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I've recently been soldering ball-grid-array parts to boards. This is relatively new to me, and there has been a few mishaps with my technique. I was just wondering how does the community perform BGA soldering? What techniques/equipment do you use to make this process more efficient and less error prone?

My technique involves using a Hakko FR-830 Preheater to do the work. I use an old board holder to hold my board in place, and then I apply some solder to the board using a syringe (ChipQuik SMD291AX). My part is a 6x6 BGA array, with the pads 1mm apart from each other in a square grid. Once I place the solder onto the pads, I slowly put the part onto the pads, aligned as close as possible. Then, once it's ready, I turn on the preheater through its temperatures from 150-300 degrees Celcius at 50 degree intervals for about a minute and a half at each temperature. The apparatus is not enclosed, so I put a piece of metal over my board holder so that the top of my PCB board is not exposed to open air.

My process is not exactly ideal, but thus far, it works alright. However, I noticed that the solder doesn't seem like it really 'melted'. I think that this might be because of my methods, and running a hot air gun on the sides doesn't really help much. Any tips or suggestions? This is all done in-house, and I have to do this by myself, so learning how to do it better would be helpful.

BestQualityVacuum
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As you'll see if you link through to the possible dup, there are ways to do this. My own humble opinion is that they're not very amenable to prototyping using hobbyist methods-- at least for my purposes.

I don't say this because I think it's impossible, I say this because I think the yield will be enough under 100% that not knowing whether your mount is good or not will be a substantial obstacle to my process.

I wouldn't take this on with less than a pro-style smd rework station with a board preheater and a hot air gun -- and preferably, access to a board inspection xray machine (though if I had an xray machine I would probably have a good reflow oven nearby!)

If I absolutely needed something done, I would probably pay the $40/hour plus setup fees to have it done at a board house, or I might try to have proto-advantage mount it for me -- http://www.proto-advantage.com/store/index.php?cPath=4000&osCsid=iucsgr96i98id45oln486h40g0 -- you give them a digikey part number and they order and mount it for you on a breakout board for a fee. The first time I used this service for BGA, I would probably have an email conversation first to assess their comfort level with BGA.

The reason why your pads don't look soldered, by the way, might have to do with different melting points for the solder on the ball and your Chipquik -- especially if your BGA uses silver solder. I thought you shouldn't need additional solder if your chip is already balled. That's the point.

Scott Seidman
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