Tent through hole pad only on top

I made a small adapter board for an infrared camera that looks like this from the bottom:

Screenshot from 2020-08-17 15-18-02

The whole bottom of the camera is a metal plate connected to ground with a little keep-out for the other pins.

Currently my board looks like this from the top:

Notice the camera footprint has copper exposed on the top and I’m afraid that the copper is wide enough so there is a risk of shorting to the ground on the bottom of the camera.

Is there a way I can extend only the top solder mask so it covers the pads but leave the bottom solder mark as-is so I can actually solder the camera?

You can tick off the Technical layers in the pad properties.

However, your board manufacturer may not like the mask covering the holes, and there should be some margin anyways even if you add a smaller mask opening manually. Otherwise the mask liquid flows to the hole.

An alternate technique (if you have the vertical clearance available) is to use a component spacer. They come in all sorts of shapes and sizes. See this DigiKey search for some ideas:

If there isn’t anything that fits there or your own preferred electronics vendor, you could design the shape yourself as a non-copper PCB, small round board with the holes drilled in the right place. Should be a super cheap board to have multiple hand-fulls made. Then just quote Ivan Miranda as you use your own designed “Spaceerrrrrs!!!”.

P.S. I would highly advise for using some sort of insulating spacer in this instance. Over time with normal handling vibration, soldermask may abrade away and short ground to your signal lines or power.

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Thanks a lot for the guidance. I will look for a spacer.

You should not rely on solder mask for this.

If it’s for a few boards, spacers can easily be made by folding a piece of PVC tape (with the glue sides to each other), then put it on the PCB and make some holes with a needle. Then put the spacer on the pins of your IC and cut it out with scissors.

Another solution is to make your annular rings smaller, so they do not extend over the glass ring in the housing, and then also put the 3 tracks on the other side of the PCB. any abraded solder mask would then simply short GND of your IC to the GND plane.

Using small annular rings is tricky though. you also have to consider tolerances of pin and hole diameters to ensure no short can occur.

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