I was creating polygon pours on a power layer. I was creating one pour for +3.3V and another for +5V. After my original outlines for the pours, I decided I wanted to make a change. I adjusted the sides of the polygons several times. One area that originally was part of the +5V polygon I changed to the +3.3V. I thought I was careful to make a cutout in the +5V into which the +3.3V was going to extend. This was verified, in my mind, because there was not any cross-hatched area showing an overlap. Additionally, when I ran a drc it did not show any errors. However, when the manufacturer ran a check they got the indication there was a short circuit between the +3.3V and the +5V.
We went back to examine the layout and discovered that in the area that we changed from +5V to +3.3V there was an unmarked overlap in the two polygons. We only saw it when we turned on the 'show' and selected the +3.3V polygon and then the +5V polygon and we could see that there was an area of overlap. With this case the autorouter connected both +3.3V signals and +5V signals to the same polygon pour. Thus, the short.
Two things are concerning. First, that the software even allowed me to do this. And second, that the drc did not flag this as an error.
Has anyone else come across this?
Fusion
