I'm the guy that wrote one of the 'very amusing' responses, and although I
was trying to be humorous, there was sincere concern behind this. For those
of you unfamiliar with the terms in SMT, 0201 is .020 x .010. Pick up your
mechanical pencil and look at the lead in it. If this is .5mm lead, then
the LONGEST dimension of one of these chips equals the thickness of that
pencil lead and the width is half of that!!! The use of these parts is NOT
for the faint of heart and should be used as a LAST resort.
A previous response listed lots of potential problems as anyone can
imagine: Placement, packaging on tape/reel, tombstoning, solder bridges.
Your yield will be exceedingly low, nearly nonexistent and most likely not
worth the extensive effort.
There are other means to put passive devices in a small space that
should be explored first. Fine pitch resistor networks on .020 pitch, or
printing resistive material on layers on/within the PCB. Try incorporating
more of this circuitry into IC's or better, use ceramic hybrids and put the
resistive material there. I'm sure there are other options that I can't
think of.
Most assembly houses (anywhere, including Japan) are not equipped for
microelectronics, and you're asking for trouble if you jump into this
without exploring other, more viable options.
"A cruel joke"? Only one a designer would play on his mfg folks, if
there's a better way of doing it.
----------
From: TechNet-request
To: TechNetSubmission
Subject: RE: 0201 components?
Date: Thursday, April 17, 1997 11:06AM
What type of components are available in 0201 size?? Who manufactures
them??
Thanks
----------
From: TechNet-request
To: technet
Subject: 0201 components.
Date: Wednesday, April 16, 1997 12:00AM
A week or so ago I posted a request for any information dealing with the
population of 0201 chips and PCB related issues. The two responses I
received, while very amusing , did not help and so I am requesting
information again. This is not a cruel joke as one respondent asked. The
density of our latest hand held scanner is requiring not only microvia
technology but also 0201 size chips.
I would appreciate any info especially from any Japanese correspondents
to this group , as I believe that it is only in Japan that these parts
are currently being run.
Regards.
Gerard O'Brien.
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