4 Layer ProtoPro

PhotoProtoPro4LayerPCB_800Our 4 Layer – ProtoPro Service is a low cost choice for four layer boards, including the solder mask and silkscreen layers. These are the same professional quality multi-layer boards as our production service, but at a fixed price and quantity. They are shipped in just 3 business days.

Multi-layer boards have many advantages over double-sided boards. They can be designed more compactly, they greatly improve noise immunity and are much easier to lay out.


4 Layer – ProtoPro boards have top and bottom copper layers with a tin/lead solder plating over the pads. Sandwiched inside areGround and Power planes. Through-hole pads can be connected to, or isolated from, the planes. These boards include top and bottom solder masks giving the boards a dark green color. On the top surface is a white silkscreen layer showing the component outlines and text.

ProtoPro designs must fit in a 21 sq-in rectangle and no dimension can exceed 12″.


  • 4 Layer – ProtoPro orders have a fixed price of $199 (plus shipping).
  • With each order, we send you 4 identical boards.
  • Orders submitted Monday through Friday by 2:00pm ET are shipped in 3 business days.
  • Paying for your boards is easy by MasterCard, Visa or American Express.

Manufacturing Specifications

ExpressPCB Manufacturing Specs PDF

 ProtoPro 4 Layer
Layers4 Layer
Lead Time3 Day
Maximum Board SizeThe board size must fit in a rectangle that is 21 square inches or smaller, and the longest dimension cannot exceed 12 inches.
Minimum Board SizeMinimum dimension in height or width is 0.35 inches.Total board area must be greater than 0.4 square-inches. (i.e. smallest square board we can make is 0.64 x 0.64 inches)
Panelize Muliple BoardsWe do not recommend that users cut apart 4 layer boards because this can result in shorts between the inner layers.
Minimum Trace and SpaceEtching resolution is: 0.006″ minimum trace width, 0.006″ minimum space width.
Inner LayersThe two inner layers can have traces or solid copper planes. Through-hole pads can either be connected to or isolated from these copper planes. The planes are inset 0.025″ from each edge of the board.
Solder MaskTop and Bottom
Silk ScreenTop
Surface FinishTin\Lead
Solder Mask Pad TolerancePads on the solder mask layers are grown by 0.003″ on all sides. As a result, very fine pitch surface mount components may not include any solder mask between the pins.
MaterialOur 4 layer laminate is constructed as a .059" FR-4 package, which includes .0007" starting copper on layers 1 and 4 (industry standard 1/2 ounce copper base). We plate an additional .001" copper on the surface after drilling and imaging, resulting in a copper thickness on the surface of ~0.0017″. The two inner layers are each constructed with .0014" copper (industry standard 1 ounce).
Dielectric ConstantThe dielectric spacing between the top layer and the “Ground” inner layer is 0.012″ with a dielectric constant of 4.6 +/-0.2. The dielectric spacing between the bottom layer and the “Power” inner layer is 0.012″ with a dielectric constant of 4.6 +/-0.2. The dielectric spacing between the “Power” and “Ground” inner layers is 0.028″ with a dielectric constant of 4.6 +/-0.2.
Plated HolesBoards are manufactured with 4 copper layers and all holes plated-through.
HolesTwenty-four hole sizes are available: 0.008″, 0.014″, 0.020″, 0.025″, 0.029″, 0.033″, 0.035″, 0.040″, 0.043″, 0.046″, 0.052″, 0.061″, 0.067″, 0.079″, 0.088″, 0.093″, 0.100″, 0.110″, 0.125″, 0.141″, 0.150″, 0.167″, 0.192″, 0.251″. Hole sizes other than those listed are not offered.
Hole ToleranceThese sizes are the finished hole diameters after plating. The 0.008″ and 0.014″ holes may be filled with solder and can only be used as via. The tolerance for the 0.020″ hole is +0.003 / -0.005. The tolerance for the other hole sizes are +/- 0.004″.
Hole Location ToleranceOur hole location tolerance is +/- 0.005”. As such, the tolerance between two holes would be +/- 0.010”.
Minimum Hole DistanceA minimum of 0.021″ space must remain between adjacent holes. For example, the center-to-center distance between two pads with 0.020″ holes must be 0.041″ or greater.
Internal Slots and CutoutsNone
Perimeter SlotsBoard perimeters are cut to shape using a 0.093″ router bit. Slots in the perimeter must be 0.100″ or wider. Narrower slots will not be milled correctly.
Perimeter RoutingThe edges of the board are cut with an accuracy of +/- 0.015″. A minimum of 0.020″ blank space is recommended between the perimeter and all features on the board. Traces placed closer than 0.015″ to the board’s edge may be routed off.
TemperatureThe maximum operating temperature is 125 degrees C.