[SI-LIST] Re: fiber-weave effect alive and well?

  • From: Jack Stone <mediwheel_js@xxxxxxxxx>
  • To: leeritchey@xxxxxxxxxxxxx, Jeff Loyer <jeff.loyer@xxxxxxxxx>, mark.hinton@xxxxxxxxxxxxx
  • Date: Mon, 3 Dec 2007 12:58:47 -0800 (PST)

Lee - Depends on your allowable DPM's, and RAS.  High volumne LEPC's might not 
be an issue now, but at 1.3 it still is.

jack ~

----- Original Message ----
From: Lee Ritchey <leeritchey@xxxxxxxxxxxxx>
To: Jeff Loyer <jeff.loyer@xxxxxxxxx>; mark.hinton@xxxxxxxxxxxxx
Cc: si-list <si-list@xxxxxxxxxxxxx>
Sent: Monday, December 3, 2007 9:22:39 AM
Subject: [SI-LIST] Re: fiber-weave effect alive and well?

Why do that and make either CAD or Fab tougher when usinghte right glass
weave solved the problem nicely?

Lee Ritchey


> [Original Message]
> From: Loyer, Jeff <jeff.loyer@xxxxxxxxx>
> To: <mark.hinton@xxxxxxxxxxxxx>
> Cc: si-list <si-list@xxxxxxxxxxxxx>
> Date: 12/3/2007 9:02:02 AM
> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
>
> Mark,
> For a low-volume test PCB, why don't you tweak the artwork 10 degrees?
>
> Jeff Loyer
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of HINTON,MARK
> Sent: Friday, November 30, 2007 2:48 PM
> To: leeritchey@xxxxxxxxxxxxx
> Cc: si-list
> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
>
> Lee,
>
> Have you tested 2116 glass yet?  I'm doing a low-volume test PCB, and I
> may have to choose between 2116 or a high-cost special order of 3113.
> If you haven't tested it yet, would you venture an educated guess on how
> it would perform?  I've got pretty wide traces (9.5 mils).
>
> Thank you,
> Mark
>
>
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Lee Ritchey
> Sent: Saturday, September 15, 2007 11:23 AM
> To: Scott McMorrow; Perry.Qu@xxxxxxxxxxxxxxxxxx
> Cc: si-list
> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
>
> The weave I document is 3313 glass.  It is widely used in Asia and is a
> stock weave from Isola.  We just completed testing on 2113 weave and
> obtained similar results.  The two thin weaves that are at the root of
> the
> problem are 106 and 1080.  3313 has not been widely used by US
> fabricators,
> I suspect because designers have been asking for the thinnest possible
> laminates and that is why 1080 and 106 are used most  often in the US.
> You
> don't get 3313 and 2113 here unless you stick to your guns and insist on
> it.  When you do, there are no real problems.
>
> We've just completed testing two designs with 48 ports of 10 GE with
> superb
> results.  One used 2113 and the other 3313.
>
> 7628 is about as coarse as the cloth used to make levis.  Not a good
> choice.
>
> Lee
>
>
> > [Original Message]
> > From: Scott McMorrow <scott@xxxxxxxxxxxxx>
> > To: <Perry.Qu@xxxxxxxxxxxxxxxxxx>
> > Cc: si-list <si-list@xxxxxxxxxxxxx>
> > Date: 9/14/2007 1:21:15 PM
> > Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> >
> > Perry
> > Fiber-weave effects are alive and well, and IMO should be considered
> by=3D20
> > every designer concerned with 6 Gbps or higher differential serial
> data=3D20
> > communications channels on PCBs, backplanes, and single-ended =
> skew=3D20
> > controlled parallel buses.  Jeff's paper is real life, building
> upon=3D20
> > about 5 years of good research at Intel.  The method that is used
> is=3D20
> > quite valid and will be seen in real designs.  The Intel research
> is=3D20
> > able to better characterize weave skew using physical nyquist sampling
>
> > techniques.  Yes, with different trace jogs you will see all sorts
> of=3D20
> > potential alignments, but in the worst case you will still find
> that=3D20
> > traces can have significant lengths of worst case fiber weave=3D20
> > alignment.  If you are trying to design systems with 1000's of=3D20
> > differential pairs, there is a statistical certainty that one or more
> of=3D20
> > those pairs will have skew close to the absolute worst case, if =
> not=3D20
> > designed to compensate for laminate weave anisotropy.
> >
> > The problem is most pronounced with weaves that have large holes
> without=3D20
> > fiber in the weave pattern, but you will also see issues with =
> core=3D20
> > materials that are often constructed with large diameter fibers,
> like=3D20
> > 7628 material. The fiberglass the Lee proposes to use does have
> some=3D20
> > benefits, however, it does not totally eliminate the fiber weave=3D20
> > problem.  It reduces it to a lower level.  Unfortunately, it is not
> a=3D20
> > widely manufactured laminate weave.
> >
> > There are patented techniques for improving weave-induced skew,
> which=3D20
> > must be licensed.  There are also some non-patented techniques,
> which=3D20
> > may also be used that are not quite as effective as the patented=3D20
> > techniques, but nevertheless can be used to design robust systems. =
> =3D20
> > There is also some silicon IP that can be used to automatically=3D20
> > compensate for skew, and is finding it's way into test
> instrumentation.
> >
> >
> > regards,
> >
> > Scott
> >
> > Scott McMorrow
> > Teraspeed Consulting Group LLC
> > 121 North River Drive
> > Narragansett, RI 02882
> > (401) 284-1827 Business
> > (401) 284-1840 Fax
> >
> > http://www.teraspeed.com
> >
> > Teraspeed(r) is the registered service mark of
> > Teraspeed Consulting Group LLC
> >
> >
> >
> > QU Perry wrote:
> > > I would be interested to see a link as well.
> > >
> > > Jeff's paper on DesignCon2007 is convincing to me that this is
> something
> > > we need to pay attention. Real life design will probably not be as
> bad
> > > as the theoretical estimate since most of the diff pair routing we
> have
> > > on the PCB is not likely to run a long length non-stop in parallel
> with
> > > edge. The "jog" as is called in the paper is very common due to vias
> etc
> > > and pretty random.
> > >
> > > Also from the data we got from PCB vendor, it appears that thinner
> > > dielectric substrate the worse fibre weave effect as the gap between
> the
> > > fiber is larger. Has this been looked at ?
> > >
> > > Regards
> > >
> > > Perry
> > >
> > >
> =3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D=
> 3D3D=3D3D3D=3D3D3D=3D3D3D=3D3
> D=3D
> 3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D
> =3D3D3D=3D3D
> > > =3D
> =3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D=
> 3D3D=3D3D3D=3D3D3D=3D3D3D=3D3
> D=3D
> 20
> > >
> > > Perry Qu=3D3D20
> > >
> > > Design & Qualification, Alcatel-Lucent Canada Inc.
> > >
> > > 600 March Road, Ottawa ON, K2K 2E6, Canada=3D3D20
> > >
> > > DID: 613-7846720  Fax: 613-5993642=3D3D20
> > >
> > > Email: perry.qu@xxxxxxxxxxxxxxxxxx=3D3D20
> > >
> > >
> =3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D=
> 3D3D=3D3D3D=3D3D3D=3D3D3D=3D3
> D=3D
> 3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D
> =3D3D3D=3D3D
> > > =3D
> =3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D3D3D=3D=
> 3D3D=3D3D3D=3D3D3D=3D3D3D=3D3
> D=3D
> 20
> > >
> > > =3D3D20
> > >
> > >  =3D20
> > >> -----Original Message-----
> > >> From: si-list-bounce@xxxxxxxxxxxxx=3D3D20
> > >> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of=3D3D20
> > >> Aubrey_Sparkman@xxxxxxxx
> > >> Sent: Friday, September 14, 2007 1:59 PM
> > >> To: leeritchey@xxxxxxxxxxxxx; rdudek@xxxxxxxxxxxxxxx;=3D3D20
> > >> si-list@xxxxxxxxxxxxx
> > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >> =3D3D20
> > >> Would you like to share a link?=3D3D3D20
> > >> =3D3D20
> > >> =3D3D20
> > >> Aubrey Sparkman=3D3D3D20
> > >> Enterprise Engineering Signal Integrity Team=3D3D3D20 Dell,
> Inc.=3D3D3D20=3D3D20
> > >> Aubrey_Sparkman@xxxxxxxx=3D3D3D20
> > >> (512) 723-3592=3D3D3D20
> > >> "Discovery consists of seeing what everybody has seen and=3D3D20
> > >> thinking what nobody else has thought." - Jonathan Swift
> > >> =3D3D20
> > >> =3D3D20
> > >> -----Original Message-----
> > >> From: si-list-bounce@xxxxxxxxxxxxx=3D3D20
> > >> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> > >> On Behalf Of Lee Ritchey
> > >> Sent: Friday, September 14, 2007 11:36 AM
> > >> To: Russell S. Dudek Jr.; si-list@xxxxxxxxxxxxx
> > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >> =3D3D20
> > >> We already have a glass weave solution.  Check my column in=3D3D20
> > >> the April issue of Circuitree magazine.
> > >> =3D3D20
> > >> Lee Ritchey
> > >> =3D3D20
> > >> =3D3D20
> > >>    =3D20
> > >>> [Original Message]
> > >>> From: Russell S. Dudek Jr. <rdudek@xxxxxxxxxxxxxxx>
> > >>> To: <si-list@xxxxxxxxxxxxx>
> > >>> Date: 9/12/2007 1:10:28 PM
> > >>> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >>>
> > >>> Steve,
> > >>> =3D3D3D20
> > >>> I agree, Fiber Weave Effect (FEW) has most certainly been=3D3D20
> > >>>      =3D20
> > >> confirmed by
> > >> such
> > >>    =3D20
> > >>> research.  However, there is a new change in the wind.   I=3D3D20
> > >>>      =3D20
> > >> have the=3D3D3D20=3D3D20
> > >>    =3D20
> > >>> unique opportunity, as a technical liaison, to enable a=3D3D20
> > >>>      =3D20
> > >> technology=3D3D3D20=3D3D20
> > >>    =3D20
> > >>> that may put
> > >>>      =3D20
> > >> an
> > >>    =3D20
> > >>> end to FWE as a consideration in high-speed designs.  We=3D3D20
> > >>>      =3D20
> > >> all know that
> > >> =3D3D20
> > >>    =3D20
> > >>> the crux of the matter is the glass weave and its effect on=3D3D20
> > >>>      =3D20
> > >> localized
> > >> Er.
> > >>    =3D20
> > >>> Either get ride of the reinforcement layer completely or
> more=3D3D3D20=3D3D20
> > >>> challenging change the fundamentals of the glass weave fabrication
> > >>>      =3D20
> > >> process (GWFP).
> > >>    =3D20
> > >>> =3D3D3D20
> > >>> We have taken the more challenging (and fun) approach and =3D
> have=3D3D20
> > >>> rocked=3D3D3D20 the fundamentals the GWFP.  I cannot disclose much
> the=3D3D20
> > >>> specifics of=3D3D3D20 the technology and our partners in such =3D
> an=3D3D20
> > >>>      =3D20
> > >> open forum. =3D3D20
> > >>    =3D20
> > >>> However, if=3D3D3D20 you are interested learning more feel =
> free=3D3D20
> > >>>      =3D20
> > >> to contact=3D3D20
> > >>    =3D20
> > >>> me and we can=3D3D3D20 get the proper NDAs in place to =3D
> facilitate=3D3D20
> > >>>      =3D20
> > >> such a discussion.
> > >>    =3D20
> > >>> =3D3D3D20
> > >>> RD
> > >>> =3D3D3D20
> > >>> Russell Dudek
> > >>> Technology Specialist
> > >>> Compunetics, Inc.
> > >>> 700 Seco Road
> > >>> Monroeville, PA 15146
> > >>> 412-858-6264
> > >>> rdudek@xxxxxxxxxxxxxxx
> > >>> www.compunetics.com <http://www.compunetics.com/> =3D3D3D20
> > >>>
> > >>> To see where no one notices the contrast of white on white is =
> =3D3D
> > >>>      =3D20
> > > an=3D3D3D20=3D3D20
> > >  =3D20
> > >>> indispensable virtue of infinite potential.
> > >>>
> > >>> =3D3D3D20
> > >>>
> > >>>
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