A headache PCB industry, customers are often designed VIA hole green oil-sided no windows or any part of the green oil window, or single-sided window for this design how do we deal with it?
We first consider the PCB surface treatment using what, if HAL (HALS), then we must avoid the use of single-sided plug hole process, because of the lower one-sided plug hole depth, likely to cause plug solder beads when HAL , the Cypriot impact on the appearance of a large tin beads.
If other surface treatments, such as ENIG, OSP, immersion silver, etc., you can accept the one-sided plug hole. After considering these factors, the customer will look green oil window design, if it is part of the window, you should try to avoid using green oil cap hole edge, allowing green oil into the hole that way, because in this way are likely to cause plug tin beads .
Based on the above two cases, the best treatment is, double-sided plug hole, or green oil cap hole edges, allowing a processing method 1-2MIL tin circle most PCB manufacturers are welcome. Of course, this situation is for ordinary plug oil photosensitive oil is not hot curing oil.
