Thanks a lot, Joyce, I have the article co-writer on-line now, and he promised to give a hand. Let's see what comes out. cu Ingemar Inge, the recent issue of CPMT has following paper: Effect of Ag Particle Size on Electrical Conductivity of Isotropically Conductive Adhesives L. Ye, Z. Lai, J. Liu, and A. Thölen [p. 299] http://www.cpmt.org/past_trans/epm_toc_9910.html you may be able to find the paper you wanted in the reference...Good luck. jk At 02:34 PM 2/14/00 -0800, you wrote: >Ingemar > >Good to hear you're out there. Unfortunately, I don't have any such paper. > >The issue you bring up is basic metal-Si (Schottky barrier diode) >semiconductor physics...not a focus to most of those in the PWB world. You >can read about this in almost any solid-state physics book. Typical voltages >to overcome the barrier can be as high as 0.5-1.0V, although it depends on >the doping level and other related stuff. Silver epoxy can be a bit more >complicated because it forms a very thin sulfuric (I think, if not it's >oxide) coating (from reacting to air and the epoxy resin) that acts like an >insulator that get's broken down easily, but can affect the Schottky >interfacial properties. Under these situations, you have various values of >Schottky barriers (think of it as a distribution of resistor values with a >critical turn-on voltage). Because the metal-Si interface is dictated by >charge carrier density and that this density is exponential with both >temperature and doping, it gets very squirrelly (for you non-english >speaking folks..."weird"). > >There is also the situation where the Si is doped such that you form Ohmic >contacts (your standard contact resistance), which also has some variation >in values, but not as severe in affecting electronic current because the >charge density does not vary significantly. > >In short, if you are looking into this, avoid non-wire bonded or metal >bumped Si devices. Look into IEEE journals in the mid-80's or look at >recent work in anisotropic conductive adhesives in flat panel displays >papers of the 90's. Call Hitachi Chemical (they are the big supplier) or 3M >(they have products out there and probably a lot of publications/patents) >for information on the adhesive electrical properties. Lastly, when I think >of RF, I track down contacts at Teradyne (think military). > >Good luck > >Carey > >-----Original Message----- >From: Ingemar Hernefjord (EMW) <[log in to unmask]> >To: [log in to unmask] <[log in to unmask]> >Date: Monday, February 14, 2000 2:19 AM >Subject: [TN] GHz and filled adhesives > > >>Gidd Moerning all, >>I have something that may be too far from PWB, but I dare try: who knows >about noise in metal filled adhesive joints? Many years back people found >that the conducting mechanism in thin silver epoxy joints reminds of that in >semiconductors, i.e. you have something like a diode, but very small >forward current drops and hardly measureable reverse blocking, anyway, it >may cause noise. Unfortunately, I have lost the article and the guy who made >research in this issue (possibly IBM, Raytheon, HP... was american I'm >sure). Anyone out there with experience from this field and RF-noise? >>txs in advance >>Ingemar Hernefjord >>Ericsson Microwave Systems >> >>############################################################## >>TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c >>############################################################## >>To subscribe/unsubscribe, send a message to [log in to unmask] with following >text in >>the body: >>To subscribe: SUBSCRIBE TECHNET <your full name> >>To unsubscribe: SIGNOFF TECHNET >>############################################################## >>Please visit IPC web site (http://www.ipc.org/html/forum.htm) for >additional >>information. >>If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or >>847-509-9700 ext.5365 >>############################################################## >> > >############################################################## >TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c >############################################################## >To subscribe/unsubscribe, send a message to [log in to unmask] with following text in >the body: >To subscribe: SUBSCRIBE TECHNET <your full name> >To unsubscribe: SIGNOFF TECHNET >############################################################## >Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional >information. >If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or >847-509-9700 ext.5365 >############################################################## > ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################