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.5mm BGA


RDR

#27337

.5mm BGA | 20 February, 2004

Help! i just rec'd my next job from our marketing people and it has a .5mm pitch BGA 8mmX8mm size. Along with this kit came the stencil. So, I have never placed this fine of a BGA before and I am pretty worried about the stencil releasing the paste the balls are .012" diameter and the pads are at .009" the stencil is 5mil with .009" round apertures. after figuring the area ratio I get 45 this is supposed to be 66 or greater is it not? We currently use type 3 paste. Is this going to work?, is anybody out there doing this now?

Thanks for the help

Russ

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#27338

.5mm BGA | 20 February, 2004

That will depend on so many factors:

solder type / flux type sphericity of balls in paste stencil type (laser chem etch, electro form etc.) print paramaters

I will tell you that it can be done.

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#27341

.5mm BGA | 20 February, 2004

Not to trivialize the comments in the above posting, but yer blanked.

The old refrain from the sales types: "I shot it, you skin and cook it!!"

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#27342

.5mm BGA | 20 February, 2004

Ken: Please tell us.

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RDR

#27343

.5mm BGA | 20 February, 2004

Kinda what I thought,

Ken, what would the parameters be relating to sphericity, flux, etc... We use type 3 63/37 usually watersoluble but for this I think I'm gonna have to use no-clean paste. When you say it can be done, what exactly does that mean? we print 10 boards get one good? if all of the variables you mention are within spec. it will be a normal process with no special worries?

Thanks again for the help

Russ

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Ken

#27350

.5mm BGA | 21 February, 2004

sphericity and consistency are important. egg shaped, dog-boned shape snd tear-drops work against you and promote clogging and in-effective "transfer efficiency".

One of the most signifficant factors will be brand/type. Not all fluxes are created equal. Especially when you consider the thixotropic variations due to air, moisture, print cycles and idle inactivity. Even under ideal conditions (stencil design, apperture design, print settings, you may find you still have difficulty -but much improved).

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RDR

#27358

.5mm BGA | 23 February, 2004

Just to finish this up, We did manage to print this little part with good success without any major re-setup of printer settings I would not recommend these parameters for production to anybody however. You can print 2-3 boards before it starts to clog the stencil. Fortunately we only had to build 5 of these and have decided to go to a 1mm pitch for the future.

For whatever it's worth Russ

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www.smtinfo.net

#27359

.5mm BGA | 23 February, 2004

Alpha Metals sells a paste developed especially for 0201's and 0.5 mm pitch BGA's. I have no idea if if does what it promises, but it might be worth to give it a try. See http://www.alphametals.com/omnixsolder/pdfs/OM_6106.PDF

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mk

#27393

.5mm BGA | 27 February, 2004

Sorry I am late with the solution but I have been out on the road.

Absolutely the reason solid solder deposit was invented.

Hands down the best and most affordable, dependable solution to your challenge. http://www.sipad.com

mkehoe@sipad.net

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