[Coco] Surface Mount Soldering

[jdaggett at gate.net]

Not really

There are several different kinds of BGA packages. When I retired the technology had only 
gotten to 20 mil balls and 50 mill pitch. Today they are pushing finer arrays. 

to give you an idea of a fine pitch BGA consider the FG484 package that Xilinx uses. It is a 
0.8 mm pitch with the balls being 0.6 mm is diameter. The largest runner you can pas 
between the pads is 6 mils(~0.23mm).  You need tohave via hole that is no more than 8 mils 
in diameter more like 5 or 6 mils.

These requirements whether hobbyist or commercial are not cheap. When you approach 3 
and 4 mil runners you move beyond the standard process of etching into the realm of fine line 
processing. It is very easy to overetch 4 mil runners and then you are left with a runner that 
has all kinds of issues. 

For the hobbyist, fine pitch QFPs (0.5 mm pitch) is small enough. You may not achieve the 
density or the pin count that the FBGA and UFBGAs provide. If you need that small, there is 
more than likely a commercial solution to meet a need.

james  

On 6 Jul 2010 at 11:06, Little John (GIMEchip.com) wrote:

> Uh Oh - I've started a debate :-)
> J/K - I've often wondered how a hobbyist could work with BGA and then I 
> decided this morning to look at youtube. Man there are all kinds of videos 
> on there - some of the techniques by hobbyists such as myself don't look 
> like they could possibly work, and yet they do. I am amazed at the ingenuity 
> of some of these folks.
> -John
> ----- Original Message ----- 
> From: "Mark Marlette" <mmarlette at frontiernet.net>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Tuesday, July 06, 2010 10:51 AM
> Subject: Re: [Coco] Surface Mount Soldering
> 
> 
> > james,
> >
> > How does one manually locate/align(x/y/z/theta,down force) of a BGA on to 
> > the pads using a hotplate?
> >
> > I use our Air-Vac DRS25 unit and I am spoiled with it.
> >
> > Mark
> > Cloud-9
> >
> >
> > ----- Original Message -----
> > From: jdaggett at gate.net
> > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > Sent: Tue, 06 Jul 2010 13:57:08 -0000 (UTC)
> > Subject: Re: [Coco] Surface Mount Soldering
> >
> > The key to using a soldering iron for SMT work is having enough flux on 
> > the board and not to
> > much solder.
> >
> > There are other alternatives to the soldering iron approach.
> >
> > One is a hot plate. A 4in square hotplate by Thermalake is very good 
> > alternative.
> >
> > Second is the few toaster oven reflow boards out there. The stand alone 
> > controllers range in
> > the $60 to $100 and then add what ever your local Walmart or Taget has in 
> > a 1500 watt
> > toaster oven.
> >
> > The lone issue with the toaster oven is that it should have burners on the 
> > top and bottom and
> > a circulating fan inside to reduce hot zones. ALso the toaster oven method 
> > needs to work at
> > max temperature to melt the newer lead free solders. Also the different 
> > preheat times will
> > need adjusting.
> >
> > I still like the hotplate for small boards. especially with BGA packages.
> >
> > james
> >
> > On 6 Jul 2010 at 0:30, Aaron Wolfe wrote:
> >
> >> On Mon, Jul 5, 2010 at 9:39 PM, Little John (GIMEchip.com)
> >> <sales at gimechip.com> wrote:
> >> > This guy has some amazing videos on SMT soldering - I never get bored 
> >> > just watching these. Some have sound, some are silent, but they are 
> >> > beatiful nonetheless :-)
> >> > http://www.youtube.com/watch?v=wQXhny3R7lk
> >> > This is the vertical drag technique that my dad uses too.
> >> > -John
> >> > P.S. check out all of this guys videos if you have time. They are 
> >> > amazing.
> >> > -Lil' J
> >> >
> >>
> >> That is interesting to watch.  I recently got a ham license and have
> >> been soldering together some very simple circuits to reduce
> >> interference when connecting a radio to an PC to decode digital
> >> modes.. anyway, boy am I bad at soldering!  That guy is like the
> >> maestro of solder.
> >>
> >> There are a lot of good "how to" videos on youtube for all kinds of
> >> things, if you're in to do-it-yourself, its a great resource.
> >>
> >>
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> >> >
> >>
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> >
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