Hello,
Can you please provide PCB Manufacturing capabilities regarding minimum soldermask opening, mininumus soldermask dam specifically.
I am using the nRF5340 SoC QFN 94 package and it will require the following:
Pad diameter: 8.858mil
Green soldermask opening: 1.968mil
Green soldermask bridge: 3mil
Thank you,
Mikael
Is this for a rigid board?
Our director of R&D will reply tomorrow and in the meantime you can see our rigid capabilities page https://www.protoexpress.com/products/rigid-pcb/
The pad diameter is fine but our minimum opening is 4 mil and the bridge/dam is 4 mil. Might be able to do the 3mil bridge but not the 1.968mil opening. Actually the 8.858 mil pad with a 1.968 mil opening doesn’t seem to make a lot of sense to me – big pad, tiny opening. Can you explain why you’re going with this?
Thank you for your reply. The dimensions I gave you, are straight from the vendors Altium footprints, which can be found here, Downloads → Reference Layout.
In v1.1 the pad size is 8.858mil with a 1.968mil opening
The nominal pin size of the aQFN is 0.20mm (~7.874mil)
Keeping their recommended pad size, an opening of >=3.5mil will not leave room for a bridge. So if I increase opening to 4mil, the opening will be overlapping.
Do you have recommendations?
Are soldermask defined pads an option?
Also just to make sure, the 4mil opening is that the total diameter of the opening or is that the expansion from the pad edge? e.g. 10mil pad size, and 18mil pad diameter (4mil expansion around the pad)
Can do a 4mil or larger mask defined pad. The actual pad is 8.858mil so there is plenty of room.