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PCB Layer Stack UpsLast Updated: May 24, 2019
With the advancement of modern electronics and miniaturization of products, the popularity of multilayer PCBs has grown. The PCB Stack Up refers to the arrangement of copper layers, silkscreen, soldermask, and insulating layers that make up the PCB layout. This PCB Stack Up has become more important as devices get smaller and faster as it is one of the most important part0 in determining the Electromagnetic Compatibility (EMC) of the final product and PCB.
PCB Layer Stack Ups
MacroFab has a set of standard default PCB layer stack ups for PCBs of layer 2 through 10. Due to complexities of additional layers we do not have a default stackup for PCBs more then 10 layers. Contact us if you need this information.
Multilayer PCBs consist of one or more layers of core and pre preg materials to isolate the copper layers from each other. Core material is a glass-reinforced copper-plated epoxy laminate sheet. This is an already cured FR4 material with a thin copper layer on it. Pre Preg is a reinforcing fabric that is pre-impregnated with the resin. This resin is an epoxy based system and is used as a glue to bind the PCB Stack Up together.
For PCBs that have 1oz (35μm) thick copper you will notice that the Copper Foil layer and Copper Plating add up to over 35μm. This is due to the plating process when vias are added to the PCB. The IPC CLASS 2 PCB standard states that via wall plating needs to be a minimal of 0.8mil (0.02mm). The starting thickness of the copper foil is 0.5oz (18μm). After plating the copper foil the final thickness ends up in the range of 38μm to 43μm in thickness.
Stack Up Related PCB Specifications
|Board Thickness Tolerance|
|Thickness < 1.0mm||± 15%|
|1.0mm ≤ Thickness ≤ 1.6mm||± 0.15mm|
|Thickness > 1.6mm||± 10%|
|Minimum Board Thickness|
|2 Layer Boards||0.2mm|
|4 Layer Boards||0.4mm|
|6 Layer Boards||0.6mm|
|8 Layer Boards||1.0mm|
|10 Layer Boards||1.0mm|
|12 Layer Boards||1.2mm|
|14 Layer Boards||1.4mm|
|16 Layer Boards||1.6mm|
|PCB FR4 Material Specifications|
|Loss Tangent @ 1MHz||0.016 – 0.020|
|Loss Tangent @ 1GHz||0.012 – 0.014|
|Dielectric constant permittivity @ 1MHz||4.3 – 4.5|
|Dielectric constant permittivity @ 1GHz||3.8 – 4.0|
|Soldermask Material Specifications|
|Type||2 Component Liquid Photoimageable Soldermask|
|Insulation Resistance (Initial)||2.8 x 10¹³Ω|
|Insulation Resistance (Conditioned)||2.5 x 10¹²Ω|
PCB Material Datasheets
Below you can find the datasheets for the materials that are used to create your PCB.
Custom PCB Stack Ups
If your PCB needs a custom stack up we can still build it! Contact us with your PCB Stack Up and PCB files and we will get you custom quote based on your specifications.