Via size vs. process reliability - Page 1
Forum section: electronics / general

author: shadewind
author_rank: Frequent Contributor
timestamp: September 27, 2011, 11:23:39 pm
content: Hi,I'm making a board that I'm gonna have made by iTead. I normally use 0.5 mm hole vias as my standard size but I'm getting a little tight on space and would like to use 0.3 mm hole vias instead. While the specs on their website say that they can do down to 0.3 mm holes, I'm wondering if it's likely that I'm going to have problems with this? I've boards made by them before that use 0.3 mm holes but none where a connection relied on a single via being correctly plate through, I've only used them for stitching and thermal purposes.What I can say about the boards I do have with small vias is that they seem without error but it's hard to test connectivity of a single via when it's part of a net with many others. If it's unlikely to be a problem, I'm thinking I might as well go down in via size all over the board.

author: Psi
author_rank: Super Contributor
timestamp: September 28, 2011, 01:54:30 am
content: Maybe send them an email and ask how reliable their 0.3mm vias are.If 0.3mm often gives trouble it's in their interest to tell you.I have been thinking about this same issue for one of my small pcbs.Although it's a different pcb manufacture (pcbcart)They say they can do down to 0.2mm but i'm not sure how reliable that actually is

author: metalphreak
author_rank: Frequent Contributor
timestamp: September 29, 2011, 03:22:59 pm
content: If the board requires that one 0.3mm via to be correctly connected, then it will show up when itead do their E-Testing. Granted, you only get 50% of your boards tested, but it means they will remake your boards if they don't turn out correctly. I would assume if they advertise 0.3mm vias as the minimum then they should be able to get atleast a 50% success rate

author: shadewind
author_rank: Frequent Contributor
timestamp: September 30, 2011, 11:03:50 am
content: Yeah I went ahead and made 0.3 mm the standard size on the board. It will be interesting to see if it works as intended

author: mobbarley
author_rank: Regular Contributor
timestamp: October 11, 2011, 06:30:51 am
content: I've used 0.4 hole 0.9 pad (huge due to the registration errors people have noted before) with iTead in a couple of designs, no problem. That 0.1mm headroom made me feel good (not sure if it helps or not! Not sure what size they actually drilled either!)

author: shadewind
author_rank: Frequent Contributor
timestamp: October 14, 2011, 03:22:07 pm
content: I ended up using the small vias all over the board with no problem whatsoever. That is, 0.3 mm hole and 0.6 mm pad. Some of the registration is a little on the loose side but nothing I would worry about.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 15, 2011, 08:06:52 pm
content: You wonder about the quality of 0.3mm via's (which is within their specs), ok...Then what makes you trust their 0.5mm vias...?

author: PCBCORE
author_rank: Contributor
timestamp: February 07, 2012, 12:13:51 pm
content: 0.3mm will be a problem if their processing capability is poor, but normally 0.3mm via is not a problem, take our factory for example,>=0.3mm via setting will be the cheapest level, 0.15mm is a limit for mechnical vias, but price gonna be expensive, so keep your vias >=0.3mmif possible....Quote from: shadewind on September 27, 2011, 11:23:39 pm

author: EEVblog
author_rank: Unknown
timestamp: February 07, 2012, 12:30:46 pm
content: Quote from: Psi on September 28, 2011, 01:54:30 amI've used PCBcart extensively for production quality boards with 0.3mm via (my standard size 0.3mm hole/0.6mm pad) for reasonably dense work, with not a single issue.Your biggest worry with a 0.3mm hole would be dill alignment, so 0.6mm pad is pretty standard for that.From memory I've also used 0.3mm/0.5mm pad and it was quite tight, but still no breakouts.Dave.