Hi TechNet! I have a question for everyone that has been generated by this
pick-n-place thread - there seems to be a fair amount of 0402 component
association with tombstoning defects. Just a quick survey:

a) What type of reflow process is being used: vapor phase, convection/air,
convection/inert, other (specify)

b) How long is the dwell time between solder stencil and component
placement?

c) Solder paste type: low residue, no clean, rosin, water soluble

I get the impression that there is a fair amount of tombstoning being seen
with 0402 components and that's something I haven't seen in our smt
process. I'll summarize the survey results that accumulate and post them on
the forum.

Dave Hillman
Rockwell Collins
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Paul <[log in to unmask]> on 09/01/99 05:38:19 PM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
      to Paul <[log in to unmask]>

To:   [log in to unmask]
cc:
Subject:  Re: [TN] Pick N Place Equipment and 0402's




Hi All,
        It simply isn't true that a Fuji CP 6 cannot place 0402's.

        We have placed several million this way.  Now I won't say that
there haven't been any problems but thrown caps are not the leading
defect.  For our process (2000 placements on first assembly) the leading
defect has been tombstoning.

        The defect level on first assembly was taken from 20,000 DPM to
200 DPM.  The second assembly is still under developement.  In fact after
I finish this email I will resume my developement.

        So I can't say that the Fuji CP 6 never throws the 0402's.
However I can say that it is happening for us less than .02% of the time.
(BTW .02% equals 200 dpm).

        I guess I could determine the rate for missing component related
defects on several packages, 0402, 0603, 0805 if only I could find the
time.

Paul Gill
MCMS inc.

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