Pin holes may occur but outgassing to the extent to blow solder from the
hole would cause a fracture or void in the copper. If glass fibers protrude
thru the plating this can also cause outgassing to that degree. These fibers
would also be easily identifiable on a structural integrity coupon
(micro-section).


James Hofer
Director of Operations
Accurate Circuit Engineering
3019 S. Kilson Dr.
Santa Ana Ca. 92707-4202
714-546-2162 work
714-473-6127 cell
[log in to unmask]
----- Original Message -----
From: "Lee Parker" <[log in to unmask]>
To: "'James Hofer'" <[log in to unmask]>; "'TechNet E-Mail Forum'"
<[log in to unmask]>
Sent: Friday, September 10, 2004 1:40 PM
Subject: RE: [TN] Blow Holes -- Where the heck does the moisture come from
anyway?


> James
>
> Pin holes can occur with out a fracture (in the normal sense) in the
> copper barrel. These pin holes are usually caused by air bubbles at
> electroless copper. Glass boundless extending into the barrel will also
> cause this problem as the copper seal around these bundles is usually
> poor.
>
> Best regards
>
> Lee
>
>
>
> -----Original Message-----
> From: James Hofer [mailto:[log in to unmask]]
> Sent: Friday, September 10, 2004 3:53 PM
> To: TechNet E-Mail Forum; Lee Parker
> Subject: Re: [TN] Blow Holes -- Where the heck does the moisture come
> from anyway?
>
> However, Were this the case you would see fracturing or voiding of the
> via.
>
>
> James Hofer
> Director of Operations
> Accurate Circuit Engineering
> 3019 S. Kilson Dr.
> Santa Ana Ca. 92707-4202
> 714-546-2162 work
> 714-473-6127 cell
> [log in to unmask]
> ----- Original Message -----
> From: "Lee Parker" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, September 10, 2004 12:31 PM
> Subject: Re: [TN] Blow Holes -- Where the heck does the moisture come
> from
> anyway?
>
>
> > Carrie
> >
> > If you cross section the vias, remove the solder from the hole and
> look
> > at the copper barrels at very high magnification (use and SEM if
> > possible)you may see pin holes in the copper or glass bundles
> protruding
> > into the hole. This coupled with moisture in the dielectric which is
> > normal can create the mechanism. When the board is quickly heated in
> > assembly (reflow or wave solder) the moisture is pressurized and flows
> > out through the pin holes into the barrels blowing the molten solder
> in
> > the barrels out onto the board.
> >
> > Best regards
> >
> > Lee
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Morse, Carrie
> > Sent: Friday, September 10, 2004 2:33 PM
> > To: [log in to unmask]
> > Subject: [TN] Blow Holes -- Where the heck does the moisture come from
> > anyway?
> >
> > Just wondering a few things here at 2:30 on Friday Afternoon:
> >
> > 1.  What else causes Blow Holes at wave on TH comps?  Is it primarily
> > moisture?
> > 2.  Where does the moisture come from?
> > 3.  Are certain board materials more likely to sponge up the moisture
> in
> > the air?
> > 4.  Can hole wall quality play a part in contributing to blow holes?
> >
> > -Carrie
> >
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