Well, I think it is more than terminology. The dry film soldermask goes on as
From: Dennis Saputelli [mailto:[EMAIL PROTECTED] i recently sent a board to a new shop for us
the notes said 'tent smallest vias'
they called and said they can't tent the vias unless they use dry film, but they usually use LPI
they said 'well we can *cover* the vias with LPI but we can't *tent* them'
so i guess there is a possibly significant issue of terminology about this
a sheet of material thermally laminated to the board. It is quite thick, and will
remain as a planar sheet, covering holes up to maybe 1/8" diameter without
sagging into the hole.
The LPI is a thick liquid squeegeed onto the board. It may fill in the holes,
or sag down and then pop, coating the hole walls partially. The very smallest
vias might actually get tented pretty well as the stuff goes on. But, then when
it is exposed and developed, the LPI in the holes may not harden, and it will then
get washed away during the development step. You've got to trust the fab shop,
as they know their processes and materials better than anybody.
Jon
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