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 > > > > > > --------------------------------------------------- > > > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > > > To unsubscribe, send a message to [log in to unmask] with following text > in > > > the BODY (NOT the subject field): SIGNOFF Technet > > > To temporarily halt or (re-start) delivery of Technet send e-mail to > > > [log in to unmask]: SET Technet NOMAIL or (MAIL) > > > To receive ONE mailing per day of all the posts: send e-mail to > > > [log in to unmask]: SET Technet Digest > > > Search the archives of previous posts at: > http://listserv.ipc.org/archives > > > Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > > > for additional information, or contact Keach Sasamori at > [log in to unmask] > or > > > 847-509-9700 ext.5315 > > > ----------------------------------------------------- > > > > --------------------------------------------------- > > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > > To unsubscribe, send a message to [log in to unmask] with following text > in > > the BODY (NOT the subject field): SIGNOFF Technet > > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > > Search the archives of previous posts at: > http://listserv.ipc.org/archives > > Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > > ----------------------------------------------------- > > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------