so what was the pad size?
32 ? (22+5+5)

Dennis Saputelli


ICT Mail wrote:

> Ivan, we have found that the best solution is PARTIAL TENTING.
> ie You need to cover the annular ring with mask but leave the hole free.
> This allows the via to be flushed of any residual etching chemicals and will
> still fill if wave soldered.
> Depending on your fabricator and process allowance, typically an 18mil hole
> could use a 22mil soldermask opening (set your mask expansion to -5mil). We
> have not had any adverse feedback in our experience.
>
> hope this helps
>
> Leon Fonstin C.I.D.
> Integrated CAD Technologies Pty. Ltd.
> http://www.ict.net.au
> IPC Certified PCB Designers
>
> -----Original Message-----
> From: Bagotronix Tech Support [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, 13 September 2001 8:11 AM
> To: Protel EDA Forum
> Subject: [PEDA] via tenting question
>
> Hello, all:
>
> I am wondering what to do about vias.  I have a design for an 8-layer 0.090
> in. PCB with about 700-800 vias 32mil pad, 18mil hole (no BGAs).  Since the
> vias can be very close (6 mil) to other vias and pads, I want to cover the
> vias with either soldermask or tent them.  What is the difference between
> just covering them with soldermask, or tenting?  I guess tenting is where
> the via holes are filled with an inert material to plug them, right?
>

--
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