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For 0.5mm Pitch QFN package the fuducial pad is required or not required?

Raam

Hi,

For 0.5mm Pitch QFN, local fuducials required or not required? IF yes, please tell me the standard fiducial pad location for the QFN component.

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    Yes. It depends on the assembly house.

    As per my understanding, you don't need to add local fiducials to any of the chips unless otherwise you are pasting the PCB using a local stencil. Global fiducials are enough otherwise.

    I normally use 3 global fiducials on geometric extends of the board.

    The size can be:

    Pad: 40 mils

    Soldermask: 80 mils

    Solder paste: 40 mils

    (Rule: If pad radius is R, Mask radius should be 2R)

    If you want to add local fiducials for the ICs you can use this values itself. Place this pad in the diagonal corners of the IC. Use an 80 mil diameter route and via keepout for the fiducials on ETCH/TOP layer.

    Hope this helps...

    Babu

Reply
  • archive

    Yes. It depends on the assembly house.

    As per my understanding, you don't need to add local fiducials to any of the chips unless otherwise you are pasting the PCB using a local stencil. Global fiducials are enough otherwise.

    I normally use 3 global fiducials on geometric extends of the board.

    The size can be:

    Pad: 40 mils

    Soldermask: 80 mils

    Solder paste: 40 mils

    (Rule: If pad radius is R, Mask radius should be 2R)

    If you want to add local fiducials for the ICs you can use this values itself. Place this pad in the diagonal corners of the IC. Use an 80 mil diameter route and via keepout for the fiducials on ETCH/TOP layer.

    Hope this helps...

    Babu

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