Interdigitated electrodes (SAW resonators)

[John Mitchell]

I am trying to find a source of interdigitated electrodes for an
electro-chemical sensor research project. Got to be cheap (ish).

Someone has suggested that I get some SAW resonator devices and lop their
tops off, exposing the chip surface and its electrode array.

Can anyone recommend a suitable device that can be so exposed fairly easily
(maybe metal can)? I would guess that a quartz substrate would be preferable
to a ceramic one for my purposes.

Any other ideas for a ready source of interdigitated elecrodes (electrode
spacing of order of 5um)?

Any replies by e-mail please.

Many thanks,

John

 

[Lewin A.R.W. Edwards]

I am trying to find a source of interdigitated electrodes for an
electro-chemical sensor research project. Got to be cheap (ish).

How cheap is cheap? Have you considered just drawing up the artwork
for a PCB and having it etched at a prototyping house? You can get it
on FR4, or on flexible film, quite cheaply.

Are there no problems with other chemicals, electrode composition,
etc, interfering with your experiment?

 

[Tim Wescott]

Lewin A.R.W. Edwards wrote:

I am trying to find a source of interdigitated electrodes for an
electro-chemical sensor research project. Got to be cheap (ish).


How cheap is cheap? Have you considered just drawing up the artwork
for a PCB and having it etched at a prototyping house? You can get it
on FR4, or on flexible film, quite cheaply.

Are there no problems with other chemicals, electrode composition,
etc, interfering with your experiment?

"Electrode spacing of 5um". Unless you know much better PCB houses than
I do.

You may be able to get this done at a thick-film hybrid place; I have no
idea of what it would cost or how many they'd want to make.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Lewin A.R.W. Edwards]

"Electrode spacing of 5um". Unless you know much better PCB houses than

Never mind, I'm on crack. I was actually working on a PCB in another
window at the time I posted my response, and somehow I read "5um" and
translated it through the grid units I was using in that other window
to be "5mil".

(retreats into distance, toking madly on a Hello Kitty bong).

 

[ddwyer]

In article <c68n4s$a14$1@beta.qmul.ac.uk>, John Mitchell
<j.b.mitchell@qmul.ac.uk> writes

I am trying to find a source of interdigitated electrodes for an
electro-chemical sensor research project. Got to be cheap (ish).

Someone has suggested that I get some SAW resonator devices and lop their
tops off, exposing the chip surface and its electrode array.

Can anyone recommend a suitable device that can be so exposed fairly easily
(maybe metal can)? I would guess that a quartz substrate would be preferable
to a ceramic one for my purposes.

Any other ideas for a ready source of interdigitated elecrodes (electrode
spacing of order of 5um)?

Any replies by e-mail please.

Many thanks,

John


There were 10.7MHz SAW bandpass filters with gold interdigitated

fingers.

SAW bandpass filters are often in metal transistor cans the aluminising
is vulnerable to corrosion but could serve your purpose.

--
ddwyer

 

[maxfoo]

On Thu, 22 Apr 2004 21:27:30 -0700, Tim Wescott <tim@wescottnospamdesign.com>
wrote:

Lewin A.R.W. Edwards wrote:

I am trying to find a source of interdigitated electrodes for an
electro-chemical sensor research project. Got to be cheap (ish).


How cheap is cheap? Have you considered just drawing up the artwork
for a PCB and having it etched at a prototyping house? You can get it
on FR4, or on flexible film, quite cheaply.

Are there no problems with other chemicals, electrode composition,
etc, interfering with your experiment?

"Electrode spacing of 5um". Unless you know much better PCB houses than
I do.

You may be able to get this done at a thick-film hybrid place; I have no
idea of what it would cost or how many they'd want to make.

that's too fine for thick film. 5 micrometers = 0.0001968498"
or 0.19685mils. a wire bond is 0.7mils. Even alumina substrate(thin film) will
be impossible. Perhaps he can find an IC chip that has a interdigital line
already on it...none come to mind immediately.




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