I made a 1x1 inch test board with a bunch of 0201 footprints plus several other test structures (I hope to fool with homebrew filled vias at some point so I included an 0.8mm BGA with drilled-out pads on the same dummy board) on DorkbotPDX's batch order. When I eagerly opened my purple envelope late last month I was quite annoyed to discover that my soldermask pattern was completely wrong!
The component values on the silkscreen were a screwup on my part but the fab had totally borked the mask. The correct pattern had the via fence unmasked and all of the areas around components masked.
After emailing back and forth with Laen we figured out the problem - my soldermask polygon had gone slightly outside the board outline and a bug in his panelization script resulted in the offending vertex being deleted, rather than clamped to the board outline. He offered to make me a new batch of boards at no cost.
The new boards arrived today and I inspected them briefly under the microscope. As usual they were superb quality, with near-perfect registration between layers.
|Pre-assembly inspection of 0201 footprints|
|Somehow I don't think this will work...|
|Paste applied with scalpel blade|
|After component placement|
I ran the board through my standard reflow profile in a toaster oven, then inspected.
|Post-reflow inspection looks good!|
|Angled view of a single component. Note the size of the component in relation to the 35 μm thickness of the 1-ounce copper trace!|