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Subject: Re: [geda-user] PCB BGA (ball grid array) Package/Footprint
From: Dave Curtis <davecurtis AT sonic DOT net>
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Date: Fri, 19 Jul 2013 19:15:40 -0700
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On Jul 19, 2013, at 5:08 PM, Russell Dill wrote:

> On Fri, Jul 19, 2013 at 10:23 AM, Dave Curtis <davecurtis AT sonic DOT net> wrote:
>> On 07/18/2013 03:33 PM, Lilith Bryant wrote:
>>> 
>>> On 2013-07-19 01:19:25 AM, Rob Butts wrote:
>>>> 
>>>> Has anyone done a PCB using the new chips with the BGA (ball grid array)?
>>>> If so, how did you define the footprint?  As through-holes?  Fab shops
>>>> must
>>>> be capable of accommodating these ICs otherwise they wouldn't exist.
>>>> 
>>>> I'm thinking they must be easy to solder since it would simply fall into
>>>> it's position with either pre-soldered holes or pre-soldered pins/balls.
>>>> 
>>> I have just finished a paying job using an iMX6 processor (624 ball
>>> 0.8mm),
>>> FPGA (256 ball 1mm), and 4xDDR3 (96 ball 0.8mm).    However, even for
>>> personal use prototypes, I wouldn't even try doing it myself.
>> 
>> What do you end up paying an assembly house to attach of those on a one-off
>> basis for a prototype?
> 
> When I looked for a board I was doing with 1 96-ball 0.8mm, 1 784-ball
> 1mm, and 5 100-ball 1mm components (as well as many other components),
> It was cheaper for me to buy an oven, a controller for it, a hot air
> gun, a steel stencil, parts for a vacuum pen system, a set of small
> test boards for developing a process, paste, and still have money left
> over to re-do in case things get screwed up. There certainly is a lot
> of upfront investment in tools and time learning, but for me, assembly
> is part of the hobby.
> 
> If you already do boards with 0.5mm qfn/qfp and 0402's, 0.8mm and 1mm
> BGAs are not a big deal. If you haven't already, I'd recommend trying
> your hand at a stencil+reflow process without BGA first. It really
> comes down to how valuable your time is, and if you consider assembly
> part of your hobby or if you want to skip past that. I know several
> other hobbyists who do BGA at home, and enjoy doing it.
> 

I'm set up with the toaster oven and reflow controller.  Have not done BGA's.
I stick to packages where I can inspect the joints under the microscope.
A friend does small BGA's with a hot plate.  Balls around the periphery only,
like 8 ball packages and such.

I'm really interested in the quantitative aspect of my question, though, 
what was the quote? If you care to tell me...

-dave