Author Topic: ENIG necessary for SMD?  (Read 3125 times)

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Offline level6Topic starter

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ENIG necessary for SMD?
« on: December 21, 2019, 11:05:44 pm »
I read somewhere that for SMD components you really want to have ENIG pads, the reason being that ENIG is flatter than HASL. Is that really the case?
 

Offline ataradov

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Re: ENIG necessary for SMD?
« Reply #1 on: December 21, 2019, 11:18:15 pm »
Depends on the complexity/price of the boards and your scale and the number of failures you are willing to accept. In small scale manufacturing it does not matter that much. if you are making iPhones, then it may make a huge difference.

Also depends on the size of components. For 0603 and up, it really makes no difference.
Alex
 

Offline Psi

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Re: ENIG necessary for SMD?
« Reply #2 on: December 21, 2019, 11:48:58 pm »
Yes ENIG is flatter, and this good for really tiny stuff and BGAs but usually you don't *need* ENIG, it just makes the yields better.

For hand assembling hobby stuff using 0402 and TQFPs HASL is 100% fine.
If your doing some advanced hobby stuff with BGAs you might want to consider ENIG to make things easier for you, but it's still not needed.
Usually if you're working with big BGAs you can afford to pay a few extra dollar for ENIG.
« Last Edit: December 21, 2019, 11:53:48 pm by Psi »
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Offline Yansi

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Re: ENIG necessary for SMD?
« Reply #3 on: December 22, 2019, 01:47:20 am »
Larger pitch BGAs work absolutely fine even with HASL.

HASL is a bit easier to handsolder too, from my experience.

 

Offline JustMeHere

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Re: ENIG necessary for SMD?
« Reply #4 on: December 22, 2019, 02:50:16 am »
I have no problem with HASL.  It might even make small components a bit easier.
 

Offline OwO

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Re: ENIG necessary for SMD?
« Reply #5 on: December 22, 2019, 05:05:08 am »
I've soldered probably 10 0.8mm pitch BGAs on HASL and haven't had a soldering defect so far. If you see significant solder residue on the pad you can use hot air + solder wick + flux to clean it up beforehand.
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Offline Siwastaja

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Re: ENIG necessary for SMD?
« Reply #6 on: December 22, 2019, 08:32:10 am »
IMHO, I suggest ENIG only for small (0.5mm pitch) BGA, LGA, QFN components; even then, it's not 100% mandatory, but may improve yield in production.

For something consisting of 0402 passives, QFP and other leaded components, definitely HASL since it's cheaper.
 

Offline T3sl4co1l

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Re: ENIG necessary for SMD?
« Reply #7 on: December 22, 2019, 11:49:15 am »
I get HASL most of the time for leaded (TSSOP, QFP, SOIC, chip R's/C's, and THT).  No problems.  ENIG or other flatter platings are preferred for leadless (DFN, SON, QFN, LGA, BGA) types.

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Offline Gyro

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Re: ENIG necessary for SMD?
« Reply #8 on: December 22, 2019, 01:54:39 pm »
I had no yield issues with 0.5mm QFPs on HASL in mass production.

For 0.5mm BGA we used ENIG but I can't say whether it was actually necessary.
Best Regards, Chris
 

Offline Psi

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Re: ENIG necessary for SMD?
« Reply #9 on: December 22, 2019, 11:39:12 pm »
I have no problem with HASL.  It might even make small components a bit easier.

I find the solder flows better onto ENIG than HASL,  but i'm not sure if its just in my head.
It could be a HASL lead vs lead free issue.  If you order lead HASL PCBs it's not always easy to know if they actually used lead or lead free.
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Offline T3sl4co1l

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Re: ENIG necessary for SMD?
« Reply #10 on: December 23, 2019, 05:40:05 am »
Hm, I've always been impressed how little lead-free solder flows over ENIG or OSP.  I've seen PDP done before, that is, paste defined pads.  Wide open copper area, selective paste.  Not often: stuff like D2PAKs, heatsinks and mounting holes (when they decide to put some solder blobs on the pad).

Tim
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Offline mvs

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Re: ENIG necessary for SMD?
« Reply #11 on: December 26, 2019, 01:44:38 pm »
I find the solder flows better onto ENIG than HASL,  but i'm not sure if its just in my head.
Usually, fresh HASL is much better then cheap (thin) ENIG on that.
 

Offline Bob Moore

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Re: ENIG necessary for SMD?
« Reply #12 on: February 24, 2020, 07:38:50 am »
I would definitely go for ENIG, especially with surface mount components, some of them are really small and a really flat surface is needed for proper soldering, and yes ENIG is more expensive than other coatings such as HASL, but the issue with HASL is that the surface is very uneven.

OSP and  ISN are also an option you can consider for SMT components, I saw an interesting comparison table here https://titoma.com/blog/pcb-surface-finish-enig-hasl-osp-isn-iag it might be helpful
Best,
Bob Moore
 


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