SCREENING... 1. Is type 4 paste necessarily required? [No, not unless you are using it for some other purpose.] 2. Is No-Clean Ok to use? [YES] 3. How thin stencil is required? 5 mils? [5 is OK, but I wouldn�t base the decision on the 0201. 6 mil is OK too.] 4. What is your aperture reduction from pad? [1:1 works, but consider pinching it 15 or a cross through the center to reduce solder balls] 5. Is the "homeplate" aperture opening required? [No, rectangles will do. Some people homeplate to reduce solder balling, but then end-up getting tombstones.] 6. Does the stencil need to be stepped? [Depends on the thickness of stencil of course, but your standard stencil thickness without stepping is probably OK] 7. What are the best screen speeds, board release, snap-off, etc. settings on both an MPM and a Fuji screener? [Whatever]
CP� 3. Is a paper tape best (like the 402s) or is plastic embossed tape ok? [Never seen plastic.]
REFLOW... 1. Is Air or Nitrogen envioronment best? [Air is fine. If you�re using N2, that�s fine too.]
TOUCH-UP... 1. Are special soldering iron tips needed for such small parts? [We don�t touch these guys. We just cut the body, remove the end caps, dress the pads, and solder a new part.]
Other comments are: * Our transition from 0603 to 0402 was probably more difficult than our transition to 0201. * 0201 that we see are not fabricated uniformly. Different sized [asymmetrical] end caps often result in tombstoning. We do not understand how to respond to this well. It may require a better understanding of pad shape and spacing. * As your designers let the pads drift further apart, you�ll see greater tombstoning. 0.008" is probably a good distance. 0.010" might be too far apart. * Your designers will want to brickwall these parts. 0.010" may be too close together, given paste print, pick, and place registration. * As with all stencil designs, focus on aspect ratios [target 3] and area ratios [target 0.8] rather than selecting a stencil thickness for your stencil. IPC-7527 - Stencil Design Guidelines may require additional development in this area.