Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

PCB delamination

Tom Gervascio


PCB delamination | 6 November, 2000

I ma trying to get some information on possible causes and screening tests for PCB delamination. Is the main cause moisture absorption of PCB material or entrapped chemicals and or air in innerlayers that expand when expsoed to subsequent reflow and wave profiles.

Over the last month we have seen a dramatic increase in the frequency of delamination of G10 multilayer boards. 1. There does not seem to be a correlation to PCB date code 2. The problems occur on multiple lines and on products that we have run before (Check a reflow profile and the peak temperatures and heating rates haven't changed) 3. 90 percent of product comes from one vendor while the balance comes from another vendor.

Is there anything else in itnernal process or material handling practices that I should look at?

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Re: PCB delamination | 6 November, 2000

Bingo! Sounds like you solved your mystery.

You've checked your key process steps, the product has been running in your processes for some time with no process changes. This all points back to one of your process input, i.e. the fab. Experience says that it is at least difficult, if not immpossible, to induce delam in the assembly processes.

Various contamination sources in the fab process can contribute to delam of the fab. Invite your fab vendor over for a look.

Happy assembling, Boca

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Re: PCB delamination | 6 November, 2000

I love this!!! Two whizzettes with the same information and they spin-off in two different directions. Gad this is great!!!

Delamination is a pretty broad topic, but that you have a problem with two suppliers makes me think the delamination is caused by something you are doing to the boards.

You�ve told us little about your process, but delamination has several broad causes: 1 Poor board quality, which can be checked at in-coming. 2 Excessive process temperature, which can be monitored. 3 Repeated reflow operations, which can be limited.

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Re: PCB delamination | 5 February, 2001

Talking about delamination...... I have a customer requesting info about the max temperature ratings for FR4. Can anyone point me to a good source? ( and yes, I HAVE checked the archives, to no avail.....)


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Re: PCB delamination | 5 February, 2001


One source for this information is form the manufacturer Park/Nelco.

They have a large website and give specifications for all sorts of laminates, including FR4.


I'm sure that other laminate manufacturers with a presence on the web wil also have similar info.


Pete B.

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Re: PCB delamination | 5 February, 2001

Thanks Pete,

Looks like I got the info I needed


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Re: PCB delamination | 5 February, 2001

Wha, Nellie!!!

Delamination & Blistering IPC-A-600D

Although it may occasionally occur because of a severe process breakdown, delamination and blistering occurs as a result of an inherent weakness of the material. Either condition represents a breakdown in the cohesive strength of the composite laminate and the internal openings that develop can mechanically weaken in the final product and also provide undesirable conductive paths between circuit elements.

Delamination or blistering may occur in clad laminate materials either between plies of laminate, or between the laminate and the foil cladding. Any occurrence, either in the as-received condition or after routine thermal stress testing at receiving inspection is evidence of a major flaw, and the material should be rejected, since the defect will almost always propagate during the normal stresses of manufacturing.

Causes of Delamination "Quality Assessment Of Printed Circuit Boards"

The reason for delamination is epoxy starvation in the glass cloth layers or an incomplete curing of the base material. It has been reported that some manufacturers of laminates have reduced the lamination press cycle a little in order to increase production. In multilayer boards, visible delamination may be due to poor lamination of layers or insufficient bonding of prepregs to the inner layer copper circuits. Here, the PCB manufacturer is in a way also the "manufacturer" of the base material.

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