Ingermar,
A simple pararmeter that will determine the thickness of the conductor that
is carrier of the GHz is the conductitivity and frequency(magnetic perm goes
to 1 at frequencies greater then kHz). We take the ratio of the classical
skin depth thickness of Ag and the Ag loaded organic matrix,we see =
(conductivity)Agorganic/(conductivity/Ag=Ag(thickness) Agorganic(thickness).
Since the conductivity of Ag is about 10 times the conducitivity of the
Agorganic matrix then the ratio of the classical skin thickness is sq root
of 10, usually the conductor is put on the conductor path 3x or more based
on uniformity etc.
If anybody needs more please contact:
Richard Haynes
[log in to unmask]
609-497-4584
==================================================================
-----Original Message-----
From: Ingemar Hernefjord (EMW) <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Tuesday, February 15, 2000 5:25 AM
Subject: Re: [TN] GHz and filled adhesives
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
>>
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