Electronic – Is it good practice to use a flood fill ground plane as a pad for a component

pcbpcb-design

We have recently had an issue with one of our products and I came across the following while reviewing the PCB. It's worth noting I don't think this is in any way related to the issue I was troubleshooting.

The three components shown in silkscreen clockwise from the top are capacitors that connect between a pin on the chip and the ground plane.

Is it standard practice to layout like this? It may be perfectly normal, it just looked a little odd to me… I would have expected 2 clear pads with a track to the ground plane or another trace. My understanding was that having separate pads would help the components centre themselves during reflow if they were placed slightly out of alignment?

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Best Answer

As said in the comments, there should be thermal reliefs. One or several short trace to the flood fill. This will avoid not only misalignment but also tombstoning. To avoid misalignment try to draw traces symmetrically.

Also, vias should be separated from pads by a short trace.

As it is, it could still solder properly in a good reflow soldering because everything is heated evenly but with the risk that it couldn't. IMO tombstoning is a real risk here, especially with small components.

Absence of thermal relief would make hand rework with an solder iron very difficult.