Thanks all. I agree with the statement that silver migration is of less importance as it's not likely to happen. BUT...if you make a simple calculation on the electrical field strength, you come to the fact that you'll have 200 V per millimeter. That is a lot. Much more than what the semi chip makers recommend. I have foundry book from Triquint, and they don't ever exceed 100 V per millimeter, which is valid for dry air. What do you think? Isn't 200 V/mm too much? Yes, Joyce, they should use a preform. With such a one, there will be no epoxy creeping up the walls of the chip. I'll check and see if preforms are allowed for Class S. Wetting maximum 50%, that's what I have been recommending for two decades, and I will insist that they adopt that in their process description. Inge -------------------------------------------------- From: "Thayer, Wayne - IIW" <[log in to unmask]> Sent: den 7 July 2010 18:05 To: <[log in to unmask]> Subject: Re: [TN] Hybrid precap q > Hi Inge- > > Yes that's scary, but it will probably work. I don't see how much you can > do about it unless you can find that it actually violates a written > specification. The usual problem I get with too much silver epoxy is > bleedout contamination of wirebonding pads, so maybe you will find poor > statistics in bondpads close to this oversized deposit. > > Other than that, if your gut tells you 50 microns is too small, then have > a chat with your gut about why. You will probably come to the conclusion > that your concern is based on potential gradient across the surface, so > then try to estimate what it is with the present design in relation to > your experience based on previous migration situations. If you find this > to be much more severe than your previous experience with known problems, > then hopefully it fails a written spec. > > Wayne > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge > Sent: Wednesday, July 07, 2010 6:16 AM > To: [log in to unmask] > Subject: [TN] Hybrid precap q > > Hi all, > will be back with quiz 11, but before that , I have a q about silver epoxy > mounting MMIC chips. The amount of glue is so rich, that the silver epoxy > wets all the way up the walls and stops just before the horizontal plane > of > the chip. Now, some conductors are as close to the chip edge as two times > the diameter of a bond wire, which is about 50 um. I dislike such a small > distance between the silver and the conductors. I'm doing a consulting > job > for a company, and they mean that this space is enough. The chips are in > a > laserwelded kovar package, so they are well protected, but I'm still not > satisfied. I've seen too much of migration issues in my days. The > packages > are class S. What are your opinions? > Thanks in advance > /Inge > > -------------------------------------------------- > From: "Whittaker, Dewey (EHCOE)" <[log in to unmask]> > Sent: den 6 July 2010 17:43 > To: <[log in to unmask]> > Subject: Re: [TN] NTC: Friday quiz 11 > >> It's like what Doug said when he was asked if he could hear in a vacuum: >> "is it turned on"? >> Dewey >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Ken Bloomquist >> Sent: Tuesday, July 06, 2010 8:18 AM >> To: [log in to unmask] >> Subject: Re: [TN] NTC: Friday quiz 11 >> >> Did we ever find out what these were? >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge >> Sent: Friday, July 02, 2010 10:40 AM >> To: [log in to unmask] >> Subject: Re: [TN] NTC: Friday quiz 11 >> >> Hi Laides and Gentlemen, >> time again for you to sharpen yourself after a whole week of sloppiness >> and >> lack of challenges. The real brainy solves both mysteries. >> Steve, are you taking the catch? Twangggg..... >> /Inge >> >> ______________________________________________________________________ >> This email has been scanned by the MessageLabs Email Security System. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> ______________________________________________________________________ >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> 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 >> ----------------------------------------------------- >> >> ______________________________________________________________________ >> This email has been scanned by the MessageLabs Email Security System. >> For more information please contact helpdesk at x2960 or [log in to unmask] >> ______________________________________________________________________ >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> 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 >> ----------------------------------------------------- > > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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 > ----------------------------------------------------- > > This e-mail and any files transmitted with it may be proprietary and are > intended solely for the use of the individual or entity to whom they are > addressed. 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For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------