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Type 4 solder paste

wgaffubar

#28010

Type 4 solder paste | 12 April, 2004

I am using Indium 92J type 4 solder paste due to a BGA site with .008" pads and stencil opening of .009" square and .005" stencil thickness. When I try the type 3 we get insuffecient print. The aspect ratio tells me that I should be using a type 4. The problem is managment does not want to spend the extra money for type 4. According to managment, Indium has told them that only 5% of USA SMT manufacturing uses type 4 for SMT production so there is a two to three week lead time when ordering it. Besides going to E-FAD ($1000 each) stencils does anyone have any luck printing a type 3 with asepct ratio less than 1.5 ??? I was told to try doing a double print. Also is anyone else using type 4 for CSP or micro BGA production??? We can not go with stepped stencils due to very bad board design used by our customer.

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#28011

Type 4 solder paste | 12 April, 2004

Can you go to a .004" stencil?

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arcandspark

#28029

Type 4 solder paste | 13 April, 2004

I would have gone to a .004" stencil but again, the board designers, which we have no control over or are we allowed to give input to, have made the pads on all connectors and many other parts so small that we are almost seeing insuffecient solder using the .005" stencil. I have most all stencil openings at 1 to 1 ratios already, even some of my 12 mil pitch components.

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Steven

#28038

Type 4 solder paste | 13 April, 2004

Try another solder paste manufacturer. Aim out of Rhode Island, Alpha and or Kester. I'm sure that they will be of better assistance than the current supplier. Good Luck

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Steven

#28039

Type 4 solder paste | 13 April, 2004

A PS to the above, it never hurts to ask for samples from vendors to see if the product works first. You did not hear this from me though.

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arcandspark

#28041

Type 4 solder paste | 13 April, 2004

I have samples coming in, AIM and ALPHA, Multicore use to have manufacturing in the same town but disappeared. Your right about getting better help fro other, Indium is the worse I have ever had to deal with. They act like I am bothering them when I call for questions or even to order more paste. We just have an Indium feild rep visit last week for the first time in over a year has anyone from Indium even bothered to call or even come by. We did a huge Taguchi study which lasted two months of eight hour per day running test, collecting data, on solder paste a couple years ago at another company, which included Alcatel, Nortel, ComPac, HP, and others, to try to find the perfect solder paste for SMT manufacturing use ( dont laugh)and out of every solder paste on the market the top three were AIM, Indium, and Alpha at that time. Things may have changed.

Thanks guys I will be trying other paste samples.

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RDR

#28044

Type 4 solder paste | 13 April, 2004

I have actually printed this same condition with type 3 paste Alpha WS709. I posted this for discussion and cannot remember what I called it. We did need to clean the stencil after every three prints. I did not check volume on these locations but just made sure that there was paste present. the solder balls on the part were 63/37 so I wasn't excessively worried about the volume of paste being completely uniform. All components placed have passed all testing that they were subjected to.

Russ

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arcandspark

#28045

Type 4 solder paste | 13 April, 2004

The problem is T.I. does not want us to use Water Soluable, only No Clean. ALso yes from your other reply we must work for the same company. We build boards and find out later sales quoted a cost that is much less than what we ended spending to build them. Then the owner want to know how come we screwed up.

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RDR

#28046

Type 4 solder paste | 13 April, 2004

in a thread titled ".5mm bga" there is a reference to a paste by alpha that is no-clean and is supposed to be made specifically for this situation. I suppose that increasing the pad dimension to .012" is out of the question?

Russ

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#28063

Type 4 solder paste | 14 April, 2004

Hi All, Just have a share with you guy. We are using T4 solder paste and also E-Stencil. We ahd try out Alpha, Kester, AIM and Qualitek. The result show Alpha had a very very heavy stack flux and can't get it clean off even by chemical wash, Kester is a good paste but service is Poor too! AIM is good but price is high ( result show same as Kester too) and run hour is short. Qualitek show high flux too. We had run mass production for about 6 years and have collected quiet sharp data on all this paste maker, most of ours product are is very very tight spec as is use in Medicial.

Regards, Hun

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arcandspark

#28066

Type 4 solder paste | 14 April, 2004

We have tried other stencils with different size openings but this company will not allow us time or money to run any experiments to define stencil criteria and printer settings, its just run, run, run. They really dont care about post reflow yields. We are only allowed one extra stencil change per build (if that)and if we get that wrong we are stuck. The board maker did not use mask defined pads on this problem PCB, and we have printing issues when using over sized opening, the solder paste squeezes out between the pad and the mask which ends up giving to much solder on some pads and we get bridging. We run 1 to 1.5 lbs pressure times squeegy length. The the boards that do use mask defined pads the oversize stencil openings work ok. I have heard of different types of metal squeegy material that may help but have no information on it.

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Kary Voegele

#28148

Type 4 solder paste | 20 April, 2004

Transistion Automation makes a great squeegee blade. I have found that it is superior to the standard steel/titanium blades generally used in production. It is made from gun barrel blue steel. It is more expensive than standrd squeegee blades, but it may be worth the added cost for your type of application. I use it in proflow applications because of its superior performance.

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#28192

Type 4 solder paste | 22 April, 2004

We used type 4 no clean from Aim too with this application. The price was only about 20 % more than type 3 powder. Works great. They didn't have a long leadtime, my paste was in stock. I have had simalar problems with Indium. They got too big too fast and don't care about us smaller shops anymore.

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arcandspark

#28321

Type 4 solder paste | 29 April, 2004

You are right about the very poor support for smaller customers. I had told them we were looking for another paste and now they have sent the reginal manager and the US sales manager has come by to see what they can do for us. All they keep saying is to go to a 4 mil stencil. I am going to try the AIM paste next. The board design is so bad (Flextronics designed) the pad spacing on some of the rnets is 4 mils, even though the rnet manufacture suggest 6mil minumum. So are fighting to many issues form to many diferent directions, and as usual all managment cares about is GET THE NUMBERS FOR THIS WEEK. Thanks for input, I have a sample of AIM now.

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Shinmoto

#28328

Type 4 solder paste | 29 April, 2004

Hi there,

We place FBGA packages on a lot of our memory modules. Our stencils have .013" square apertures and a .005" foil thickness. We are using a type 4 paste from Senju Comtek. The price difference is not that significant and readily available when scheduled. For us, it's worth the extra cost for the right solder type, than reworking a FBGA component due to insufficience due to a bad print.

Good luck!

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SWagner

#28348

Type 4 solder paste | 30 April, 2004

You could comprimise on the E-Fab stencil and buy a laser cut nickle, it will have similar release characteristics to an E-Fab and only costs $600, they can be purchased from Stork Veco, they are located in Europe.

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