--- Wed May 29 2013 | 00:00 | |
berndj | anyone used magic(1)? i'm struggling with making labels | 05:16 |
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berndj | azonenberg: you have been summoned in #geda on OFTC; people want to know about your BGA process | 17:02 |
berndj | what pitch do you manage to do? | 17:03 |
azonenberg | berndj: I have perfect yield so far on 1mm (seven boards with a single FTG256 part on each) | 19:29 |
azonenberg | as well as 1/3 on 0.5mm (three boards with a CPG56 part on each) | 19:29 |
azonenberg | bear in mind, the 0.5mm parts were my first BGAs ever | 19:29 |
azonenberg | and failed due to misalignment, not shorting etc | 19:30 |
azonenberg | so i could probably do better now | 19:30 |
berndj | heh, we were wondering about 0.5mm | 19:30 |
azonenberg | It's doable | 19:30 |
azonenberg | I do not suggest it as a first chip, though | 19:30 |
azonenberg | qualify the process with 1mm | 19:30 |
azonenberg | then do 0.8 | 19:30 |
azonenberg | then move down | 19:30 |
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) | 19:30 |
berndj | 1/3 of all chips or 1/3 of all balls? | 19:31 |
azonenberg | 0.8 and above you can do standard dogbone | 19:31 |
azonenberg | I did three chips | 19:31 |
azonenberg | One worked | 19:31 |
berndj | heh. cool | 19:31 |
azonenberg | The other two were so misaligned that the balls werent even touching the pads | 19:31 |
azonenberg | i just melted holes in the soldermask | 19:31 |
azonenberg | But like i said, they were my first bgas ever | 19:31 |
azonenberg | i didnt really know what i was doing | 19:31 |
azonenberg | Knowing what i do now, i'm pretty sure i could make it work | 19:32 |
berndj | whoah, you tried them before you did the coarser-pitched ones? | 19:32 |
azonenberg | Yes | 19:32 |
azonenberg | they were the cheapest bgas i could find | 19:32 |
azonenberg | coolrunner-ii CPLDs | 19:32 |
azonenberg | $1.20 or so per chip | 19:33 |
azonenberg | whereas the cheapest FTG256 i could find was a spartan3a for $10ish | 19:33 |
berndj | you're nuts man! | 19:33 |
azonenberg | You're talking to the guy who did 01005s at home | 19:33 |
berndj | i know! | 19:33 |
azonenberg | lol | 19:33 |
azonenberg | (and who thought that wasn't small enough, and wants to do an ASIC now) | 19:33 |
azonenberg | :p | 19:33 |
berndj | aren't 01005s kinda hard to see with the naked eye? | 19:33 |
azonenberg | http://3.bp.blogspot.com/-5BuN6Dll398/T99z9JTK4OI/AAAAAAAAAJg/jFDWdrNmEZE/s1600/S7302790_cropped.jpg | 19:34 |
berndj | what's your asic roadmap btw - DIY process or MOSIS? | 19:34 |
azonenberg | thats a DIP14 for scale | 19:34 |
azonenberg | I want to dual-track | 19:34 |
azonenberg | in-house process to make some 74xx chips etc for the 1337 points and educational value | 19:34 |
azonenberg | then a mosis chip fast enough to actually compete with fpga-based stuff | 19:34 |
azonenberg | i'll learn a lot more from making my own process, i'm sure | 19:35 |
berndj | err, is your DIP-sized board stuffed or is it empty? | 19:35 |
azonenberg | The second column is loaded | 19:35 |
berndj | second row from left looks like it's been worked on, but i can't see the dust grains | 19:35 |
azonenberg | i wasnt using a stencil so the paste is a little bit messy | 19:35 |
azonenberg | http://1.bp.blogspot.com/-nPrj9U3GI_8/T99zSMw3JwI/AAAAAAAAAJI/AL3lkhQeqgk/s1600/S7302788.JPG | 19:35 |
azonenberg | There's a better view post-reflow | 19:35 |
azonenberg | http://4.bp.blogspot.com/-QAcT_lQWLoM/T99wS8uPcjI/AAAAAAAAAIY/idVAhRds39c/s1600/S7302743_annotated.jpg | 19:36 |
azonenberg | This is my old tweezers, lol | 19:36 |
azonenberg | on 0.5mm QFP footprint for scale | 19:36 |
berndj | this is just soldering on boards you got made, not DIY boards too? | 19:36 |
azonenberg | i got new tweezers just for 01005s http://1.bp.blogspot.com/-kBZPenm0cPA/T99wgnyWWuI/AAAAAAAAAIg/oqYNUxCN20A/s1600/S7302741_annotated.jpg | 19:36 |
Sync_ | ah 01005 tends to get annoying with your regular soldering iron | 19:36 |
azonenberg | There's no reason to maky my own boards | 19:36 |
azonenberg | oshpark is cheap, better quality, and fast turnaround | 19:36 |
azonenberg | the reason to make an asic is different | 19:36 |
azonenberg | mosis is expensive and slow | 19:37 |
Sync_ | I had to rework some boards that had a few misplaced components | 19:37 |
azonenberg | Sync_: lol | 19:37 |
Sync_ | but it's possible but no fun | 19:38 |
berndj | bypassing mosis would be more expensive and slower still? | 19:38 |
berndj | or do you have access to a school fab? | 19:38 |
Sync_ | but bga at home is no big deal | 19:38 |
azonenberg | berndj: I meant, home fab | 19:38 |
azonenberg | You'd get faster turn times for sure | 19:38 |
azonenberg | but the main reason is still education | 19:38 |
berndj | yeah, we're waiting for you to liberate the world with a home fab process | 19:38 |
Sync_ | it's handy to have a laser reballer if you get it wrong | 19:38 |
--- Thu May 30 2013 | 00:00 |
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