Thanks for the response Victor,
Steve is posting the pictures.
The anomaly was not present on time zero boards.
Another board that was HASL finish had the same growth.  It went through 
he same HALT testing.  It was also  from the same supplier.
There was no re-work or repair performed in any of the areas.
It appears crystalline in nature, however the only magnification I have at 
the moment to look at the PCB is 20X.

Tom Burek, CID+




<[log in to unmask]> 
11/14/2007 10:54 AM

To
<[log in to unmask]>, <[log in to unmask]>
cc

Subject
RE: [TN] Green Growth between PCB traces






Can you post a photo of this anomaly?
Is this anomaly on time zero boards? 
Is this anomaly on other Rel. environment boards?
Was a rework/repair conducted near this location?
Is it crystalline in nature?

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Tom Burek
Sent: Wednesday, November 14, 2007 11:44 AM
To: [log in to unmask]
Subject: [TN] Green Growth between PCB traces

Hello everyone,
Has anyone ever seen or experienced the phenomenon of this green growth 
between the traces and even on some of the pads.
It almost appears as if it is leaching out from under the etchback of the 
traces into the space between the traces. 
Oddly enough it is only on one side of the board, the bottom side, 
opposite the component side.
It will not wash off with DI or Alcohol and a Q-tip, however it will scrub 

off with a stiff bristle brush or very gently with an exacto knife.
The soldermask is very thin in spots, (white solder mask).

The PCB is ENIG with white soldermask.  FR4 material (IPC-1401/21).
The boards had just gone through HALT testing, (Thermal Shock: 2 hrs. @ 
85°C then 2 min. 5 sec. swing to  -40°C for 2 hrs. This was repeated until 

it failed after 136 hrs.) We think this green stuff might have caused the 
failure. 
 With the temperature swings, often there is condensation created so, 
possibly created by humidity? 
Is there something in the PCB fabrication process that could have lay 
dormant until it experienced thermal shock?

I know an analysis of the green stuff is necessary, but I was wondering if 

anyone has ever seen of experienced this type of growth before.

Thank you in advance.

I have attached some pictures, but I know somehow they are suppose to get 
to Steve to post. 



Tom Burek, CID+

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