日本語
I came across an interesting effect on a PCB today. There seems to be small holes or voids in the copper, which at first I thought was micro via stitching, until I remembered it's a single-layer board. The effect is locally uniform, with centres at about 0.25 mm, but comes and goes in patches across the board.
I assume this is a manufacturing defect, but does anyone know the mechanism that causes it?
- Comments(1)
A****min
May 23.2019, 10:24:14
It looks like the PCB software generated a grid to fill the planes, with line widths that are not sufficient to cover the whole area. I remember some PCB software from 20 years ago that did this as default. If the clearance between two lines is below the minimum clearance the PCB manufacturer guarantees, you will get that kind of holes in the copper. The defect is not uniform because of variations of the focus resolution of the photo process. You get a better focus right under the light source, but if you are too offset on the side it will blur a bit and won't produce holes as big.
