Soldering to glass

P

Piotr Wyderski

Guest
I have recently conducted some research on binding SMD components with
glass and ceramic substrates using pure indium and indium alloys. The
results are very satisfactory, and the technique may find some
applications in HV and high power density solutions. One can directly
solder a MOSFET to a ceramic heatsink or a string of HV resistors to an
insulating glass plate without prior metalisation.

The only thing to improve is the initial wettability. Do you happen to
know of any tips regarding the composition of the alloy or the
preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Best regards, Piotr
 
Piotr Wyderski wrote...
I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.
Click to expand...

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.


--
Thanks,
- Win
 
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.
Click to expand...

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Sunday, 19 April 2020 16:59:13 UTC+1, Phil Hobbs wrote:
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.
Click to expand...

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

John
 
On 19 Apr 2020 04:16:05 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.
Click to expand...

Seems to me that epoxy would work as well, maybe better. If the parts
are flat, epoxy with some compression would flow out to make a very
thin layer. The glass or ceramic may well dominate theta anyhow.

DPAK thick-film resistors are great for heatsinking.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On 2020-04-19 12:34, jrwalliker@gmail.com wrote:
On Sunday, 19 April 2020 16:59:13 UTC+1, Phil Hobbs wrote:
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

John
Click to expand...

With what? I'd expect that to fall apart when you ablated the binder.

The indium solder technique is hermetic, which helps in many cases.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Sunday, April 19, 2020 at 4:16:16 AM UTC-7, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory,

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.
Click to expand...

A possible concern, is that indium forms a transparent oxide that is
conductive. How does one debug a HV circuit when conductive
tracks on the board aren't carbonized, but... transparent and
invisible?
 
On Sunday, 19 April 2020 19:33:59 UTC+1, Phil Hobbs wrote:
On 2020-04-19 12:34, jrwalliker@gmail.com wrote:

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

With what? I'd expect that to fall apart when you ablated the binder.

The indium solder technique is hermetic, which helps in many cases.
Click to expand...
The thick-film inks are a blend of powdered glass and metal particles,
so when the ink is fired the glass particles fuse to the glass binder
in the alumina. (Most commercial alumina is made by sintering a mixture
of alumina with a small percentage of glass.)
The final result is a mostly metallic coating strongly bonded to the
surface of the alumina. Tin/lead solder wets it nicely when the metal
is silver or silver/palladium. The glass component means that it can
be hermetic. I used this technique in an implantable medical application
a long time ago.
Indium is nice, but as already mentioned it is unsuitable for high
temperatures.

John
 
On Sunday, 19 April 2020 19:45:05 UTC+1, whit3rd wrote:
On Sunday, April 19, 2020 at 4:16:16 AM UTC-7, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory,

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

A possible concern, is that indium forms a transparent oxide that is
conductive. How does one debug a HV circuit when conductive
tracks on the board aren't carbonized, but... transparent and
invisible?
Click to expand...

So does tin.

John
 
On 2020-04-19 14:45, whit3rd wrote:
On Sunday, April 19, 2020 at 4:16:16 AM UTC-7, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory,

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

A possible concern, is that indium forms a transparent oxide that is
conductive. How does one debug a HV circuit when conductive
tracks on the board aren't carbonized, but... transparent and
invisible?
Click to expand...

The vapour pressure of indium is insignificant at soldering
temperatures. It boils at around 2000 C.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 2020-04-19 15:54, jrwalliker@gmail.com wrote:
On Sunday, 19 April 2020 19:33:59 UTC+1, Phil Hobbs wrote:
On 2020-04-19 12:34, jrwalliker@gmail.com wrote:

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

With what? I'd expect that to fall apart when you ablated the binder.

The indium solder technique is hermetic, which helps in many cases.

The thick-film inks are a blend of powdered glass and metal particles,
so when the ink is fired the glass particles fuse to the glass binder
in the alumina. (Most commercial alumina is made by sintering a mixture
of alumina with a small percentage of glass.)
The final result is a mostly metallic coating strongly bonded to the
surface of the alumina. Tin/lead solder wets it nicely when the metal
is silver or silver/palladium. The glass component means that it can
be hermetic. I used this technique in an implantable medical application
a long time ago.
Indium is nice, but as already mentioned it is unsuitable for high
temperatures.

John
Click to expand...

Okay, so it's basically a mixture of metal and frit, like cermet. Good
to know.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Sun, 19 Apr 2020 11:45:01 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, April 19, 2020 at 4:16:16 AM UTC-7, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory,

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

A possible concern, is that indium forms a transparent oxide that is
conductive. How does one debug a HV circuit when conductive
tracks on the board aren't carbonized, but... transparent and
invisible?
Click to expand...

Right, who wants metal melted under their high-voltage resistor?

Use epoxy.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Sunday, 19 April 2020 23:00:59 UTC+1, George Herold wrote:
The indium solder technique is hermetic, which helps in many cases.

What about Gallium? Doesn't that wet glass too?
https://www.indium.com/blog/liquid-metal-wetting.php
Click to expand...
Gallium is really good at making other metals brittle by grain boundary
attack.

John
 
On Sunday, April 19, 2020 at 2:33:59 PM UTC-4, Phil Hobbs wrote:
On 2020-04-19 12:34, jrwalliker@gmail.com wrote:
On Sunday, 19 April 2020 16:59:13 UTC+1, Phil Hobbs wrote:
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

John


With what? I'd expect that to fall apart when you ablated the binder.

The indium solder technique is hermetic, which helps in many cases.
Click to expand...

What about Gallium? Doesn't that wet glass too?
https://www.indium.com/blog/liquid-metal-wetting.php

George H.


Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
Click to expand...
 
On 2020-04-19 18:00, George Herold wrote:
On Sunday, April 19, 2020 at 2:33:59 PM UTC-4, Phil Hobbs wrote:
On 2020-04-19 12:34, jrwalliker@gmail.com wrote:
On Sunday, 19 April 2020 16:59:13 UTC+1, Phil Hobbs wrote:
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.

Another approach (which I have used) is to fire a patch of silver or
silver/palladium thick film ink onto an alumina substrate and then
solder onto that metallic coating.

John


With what? I'd expect that to fall apart when you ablated the binder.

The indium solder technique is hermetic, which helps in many cases.

What about Gallium? Doesn't that wet glass too?
https://www.indium.com/blog/liquid-metal-wetting.php
Click to expand...

Yup. It's liquid near room temperature, though, and is pretty
reactive--it gets dross all over it.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-04-19 07:16, Winfield Hill wrote:
Piotr Wyderski wrote...

I have recently conducted some research on binding SMD components
with glass and ceramic substrates using pure indium and indium
alloys. The results are very satisfactory, and the technique may
find some applications in HV and high power density solutions.
One can directly solder a MOSFET to a ceramic heatsink or a
string of HV resistors to an insulating glass plate without
prior metalisation.

The only thing to improve is the initial wettability. Do you
happen to know of any tips regarding the composition of the
alloy or the preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Soldering HV components to a ceramic heatsink with indium is
a fascinating idea. For those who often run things hot, its
low 150C limit may be an issue, but alloys may be in order.

You can indium-solder to glass and ceramics. It's much easier if you
have an ultrasonic soldering iron. Those cost kilobucks unfortunately,
but they sure are fun.
Click to expand...

I second this. I've soldered onto glass without exotic solder using an
ultrasonic soldering iron. Didn't even use flux.
 
On Sun, 19 Apr 2020 10:30:31 +0200, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

I have recently conducted some research on binding SMD components with
glass and ceramic substrates using pure indium and indium alloys. The
results are very satisfactory, and the technique may find some
applications in HV and high power density solutions. One can directly
solder a MOSFET to a ceramic heatsink or a string of HV resistors to an
insulating glass plate without prior metalisation.

The only thing to improve is the initial wettability. Do you happen to
know of any tips regarding the composition of the alloy or the
preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Best regards, Piotr
Click to expand...

I think alumina can serve as an insulator, while improving
thermal characteristics. Simple copper-on-alumina fabs are
already available.

Glass? Who needs it?

RL
 
On Mon, 20 Apr 2020 11:12:42 -0400, legg <legg@nospam.magma.ca> wrote:

On Sun, 19 Apr 2020 10:30:31 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

I have recently conducted some research on binding SMD components with
glass and ceramic substrates using pure indium and indium alloys. The
results are very satisfactory, and the technique may find some
applications in HV and high power density solutions. One can directly
solder a MOSFET to a ceramic heatsink or a string of HV resistors to an
insulating glass plate without prior metalisation.

The only thing to improve is the initial wettability. Do you happen to
know of any tips regarding the composition of the alloy or the
preparation of the substrate?

Will indium bind to AlN? I have no sample to perform a test.

Best regards, Piotr

I think alumina can serve as an insulator, while improving
thermal characteristics. Simple copper-on-alumina fabs are
already available.

Glass? Who needs it?

RL
Click to expand...

AlN conducts heat almost as well as aluminum alloy, and it's an
excellent HV insulator.

https://www.dropbox.com/s/vsumcjjawrtiu0o/AlXX.JPG?raw=1

https://www.dropbox.com/s/9vt61si6taj2ivw/DSC02177.JPG?raw=1




--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Monday, April 20, 2020 at 8:07:21 AM UTC-7, legg wrote:
On Sun, 19 Apr 2020 10:30:31 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

I have recently conducted some research on binding SMD components with
glass and ceramic substrates ...

I think alumina can serve as an insulator, while improving
thermal characteristics. Simple copper-on-alumina fabs are
already available.

Glass? Who needs it?
Click to expand...

Porcelain-on-steel is a common heavy-duty circuit substrate; i've got
a few relay boards in my junk box of that construction. It also tolerates
environments (like oil baths) that few polymers can handle, and has excellent
heatsinking capability.
 
legg wrote:

I think alumina can serve as an insulator, while improving
thermal characteristics. Simple copper-on-alumina fabs are
already available.
Click to expand...

Available -- yes, one can buy DBC boards, but it might be too expensive
for one-offs.

> Glass? Who needs it?

It is dirt cheap and easily available.

Best regards, Piotr
 
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