4 Layer Prototype Service

Pricing

$10 per square inch, which includes three copies of your design. For example, a 2 square inch board would cost $20 and you’d get three copies of your board. You can order as many copies as you want, as long as they’re in multiples of three.

Turn Times

Orders are sent to fabrication every other day, and have a turn time from the fab of one week. 95% of our 4 layer orders ship within 12 days.

You can get a quote, approve a design, and pay for an order at OSH Park.

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

Need more than 150 square inches of boards? Our 4 Layer Medium Run Service is a less expensive option for larger orders.

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
  • 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 100 mil width on internal cutouts. See our Slots page for further information.
  • Manufactured in the United States.
  • Castellations are allowed, but not officially supported.
  • We do not support blind or buried vias.
  • Non-plated slots wider than 100 mil (2.54mm) are allowed, but not officially supported.
  • Plated slots and smaller slots are possible, but not officially supported. See our Slots page for more.

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.

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)
Maximum plated hole size 260 mil (6.604mm)
Maximum non-plated hole size None
Via plating thickness 1mil (0.0254mm)
Blind Vias No
Buried Vias No