Empathy List Archives

AK

Attila Kinali

Thu, Apr 6, 2017 4:38 AM

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

		Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor

Moin, I recently wondered, why people around voltage metrology hardly talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. They have surface resistivity that is as high as PTFE, have higher thermal conductivity, lower thermal expansion (AlN is even pretty close to Si). So, why then does it hardly ever get mentioned? Is it the cost of those? Or is there something I am missing? Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor

PK

Poul-Henning Kamp

Thu, Apr 6, 2017 5:47 AM

In message 20170406063848.2bac84ef9bec7c9c55694bbc@kinali.ch, Attila Kinali w
rites:

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

I would worry about piezoelectricity ?

Also, most ceramics have hideous thermal expansions...

--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

-------- In message <20170406063848.2bac84ef9bec7c9c55694bbc@kinali.ch>, Attila Kinali w rites: >I recently wondered, why people around voltage metrology hardly >talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. >They have surface resistivity that is as high as PTFE, have >higher thermal conductivity, lower thermal expansion (AlN is >even pretty close to Si). So, why then does it hardly ever get >mentioned? Is it the cost of those? Or is there something I am >missing? I would worry about piezoelectricity ? Also, most ceramics have hideous thermal expansions... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

A

acbern@gmx.de

Thu, Apr 6, 2017 8:13 AM

well, certain Rogers materials have an even higher surface resistance than PTFE, and are the preferred choice in that case.

Gesendet: Donnerstag, 06. April 2017 um 06:38 Uhr
Von: "Attila Kinali" attila@kinali.ch
An: volt-nuts@febo.com
Betreff: [volt-nuts] PCBs with ceramic substrates

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

		Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

well, certain Rogers materials have an even higher surface resistance than PTFE, and are the preferred choice in that case. > Gesendet: Donnerstag, 06. April 2017 um 06:38 Uhr > Von: "Attila Kinali" <attila@kinali.ch> > An: volt-nuts@febo.com > Betreff: [volt-nuts] PCBs with ceramic substrates > > Moin, > > I recently wondered, why people around voltage metrology hardly > talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. > They have surface resistivity that is as high as PTFE, have > higher thermal conductivity, lower thermal expansion (AlN is > even pretty close to Si). So, why then does it hardly ever get > mentioned? Is it the cost of those? Or is there something I am > missing? > > Attila Kinali > > -- > You know, the very powerful and the very stupid have one thing in common. > They don't alters their views to fit the facts, they alter the facts to > fit the views, which can be uncomfortable if you happen to be one of the > facts that needs altering. -- The Doctor > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. >

CC

cheater00 cheater00

Fri, Apr 7, 2017 6:12 PM

Hi Attilla,
My #1 worry would be fragility.

On Thu, 6 Apr 2017 06:39 Attila Kinali, attila@kinali.ch wrote:

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

                     Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

Hi Attilla, My #1 worry would be fragility. On Thu, 6 Apr 2017 06:39 Attila Kinali, <attila@kinali.ch> wrote: > Moin, > > I recently wondered, why people around voltage metrology hardly > talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. > They have surface resistivity that is as high as PTFE, have > higher thermal conductivity, lower thermal expansion (AlN is > even pretty close to Si). So, why then does it hardly ever get > mentioned? Is it the cost of those? Or is there something I am > missing? > > Attila Kinali > > -- > You know, the very powerful and the very stupid have one thing in common. > They don't alters their views to fit the facts, they alter the facts to > fit the views, which can be uncomfortable if you happen to be one of the > facts that needs altering. -- The Doctor > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. >

BB

Bob Bownes

Fri, Apr 7, 2017 6:52 PM

We used them in the supercomputer space long long ago. Mount 8 die to
ceramic substrate, mount those to Rogers boards. Thermal wasn't really an
issue as everything was bathed in Flourinert™.

Was an interesting project. The Unix kernel scheduler had to make
scheduling decisions based on all the usual criteria plus how far away the
free CPU and/or memory was.

Bob

On Fri, Apr 7, 2017 at 2:12 PM, cheater00 cheater00 cheater00@gmail.com
wrote:

Hi Attilla,
My #1 worry would be fragility.

On Thu, 6 Apr 2017 06:39 Attila Kinali, attila@kinali.ch wrote:

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

                     Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/volt-nuts
and follow the instructions there.

We used them in the supercomputer space long long ago. Mount 8 die to ceramic substrate, mount those to Rogers boards. Thermal wasn't really an issue as everything was bathed in Flourinert™. Was an interesting project. The Unix kernel scheduler had to make scheduling decisions based on all the usual criteria plus how far away the free CPU and/or memory was. Bob On Fri, Apr 7, 2017 at 2:12 PM, cheater00 cheater00 <cheater00@gmail.com> wrote: > Hi Attilla, > My #1 worry would be fragility. > > On Thu, 6 Apr 2017 06:39 Attila Kinali, <attila@kinali.ch> wrote: > > > Moin, > > > > I recently wondered, why people around voltage metrology hardly > > talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. > > They have surface resistivity that is as high as PTFE, have > > higher thermal conductivity, lower thermal expansion (AlN is > > even pretty close to Si). So, why then does it hardly ever get > > mentioned? Is it the cost of those? Or is there something I am > > missing? > > > > Attila Kinali > > > > -- > > You know, the very powerful and the very stupid have one thing in common. > > They don't alters their views to fit the facts, they alter the facts to > > fit the views, which can be uncomfortable if you happen to be one of the > > facts that needs altering. -- The Doctor > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. >

RK

Rob Klein

Fri, Apr 7, 2017 7:30 PM

In general, metrology equipment doesn't get thrown about much ...

I know some calibrators have (heated) modules on ceramic substrates, so it's not that it is completely unheard of.

⁣Met vriendelijke groet,
Rob Klein

verstuurd vanaf mijn smartphone

Op 7 apr. 2017 20:12, om 20:12, cheater00 cheater00 cheater00@gmail.com schreef:

Hi Attilla,
My #1 worry would be fragility.

On Thu, 6 Apr 2017 06:39 Attila Kinali, attila@kinali.ch wrote:

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

                     Attila Kinali

--
You know, the very powerful and the very stupid have one thing in

common.

They don't alters their views to fit the facts, they alter the facts

to

fit the views, which can be uncomfortable if you happen to be one of

the

facts that needs altering. -- The Doctor

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

In general, metrology equipment doesn't get thrown about much ... I know some calibrators have (heated) modules on ceramic substrates, so it's not that it is completely unheard of. ⁣Met vriendelijke groet, Rob Klein verstuurd vanaf mijn smartphone Op 7 apr. 2017 20:12, om 20:12, cheater00 cheater00 <cheater00@gmail.com> schreef: >Hi Attilla, >My #1 worry would be fragility. > >On Thu, 6 Apr 2017 06:39 Attila Kinali, <attila@kinali.ch> wrote: > >> Moin, >> >> I recently wondered, why people around voltage metrology hardly >> talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. >> They have surface resistivity that is as high as PTFE, have >> higher thermal conductivity, lower thermal expansion (AlN is >> even pretty close to Si). So, why then does it hardly ever get >> mentioned? Is it the cost of those? Or is there something I am >> missing? >> >> Attila Kinali >> >> -- >> You know, the very powerful and the very stupid have one thing in >common. >> They don't alters their views to fit the facts, they alter the facts >to >> fit the views, which can be uncomfortable if you happen to be one of >the >> facts that needs altering. -- The Doctor >> _______________________________________________ >> volt-nuts mailing list -- volt-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> and follow the instructions there. >> >_______________________________________________ >volt-nuts mailing list -- volt-nuts@febo.com >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >and follow the instructions there.

D

David

Sat, Apr 8, 2017 3:28 PM

I assume for cost reasons everybody likes to stay as close to FR4 type
materials as possible. This goes double if you have a qualified FR4
type of material which does not suffer from hook and other problems
which are a good reason to use a better material.

I have noticed that special substrates are more common in older
instruments before good or at least not bad FR4 became available.
Tektronix used polysulfone and then later some other white plastic for
high impedance circuits before they solved the FR4 hook problem and
then later they used ceramic substrates for hybrid type construction
even where they did not have to.

On Thu, 6 Apr 2017 06:38:48 +0200, you wrote:

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

		Attila Kinali

I assume for cost reasons everybody likes to stay as close to FR4 type materials as possible. This goes double if you have a qualified FR4 type of material which does not suffer from hook and other problems which are a good reason to use a better material. I have noticed that special substrates are more common in older instruments before good or at least not bad FR4 became available. Tektronix used polysulfone and then later some other white plastic for high impedance circuits before they solved the FR4 hook problem and then later they used ceramic substrates for hybrid type construction even where they did not have to. On Thu, 6 Apr 2017 06:38:48 +0200, you wrote: >Moin, > >I recently wondered, why people around voltage metrology hardly >talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. >They have surface resistivity that is as high as PTFE, have >higher thermal conductivity, lower thermal expansion (AlN is >even pretty close to Si). So, why then does it hardly ever get >mentioned? Is it the cost of those? Or is there something I am >missing? > > Attila Kinali

AK

Attila Kinali

Sun, Apr 9, 2017 1:52 PM

On Fri, 07 Apr 2017 21:30:56 +0200
Rob Klein rob.klein@smalldesign.nl wrote:

In general, metrology equipment doesn't get thrown about much ...

I know some calibrators have (heated) modules on ceramic substrates, so it's not that it is completely unheard of.

So, in summary, if the right substrate is used, then it's very usefull?

What about piezoelectricity? Is that a concern with the sintered substrates?
Or is that only a problem with mono-crystaline materials?

		Attila Kinali

--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson

On Fri, 07 Apr 2017 21:30:56 +0200 Rob Klein <rob.klein@smalldesign.nl> wrote: > In general, metrology equipment doesn't get thrown about much ... > > I know some calibrators have (heated) modules on ceramic substrates, so it's not that it is completely unheard of. > So, in summary, if the right substrate is used, then it's very usefull? What about piezoelectricity? Is that a concern with the sintered substrates? Or is that only a problem with mono-crystaline materials? Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson

CC

cheater00 cheater00

Sun, Apr 9, 2017 3:36 PM

Hi Rob, thanks for your email.

My take is you want your standards and calibrated equipment to last very
long due to increasing stability, and that is in direct opposition to
making them out of fragile materials, even if they don't get thrown around.
Accidents happen, people trip over, this can't really be helped. I'm no
metrology expert by any degree, it just seems to me that making it even
easier to break your $250k box is a bad idea if it can be wholly avoided by
using a different material that'll meet requirements too.

You're right that it's not unheard of - ceramics were even used in mobile
testing equipment eg by tek - but they didn't know better back then, or
they didn't care because equipment would be phased out before it had chance
to break.

On Fri, 7 Apr 2017 22:32 Rob Klein, rob.klein@smalldesign.nl wrote:

In general, metrology equipment doesn't get thrown about much ...

I know some calibrators have (heated) modules on ceramic substrates, so
it's not that it is completely unheard of.

⁣Met vriendelijke groet,
Rob Klein

verstuurd vanaf mijn smartphone

Op 7 apr. 2017 20:12, om 20:12, cheater00 cheater00 cheater00@gmail.com
schreef:

Hi Attilla,
My #1 worry would be fragility.

On Thu, 6 Apr 2017 06:39 Attila Kinali, attila@kinali.ch wrote:

Moin,

I recently wondered, why people around voltage metrology hardly
talk about ceramic substrates (Al2O3, AlN, ...) for PCBs.
They have surface resistivity that is as high as PTFE, have
higher thermal conductivity, lower thermal expansion (AlN is
even pretty close to Si). So, why then does it hardly ever get
mentioned? Is it the cost of those? Or is there something I am
missing?

                     Attila Kinali

--
You know, the very powerful and the very stupid have one thing in

common.

They don't alters their views to fit the facts, they alter the facts

to

fit the views, which can be uncomfortable if you happen to be one of

the

facts that needs altering. -- The Doctor

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

Hi Rob, thanks for your email. My take is you want your standards and calibrated equipment to last very long due to increasing stability, and that is in direct opposition to making them out of fragile materials, even if they don't get thrown around. Accidents happen, people trip over, this can't really be helped. I'm no metrology expert by any degree, it just seems to me that making it even easier to break your $250k box is a bad idea if it can be wholly avoided by using a different material that'll meet requirements too. You're right that it's not unheard of - ceramics were even used in mobile testing equipment eg by tek - but they didn't know better back then, or they didn't care because equipment would be phased out before it had chance to break. On Fri, 7 Apr 2017 22:32 Rob Klein, <rob.klein@smalldesign.nl> wrote: > In general, metrology equipment doesn't get thrown about much ... > > I know some calibrators have (heated) modules on ceramic substrates, so > it's not that it is completely unheard of. > > > > ⁣Met vriendelijke groet, > Rob Klein > > verstuurd vanaf mijn smartphone > > Op 7 apr. 2017 20:12, om 20:12, cheater00 cheater00 <cheater00@gmail.com> > schreef: > >Hi Attilla, > >My #1 worry would be fragility. > > > >On Thu, 6 Apr 2017 06:39 Attila Kinali, <attila@kinali.ch> wrote: > > > >> Moin, > >> > >> I recently wondered, why people around voltage metrology hardly > >> talk about ceramic substrates (Al2O3, AlN, ...) for PCBs. > >> They have surface resistivity that is as high as PTFE, have > >> higher thermal conductivity, lower thermal expansion (AlN is > >> even pretty close to Si). So, why then does it hardly ever get > >> mentioned? Is it the cost of those? Or is there something I am > >> missing? > >> > >> Attila Kinali > >> > >> -- > >> You know, the very powerful and the very stupid have one thing in > >common. > >> They don't alters their views to fit the facts, they alter the facts > >to > >> fit the views, which can be uncomfortable if you happen to be one of > >the > >> facts that needs altering. -- The Doctor > >> _______________________________________________ > >> volt-nuts mailing list -- volt-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > >> and follow the instructions there. > >> > >_______________________________________________ > >volt-nuts mailing list -- volt-nuts@febo.com > >To unsubscribe, go to > >https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > >and follow the instructions there. > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. >

CH

Chuck Harris

Sun, Apr 9, 2017 4:17 PM

Why exactly do you think ceramic is delicate?

It is used to make knifes, pistols, internal combustion
engines, turbines, brake linings, clutches,... and even
insert tooling for machining very hard materials.

It isn't your mother's teapot!

Or, are you the proverbial "bull in a china shop" in
everything you do?

-Chuck Harris

cheater00 cheater00 wrote:

Hi Rob, thanks for your email.

My take is you want your standards and calibrated equipment to last very
long due to increasing stability, and that is in direct opposition to
making them out of fragile materials, even if they don't get thrown around.
Accidents happen, people trip over, this can't really be helped. I'm no
metrology expert by any degree, it just seems to me that making it even
easier to break your $250k box is a bad idea if it can be wholly avoided by
using a different material that'll meet requirements too.

You're right that it's not unheard of - ceramics were even used in mobile
testing equipment eg by tek - but they didn't know better back then, or
they didn't care because equipment would be phased out before it had chance
to break.

Why exactly do you think ceramic is delicate? It is used to make knifes, pistols, internal combustion engines, turbines, brake linings, clutches,... and even insert tooling for machining very hard materials. It isn't your mother's teapot! Or, are you the proverbial "bull in a china shop" in everything you do? -Chuck Harris cheater00 cheater00 wrote: > Hi Rob, thanks for your email. > > My take is you want your standards and calibrated equipment to last very > long due to increasing stability, and that is in direct opposition to > making them out of fragile materials, even if they don't get thrown around. > Accidents happen, people trip over, this can't really be helped. I'm no > metrology expert by any degree, it just seems to me that making it even > easier to break your $250k box is a bad idea if it can be wholly avoided by > using a different material that'll meet requirements too. > > You're right that it's not unheard of - ceramics were even used in mobile > testing equipment eg by tek - but they didn't know better back then, or > they didn't care because equipment would be phased out before it had chance > to break.

volt-nuts@lists.febo.com

PCBs with ceramic substrates