Severe Delamination After Trim and Form

Guest

Hi,
Is someone give me idea what are the attributes of severe delamination post TFS process. CSAM check prior TFS shows no evidence of delamination but after TFS, delamination takes place.

Thanks in advanced
Bibo

Posted: Mon Jul 18, 2026 2:12 pm Post subject:

one experience we had before showed localized delam only. that means the delam is always on one area of the package only.

Guest

Hi,
Thanks. Any idea why?

Bibo

Posted: Mon Jul 18, 2026 7:49 pm Post subject:

Hi Bibo,

Where is the delamination seen ? Is it happening without any stress (Preconditioning / IR reflow). What is the package type and dimensions ? How many stages does your TFS process has ? Did you analyze in which stage delamination occur ?

regards,

Bala.

Posted: Tue Jul 19, 2026 4:25 pm Post subject:

bibo, if i remember right, a molding compound debris got stuck in one part of the DTF and it was acting like a fulcrum causing delam in the same part of the package. i was just the FA tech that time (long time ago) so i don't remember the exact details anymore. what i remember is that the delam we saw in the parts are in the same area. by the way, i am the guest who posted above.

Posted: Thu Jul 21, 2026 1:08 pm Post subject:

Ideally, there should be no delamination after trimand form - there should be no contact between the t/f tool and the package.

Maybe the other guest was correct. There could be some debris on the f&f tool where the package body was seated and hence act as fulcrum. If this is the case, you're in for serious reliability problem because of possible scenario: mold parting line microcrack or separation, lifted bonds at customer end and possible die crazing on the processed units.

It will be better if you can have a physical cross-sectioned at the delam area.

Guest

also check for worn-out blades and punches...

Guest

If you 're really sure that the delam is happenning during your forming process, you have to do the process mapping of your forming tools. It is not clear what package type you are referring to ,is it gull wing type or j-bend type , because for thin packages with less than 1mm thickness, definitely it will cause package cracks, for thicker packages , there must be some tool marks dependent on the the ammount of stress induced on the package. I remember last time that we encountered an issue of delam and die crack without any external crack manifestation on package surface but there was a localized position with microscopic shallow circular impression on package which came from an stuck up ejector pin of pressure pad. Normally the package is free from any mechanical contacts of the forming tool, the form anvil and the pressure pad are the one holding/clamping the leadframe while the body has a gap on top and bottom except for the ejctor pin that is pushing the package especially on the final forming stage.

Another thing, if the delam is located on the parting line, there must be a microgap, if this is the case , you have problem on the clamping between your strippers, pressure pads and form anvils, you need to check also all the springs and penetration of your tool especially the stopper, kindly check if somebody altered it by grinding or putting some shims or spacers, or check the history if you encountered stand-off or coplanarity issues prior to your delam issue or if the issue happened after doing the preventive maintenance of the tool. Those are good data that can give you leads on finding the true root cause of the problem.You have to replicate it also after finding the root cause to ensure that you really understand it and to avoid it from happenning again or else it will die with a natural death.

I hope this will help.