Lum Wee Mei,
I looked at the pictures of your PCBs on Steve's site and it was the
same thing I ran in to a month ago. I was convinced it was a
delamination, the board vendor said no way - it was pink ring. I sent a
board to a third party test house and they did a microsection - sure
enough it was a delamination. So be careful in judging pink ring -vs-
delam unless you have a microsection to make a better determination.
Tom
Lum Wee Mei wrote:
>
> Glenn,
>
> Thanks for your input. The information has been very useful and I am digging up
> more information on "pink ring" and looking into the IPC-6015 for details.
>
> Steve,
> I am most grateful to you for the fast service despite almost 8:45pm your time.
>
> Regards,
> Wee Mei
>
> [log in to unmask] wrote:
>
> > Scary world, I just went through something very similar to this. It turned
> > out to be "Pink Ring". Maybe somebody has a better explanation, but it was
> > loss of black oxide around certain vias, mainly power and ground planes, due
> > to full metal (no spokes). My pictures look a lot like yours! We decided
> > it wasn't a defect since, according to IPC-6015, it didn't affect
> > functionality. And, that was after accelerated life testing.
> >
> > Glenn
> >
> > -----Original Message-----
> > From: Lum Wee Mei [mailto:[log in to unmask]]
> > Sent: Monday, May 19, 2003 4:56 PM
> > To: [log in to unmask]
> > Subject: [TN] What is this defect?
> >
> > Hello,
> >
> > I have a defect that looks like delamination. One important observation
> > noted is that this defect is found only around PTH vias NOT component
> > holes. In addition, this "suspected delamination" surfaces are very flat
> > to touch - no bulging. I do not think it is delamination because I have
> > never seen delamination occurs around PTH. However, I am be wrong. This
> > defect appear in several areas on the board but funny observation is
> > that 3 out of 5 pcs of the fabricated boards have the same defect at the
> >
> > same locations, around P3 and P4. The only difference is the intensity
> > of the defect.
> >
> > This is a 8-layer design with L4 as power and L5 as ground. As such,
> > clearances are expected for pads not to be shorted to these
> > layers.However, instead of solid round clearance around the pads,
> > irregular shapes are found. In one of them, the clearance actually
> > overlap each other. The layer stackup is as follows :
> >
> > ---------------------------18um
> > prepreg 1080+7628
> > -----------------------core 0.21mm(35um/35um)
> > prepreg 1080*2
> > -----------------------core 0.21mm(35um/35um)
> > prepreg 1080*2
> > -----------------------core 0.21mm(35um/35um)
> > prepreg 1080*2
> > ---------------------------18um
> >
> > I have seek Steve's kind assistance to download 4 pictures of the
> > defects. Kindly look at them. I would appreciate your opinions on :
> > 1. If this is not delamination, what defect is it?
> > 2. What is or are the likely cause(s)?
> > 3. Does it has impact to reliability?
> >
> > Thanking you all in advance.
> >
> > Regards,
> > Wee Mei
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