4 Layer Medium Run Service

Moving to a small production run? Our medium run service will help bridge the gap between prototypes and a full panel.


$2 per square inch, 100 square inch minimum. You can have as many different designs as you want, as long as each design is ordered in a multiple of 3 boards.

For example, if you have two 25 square inch designs, you could order 3 of each for a total cost of $300.

100 inches is just the minimum order. You can order as much as you’d like beyond that.

Turn Times

Fabrication time can vary for medium run orders. Boards typically ship within 14 calendar days but may take up 4 weeks.

To make an order, please contact [email protected]

We do not offer Super Swift Service for 4 layer boards.

For faster options, you may be interested in our Standard 4 Layer Service.

Fabrication Specs

4 Layer PCB Specs

Quick Specs

  • 5 mil (0.127mm) minimum trace width
  • 5 mil (0.127mm) minimum trace spacing
  • 10 mil (0.254mm) minimum drill
  • 20 mil (0.508mm) minimum drill slot
  • 4 mil (0.1016mm) annular ring
  • PCB thickness of 1.6mm (.063”)
  • 1oz copper on both sides (1.4mil,35um)
  • 0.5oz copper on internal layers (0.7mil, 17.5um)

Detailed Specs

  • ENIG (gold) finish for superior soldering and environmental resistance.
  • Solder resist and silkscreen on both sides.
  • Minimum 15 mil keepout distance from traces to the board edge.
  • PCB substrate is FR408 (180Tg).
  • PCB substrate is compatible with a lead-free process.
  • The boards themselves are also lead free and RoHS compliant.
  • PCB Substrate dielectric constant of 3.66 at 1GHz
  • Minimum 4 mil (0.1016mm) soldermask web.
  • Maximum soldermask expansion is 2.5mil (0.0635mm).
  • Minimum 68 mil (1.7272mm) width on internal cutouts. See our [Outline][outline] page for detailed information.
  • Manufactured in the United States.
  • Castellations are allowed, but not officially supported.
  • We do not support blind or buried vias.
  • Drill slots are supported from most tools, when used in typical ways. See our Slots page for detailed information.

4 Layer Stackup

The current 4 layer board stackup is as follows:

Thickness Layer Tolerance
1 mil (0.0254mm) solder resist +/-0.2mil (0.0051mm)
1.4 mil (0.0356mm) 1 oz copper  
6.7 mil (0.1702mm) FR408 prepreg +/-.67mil (0.017mm)
0.7 mil (0.0178mm) 0.5 oz copper  
47 mil (1.1938mm) FR408 core +/-4.7mil (0.1194mm)
0.7 mil (0.0178mm) 0.5 oz copper  
6.7 mil (0.1702mm) FR408 prepreg +/-.67mil (0.017mm)
1.4 mil (0.0356mm) 1 oz copper  
1 mil (0.0254mm) solder resist +/-0.2mil (0.0051mm)

The substrate for both the core and prepreg is FR408, with a dielectric constant of 3.66 at 1GHz, and is compatible with a lead free process. The boards themselves are also lead free and RoHS compliant.

The prepreg is comprised of 2 layers of Isola 2113.

Layer Naming

When sent to fabrication, the layers are manufactured in the following order according to their file extension. We advise following this naming scheme if your design is sensitive to distance of the inner planes in order to avoid any confusion.

Layer Suggested File Extension  
Layer 1 .GTL Top or Front layer
Layer 2 .G2L Internal plane
Layer 3 .G3L Internal plane
Layer 4 .GBL Bottom or Back layer

Internal Plane Polarity

When submitting gerbers, we need the “positive” internal planes, meaning that lines represent copper, not the absence of copper.

Some CAD tools will generate the internal planes as power planes with “negative” polarity so the lines indicate where copper should be removed. To work around this, declare the internal planes as signal layers and use a copper pour to define the power plane.

Take a look at our Positive and Negative Gerbers page for more information.

4 Layer Drill Specs

Spec Size
Minimum annular ring 4 mil (0.1016mm)
Minimum hole size 10mil (0.254mm)
Minimum slot size 20mil (0.508mm)
Maximum plated hole size 250 mil (6.35mm) (See note)
Maximum non-plated hole size 250 mil (6.35mm) (See note)
Drilled hole positional tolerance 2 mil (0.0508mm)
Drilled hole size tolerance +/-2.5 mil (0.0635mm)
Via plating thickness 1mil (0.0254mm)
Blind Vias No
Buried Vias No

Note: Holes larger than 250 mil will be milled with larger tolerances. These are fabbed using a 5mil(0.127mm) positional tolerance, and +/-5mil(0.127mm) hole size tolerance.