This is a very simple problem to solve.
Here is how: Looking at the picture, you have the design rules set to something like:
- line to line spacing 7 mils
- line to via 5 mils
- via to shape 5 mils
- line to shape 25 mils
So you allow as little as 5 mils from a via to a shape, but from a line to a shape you ask for 25 mils -- why do you need such a high clearance? Is it for PCB manufacturability or signal integrity (SI)? PCB manufacturability is definitely not an issue because if you can etch 5 mils between other copper objects, you can do that also around shapes. From SI point of view, if there is GND plane adjacent to this signal plane, that plane is most likely just a few mils away so having the GND shape close is not an issue either. How to fix the problem: Set the line-shape DRC to the same value as via-shape and you will not have this issue anymore.
For example, set both to 5 mils or both to 10 mils, or whatever value you are OK with. I see this issue of GND pouring all the time. I work with a lot of layout designers and I do see the DRC rules are many times quite arbitrarily selected too large. My recommendation, in general, is to have for all the same-plane, copper-to-copper objects spacings as similar as possible, in any pair combinations of line, via, pad, pin_TH and shape; there are 15 combinations.
How to set them the right way?
- First, make all of them as small as possible, as allowed by PCB manufacturing and assembly, but do challenge them is they look unreasonably large. The smaller you can get them the easier will be to complete the board (quite obvious but overlooked).
- Then take the largest number off all, and use that for all the other ones. This way GND pours will work the best and will have the same gap from all the other objects. Essentially, a GND poor is just another wire that is wider - so treat it as a wire and have for it the same DRC rules as for a wire.
Hope this answer helps somebody else also as it comes late.
Please post some comments if you find anything not right.
Thanks for reading (and hope useful.)