I just learned from the websites of a couple of board manufacturers that they can go as low as 0.8mm on a 4-layer board.
I think going to 1.0 mm (instead of my standard use of 1.6 mm) would be helpful since I am trying to optimize on space. Since there is a high density of traces, it would be desirable to have the convenience of the additional 2 layers during signal routing.
However, due to lack of experience with having 4-layer boards manufactured, I am concerned that issues may come up with a 4-layer board at such low thickness, e.g., problems with blind/buried vias, longterm robustness of the board, problems during pick-and-place assembly, etc.
For my final manufacturing, should I play it safe by sticking with the 1.6 mm thickness?
Or is board-manufacturing sufficiently reliable that I can expect the 1.0 mm 4-layer board to have no issues — is it common in the industry to go to such low thickness?
UPDATE:
Details of PCB (as requested below):
- 50 mm X 50 mm
- Two Micro-USB connectors present (into which of course USB cables will be inserted/removed)
- PCB secured into groove-type slots within plastic enclosure
- No long/thin components: Only standard ICs, e.g., QFP-48 microcontroller, voltage regulator, etc.
- One "heavy" component: A small OLED display panel is inserted into the 10-pin female headers located on the PCB.
Best Answer
You won't experience problems with vias: 8 or 10 layer boards 1.6 mm thick are common, and then the individual layers are thinner than a 4 layer board of 1.0 mm thickness.
A 1.0 mm PCB will be less stiff than a 1.6 mm, but unless you want to place a heavy transformer on it (don't!) this won't be a problem either.
Standard thickness panels may be up to 635 mm (25 inch) wide, but your manufacturer will limit that for 1.0 mm thickness. Ask him how wide a panel may be.
Overall, a 1.0 mm board is a bit less stiff, but for boards up to Eurocard format (160 mm x 100 mm) I wouldn't worry about it.