PCB Layer Stack

edited October 2019 in Making Your PCB
Working on the PCB Layer Stack and outputting Gerber job file.
The PCB Layer Stack determines, among other things, the permissible layer for blind/buried vias.

Here's a sample 4 layer stack (This is not the same as the Layers panels)

CLICK TO ENLARGE

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The developer of AutoTRAX DEX. 
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Comments

  • In the above stack buried vias can only connect Inner1 and Inner 2

    Blind vias connections depend on how the board is stacked during assembly.

    If both outer copper and prepregs are stacked with the core then blind vias are not possible.

    I will detail this in the help file when done.
    The developer of AutoTRAX DEX. 
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  • edited October 2019
    Possible vias.

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    The developer of AutoTRAX DEX. 
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    The developer of AutoTRAX DEX. 
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    The developer of AutoTRAX DEX. 
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  • 6 Layers


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    The developer of AutoTRAX DEX. 
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  • 8 Layers


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    The developer of AutoTRAX DEX. 
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  • This would be so beautiful. This picture can be used to send to the board manufacturer as part of the PCB specification. I think it will also be very educational for any use who has not seen this before.

    But I don't recognize the situation that you can't go down to the inner layer (inner 1) of a 4 layer board. I am pretty sure that I learned that it was cheaper to connect just top to inner 1 and not top to inner 2. All through the entire PCB is always OK.

    Another important thing to know is that the length (or depth) of vias defines the minimum possible diameter of the via. This also results in that a thinner PCB can have smaller vias. This are things to check with the board manufacturer.
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  • This is going to be part of the Gerber Job Specification file included with the Gerber Files et. al.

    It will also have data for layer simulation/transmission line/analog stuff.
    The developer of AutoTRAX DEX. 
    pdf
    pdf
    GerberJobSpec.pdf
    611K
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  • I just read this at a random Googled manufacturer (Ourpcb.com)

    "Thanks to laser drilling which helps to manufacture of the blind via in a blind via PCB by controlling the depth of drilling. Some manufactures limits connection via to even the number of layers from the top surface and they also don’t allow blind via from the bottom layer and it is the standard practice of manufacturing industry."


    Wasn't aware of that, if true. But there are many small things, especially considering vias, that affects the cost and it would be great if DEX gives the user the option to select between those options to reduce cost. It would be even better if DEX could inform the user that he is making a PCB that uses a more expensive design. It's the problem withe that the design program should be able to do EVERYTHING. (There are always some user that asks for that weird feature). Even if it is super expensive and you have to call Würth to make the PCB.
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  • Here is a picture of most via options considering costs. (There are several more but I think these are the most common).

    picture
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  • It's to do with how the build-up the board.

    Cores have copper on top and bottom. This is the basic 2-sided board.

    Cores drill holes connect top to bottom and are plated if they have buried vias.

    To make more than 2 layers either:

    1. Another core is 'glued' to the first core using 1 or more prepreg sheets or

    2. A single copper sheet is glued to the core using 1 or more prepreg.

    This process can continue.

    As the board is build up, it is pressed together, and drill as required.

    A single copper and prepregs cannot be drilled.

    This can be complex and expensive.

    Most PCB manufactures limit your options.

    If you are making Apple PCBs then you set up a factory to do your boards.


    The developer of AutoTRAX DEX. 
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  • edited October 2019
    Coming soon:

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    The developer of AutoTRAX DEX. 
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    The developer of AutoTRAX DEX. 
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  • In the interest of clarity I think that the text "Number of Layers" in the PCB Stack tab above should be Number of Inner Layers as you do in the Layers tab.
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  • edited October 2019
    In the interest of clarity I think that the text "Number of Layers" in the PCB Stack tab above should be Number of Inner Layers as you do in the Layers tab.
    Now uploaded.

    Changed both to total layers. You can enter 1 for single sided.

    Notice text font colors/bold/italic

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    The developer of AutoTRAX DEX. 
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  • Added 2 read-only layers top solder mask and bottom solder mask.
    The developer of AutoTRAX DEX. 
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  • edited October 2019
    Improved graphics/info.

    Click to enlarge.

    image
    The developer of AutoTRAX DEX. 
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