4 Layer Prototype Service


$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 weekly, and have a turn time from the fab of about two weeks.

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

Detailed Specs

4 Layer Stackup

The current 4 layer board stackup is as follows:

Thickness Layer Tolerance
1 mil solder resist +/-0.2mil
1.4 mil 1 oz copper  
6.7 mil FR408 prepreg +/-.67mil
0.7 mil 0.5 oz copper  
47 mil FR408 core +/-4.7mil
0.7 mil 0.5 oz copper  
6.7 mil FR408 prepreg +/-.67mil
1.4 mil 1 oz copper  
1 mil solder resist +/-0.2mil

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
Minimum hole size 10mil
Maximum plated hole size 260 mil
Maximum non-plated hole size None
Via plating thickness 1mil
Blind Vias No
Buried Vias No