[SI-LIST] Re: PCB STACKUP

  • From: Aubrey_Sparkman@xxxxxxxx
  • To: perry.qu@xxxxxxxxxxx, mkhusid@xxxxxxxxxx
  • Date: Thu, 22 Jan 2004 11:15:48 -0600

At a high-level, asymmetry causes warped boards.  Warped boards causes
assembly issues.

Aubrey Sparkman 
Enterprise Engineering Signal Integrity Team 
Dell, Inc. 
Aubrey_Sparkman@xxxxxxxx 
(512) 723-3592


> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Perry Qu
> Sent: Thursday, January 22, 2004 9:40 AM
> To: mkhusid@xxxxxxxxxx
> Cc: 'Nosovitski, Alexander (Contr) '; 'si-list@xxxxxxxxxxxxx '
> Subject: [SI-LIST] Re: PCB STACKUP
> 
> 
> Can someone comment on the impact of assymetrical stackup on 
> PCB yield ?
> 
> Thanks
> 
> Perry
> 
> Michael Khusid wrote:
> 
> > Alexander,
> >
> > Unless I miscounted, I can see 27 layers in your stackup. 
> An odd number of
> > layers will get you an assymetrical stackup and will cause 
> PCB warpage.
> >
> > Michael
> >
> > -----Original Message-----
> > From: Nosovitski, Alexander (Contr)
> > To: si-list@xxxxxxxxxxxxx
> > Sent: 1/21/04 4:02 PM
> > Subject: [SI-LIST] PCB STACKUP
> >
> > Hello si-list,
> >
> > The design I am working on has a dense placement.
> >
> > The proposed stack up looks as follow:
> >
> > TOP
> > POWER_ANALOG
> > DIFF_SIGNAL (Gb/s signals)
> > AGND
> >
> > GND
> > POWER
> > S
> > S
> > GND
> > POWER
> > S
> > S
> > GND
> > SPLIT_POWER
> > GND
> > S
> > S
> > POWER
> > GND
> > S
> > S
> > GND
> >
> > AGND
> > DIFF_SIGNAL_ANALOG (Gb/s signals)
> > POWER ANALOG
> >
> > BOTTOM
> >
> > All signal layers are 0.5 Oz copper and
> >
> > All planes are solid ( except one in the middle) with  0.5 
> Oz copper.
> >
> > The diff. signals are running at 2.5Gb/s.
> >
> > There are different opinions about analog plane location.
> >
> > Could the arrangement above cause a problem?
> >
> > What else should I be concern about?
> >
> > Any help or suggestion is appreciated!
> >
> > Regards,
> >
> > Alexander Nosovitski
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Salkow, Steven [mailto:steven.salkow@xxxxxxxx]
> > Sent: Wednesday, January 21, 2004 1:57 PM
> > To: weirsp@xxxxxxxxxx; fred@xxxxxxxxxxxxx; kar_thik_v1@xxxxxxxxx
> > Cc: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Re: Looking for thin dielectric tape
> >
> > 4 mil prepreg (pcb laminate) is generally available from 
> anyone doing
> > multilayer PCB. You may also get samples from laminate 
> vendors (dupont,
> > Norplex) (sprayed with Scotch 444 adhesive for cold 
> adhesion to copper
> > foils)
> > 3M (tape division) have exactly what your looking for up to 36" wide
> > slit to any width but they have minimum qtys
> >
> > see
> > 
> http://products3.3m.com/catalog/us/en001/utilities_telecom/oem
> _electrica
> > 
> l/node_R5MTBSFVGPbe/root_GST1T4S9TCgv/vroot_GSHBRQT7DVge/gvel_
> BBGZX3B1QG
> > gl/theme_us_oemeletrical_3_0/command_AbcPageHandler/output_html
> >
> > Catalog on the above page for download
> >
> > Steve Salkow
> > Lockheed Martin
> > 3200 Zanker Road
> > San Jose, CA 95134
> > (408) 473-4058 (san Jose)
> > (408) 742-4162 (Sunnyvale)
> > steven.salkow@xxxxxxxx
> > salkow@xxxxxxxxxxxx
> > (925) 462-1075 Home
> > (925-) 487-5946 Cell
> > (408) 468-7271 Numeric Pager
> >
> > -----Original Message-----
> > From: si-list-bounce@xxxxxxxxxxxxx
> > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of steve weir
> > Sent: Tuesday, January 20, 2004 11:17 PM
> > To: fred@xxxxxxxxxxxxx; kar_thik_v1@xxxxxxxxx
> > Cc: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Re: Looking for thin dielectric tape
> >
> > If you want to lay out a board, onesy, twosy, Express PCB 
> is not a bad
> > way
> > to go.  www.expresspcb.com It sure beats the Bishop 
> Graphics adhesive
> > backed Cu tape, or a bathroom full of ferric chloride.
> >
> > Steve.
> > At 01:44 PM 1/20/2004 -0800, Fred Townsend wrote:
> > >The last time I check you could still get mylar sheeting at most
> > >drafting and staionary stores. You would to apply your own 
> adhesive.
> > >Comes in 4 and 7 mil thicknesses. You can also get 
> polyester sheeting
> > >frosted one side and adhesive on the other for making 
> labels.  Failing
> > >that how about 3M's double sticky magic tape?
> > >
> > >Fred Townsend
> > >
> > >Karthik V wrote:
> > >
> > > >Hello,
> > > >
> > > >         I am a student at the State University of New York. I am
> > > looking for a double sided sticky dielectric tape (more 
> like a sheet )
> > of
> > > thickness about 4mils (0.1mm) and with a dielectric constant of
> > > around  4, to use between copper sheets - to make a 
> "temporary board".
> > I
> > > tried things like epoxy, but it's almost impossible to 
> get it so thin
> > and
> > > still provide infinite DC resistance.
> > > >
> > > >          Could anyone point me to places where I could 
> look for this
> >
> > > kind of stuff. Is there anything else I could try to get the
> > dielectric
> > > (with Dk around 4) so thin ( apart from elaborate processes )   .
> > > >
> > > >thanks in advance,
> > > >Karthik,
> > > >
> > > >---------------------------------
> > > >Do you Yahoo!?
> > > >Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
> > > >
> > > 
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> 
> --
> Perry Qu
> 
> Design & Qualification       |      600 March Road
> Alcatel Canada               |      Ottawa, ON K2K 2E6, Canada
> 
> DID: (613) 7846720           |      FAX: (613) 5993642
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