[SI-LIST] Re: Fiber Weave Effect

  • From: "Istvan Nagy" <buenos@xxxxxxxxxxx>
  • To: <leeritchey@xxxxxxxxxxxxx>, <jeff.loyer@xxxxxxxxx>, <Alexander.Ippich@xxxxxxxxxxxxx>, "si-list" <si-list@xxxxxxxxxxxxx>
  • Date: Sat, 19 Jan 2013 10:55:36 -0800

Hi,

I found an article where they have described 106-LD and 1080-LD, for laser 
drilling.
They were more tight than the normal 106 and 1080, but only in one 
direction. The no-glass-hole was more or less eliminated, but they still had 
1layer-2layer waves on them. For 0deg/90deg routing, the difference is that 
you don't have no_glass-1layer wave-s in the weave, only the 1layer-2layer, 
and for 45deg routing the no_glass-2layer wave was eliminated.

Another article from dielectricsolutions.com describes spread-weave as they 
manufacture their NovaSpeed glass-fabrics.  These are tight in both 
directions (as opposing to the above 106-LD). Their article describes the 
glass coverage with 3 numbers, the portion covered by 2 layer glass, 1 layer 
glass and no-glass. For example 77-22-1. Something like this would perfectly 
specify the glass for high-speed design purposes, so then the design 
engineer could decide what is good enough and what is not, without 
requesting vendor specific photos (that are impossible to get) of the glass 
fabric, or without gambling. IPC and the industry should pick this up.
It would be nice to know which material manufacturers put this NovaSpeed 
glass fabric into their prepregs/laminates.

NanYa claims to have 1067,1086 glas styles in the glass fabric section, but 
their NPLDII/NPLDIII laminate (these ones have low enough loss) datasheets 
don't have these glass styles listed only the traditional ones.

This IPC committee develops the glass fabric/style standard (IPC-4412A):
http://www.ipc.org/CommitteeDetail.aspx?Committee=3-12D
If you check their meeting minutes, the spread glass was on their agenda 
years ago, but somehow they did not discuss it properly and did not add this 
into the standard.

Regards,
Istvan Nagy


-----Original Message----- 
From: Lee
Sent: Friday, January 18, 2013 9:46 AM
To: jeff.loyer@xxxxxxxxx ; Alexander.Ippich@xxxxxxxxxxxxx ; 
buenos@xxxxxxxxxxx ; si-list
Subject: [SI-LIST] Re: Fiber Weave Effect

My experiences are similar to those outlined below.  IPC standards always
lag the industry.   Isn't that what standards do- document the past!

From what I can tell, spreading is done to improve the quality of laser
drilled blind vias, not for signal integrity reasons.  For that reason,
spread glass will be most available where that kind of PCB is being
manufactured.

The laminate suppliers who cater to the "high speed" market are gradually
adding these glasses for reasons that I discuss in my upcoming paper at
DesignCon.  True, there are no standards yet.  3313 is available
mechanically spread in both direction or in only one.  You can see that in
the test results we got.

I have been a proponent of 3313 glass for fast diff pairs.  The glass I used
when we got the best results was from Matsushita.  Turns out that not all
laminate suppliers were using the same glass supplier, so we found two very
different results.

Maybe some of us need to step in at IPC and get these standards updated.

If it isn't one thing, it is another!   Plenty of challenges to keep us
busy!

-----Original Message----- 
From: Loyer, Jeff
Sent: Friday, January 18, 2013 8:05 AM
To: Alexander.Ippich@xxxxxxxxxxxxx ; buenos@xxxxxxxxxxx ; si-list
Subject: [SI-LIST] Re: Fiber Weave Effect

My experience matches Alexander's - there is a lot of ambiguity in the term
"spread glass"; it can mean different things, depending on the vendor.
The best definitions I have seen came from an Isola presentation ("Glass
Fabric", July 2012) with the following definitions:
". Expanded Weave - Glass Spread More than Standard in one Direction
. Open Weave - Same as Expanded
. Open Filament - Same as Expanded
. Spread Glass - Glass Spread by a # of Different Ways
. Mechanically Spread (MS) Glass - Glass is Mechanically Spread in both the
warp and fill directions.
. Square Weave - Glass that has a Balanced Density and/or Yarn Counts in
Warp and Fill Directions.
. Flat Glass - Glass is made from fibers with little or no twist.
Isola does not offer Flat Glass. Spread Glass is "Flatter" but not truly a
Flat Glass."
In the presentation, they (Isola) offer "Square", "Expanded", Spread", and
"MS Spread".  I've never seen totally Flat Glass, except perhaps RCC (which
has no glass) or Thermount (which is not woven).

I've also seen presentations which show:
Nanya offers "Spread Weave"
Rogers offers "Spread Glass"
Lee Ritchey advocates a 3313 style glass, though I don't know what materials
that's available for
Compunetics and Dielectric Solutions had some early solutions (NovaSpeed
1080, see "Advanced Glass Reinforcement Technology for Improved Signal
Integrity")
Thermount offers non-woven products

This is a compilation of the data I currently have - I welcome others adding
to it.
Note: this list in no way represents endorsement of any product.

Regarding how to distinguish 1080 from spread glass 1080 - it should
specifically say it is spread glass (or some other term) in the vendor's
stackup drawing; it may not have a unique number designation.

I hope this helps,
Jeff Loyer


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Alexander Ippich
Sent: Thursday, January 17, 2013 11:01 PM
To: buenos@xxxxxxxxxxx; si-list
Cc: Alexander Ippich
Subject: [SI-LIST] Re: Fiber Weave Effect

Istvan,

this is another issue, where the standardization of for example IPC lags
behind the needs of the industry quite a bit...

You are absolutely right, looking at the IPC 4412 does not tell you, if this
is a "spread" glass or not. I have put "spread" in double quotes, because
this term is not specified itself yet (to my knowledge).
Terms like square weave only adds to this confusion. These are terms coined
by individual manufacturers. In the case of square weave, this is something
Isola has a patent to.

Regarding "spread" glass, there are the newer glass styles, like 1067, 1086,
3313,.. that are woven in a way to minimize the gaps between the glass
strands right from the beginning. But be careful, this does not mean, that
the glass is totally homogenous - it still has gaps (high resin content) and
conglomeration of glass fibres (low resin content).
Then there are base material manufacturers, that still use the traditional
glass styles (like 106, 1080), but use a process like water spreading or air
spreading to open up the strands of glass to get to a more homogenous
distribution of the glass fibres.


Again, since there is no standard yet, you can not put a number to the
"degree of spread". You need to look at sample pictures (and yes, very
likely the nicer ones will be shown around).

Bottom line, since all of these glass styles do not result in a "100% tight
fabric", they will never solve the fibre weave effect completely. So at the
end of the day, you will need to do actual measurements on actual
prototypes.

Best regards,
alex


_______________________________________________________________
Alexander Ippich
Sr. Signal Integrity Engineer

Multilayer Technology GmbH & Co. KG

Herrenberger Strasse 110
71034 Boeblingen - Germany

Email        alexander.ippich@xxxxxxxxxxxxx

Pers. haftender Gesellschafter: Multilayer Technology Geschäftsführungs
GmbH,
Geschäftsführer: Werner Widmann
Sitz der Gesellschaft: Böblingen, Amtsgericht Böblingen HRA242264

http://www.multek.com


Endless innovation creates changes for tomorrow



-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Istvan Nagy
Sent: Friday, January 18, 2013 5:10 AM
To: si-list
Subject: [SI-LIST] Re: Fiber Weave Effect

Hi all,

I would like to join this conversation.

I am trying to find out about a possibly complete list of available
spread-glass materials.
Who makes these, and which products, which glass styles?

From different sources what I have found is not consistent.
- For example some people say new glass styles were invented to have thin
materials with spread-glass fabric, so we can distinguish.
- I think I have read somewhere (don't remember where) that existing glass
styles (like 1080) have traditional and also spread-glass option. If both
are called 1080, then how to distinguish?

I found an IPC spec (IPC-xxx amendment 1) That lists glass styles, but how
to find out which is a loose fabric and which ones are tight spread-glass
fabrics?
Some Isola datasheets mention spread-glass and square-weave glass (what's
that?) as option, while some other Isola datasheets only mention standard
E-glass option. Most material manufacturer datasheets don't mention anything
about this.
For example someone said 1067 is spread-glass. Is it guaranteed that if we
get 1067 anywhere it will be 99% tight spread-glass fabric?
I also saw photo examples of spread glass fabrics in technical papers, but I
guess those have shown the nicest ones. How does an 1067 or 1086 really look
like? Do they completely solve the fiber weave effect (100% tight fabric) or
they just improve on it (littlebit smaller holes than usual)?

Does anyone have a list of specific existing materials and glass styles with
spread-glass?
I mean not just 1-2 examples, but a longer list if possible.

Regards,
Istvan Nagy




-----Original Message-----
From: Scott McMorrow
Sent: Sunday, January 06, 2013 10:41 AM
To: dudi@xxxxxxxxxxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Fiber Weave Effect

Here is our paper on laminate weave skew from 7 years ago.
http://www.teraspeed.com/papers/The%20Impact%20of%20PCB%20Laminate%20Weave%20paper.pdf

http://www.teraspeed.com/papers/Laminate%20Weave_DesignCon%20Slides.pdf

-- 

Scott McMorrow
Teraspeed Consulting Group LLC
16 Stormy Brook Road
Falmouth, ME 04105

(401) 284-1827 Business

http://www.teraspeed.com

Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC


On Sun, Jan 6, 2013 at 9:52 AM, Dudi Tash <dudi@xxxxxxxxxxxxxxxxx> wrote:

> Hi All,
> I'm looking for some books regarding the Fiber Weave Effect. Good
> articles are welcomed as well. I've read the Altera and PCISIG papers
>
> Please advise
>
> Best Regards,
> Dgtronix Ltd. I Founder & CEO I Dudi Tash
> eFax: +972-3-7256490 I Mobile: +972-54-6345629 I Office:
> +972-9-9660967 www.dgtronix-tech.com<http://www.dgtronix-tech.com/>
>
> [cid:image001.jpg@01CDEC2E.48C05F30]<http://www.dgtronix-tech.com/>
> [cid:image002.jpg@01CDEC2E.48C05F30]
>
> [cid:image003.jpg@01CDEC2E.48C05F30]
>
>
> *This email contains confidential and proprietary information of
> Dgtronix
> Ltd.*
>
>
>
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-- 

Scott McMorrow
Teraspeed Consulting Group LLC
16 Stormy Brook Road
Falmouth, ME 04105

(401) 284-1827 Business

http://www.teraspeed.com

Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC

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