Guest
 Posted: Mon Nov 17, 2025 10:45 am Post subject: Missing Die Overcoat |
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| We have a lot that didn't get a die overcoat. Some say this might be a rel issue. Some say that good units after etest will be good. Is this correct? Can we simply release the lot after production testing? Need ur advice on this.
Thanks, Resident Engr |
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Joined: 20 Jun 2026
Posts: 43
| Posted: Tue Nov 18, 2025 10:15 am Post subject: |
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| If the die overcoat is supposed to be there because the die is sensitive to package stress, then etest can screen out all units that will fail because of no overcoat. The pkg stress will cause 'affected' units to shift parametrically and fail during etest.
FARel Engr |
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Joined: 16 Jun 2026
Posts: 108
Location: Paranaque City, Phils.
| Posted: Tue Nov 18, 2025 10:35 am Post subject: |
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| FARel Engr,
Stress levels on the die may be different at different temperatures. I would suggest to Resident Engr to do the test over the entire temperature range that they're guaranteeing the device to work. If this is 0-125 deg C, then they should test at 0, 25, and 125 deg C. EE |
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Guest
| Posted: Wed Nov 19, 2025 10:14 am Post subject: |
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| suggest you do SHRT before your 3-temp testing. delam after SHRT might change stress profile on the die. better to make sure boardmount will not induce unexpected failures.
tonks |
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Guest
| Posted: Fri Nov 21, 2025 2:04 pm Post subject: |
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| Thanks guys for your inputs. We just scrapped the lot because the quantity is not so high and the yield wasnt good.
Resident Engr |
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