Tim,
As Stephen Gregory replied, DuPont is a very large green tape (Low
Temperature Co-fired Ceramic - LTCC) and thick film products supplier.
We happen to use it by the pallet load for various products ranging from the
more mundane to the quite impressive. The ability to separately construct
individual layers, and only laminate known good layers, was a gigantic
improvement over multi-layer thickfilm fabrication techniques. It comes
with some disadvantages too, however. Notably, it costs a bit more than
multi-layer thick film material sets, but when high density and medium to
high layer counts are required, the yield increase offsets the added cost.
If one can accomplish a design in less than 4 conductive layers with 10 mil
line and space, multi-layer thick film is the way to go. If the circuit
requires about 6 (or more) conductive layers, or having 5 mil line and space
- LTCC usually wins the cost war (unless the application can also be
suitable served by a multi-layer organic laminate).
We are able to construct components such as capacitors and inductors for
(high freqency applications) into the various internal layers leaving outer
layers for application of chip and wire, SMT, or Flip Chips. The
higher-than-desired dielectric constant of LTCC will keep it out of some
applications, but the ability to make decent strip lines and shielded
structures off-sets this somewhat.
Our standard vias are 6 or 8 mils in diameter. 4 mil vias are more
difficult, but producable. Some panels have had as many as 10K vias in a
4.5x4.5" area. Via capture pads need only be the same diameter as the via
itself. Check out the on-line design guide at
<http://www.ctscorp.com/ffabout.htm.> for more info.
It works well for such items as implantable medical devices (reliability &
circut density critical); hermetic military (space, air, ground) devices,
but alas, that market is dwindling; and automotive where high temperature
operation (under the hood) and size are becoming increasingly critical -
reliability too.
In conclusion, it does have a niche. It it not suitable to replace organic
laminates in all applications, only speciallized ones.
Disclaimer - I certainly did not intend this to be interpreted as a sales
pitch of any kind. I have just tried to illustrate a few uses and
capabilities of the LTCC material sets that my employer utilizes.
Steven Creswick
CTS RF Integrated Modules
At 10:44 AM 5/19/00 -0700, you wrote:
>Well Chuck,
>since YOU mentioned it, what is Green Tape?
>Tim Reeves
>ECD
>
>> ----------
>> From: Chuck Brummer
>> Sent: Friday, May 19, 2000 8:04
>> Subject: Re: Thick film lay-out
>>
>> No problem with Green Tape. I was just curious whose head would pop up if
>> I mentioned
>> it. I always thought that Green Tape was a great answer to certain
>> problems.
>>
>> Thanks for smiling.
>>
>> Creswick wrote:
>>
>> > Chuck,
>> >
>> > Is there a problem with questions regarding Green Tape (LTCC)??
>> >
>> > Everyone needs a niche ..... After all, it is merely another form of
>> (high
>> > operating temp)'substrate' material.
>> >
>> > Keep on smiling!
>> >
>> > You 'organic boys' can be such fuddy duddys at times.
>> >
>> > Friday is almost upon us
>> >
>> > Steven Creswick - CTS
>> >
>> > At 02:16 PM 5/18/00 -0700, you wrote:
>> > >Hi Anne,
>> > >
>> > >Check with your local DuPont rep. He/She can show you their products
>> for
>> > applying
>> > >thick film dielectric to bare thick substrates.
>> > >
>> > >Gee, next someone will ask about Green Tape.
>> > >
>> > >Chuck Brummer
>> > >Acuson
>> > >
>> > >Anne Ledger wrote:
>> > >
>> > >> Good afternoon all,
>> > >>
>> > >> We have a customer that is looking for a contractor to
>> > >> provide a "thick film lay-out". Here I am, clueless again.
>> > >> Does anyone recognize the terminology? Can I get a
>> > >> explanation? Thanks for the help.
>> > >>
>> > >> Anne Ledger
>> > >> EMDS, Inc.
>> > >> [log in to unmask]
>> > >>
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