.4+ 0.1+ 0.05 = 0.55mm Drilled Hole Size
Please note that all drilled hole sizes are rounded up to the nearest 0.05mm.
| Plating Allowance Table | |
|---|---|
| Immersion Gold/Nickel (AUNIC) | +0.1mm (0.004") |
| Immersion Tin (ITIN) | +0.1mm (0.004") |
| Hot Air Solder Level (HASL) | +0.1mm (0.004") |
Blind Vias Design Rules
| Via Type | Finished Hole Diameter | Dielectic Type | Cu Plated Thickness | Max Aspect Ratio | Max No of Layers Connected | Min annular ring-finished hole to pad |
|---|---|---|---|---|---|---|
| Laser Drilled Microvia | 0.1mm - 0.05mm | RCC | 20-25 microns | 1 | 2 | 0.125mm |
| Z Axis Controlled Mechanical | >=0.15mm | Prepreg / RCC | 20-25 microns | 1 | dependant on hole size | 0.125mm |
| Multiple Lamination | >=0.15mm | Prepreg | 18-25 microns | 7.3 | dependant on hole size | 0.125mm |
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