Scott,
Entrapment of process chemicals could arise, especially if using OSP.
Blow out of entrapped air causing a volcano looking tent.

We have resorted to a 1:1 of the finished hole diameter to allow venting.
This has worked quite well.
Keep in mind LPI sticks to Cu much better than Au.

Have a nice day,

Shawn Utz
Tera Computer Co.

>
> From: Scott Buscomb <[log in to unmask]>
> Subject:      [DC] Soldermask over Vias
> To: [log in to unmask]
> Content-Type> : > text/plain> ; > charset=us-ascii>
> Content-Length: 1048
>
> What are the drawbacks to tenting vias? I am planning on tenting vias
> using LPI both sides on SMOBC. The vias are .013 and .020. I realize the
> LPI is pulled into the holes causing a thinning of the mask.
> I am trying to prevent solder bridging during reflow and wave soldering.
>
> Any comments would be appreciated.
> TIA,
> Scott Buscomb
>
> ################################################################
> DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
> To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
> To unsubscribe:   SIGNOFF DesignerCouncil
> ################################################################
> Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
> ################################################################
>
>

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################