Hi L.A.,
should have read more carefully, it's not an american 0603, but an american
0201. Sorry! Since we didn't do this kind of parts, I can only refer you to
2 sources of information:
http:\\smtinfo.net
http://www.engentaat.com
I know that both Engent and Universal can help you with the process
development, but I think any major equipment manufacturer could do this for
you.
It is no easy task, I would work it out like this: find a good solution for
manufacturing, get from there the landpattern, orientation and pad to pad
spacing that work and impose this design to your PCB designers.
Regards,
Ioan
> -----Original Message-----
> From: Le Ai Quoc [SMTP:[log in to unmask]]
> Sent: Thursday, October 14, 2004 10:41 PM
> To: TechNet E-Mail Forum; Tempea, Ioan
> Subject: Re: [TN] Aperture for 0603mm chip
>
> Thank you Ioan,
> The gap between the pads is 0.3mm (if it is 0.023" (0.6mm), the chip whose
> length is 0.6mm could not get good wetting in all cases). The size of pad
> is
> 0.3x0.3mm. We are using Pb-free solder paste for that PCBA. With the pad
> design like this, each electrode of part will sit on pad about 0.15mm in
> ideal case. How big is the misalignment which is allowed for this part?
> Printing result is registered well, no offsets at placement (I checked
> with
> microscope) and we are doing the aperture 100% as pad size.
> What is the ideal time for pre-heating at reflow? Now we don't get any
> case
> of solder ball at these chips with current profile.
> I heard that there are some aperture styles which can prevent this
> problem.
> Also, I have never heard about anti-Manhattan/tombstoning solder paste,
> what
> is that?
>
> Thanks and best regards,
> L. A. Quoc
>
>
> ----- Original Message -----
> From: "Tempea, Ioan" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, October 14, 2004 7:54 PM
> Subject: Re: [TN] Aperture for 0603mm chip
>
>
> > Quoc,
> >
> > I don't see you mentioning land pattern design. If the gap between the
> pads
> > is bigger than 0.023", you start increasing your probability of
> tombstoning.
> > Then, in case your soldering paste (if no-clean) does not create
> mid-chip
> > balls, you could print 1:1, no homeplating, although we reliably do
> > homeplating on 0603s that have a good pad
> > design.
> >
> > After this you just check your process step by step: the printing shall
> be
> > well registered, no offsets at placement and yes, the reflow recipe has
> an
> > influence, if everything else is OK. You will need longer preheating, to
> > make sure that the paste on both pads melts at the same time when
> hitting
> > the spike. But a good reflow recipe will not correct poor printing or
> > insertion.
> >
> > Also there are so called anti-tombstoning pastes out there, that are
> worth
> > trying.
> >
> > Good luck,
> > Ioan
> >
> > > -----Original Message-----
> > > From: TechNet [SMTP:[log in to unmask]] On Behalf Of Le Ai Quoc
> > > Sent: Wednesday, October 13, 2004 11:32 PM
> > > To: [log in to unmask]
> > > Subject: [TN] Aperture for 0603mm chip
> > >
> > > Hi Technetters,
> > > Do you know the opening style (aperture) for stencil (metal mask)
> applied
> > > for printing solder paste on resistance, capacitor chip 0603mmm to
> prevent
> > > "Tombstone/Manhattan" after reflow. Also, pls. advise about stencil
> > > thickness.
> > > Last but not least, is the reflow profile important for this defect?
> Any
> > > suggestion?
> > > Thanks in advance,
> > > Le Ai Quoc
> > >
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