PCB finish Immersion gold Vs HASL lead free

Thread Starter

DJ_AA

Joined Aug 6, 2021
308
Hi

I am creating a small batch of PCBs.

Out of curiosity, what do people generally use for their finish on surface?

Immersion gold or Standard HASL lead free?

Is there any perticualur reason why Immersion gold should be always used, in terms of design constraints or requirments?

Thanks
 

Ian0

Joined Aug 7, 2020
10,045
Hi

I am creating a small batch of PCBs.

Out of curiosity, what do people generally use for their finish on surface?

Immersion gold or Standard HASL lead free?

Is there any perticualur reason why Immersion gold should be always used, in terms of design constraints or requirments?

Thanks
I use HASL.
Gold doesn’t tarnish, so, in theory, unused boards will keep longer before becoming difficult to solder. In practice, HASL doesn’t tarnish much either.
I did find one manufacturer who didn‘t get HASL quite right leaving bumps of solder too high, and surface mount components wouldn‘t sit on top of them and moved around during the soldering process
 

Ervin2022

Joined Mar 30, 2022
18
Hi

I am creating a small batch of PCBs.

Out of curiosity, what do people generally use for their finish on surface?

Immersion gold or Standard HASL lead free?

Is there any perticualur reason why Immersion gold should be always used, in terms of design constraints or requirments?

Thanks
Hello,
While HASL is probably cheaper, it does have some drawbacks that you might want to consider.
HASL creates a very strong thermal shock, and "Leadfree HASL" is even higher in temperature. For a polymer based board - thermal shock is always a risk. All vias, but especially high aspect ratio vias are very sensitive to CTE issues.
Also, as another replier already mentioned, planarity of the finish is an issue - HASL might very easily create uneven bumps, while ENIG is a high planarity finish. ENIG is sometimes related to "Tin whiskering" fault, so you might look at other planar finishes - such as OSP, ENEPIG, ImAg, etc.
Cost is always a major factor, however you should consider not only the cost of the finishing , but also the implications on the cost of the assembly.

Best of luck,
Ervin
 

Thread Starter

DJ_AA

Joined Aug 6, 2021
308
Hi Thanks

Generally i use HASL on all PCB, I have not had any issues with them, even though the gold finish has much smoother surface.

I use Gold finish on one perticular design,as it includes LGA module and you can not see all the pins, therefore wanted to ensure soldering is done correctly in the process.
 
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