I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.
Photo resolution is too low to see details. Would prefer a microscope photo with diffuse lighting.
To me, the pad surface looks partly like silver metallic rather than white. What's the gold process? If it's nickel-gold, could it be that the final gold layer is damaged?
as you can see, on the Annula Ring, we have some white residue, I mark on picture below. It's happen when we do solder mask -> exposure -> cure (enough time) -> develop soldermask -> test (we find the residue at this step.
this residue some time can be cleaned by gently wiping, some time it's can not clean and we have to remove all the solder mask and do it again. Because this white residue, when we do next step (do reflow, it's cannot be welded).
I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.
it's not the problem with the plating. As i noted above. I send you picture with a mark, picture below. You can see it's has a white residue on annular ring. The process is : Clean acid -> do Solder mask -> exposure -> cure (enough heat and times) -> develop -> test (we find the white residue at this step).
It's very serious. because if we have this white residue, when we do next step we can not do reflow, can not be welded.
Photo resolution is too low to see details. Would prefer a microscope photo with diffuse lighting.
To me, the pad surface looks partly like silver metallic rather than white. What's the gold process? If it's nickel-gold, could it be that the final gold layer is damaged?
Thank you for your reply. Sorry with the picture, I think it's clear enough to see the white residue. I send a picture with a mark, picture below. It's not from plating, we have no damaged with the gold plating.
the process is : Clean with acid -> do solder mask -> exposure -> cure (with enough heat and times) -> develop -> test (we found the white residue at this step)
this is the serious issue. Because if we have the white residue we can not do the next step ( reflow.. it's cannot be welded).
I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.
Sorry again about the picture
But we have many many problem with this white residue . You can see, that white color on the annular ring. That the white residue.