ENIG necessary for SMD? - Page 1
Forum section: electronics / beginners

author: level6
author_rank: Regular Contributor
timestamp: December 21, 2019, 11:05:44 pm
content: 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?

author: ataradov
author_rank: Super Contributor
timestamp: December 21, 2019, 11:18:15 pm
content: 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.

author: Psi
author_rank: Super Contributor
timestamp: December 21, 2019, 11:48:58 pm
content: 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.

author: Yansi
author_rank: Super Contributor
timestamp: December 22, 2019, 01:47:20 am
content: Larger pitch BGAs work absolutely fine even with HASL.HASL is a bit easier to handsolder too, from my experience.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: December 22, 2019, 02:50:16 am
content: I have no problem with HASL. It might even make small components a bit easier.

author: OwO
author_rank: Super Contributor
timestamp: December 22, 2019, 05:05:08 am
content: 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.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 22, 2019, 08:32:10 am
content: 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 22, 2019, 11:49:15 am
content: 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.Tim

author: Gyro
author_rank: Super Contributor
timestamp: December 22, 2019, 01:54:39 pm
content: 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.

author: Psi
author_rank: Super Contributor
timestamp: December 22, 2019, 11:39:12 pm
content: Quote from: JustMeHere on December 22, 2019, 02:50:16 amI 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 23, 2019, 05:40:05 am
content: 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

author: mvs
author_rank: Frequent Contributor
timestamp: December 26, 2019, 01:44:38 pm
content: Quote from: Psi on December 22, 2019, 11:39:12 pmUsually, fresh HASL is much better then cheap (thin) ENIG on that.

author: Bob Moore
author_rank: Newbie
timestamp: February 24, 2020, 07:38:50 am
content: 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 herehttps://titoma.com/blog/pcb-surface-finish-enig-hasl-osp-isn-iagit might be helpful