Tolerances Multilayer – Stackups
- PCB manufacturers specify a thickness tolerance of ±10 %.
- The built-up copper layer also has a tolerance of ±10 %. This must be considered when calculating the trace thickness.
- The milling tolerance for outer contours is ±0.1 mm up to a size of 100 mm. Above 100 mm, this can be up to ±0.2 mm.
- The thicker the material thickness of the multilayer, the more dimensionally stable the core / finished ML.
- The thicker the prepreg thickness, the more dimensionally stable the fabric.
- The thinner the prepreg, the greater the resin content.
- The thicker the inner layer of copper, the more resin-rich prepregs must be used to fill the copper areas that have been etched away.
- If you require smaller tolerances for installation reasons, please specify this separately in advance.
Tolerances of Plated Through Holes (PTH)
The diameter tolerance is specified as -0.05 / +0.1 mm. The position tolerance of the holes is ±0.1 mm.
Tolerances from conductor pattern to hole pattern are specified as follows:
| Outer Contour | Tolerance |
|---|---|
| < 30 mm | ±0.05 mm |
| < 150 mm | ±0.1 mm |
| > 150 mm | ±0.15 mm |
Thickness of Solder Mask
- When specifying PCB thicknesses, please also note the layer thicknesses during solder mask application.
- The solder mask layer is typically between 40 µm - 80 µm thick. This thickness must be counted when specifying the PCB thickness. I.e. a PCB with a thickness of 1.5 mm can be up to 1.73 mm thick with tolerance and lacquer.