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board delaminated after reflow

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#58529

board delaminated after reflow | 7 April, 2009

Board delaminated after reflow - see attached picture. Does moisture cause this problem?

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#58533

board delaminated after reflow | 8 April, 2009

We don't view this as "board delamination." It looks more like "solder mask bubbling." It may be the picture. Please describe the issue or enclude additional pictures.

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#58534

board delaminated after reflow | 8 April, 2009

push the "bubling" and it springs back. It does not look like solder mask. We may have to fight with board house as they don't think it's their problem. Do you know any way to find the real reason? Any idea or help will be appreciated.

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#58535

board delaminated after reflow | 8 April, 2009

That is a delamination. It is indeed from moisture. You need to bake the boards for at least 8 hours and you should be good to go.

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#58536

board delaminated after reflow | 8 April, 2009

We had the exact same problem in early stages of lead-free. Very random positions of defect + some boards were 100% O.K. and others were an explosion of what I see in your picture. Turned out to be bad processing/materials from board house. I'm don't remember exactly what the process problem was called but we ended up going to a different material and have not had a problem since.

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#58539

board delaminated after reflow | 8 April, 2009

Hi,

Need a little more info,

1) this board is definitely delaminated 2) this board looks like a Std FR4 board with 63/37 Hot air finish with probably 140 tg. material. Was this reflowed under lead free temps?

3) Do you Pre-bake product

4) What is the date code on the board. 5) was there a moisture gauge in the vacuumed sealed bag the boards were in or a descant pack.

6) Check fabrication notes to make sure what your customer called out for material, RoHs or Non-RoHs. and then find out what material your board shop used.

I would find our what material was used to fabricate product and double check if correct profile was used.

Regards,

Board House

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#58540

board delaminated after reflow | 8 April, 2009

2) STD FR4 material with HASL finish, 4 layer board. Reflowed under tin-lead temps with another 4 layer board same time(no delamination problem).

3) We uasualy do not pre-bake board unless board is too old.

4) We do not have the board on hand right now so can not check date code. The board is about 2-3 weeks old. After we found delamination problem, the board house brought us a same board from their stock and reflowed it under same profile, got same problem.

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#58544

board delaminated after reflow | 8 April, 2009

The things to ask your board supplier would be:

1) Was the Pre-preg material that was used on this board within its Shelf life? and ask for the Incoming inspection CofC for the Pre-preg material. 2)Was this order shipped from Stock - this is why I asked about the Date code. FR4 material can suck up moisture as its sits in and uncontrolled environment.

From the looks of the board I see some dry weave in the left edge of the board and more on right side of board, which would lead me to believe that boards had resin starvation issues. Could be caused by old pre-preg material or wrong Press cycle selected. Pic's attached. You should not be able to see the weave of the material this easy.

Was this the first time that you had De-Lam on this Part number? if not you may want to change the stack-up of the board and go with Higher resin pre-preg or go with 2 ply pre-preg. This would remove any resin starvation issues. Just a suggestion.

I would say this issue is a board supplier issue not Assembly.

Regards, Boardhouse

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#58615

board delaminated after reflow | 16 April, 2009

We have seen this exact same problem. Our vendor agreed it was their problem and also agreed it was a moisture issue within the PCB layers, not the solder mask. We have taken to baking our boards, especially when they are manufactured during the late spring and summer when it is humid.

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