Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


0201s

Spanky

#6015

0201s | 19 April, 2001

All, We are getting ready to start running with 0201 passives. I have never run these before. We have run some 0402s however. We don't have any assemblies in-house yet, so I can't give any intelligent information regarding the board design (size, thickness, heat sinking, parts shadowing, number of 201s, etc.) I would just like some preliminary info to have as a basis before we do fire up. I have done some reading up and have been given info "in theory". But I need some practical info from the guys actually building them now. Nothing in the archives was as technical or specific as I am looking for. Can anyone enlighten me?

SCREENING... 1. Is type 4 paste necessarily required? 2. Is No-Clean Ok to use? 3. How thin stencil is required? 5 mils? 4. What is your aperture reduction from pad? 5. Is the "homeplate" aperture opening required? 6. Does the stencil need to be stepped? 7. What are the best screen speeds, board release, snap-off, etc. settings on both an MPM and a Fuji screener?

CP... 1. What's the best nozzle for pick and place? 2. Do you have any tip plugging problems? 3. Is a paper tape best (like the 402s) or is plastic embossed tape ok? 4. Is there any special camera considerations? 5. Is alignment generally a problem. 6. What problems (if any) have you noticed with a HASL board?

REFLOW... 1. Is Air or Nitrogen envioronment best?

TOUCH-UP... 1. Are special soldering iron tips needed for such small parts?

Thanks in advance... Spanky

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J.D.

#6017

Real World Experiance with 0201s | 19 April, 2001

Spanky,

It sounds like you are looking for a recipe to use when you do get an assembly in that has 0201's on it. We have worked with our customers worldwide in the development of the process to use 0201's. Most equipment manufacturers out there say "the machine is capable" or "we have tested our machines in the lab". Of course, this does you no good since every lab machine is fully PMed, babied and polished on a daily basis. Since we developed our process with our customers it is made to be the most robust and reliable process that can be applied in the real world. I can't give you everything in the recipe but I can answer your questions. My purpose of course is to sell equipment and I can tell you this. If you purchased your equipment before 2000 you might be able to pick and place 0201's but at defect levels that would probably be in the thousands PPM's. Why? This process needs a +/- 50 Micron or better accuracy machine to give you acceptable PPM defect levels. I can show you the testing and math that proves this out. Please call me and I will go through this with you.

Answers:

SCREENING 1. Yes, type 5 if possible but type 4 will work 2. No-clean is O.K. 3. 4 mil would be nice but if you have a good screener 5 mil will work. This depends on your spacing between components, aspect ratios and the snap-off setting you should use. 4. Call me and I will give you this 5. Yes 6. Yes and No this depends on the screener, paste, spacing, aspect ratios, blade type and snap-off. 7. I don't know their machines but with our offerings I can give you these settings. Just call me.

CP 1. One that is barely larger than the 0201 2. Yes, this can happen with conventional paper tapes 3. No one is packaging them in plastic that I know of 4. This is machine specific and I can give you the settings for our equipment 5. This is dependent on your machine accuracy and spacing between components. 6. Conventional PCB's will be O.K. up you a certain spacing level between components. After that you need to find a PCB vendor who can handle the spacing between components. I do know of one or two off the top on my head. Again, just call me.

REFLOW 1. This depends on your solder paste type. Not 0201's.

TOUCH-UP 1. What you use for 0402's should work but this is still a contentious part of the process.

Just call me and I will share what I know from our customers.

Sincerely,

J.D. Talken Panasonic Create (847)288-4569 jtalken@panasonicfa.com

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#6024

0201s | 19 April, 2001

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.

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