I received the TMA graph from Dupont from 25-200C. Draw two straight lines
below and over Tg (115).
The difference between the graph and the lines is negligible .
CTE 25-115C : 27ppm/C
CTE 115-200C: 47.2ppm/C
Regards
> -----Original Message-----
> From: Mcmaster, Michael [SMTP:[log in to unmask]]
> Sent: 25 mars, 2003 13:22
> To: [log in to unmask]
> Subject: Re: [TN] FW: [TN] TCE above Tg for Dupont CB100 silver resin
>
> Substates typically have anisotropic CTEs in X/Y and Z because of the
> effect of the glass reinforcement limiting expansion in the X/Y direction.
> CB-100 is a silver filled epoxy. Unless there is something about the size
> and shape of the filler and application method that would provide an
> orientation to the filler (I'm unaware of any of this being done with this
> material), CB-100 should have isotropic CTE values.
>
>
> Mike McMaster
> RF Product Engineer
> Merix Corporation
> 503-992-4263
>
>
>
> ----------
> From: Yuan Li[SMTP:[log in to unmask]]
> Reply To: TechNet E-Mail Forum.;Yuan Li
> Sent: Tuesday, March 25, 2003 10:02 AM
> To: [log in to unmask]
> Subject: Re: [TN] FW: [TN] TCE above Tg for Dupont CB100 silver
> resin
>
> Is it the CTE on Z-direction?
> The CTEs on X- and Y- directions above Tg are lower for BT substrates.
>
>
>
> -----Original Message-----
> From: peter blokhuis [ <mailto:[log in to unmask]>]
> Sent: Tuesday, March 25, 2003 6:07 AM
> To: [log in to unmask]
> Subject: Re: [TN] FW: [TN] TCE above Tg for Dupont CB100 silver resin
>
> Methode Electronics <http://www.methode.com/mdc/via.pdf>
> has a similar material (their 1210) with a Tg of
> 190ppm/C above their Tg of 120C. Perhaps this will be
> close enough for your needs.
> Peter Blokhuis
>
>
> --- joyce <[log in to unmask]> wrote:
> > if it is standard epoxy filled with silver, my guess
> > is 3x TCE above Tg.
> > With absent of data and not going to do any test
> > (which I think you
> > really should do the test... rather than question it
> > endlessly, why not
> > just pay few $ run a TMA?), I would design per 3x
> > TCE above Tg, provide
> > you cure it properly. On the other hand, why Dupont
> > not provide above
> > Tg data? very strange...
> >
> > my 2 cents.
> >
> > jk
> >
> > -----Original Message-----
> > From: TechNet [ <mailto:[log in to unmask]>] On Behalf Of
> > Mcmaster, Michael
> > Sent: Monday, March 24, 2003 5:41 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] FW: [TN] TCE above Tg for Dupont
> > CB100 silver resin
> >
> >
> >
> > I'm going to have to disagree with Guy on this.
> > There's nothing that
> > says CTE above Tg has to be non-linear. Nor is
> > there anything that says
> > it has to be linear, especially when working with
> > systems like today's
> > high performance epoxy systems.
> >
> > There are multiple ways to define, measure, and
> > determine Tg, but it is
> > generally regarded as the temperature below which
> > free rotations cease
> > because of intramolecular energy barriers. In other
> > words, the material
> > acts as a glass.
> >
> > Above Tg the polymer achieves what is known as
> > segmental mobility. The
> > reason for this is that as you heat the material up
> > it expands (the
> > CTE). This expansion results in an increase in free
> > volume. Below, Tg,
> > the free volume is too small to allow segmental
> > mobility, whereas above
> > Tg, the free volume is large enough.
> >
> > The Tg the shows up as a discontinuity in the
> > specific volume vs
> > temperature curve. For amorphous polymers,
> > especially something like a
> > cross-linked epoxy, the transition is not clean.
> > Difference in cross
> > link density, segment length, initial free volume
> > and other factors mean
> > that different sections of the material achieve the
> > necessary free
> > volume for segmental mobility at different
> > temperatures. As a result,
> > the glass transition is usually not abrupt (like
> > say, the melting of
> > water, another transition). So while the Tg is
> > reported as a single
> > temperature, that's rarely true. The temperature is
> > usually arrived at
> > by extrapolating the specific volume vs temperature
> > curves above and
> > below Tg. The reported Tg is the intersection of
> > the two lines, even
> > though the transition itself started below and
> > continued above this
> > temperature.
> >
> > For CTE above Tg to be restricted to "non-linear" or
> > "linear" is
> > unfounded. I've seen plenty of TMA scans that
> > exhibit linear behavior
> > for at least some section above the Tg. I've also
> > seen materials that
> > exhibit very non-linear behavior. Much of this has
> > to do with the
> > highly variable structures and compositions of
> > polymeric materials. You
> > have materials that are difunctional,
> > tetrafunctional, mulitifunctional
> > and then the co-polymer blends that tend to exhibit
> > multiple transitions
> > to the point where you can't find two lines from a
> > TMA scan to
> > extrapolate to an intersection. In some cases, it's
> > nearly impossible
> > to get a good Tg determination from TMA alone and
> > alternative methods
> > such as DSC and DMA must be used. But these look at
> > properties other
> > than volume to determine the transition and don't
> > necessarily give the
> > same result.
> >
> > And I'm guessing that you don't really care whether
> > it's truly linear or
> > not as along as it's a reasonable approximation of
> > the CTE in the
> > temperature range of interest. In all likelihood
> > you want to know how
> > the material is going to perform during reflow
> > soldering (from below to
> > above Tg). And maybe the properties during the
> > operational life (likely
> > below Tg). So you need to know the Tg, preferably
> > measured with TMA
> > since that is how CTE is measured also. You need to
> > know the
> > temperature range for the CTE measurements. You at
> > least want the value
> > above and below Tg. Reporting and using a CTE value
> > that is the
> > combination of the values above and below Tg is not
> > of any practical
> > value. The material exhibits this particular
> > behavior only at one very
> > specific temperature during the transition phase.
> > It's akin to a
> > stopped watch being right twice per day.
> >
> > Like you, I've had no luck determining the CTE of
> > CB-100 above Tg.
> >
> > Mike McMaster
> > RF Product Engineer
> > Merix Corporation
> > 503-992-4263
> >
> >
> >
> > ----------
> > From: Arbour,
> > Michel[SMTP:[log in to unmask]]
> > Reply To: TechNet E-Mail Forum.;Arbour, Michel
> > Sent: Monday, March 24, 2003 6:10 AM
> > To: [log in to unmask]
> > Subject: [TN] FW: [TN] TCE above Tg for
> > Dupont CB100 silver resin
> >
> >
> > > OK,
> > > So the values for ZTCE > Tg given in the material
> > specs or various
> > > articles
> > > are linear approximation of the behaviour of ZTCE
> > >Tg . Right ??
> > >
> > > And the Zaxis expansion% (50 to 288C) is the
> > "real" value ?
> > >
> > > Ref. : circuitree magazine Feb. 2001: High
> > reliability/Low CTE epoxy
> > > technology,
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Guy Ramsey [SMTP:[log in to unmask]]
> > > > Sent: 21 mars, 2003 16:01
> > > > To: 'TechNet E-Mail Forum.'; 'Arbour, Michel'
> > > > Subject: RE: [TN] TCE above Tg for Dupont
> > CB100 silver resin
> > > >
> > > > TCE above Tg is non-linear. What you're asking
> > for is like asking
> > for
> > > > the distortion characteristics of a amp is after
> > clipping.
> > > >
> > > > > -----Original Message-----
> > > > > From: TechNet [ <mailto:[log in to unmask]>] On
> > Behalf Of Arbour, Michel
> >
> > > > > Sent: Friday, March 21, 2003 2:52 PM
> > > > > To: [log in to unmask]
> > > > > Subject: [TN] TCE above Tg for Dupont CB100
> > silver resin
> > > > >
> > > > >
> > > > > Hello Techies,
> > > > > By any chance, would you know what is
> > the TCE > Tg
> > > > > for Dupont CB100 silver resin ??
> > > > >
> > > > > Can't get that info from DuPont's
> > Micro-Circuit
> > > > > Materials group in the U.S. . They have not
> > measured that
> > > > > characteristic they said...
> > >
> > >
> > ---------------------------------------------------
> >
> === message truncated ===
>
>
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