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How To Paste Soldar mask on Both sides of VIAS

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aliraza786

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Hello i have made a double side pcb, but the VIAS comes under the SMD IC which has Ground plane so when i solder the IC VIAS becomes short with the IC, is there any way i can paste resist layer on these VIAS in ARES Porteus ? i need it urgently, and also is there any way to make this board work ? how can i paste resist layer on this board manually ? is there any way ? No_solder_mask_on_vias.jpg
 

FvM

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In a full featured PCB layout tool, the solder mask opening of vias can be edited and e.g. set to no completely tented via. No idea if Proteus Ares can be considered a full featured layout tool in this regard.

If the component has an exposed ground pad, I would check in a first order if it needs to be connected. It's often a required ground connection and/or required for heat sinking. If the exposed pad can stay unconnected, you can use adhesive film to isolate it.

Soldermask covering won't be normally accepted as a reliable means to isolate a pad. But it can be O.K. for a hobby circuit.
 

senilicus

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Typically a case of an incorrect footprint. The EP pad is there for a reason, Either providing a ground connection with low inductance (by adding Via in Pad) or as a way to transfer heat away from the device.

As FvM stated, soldermask cannot be used as an isolator, so placing a thin piece of kapton tape might do the trick. You still have to make sure that you can leave the EP pad unconnected.

The final step would be to correct the footprint for the device in the library.
 

marce

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Trouble with adding tape is it raises the pads you want soldering off the board, this can cause more problems especially on a small BTC (bottom terminated component).
 

FvM

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Trouble with adding tape is it raises the pads you want soldering off the board, this can cause more problems especially on a small BTC (bottom terminated component).

Agreed. I would consider the kapton film suggestion as a way to get a functional prototype or pre-series with some effort and redesign the board according to state-of-the-art.
 

ArticCynda

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Why don't you simply move the vias outside the IC? There is only a single row of pins and plenty of space available, so there should be no reason to place vias under a part that actually requires an exposed pad for heat dissipation.
 

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