Tolerances in PCB Manufacturing

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 < 30 mm = ±0.05 mm
  • Outer contour < 150 mm = ±0.1 mm
  • Outer contour > 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.