azonenberg changed the topic of #homecmos to: Homebrew CMOS and MEMS foundry design | Wiki: http://homecmos.drawersteak.com/wiki/Main_Page | Repository: http://code.google.com/p/homecmos/ | Logs: http://en.qi-hardware.com/homecmos-logs/
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<berndj> anyone used magic(1)? i'm struggling with making labels
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<berndj> azonenberg: you have been summoned in #geda on OFTC; people want to know about your BGA process
<berndj> what pitch do you manage to do?
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<azonenberg> berndj: I have perfect yield so far on 1mm (seven boards with a single FTG256 part on each)
<azonenberg> as well as 1/3 on 0.5mm (three boards with a CPG56 part on each)
<azonenberg> bear in mind, the 0.5mm parts were my first BGAs ever
<azonenberg> and failed due to misalignment, not shorting etc
<azonenberg> so i could probably do better now
<berndj> heh, we were wondering about 0.5mm
<azonenberg> It's doable
<azonenberg> I do not suggest it as a first chip, though
<azonenberg> qualify the process with 1mm
<azonenberg> then do 0.8
<azonenberg> then move down
<azonenberg> The bigger problem with 0.5mm is that you need microvias or super-tiny traces to break it out unless it's like CPG56 (two concentric rings with routing space between them)
<berndj> 1/3 of all chips or 1/3 of all balls?
<azonenberg> 0.8 and above you can do standard dogbone
<azonenberg> I did three chips
<azonenberg> One worked
<berndj> heh. cool
<azonenberg> The other two were so misaligned that the balls werent even touching the pads
<azonenberg> i just melted holes in the soldermask
<azonenberg> But like i said, they were my first bgas ever
<azonenberg> i didnt really know what i was doing
<azonenberg> Knowing what i do now, i'm pretty sure i could make it work
<berndj> whoah, you tried them before you did the coarser-pitched ones?
<azonenberg> Yes
<azonenberg> they were the cheapest bgas i could find
<azonenberg> coolrunner-ii CPLDs
<azonenberg> $1.20 or so per chip
<azonenberg> whereas the cheapest FTG256 i could find was a spartan3a for $10ish
<berndj> you're nuts man!
<azonenberg> You're talking to the guy who did 01005s at home
<berndj> i know!
<azonenberg> lol
<azonenberg> (and who thought that wasn't small enough, and wants to do an ASIC now)
<azonenberg> :p
<berndj> aren't 01005s kinda hard to see with the naked eye?
<berndj> what's your asic roadmap btw - DIY process or MOSIS?
<azonenberg> thats a DIP14 for scale
<azonenberg> I want to dual-track
<azonenberg> in-house process to make some 74xx chips etc for the 1337 points and educational value
<azonenberg> then a mosis chip fast enough to actually compete with fpga-based stuff
<azonenberg> i'll learn a lot more from making my own process, i'm sure
<berndj> err, is your DIP-sized board stuffed or is it empty?
<azonenberg> The second column is loaded
<berndj> second row from left looks like it's been worked on, but i can't see the dust grains
<azonenberg> i wasnt using a stencil so the paste is a little bit messy
<azonenberg> There's a better view post-reflow
<azonenberg> This is my old tweezers, lol
<azonenberg> on 0.5mm QFP footprint for scale
<berndj> this is just soldering on boards you got made, not DIY boards too?
<Sync_> ah 01005 tends to get annoying with your regular soldering iron
<azonenberg> There's no reason to maky my own boards
<azonenberg> oshpark is cheap, better quality, and fast turnaround
<azonenberg> the reason to make an asic is different
<azonenberg> mosis is expensive and slow
<Sync_> I had to rework some boards that had a few misplaced components
<azonenberg> Sync_: lol
<Sync_> but it's possible but no fun
<berndj> bypassing mosis would be more expensive and slower still?
<berndj> or do you have access to a school fab?
<Sync_> but bga at home is no big deal
<azonenberg> berndj: I meant, home fab
<azonenberg> You'd get faster turn times for sure
<azonenberg> but the main reason is still education
<berndj> yeah, we're waiting for you to liberate the world with a home fab process
<Sync_> it's handy to have a laser reballer if you get it wrong