I am processing PCB's that have an n-tech osp coating and am finding huge inconsistencies in wetting. Some boards process clean with good wetting and the next has terrible wetting. The boards are stored and handled properly.
Has anyone had this type of problem before? Is there a better alternative osp or coating? is there any process changes that should be made with the n-tech?
Never heard of N-Tech. Whose material do they use? Two common materials are: Imidazole (Via Systems) and Entek (Enthone)
OSP is a lacquer that fabs apply to boards by either spraying or dipping. What thickness control does your fab use? For instance, Enthone-OMI specifies thickness range is to be 0.2 to 0.5 um (0.000000787 to 0.00000197") for ENTEK Plus CU-106A. Obviously, that leaves lots of room for variation, assuming the fab does things correctly.
So, what's the mean and range of OSP thickness on your boards?