[SI-LIST] Re: Board design adjustments by manufacturers
- From: Hermann Ruckerbauer <Hermann.Ruckerbauer@xxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Tue, 09 Sep 2014 08:42:20 +0200
HI Yuriy,
I think this is a really interesting topic. My understanding is, that
the CAM software they use is that powerfull that they e. g. define
conditions for traces based on which do the change (e. g. in order to do
different changes to 85 ohm traces vs. 100ohm traces). I had already
cases where they moved traces in order to increase pad to trace spacing
to get a higher yield .. but on cost of performance of the trace they
moved ..
If one is lucky the board vendor asks if he is allowed to do so .. if
not this is just done without any feedback ..
The interessting part is: my customers do not believe that these changes
are done and it is really difficult to convince them that these changes
are possible in the CAM software ..
Currently I still rely on putting a reference trace on each design that
I can characterize and based on this I adjust my simulation to match the
bahaviour. But I guess this approach is not accurate enough for your
intention.
I guess forming specific structures would allow you to characterize
things one by one: Forming a capacitor should allow to characterize
material and stackup by minimizing etching impact ..
I would expect, that one could find specific structures that will allow
a complete characterization of different board parameters you mentioned ..
But I can not answer your question directly as I have no name of CAM
software that is that powerfull .. but I guess there are some PCB
manufacturing people on this list as well..
Hermann
Upcoming Events:
=================
"Open the Black Box of Memory"
What you always wanted to know about Memory!
.. But never had the right expert to ask!
September 22./23. 2014 in Copenhagen (some seats still available)
September 24./25. 2014 in Copenhagen (Sold out)
vist www.EyeKnowHow.de/en/seminars/
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Itzlinger Strasse 21a
94469 Deggendorf
Tel.: +49 (0)991 / 29 69 29 05
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
Am 08.09.2014 um 22:48 schrieb Yuriy Shlepnev:
> Hello Everyone,
>
> After going through a multiple analysis to measurement validation projects, I
> realized that almost all boards are not manufactured as designed (what a
> surprise :-)). As a consequence the analysis to measurement validation may
> require investigation of the manufactured board geometry, that includes
> cutting the board and taking measurements on the cross-sections (usually
> important only above 10 GHz). Now I am trying to figure out what board design
> adjustments are needed and where to get those numbers without
> cross-sectioning for the accurate post-layout electromagnetic analysis.
> In particular, is there any way to get the following numbers without cutting
> the board?
> - change thickness of layers (account for plating and variations in thickness
> of laminates);
> - change trace width and shape (account for etching and plating);
> - change spacing between traces in diff pairs (if adjusted for the "impedance
> control");
> How board manufacturers actually adjust trace widths or spacing for a given
> design in the "impedance controlled" process if they have just Gerber or
> ODB++ data? Is there any software that does it?
>
> A relevant question - are there board manufacturers out there who provide
> probability distribution data for stackup layer thicknesses, strip widths,
> back-drilling depth etc.?
>
> Can anybody point me to a source of information on this subject.
>
> Best regards,
> Yuriy
>
> Yuriy Shlepnev, Ph.D.
> President, Simberian Inc.
> 3030 S Torrey Pines Dr. Las Vegas, NV 89146, USA
> Office +1-702-876-2882; Fax +1-702-482-7903
> Cell +1-206-409-2368; Virtual +1-408-627-7706
> Skype: shlepnev
>
> www.simberian.com
> Simbeor – Accurate, Fast, Easy and Affordable Electromagnetic Signal
> Integrity Software
> 2010 and 2011 DesignVision Award Winner
>
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List forum is accessible at:
> http://tech.groups.yahoo.com/group/si-list
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
>
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
