faster PCB laminate...

J

John Larkin

Guest
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
 
On 2020-10-16 14:21, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...

What did you use in that board that warped into the shape of a candy
dish? (You\'ll use it on both sides this time I\'m sure.) ;)

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
 
Am 16.10.20 um 20:21 schrieb John Larkin:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...

Rogers 4003 or its flame retardent variations. It has an expansion TC
much like FR4, so you can use it just for the top layer in a multi layer
board.

I currently use Rogers TMM6. That is electrically fine, Er=6,
but mechanically like cold candle wax. I broke a 25 mil board
accidentally when fastening a SMA connector with fingers only
and not much force. But the board house had TMM6. They warned us
that a run of 50 of our small boards might take some months
because of delays in getting the raw sheets.

OTOH a different customer made some boards for pipeline pigs
and we knew that FR-4 swells in hydrocarbon athmosphere, cracking
the vias in thick multilayers. And we had lots of layers for
fat FPGAs and for passive cooling, transporting the heat with
wedge locks to the torpedo-shaped chassis. The mechanics was
a little wonder by itself: large parts milled from huge alu bars
and soldered together in a salt bath.

But I digress. We choose boards made from Kapton, but the
layers delaminated. It turned out that the Kapton prepregs
have a very short shelf life, and it is not necessarily good
if the board house can deliver too quickly just because they
have material left from a project 2 months ago.


Last month, the board house made me a 4L-multilayer TMM6 + FR4 + FR4.
That seems to work. The TMM6 is probably too cheesy to introduce
warping.

The material is some organic stuff mixed with ceramic
powder. I had no adhesion problems, but could peel off the
copper easily around that ring resonator I showed last week.

A highly polished egg in a teflon pan has no adhesion, there
are not many parameters to change that.


regards, Gerhard
 
On Fri, 16 Oct 2020 15:28:48 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-16 14:21, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

What did you use in that board that warped into the shape of a candy
dish? (You\'ll use it on both sides this time I\'m sure.) ;)

Cheers

Phil Hobbs
Click to expand...

The fidget spinner? Can\'t recall, except that the top layer was some
special stuff and the rest was FR4.
 
On Fri, 16 Oct 2020 21:41:03 +0200, Gerhard Hoffmann <dk4xp@arcor.de>
wrote:

Am 16.10.20 um 20:21 schrieb John Larkin:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

Rogers 4003 or its flame retardent variations. It has an expansion TC
much like FR4, so you can use it just for the top layer in a multi layer
board.

I currently use Rogers TMM6. That is electrically fine, Er=6,
but mechanically like cold candle wax. I broke a 25 mil board
accidentally when fastening a SMA connector with fingers only
and not much force. But the board house had TMM6. They warned us
that a run of 50 of our small boards might take some months
because of delays in getting the raw sheets.

OTOH a different customer made some boards for pipeline pigs
and we knew that FR-4 swells in hydrocarbon athmosphere, cracking
the vias in thick multilayers. And we had lots of layers for
fat FPGAs and for passive cooling, transporting the heat with
wedge locks to the torpedo-shaped chassis. The mechanics was
a little wonder by itself: large parts milled from huge alu bars
and soldered together in a salt bath.

But I digress. We choose boards made from Kapton, but the
layers delaminated. It turned out that the Kapton prepregs
have a very short shelf life, and it is not necessarily good
if the board house can deliver too quickly just because they
have material left from a project 2 months ago.


Last month, the board house made me a 4L-multilayer TMM6 + FR4 + FR4.
That seems to work. The TMM6 is probably too cheesy to introduce
warping.

The material is some organic stuff mixed with ceramic
powder. I had no adhesion problems, but could peel off the
copper easily around that ring resonator I showed last week.

A highly polished egg in a teflon pan has no adhesion, there
are not many parameters to change that.


regards, Gerhard
Click to expand...

I\'m thinking that I want lower Er than FR4, so 50 ohm microstrips can
be wider hence less lossy. I think.

I love Duroid for hacking. You can slit the copper easily with an
X-acto knife and peel strips right off.
 
On Friday, October 16, 2020 at 3:41:12 PM UTC-4, Gerhard Hoffmann wrote:
Am 16.10.20 um 20:21 schrieb John Larkin:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

Rogers 4003 or its flame retardent variations. It has an expansion TC
much like FR4, so you can use it just for the top layer in a multi layer
board.

I currently use Rogers TMM6. That is electrically fine, Er=6,
but mechanically like cold candle wax. I broke a 25 mil board
accidentally when fastening a SMA connector with fingers only
and not much force. But the board house had TMM6. They warned us
that a run of 50 of our small boards might take some months
because of delays in getting the raw sheets.

OTOH a different customer made some boards for pipeline pigs
and we knew that FR-4 swells in hydrocarbon athmosphere, cracking
the vias in thick multilayers. And we had lots of layers for
fat FPGAs and for passive cooling, transporting the heat with
wedge locks to the torpedo-shaped chassis. The mechanics was
a little wonder by itself: large parts milled from huge alu bars
and soldered together in a salt bath.

But I digress. We choose boards made from Kapton, but the
layers delaminated. It turned out that the Kapton prepregs
have a very short shelf life, and it is not necessarily good
if the board house can deliver too quickly just because they
have material left from a project 2 months ago.


Last month, the board house made me a 4L-multilayer TMM6 + FR4 + FR4.
That seems to work. The TMM6 is probably too cheesy to introduce
warping.

The material is some organic stuff mixed with ceramic
powder. I had no adhesion problems, but could peel off the
copper easily around that ring resonator I showed last week.

A highly polished egg in a teflon pan has no adhesion, there
are not many parameters to change that.


regards, Gerhard
Click to expand...

I recently looked into adhesives for gluing silicone and polypropylene. For both the answer is usually chemically or thermally(*) wrecking a thin layer on the surface, which can then be wet by or otherwise accept an adhesive.

I\'d think something similar should work with teflon too.

(*) (e.g. flame or plasma treatment to singe the surface)

Cheers,
James Arthur
 
On Fri, 16 Oct 2020 11:21:46 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...

Rogers RO3003?

I used this ten years ago to stabilze temperature coeffiicent
(compared to FR4). The 3003 had the same general processing
characteristics as FR4, but far better controlled characeteristics,
and lower tempco. We did have to change trace widths to preserve
characteristic impedances.

Joe Gwinn
 
On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...

Check this out:
https://www.isola-group.com/wp-content/uploads/PCB-Material-Selection-for-RF-Microwave-and-Millimeter-wave-Designs-1.pdf
 
On Sat, 17 Oct 2020 23:22:49 -0700 (PDT), Flyguy
<soar2morrow@yahoo.com> wrote:

On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

Check this out:
https://www.isola-group.com/wp-content/uploads/PCB-Material-Selection-for-RF-Microwave-and-Millimeter-wave-Designs-1.pdf
Click to expand...

Nice discussion of copper roughness.

Our board houses are suggesting Rogers RO4350B or the apparent
equivalent Isola MT40. Both have DK about 3.5 and lower loss than FR4.
I\'ll get some samples and hack some microstrips and compare them to
FR4.

A board I\'m doing now has 3\" traces and I\'d like to go as fast as I
can with essentially CML logic signals. I\'m seeing about a 60 ps
(corrected) rise time on a wide 3\" trace on 62-mil FR4.

https://www.dropbox.com/sh/2prom08kpoehdij/AABmxgiImIOjwzPbh-O9lonra?dl=0

That\'s my MMIC-based signal detector on the TX+ line.






--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
jlarkin@highlandsniptechnology.com wrote:

On Sat, 17 Oct 2020 23:22:49 -0700 (PDT), Flyguy
soar2morrow@yahoo.com> wrote:

On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100
ps edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide
effect that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two
or three projects.

Check this out:
https://www.isola-group.com/wp-content/uploads/PCB-Material-Selection-f
or-RF-Microwave-and-Millimeter-wave-Designs-1.pdf

Nice discussion of copper roughness.

Our board houses are suggesting Rogers RO4350B or the apparent
equivalent Isola MT40. Both have DK about 3.5 and lower loss than FR4.
I\'ll get some samples and hack some microstrips and compare them to
FR4.

A board I\'m doing now has 3\" traces and I\'d like to go as fast as I
can with essentially CML logic signals. I\'m seeing about a 60 ps
(corrected) rise time on a wide 3\" trace on 62-mil FR4.

https://www.dropbox.com/sh/2prom08kpoehdij/AABmxgiImIOjwzPbh-O9lonra?dl
=0

That\'s my MMIC-based signal detector on the TX+ line.
Click to expand...

Find out what cars use for navigation, lane following and blind spot
detection. They work at 77GHz and need to be inexpensive.

--
Science teaches us to trust. - sw
 
John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...
What about:
MEGTRON 7 Series of PCB

Ultra-low Loss, Highly Heat Resistant Circuit Board Materials.
LaminateR-5785(N)/Prepreg R-5680(N) The ultra-low dielectric constant
(Dk) and dissipation factor (Df) make MEGTRON 7 ideal for high speed and
large data volumes associated with servers and routers required for 5G.
The MEGTRON 7 family, including MEGTRON 7(N), MEGTRON 7(GE) and MEGTRON
7(GN), is High Density Interconnect (HDI ...
 
On Tue, 20 Oct 2020 21:53:16 -0700, Robert Baer
<robertbaer@localnet.com> wrote:

John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.



What about:
MEGTRON 7 Series of PCB

Ultra-low Loss, Highly Heat Resistant Circuit Board Materials.
LaminateR-5785(N)/Prepreg R-5680(N) The ultra-low dielectric constant
(Dk) and dissipation factor (Df) make MEGTRON 7 ideal for high speed and
large data volumes associated with servers and routers required for 5G.
The MEGTRON 7 family, including MEGTRON 7(N), MEGTRON 7(GE) and MEGTRON
7(GN), is High Density Interconnect (HDI ...
Click to expand...

Our board houses are suggesting the Rogers or Isola materials, as
being something they can get and usually work with. They claim they
can do just the top layer of a 4-layer board with the good stuff and
keep it flat.

Here is our fidget-spinner board fabbed that way.

https://www.dropbox.com/s/yibz36f0ex7z1sp/MOV02429.MPG?raw=1





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
jlarkin@highlandsniptechnology.com wrote:
On Tue, 20 Oct 2020 21:53:16 -0700, Robert Baer
robertbaer@localnet.com> wrote:

John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.



What about:
MEGTRON 7 Series of PCB

Ultra-low Loss, Highly Heat Resistant Circuit Board Materials.
LaminateR-5785(N)/Prepreg R-5680(N) The ultra-low dielectric constant
(Dk) and dissipation factor (Df) make MEGTRON 7 ideal for high speed and
large data volumes associated with servers and routers required for 5G.
The MEGTRON 7 family, including MEGTRON 7(N), MEGTRON 7(GE) and MEGTRON
7(GN), is High Density Interconnect (HDI ...

Our board houses are suggesting the Rogers or Isola materials, as
being something they can get and usually work with. They claim they
can do just the top layer of a 4-layer board with the good stuff and
keep it flat.

Here is our fidget-spinner board fabbed that way.

https://www.dropbox.com/s/yibz36f0ex7z1sp/MOV02429.MPG?raw=1
Click to expand...
I have found that Megtron is as easy to work with as FR4, and that
their PPO is better than Isola\'s.
 
On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.
Click to expand...

I\'ve used Rogers 4350 and Panasonic Meg 6. I\'ve heard there are Meg 6 supply issues due to the tsunami.

How about EMC EM-890K? Dk is around 3.
 
On 2020-10-23 22:01, Simon S Aysdie wrote:
On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

I\'ve used Rogers 4350 and Panasonic Meg 6. I\'ve heard there are Meg 6 supply issues due to the tsunami.
Click to expand...

The 2011 one? I know 2020 has lasted at least a decade so far, but you
seem to be going the other direction. (Good on ya if you can make it
stick.) ;)

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 Friday, October 23, 2020 at 7:36:43 PM UTC-7, Phil Hobbs wrote:
On 2020-10-23 22:01, Simon S Aysdie wrote:
On Friday, October 16, 2020 at 11:21:59 AM UTC-7, John Larkin wrote:
We normally make boards from FR4, specifically the Isola 370HR or
equivalent. It\'s usually fine but is lossy for fast stuff, like 100 ps
edges on long runs, \"long\" being maybe 1 inch.

We\'ve used teflon/Duroid boards, which are more like leather than
fiberglas. They are expensive and pad adhesion is terrible.

So, has anyone used something in-between? Rigid like FR4, lower
dielectric constant, lower losses, and less of the black-oxide effect
that adds skin losses. But we still want decent pad adhesion.

I may have asked this before, but it\'s become serious lately on two or
three projects.

I\'ve used Rogers 4350 and Panasonic Meg 6. I\'ve heard there are Meg 6 supply issues due to the tsunami.

The 2011 one? I know 2020 has lasted at least a decade so far, but you
seem to be going the other direction. (Good on ya if you can make it
stick.) ;)
Click to expand...

I was going by what someone else wrote that I have but cannot quote. The more recent event may not be a tsunami even though that is what was written. I do recall supply issues due to a natural event much more recent than 2011, but I wasn\'t paying much attention. Perhaps it was this--I don\'t know:

https://www.tellerreport.com/business/2019-10-21---panasonic-is-concerned-about-production-impact-due-to-prolonged-shutdown-%7C-nhk-news-.HJMD2165tH.html
 
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