Ingemar, I feel that the softening of the solder has a negative impact on adhesive adhesion. Possibly it is oxidation related, or surface energy? Maybe it is like wedge bonding to Tin or Pb ... just doesn't work :-) At least not for me... No, Ingemar, I don't have any experience with the use of a heat gun to solder items together, but i can imagine how it could work out. It would seem that as long as one pre-heated the components to the maximum extent possible it would be most benign for the components. Sounds like you are trying to do just that! The only other thing that I could suggest would be a hotplate, or heat column to place the package onto, to essentially pre-heat the entire package. I don't know if this would offer any significant advantage over your present set-up or not. Have a nice weekend ! Steve ________________________________ From: Inge [mailto:[log in to unmask]] Sent: Fri 10/3/2008 2:02 PM To: Creswick, Steven; TechNet E-Mail Forum Subject: Re: [TN] "Conductive" Bonding Material Hi Trikeman, Yes, argon ion bombardment would do the same job after hours of exposure. Etching took seconds. Don't understand how 'softening' the solder could make it more attractive for adhesives. The surface energy may increase, if that's what you mean. I have no experience from that. Yes, it's 84-1LMI. The english gentleman I suggested seems to pretend he is innocent. Maybe he is on his yearly african safari. By the way, do you have experience from soldering compressed glass Kovar Au-flash/Ni feedtrues with a heatgun. The manufacturers recommend preheating the nickel plated package to 150C before gunning. I apply the heat slowly so that there should be no heat shock. The feedtrues are very tough, and according to the MIL spec, they are designed to withstand immersion test -55C. Inge ----- Original Message ----- From: "Creswick, Steven" <[log in to unmask]> To: "TechNet E-Mail Forum" <[log in to unmask]>; "Inge" <[log in to unmask]> Sent: Wednesday, October 01, 2008 5:28 PM Subject: RE: [TN] "Conductive" Bonding Material Inge, How about an agressive argon plasma etch to roughen up the surface a bit? I also thought it had something to do with my cure temps on the order of 150-160-175C for some adhesives, being close to the plastic region of the generic [old Sn/Pb] solders and essentially trying to make the adhesive bond to a 'moveable' surface ... :-) What is 1LMI? All I can think of is Ablebond 84-1LMI - a real good Ag-filled conductive adhesive Steve _____ From: TechNet on behalf of Inge Sent: Wed 10/1/2008 4:52 PM To: [log in to unmask] Subject: Re: [TN] "Conductive" Bonding Material The problem with tin and lead is that it is so 'flat' , seen from a nano-level. Conductive silver (or other metal) filled adhesives do not stick to the metal part chemically, at least not on a essential basis, but rather on a mechanical one. There are more binding mechanisms, but let's discuss the one that is most important for succeeding for glueing to a solder. A solder is amazingly smooth and dense, still seen microscopically, depending on the way it solidifies. One could see that indirectly by putting a drop of water on the solder: it forms a sphere instead of wetting and spreading. High surface tension, with other words. The solder could not break the droplet's surface tension. Adhesives have a liquidous part, which is necessary for being dispensable. That ingredient is not very wetting by nature either, and furthermore, the whole paste has a very high viscosity. Now, we want a surface that is like a burdock, or how can I describe it, a surface with billions of microscopic superficial voids and cavities. If the wet phase of the glue has matching surface tension, and a low viscosity, and you give it time, it will creep into all the microscratches and after curing creating millions of micro'hooks'. How do we obtain such a condition with solder then? You need both remove the always present oxide and also create the rough surface. We found that a slight etching could do the job. We were in a situation when we just had to fix it. Did not like it, but got a acceptable result. I don't recommend the method, too many traps to fall into, but thought it might be of interest to someone, who could perhaps develop the idea on a more adequate way, the inventor of 1LMI, for instance. Let's see if he takes the bate. What adhesive? Don't remember exactly, think it was a 1,000 mPas light curing epoxy, probably from Epotek, as it was named at that time. The bonding had no requirements on being very strong, and was not either. Just had to keep a grounded copper foil. Soldering was forbidden of a special reason. Inge ----- Original Message ----- From: "Douglas O. Pauls" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, October 01, 2008 12:06 PM Subject: Re: [TN] "Conductive" Bonding Material > Thermally conductive or electrically conductive? > > Doug Pauls > Rockwell Collins > > > > "Joe Lara (Select Circuits)" <[log in to unmask]> > Sent by: TechNet <[log in to unmask]> > 10/01/2008 01:03 PM > Please respond to > TechNet E-Mail Forum <[log in to unmask]>; Please respond to > "Joe Lara (Select Circuits)" <[log in to unmask]> > > > To > [log in to unmask] > cc > > Subject > [TN] "Conductive" Bonding Material > > > > > > > Good Morning / Afternoon Tech Net Guru's, > > Has anyone used a "Conductive" bonding material on a ceramic circuit > board? > If so what material was used and what was the quality of the result. > > > > Thanks in advance! > > Joe > > > ***************** E-mail Confidentiality Disclaimer ***************** > > This e-mail message may contain privileged or confidential information. If > you are not the intended recipient, you may not disclose, use, > disseminate, distribute, copy or rely upon this message or attachment in > any way. If you received this e-mail message in error, please return by > forwarding the message and its attachments to the sender. Select Circuits > and its affiliates do not accept liability for any errors, omissions, > corruption or virus in the contents of this message or any attachments. > > ***************** E-mail Confidentiality Disclaimer ***************** > > --------------------------------------------------- > 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 > ----------------------------------------------------- > > > --------------------------------------------------- > 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 > ----------------------------------------------------- > --------------------------------------------------- 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 ----------------------------------------------------- THE INFORMATION CONTAINED IN THIS E-MAIL MESSAGE AND ANY ATTACHMENTS SENT FROM GENTEX CORPORATION IS GENTEX CONFIDENTIAL INFORMATION INTENDED ONLY FOR THE PERSONAL USE OF THE INDIVIDUAL OR ENTITY NAMED ABOVE. If you are not the intended recipient, you are hereby notified that any review, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail, and delete this e-mail message and any attachments from your computer. [gntx v.1] --------------------------------------------------- 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 -----------------------------------------------------