User Guide

MultilayerBoardswith ThroughVias
This type should be preferred if possible. Vias go through all signal lay
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ers and will be drilled at the end of the production process. The produc
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tioncostsarerelativelymoderate.
LayerSetup
The settings concerning layer composition and number of signal layers
aremadeintheDesignRules, Layers tab, Setup.Seepage 100.
For through vias the setup is very simple. No considerations about
thicknessofcopperandisolationlayersarenecessary.
Simply join two layers by an asterisk (like 1*2 or 3*16) to one core and
combine several cores. This is symbolized by a plus character (like in
1*2+3*4). The isolation layer between two copper layers is called
prepreg. To express the possibility to have vias through all layers the
wholeexpressionissetintoparanthesis.
Examples:
4layers: (1*2+3*16)
6layers: (1*2+3*4+5*16)
8layers: (1*2+3*4+5*6+7*16)
Here vias always have the length 1-16. They are reachable from all layers
(seealsothehelpfunctionforVIA).
Multilayerwith BlindandBuriedVias
In high density boards it is often necessary to use blind and burid vias.
These kinds of vias don't connect all layers, but are only reachable from
a certain number of layers. How these layers are connected depends on
the manufacturing process of the board which has to be determined in
theLayersetupintheDesignRules.
Please contact your boardhouse before
starting your work! Check which
Layersetupissuitableforyourpurpose.
Disambiguation
Core:
The non-flexible kernel which is coated with copper on one or on both
sides.
Prepreg:
Flexible glueing or isolating layer which is used in the manufacturing
process of a multilayer board to press inner and outer layers onto each
other.
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EAGLEManual