Wafer/Die thickness Change

Guest

Is wafer thickness or die thickness change can be considered as major change that will affect form functio and fit
Is there any calculator that can assess if this change will pose for reliability risk?

qtp girl

Posted: Wed Jul 21, 2026 1:41 pm Post subject:

Hi QTP Girl,

A change in the die thickness will affect several things: 1) the amount of plastic on top of the die; 2) the flexural strength of the die itself; 3) the loop profile of the wires; 4) the proximity of the wires to the top surface, etc. These all play a part in the general reliability of the device, so it is prudent to do rel assessments on affected samples whenever a 'significant' change in the die thickness is encountered.

That being said, I must admit that I never saw a device fail in the rel assessments we've done in the past for a change in the die thickness. Maybe we weren't really changing the die thickness too much.

Then again, we all know that there's a point wherein the change will start affecting the device. Unfortunately, I'm not aware of any calculation technique to determine that critical point. If you're in doubt, it is always better to conduct a rel assessment than rely on calculations, so I would suggest that you go that route - perform rel assessments, that is.

Thanks and keep on posting!!!

EE