Shoukai,

Have a look in Xilinx's manual, they use to have answers on most things:

http://www.xilinx.com/bvdocs/userguides/ug112.pdf

Even Amkor have  good papers :

http://www.amkor.com/products/notes_papers/Reliability_of_Lead-Free_Sold
er_Connections_Whitepaper.pdf

There are many factors that can cause openings, TN archive is filled by
answers on your question, but I think you need investigate your balls
before we can give you a certain answer.

 Someone will probably give you a troubleshooting list. Georg Wenger,
for instance. He helped us with SuperBGA problems some years back, will
see if I can find that excellent list.

I'm afraid you will be drowned with e-postings now. A good start is to
read basics like the above. 

Inge

-----Ursprungligt meddelande-----
Från: TechNet [mailto:[log in to unmask]] För shoukai zhang
Skickat: den 19 oktober 2005 14:55
Till: [log in to unmask]
Ämne: [TN] PBGA soldejoint open , what's the max. ramp up rate
requirement of wave soldering?--

Hi all,

We encountered solderjoints opening (cross section show out) of PBGA
component which placed on top of PCBA after passing through wave
soldering, we measured the BGA ball peak temperature and it is about 170
degree C, also we notice IPC7095 define that BGA ball temperature should
be under 150 degree C during wave soldering.

Now, my questions are:

1. what possible factors you think which cause PBGA solderjoint opening
during wave soldering, the peak temperature of solder ball?
2. We know that IPC/JEDEC J-STD-020C defines average ramping up rate is
3 degree C/s for moisture sensitive SMD during reflow soldering, are
there similar industrial standards define maximum ramping up rate for
PBGA(placed on topside PCBA) during wave soldering? What the maximum
ramping up rate of wave soldering is?

3. Why IPC 7095 defines BGA ball temperature should be under 150 degree
C during wave soldering? To prevent solder ball remelting?

Thanks for any response!

Best regards,

Shoukai Zhang


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