Guest
 Posted: Mon Nov 15, 2025 6:01 pm Post subject: IR temp profile for Thin and Thick package |
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| Why temperature at IR reflow applied for thin package has more than thick package (I think thick and small package shall be used the same temperature)
Refer JDEC Thank you in advance |
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| Posted: Mon Nov 15, 2025 7:26 pm Post subject: |
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| Tata, it could be that your customer for the thin package will use it for lead-free processing. Board-mounting for Pb-free components is done at a higher temp , i.e., 260 deg C. Pls check if your thin package is for Pb-free processing and your thick package isn't. |
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| Posted: Tue Nov 16, 2025 9:00 am Post subject: |
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| Thank you for your suggestion. Refer JEDEC spec STD-020-C for all
packages use Pb-free process. It wrote that ; 1) Package thickness <1.6mm IR peak temp. require 260 degree C 2) Package thickness >/=2.5 mm IR peak temp. require 245 degree C * I wonder why temperature peak for thin package has used higher than thick package, in my view ; a) Thick package shall be used higher temp than thin package b) If your suggestion is about melting point at board mounting, why we don't measure at only melting area (outer lead tip) for all package type? |
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Guest
| Posted: Tue Nov 16, 2025 1:32 pm Post subject: |
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| Hi all,
Tata is right in saying that JEDEC requires a different IR reflow temp for a thick or high-volume package and for a thin/small package. I believe the reason for this is the fact that smaller/thinner packages reach a higher maximum temp than larger/thicker packages during board mounting. Note that in the real world, both the small and large packages can go into the same board and soldered at the same time. Since they will all be subjected to the same temp profile, the larger packages will be slower in heating up than the smaller ones. Thus, at the end of the reflow, it's really possible that the max. temp reached by the smaller packages will be higher than that of larger packages. For this reason, smaller packages must be qualified to a higher reflow temp than large packages, hence the difference. By the way, I'm not sure if this is the right explanation, but this is the drift of the conversation we were having just a month ago. Let me know if there are other reasons for the difference. Thanks, Buchokoy |
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Guest
| Posted: Wed Nov 17, 2025 3:30 pm Post subject: |
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| Dear Buchokoy,
Thank you very much, your answer made me feel very very good. Tata |
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