Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


non-wetting

xzinxzin

#19952

non-wetting | 16 May, 2002

anyone experience to solve the non-wetting on Microleadframe packages component terminal sides. 1)I test the components solderbility in dip and look test, in solder pot at 240 deg C,the wetting on the sides is ok. but I run on mass production in reflow oven, I got non-wetting on the terminal sides of the components. 2)solder paste is water soluble solder paste and max-peak temperature is 215 deg C, the reflow time is 64 sec. anyone experience to have to solve this problems

reply »

#19968

non-wetting | 17 May, 2002

First thing that comes to mind is that your �dip & look� testing at 240�C clearly doesn�t represent the in-use application of 215�C. So, what are the test results at 215�C?

Other questions are: * Can we assume that the solderability of other components is good? * Can you reflow, under normal conditions, another, similar component to these pads [even if it doesn�t fit quite properly]? * What is the solderability protection on the terminations of your micro-leadframe package? * Your peak temperature is 215�C and your time above 183�C is 64 sec, what is your time above 210�C?

reply »

xzinxzin

#19973

non-wetting | 17 May, 2002

*the other components are 0402 and SOIC 16, the solderability were good. *the protection on the terminations of microleadframe package is Cu(copper),somebody call that leadless leadframe package(LLP). *the time above 210 deg C is about 10 sec. *I used OMG Microbond solder paste, peak temperature is 215 deg C.If increase more than 215 deg C, we found that white residue on the solder joint of components and joints become wrinkle. pls give me any idea to solve this problem

reply »

#19974

non-wetting | 18 May, 2002

Copper teminations with no solderability protection on your LLP. Hmmm seems unusual, but it could be that the flux in your solder paste is not active enough to remove the corrosion on the Cu leads.

OMG Microbond solder paste develops white residue on the solder joint of components and joints become wrinkly above a 215�C. Hmmm seems unusual, but it could be. * Assuming you're using a no-clean solder paste: if it is going 'milky' colored, that is usually caused from water, even moisture in the air. * Often wrinkly solder connections are caused by rapid cool-down.

reply »

xzinxzin

#19976

non-wetting | 19 May, 2002

I using water-soluble solder paste, the solder paste recommended, the peak temperature is 215 deg C, the dwell time above 183 deg C is 60-90 sec. **How I can do, the flux in solder paste is active enough to remove the corrosion on the Cu leads to get proper fillet to the terminal sides of the component. **Can I try the way that: 1)apply the water-soluble flux on the components after reflow process, and 2)proceed to the second reflow for the components. any commend, dangerous to do the those way to get proper fillet. How many cycles times allow to proceed in reflow for these type of packages. pls advise to me

xzinxzin process engineer ven.....

reply »

ianchan

#19985

non-wetting | 20 May, 2002

xzinxzin, de' process engineer,

Hi mate,

am just making a wild guess, are you asking all this abt a certain MAXIM 3286/3296 MLF package that goes into a fibre optics produce, and is a product that numerous persons in this market are practically knotting their thumbs and twisting their hair, in a bid to capture this potential business market from that other subbie?

reply »

#19987

non-wetting | 20 May, 2002

Oooo, sorry I was napping. You said, you used water washable fluxed solder paste earlier, didn�t you?

The component terminations are bare copper? And they�re supposed to be that way? Very peculiar. What are the description, part number, and supplier of these parts?

By saying, � � it could be that the flux in your solder paste is not active enough to remove the corrosion on the Cu leads.� It means, �I would use a different solder paste with flux that is more active.�

Alternatives: * I�m not happy about it, but I know that our people have little squirt bottles of active wave solder flux and prior to reflow, they apply extra flux on components that don�t solder well. [I do not like this because (1) WS flux is designed to be activated with a different recipe that a reflow process, (2) it�s difficult to control the amount of flux applied with a squirt bottle, and (3) the density of this flux is uncontrolled.] * Another thing you could do is pre-tin the component leads [or have someone pre-tin them for you].

If you see white res with a water washable flux, you might be getting the running too hot. So, this gets you to the => Are you sure you are using the correct solder paste question, once again.

How many cycles times allow to proceed in reflow for these type of packages. => Dunno. What does the supplier say?

reply »

hayashi

#19991

non-wetting | 21 May, 2002

> *the other components are 0402 and SOIC 16, the > solderability were good. *the protection on the > terminations of microleadframe package is > Cu(copper),somebody call that leadless leadframe > package(LLP). *the time above 210 deg C is about > 10 sec. *I used OMG Microbond solder paste, peak > temperature is 215 deg C.If increase more than > 215 deg C, we found that white residue on the > solder joint of components and joints become > wrinkle. pls give me any idea to solve this > problem

Dear Friend, All I can say is you can sock the component is Hydrochloride Acid . This will remove the oxide on the BCC layer to allow a better wetting. As for the double reflow, it is not recommended. As this will damage the BCC and the internal wire bonding.

In Japan , we are mass producing the production for these kind of BCC. It is not worth doing the test unless the quantity justify your testing. Further to that, OMG is not recommended why not you try Interflux,Kester or Selayang. They are more reliable than OMG.

http://www.interfluxusa.com/products_2.html

Another method is , why not increase the temperature for the reflow ? Check with your client what is the maximum temperature for the components. Oxide can be removed by higher temperature.

This is what I feel just try it as I know that your company can handle these testing cost. If I am not wrong you must be in Venture manufacturing doing the test.

Regards Hayashi Rumada Matsu....

reply »

xzinxzin

#20007

non-wetting | 22 May, 2002

*yes, I used water soluble solder paste (OMG-WS-300), the flux type is ORM0. The component terminations are bare copper,and they�re supposed to be that way. The supplier of these parts is MAXIM, produced from Philipine, get from customer. * We can not change the solder paste, before customer did not approved, that is very difficult to me.Hamm, how I can do now. anybody experience for this process difficulities. pls advice to me. thank dave

reply »

ianchan

#20037

non-wetting | 22 May, 2002

xzinxzin, de Process Engineer,

Ah....HAH! bingo!

go search the fine SMTnet archives. cuppa of threads posted within specific to this nature of inquiry of yours.

reply »

#20038

non-wetting | 22 May, 2002

Ah, the customer is always correct, again. And you are officially �painted into a corner�. Actually, your customer is not correct. Thinking that money is going to be saved by specifying copper component terminations [or whatever in the world they were thinking] is just foolish.

This is a little bit like past times when there was so many requirements about the way you have to do something [ie, use this flux, use that temperature, don't do this, do that, etc.] that when something is not anticipated or is just a liddie bit off, the whole job grinds to a stop.

In part, that is why people stopped using US military specifications. Now, enlightened customers specify the results you should obtain, rather than telling you how you should go about obtaining those results.

OK, enough �soap box� oratory. Given that the responses you've gotten so far here do not make you want to stand-up, hoist the flag, and salute; consider a sit-down between your: * Customer * Paste suppler * Component supplier

... to reach consensus on an approach to take.

You need relief on either: * Component lead finish [I want to say all of our Maxim QFN are solder plated, but there maybe a couple of ENIG jobbies in there somewhere.] * Solder paste selection.

� and your customer holds those cards.

reply »

SMT Equipment

PCB machines