Photographs of corrosion and surface defects
Photographs of flaws in the Allflex films were taken when the boards arrived in September '08 and again in March '09 after being stored in a dry Nitrogen environment. The first two photographs below show that there was already evidence for corrosion or poor quality of the copper surface on one of the 5 micron boards when they arrived from the manufacturer, but it is not clear that this problem became worse over time.
There are marks on one of the 5 micron center boards that from a distance look like fingerprints but actually turn out to be scuff/scratch marks:
Here are some other examples of flaws found on the 5 micron boards:
There is evidence for degradation of 2 traces on the same 5 micron center board that I was not able to verify already existed when the board came from the manufacturer:
Below are before and after photographs for one of the central 2 micron boards. There is evidence for either oxidation of the copper or left-over photo-resist material present upon arrival of the boards from the manufacturer. Again, it does not appear that these flaws got worse over time.
Almost all of the 2 micron boards have regular marks indicating possible left-over contamination from rollers:
Here are some more examples of localized surface defects on the 2 micron boards: