Bill

I'm running a little behind in reading my Technet.  I'm busy trying to keep
our lead times down to 6 weeks :-).  I noticed you haven't gotten a response
on this so I thought I'd still post a reply to your question.

We build boards with standard cores as thin as 2.5 mils (single-ply 1080
prepreg).  These can be signal/signal, signal/plane or plane/plane.  Of
course there is also the ZBC 2.0 mil core, but it's pretty limited to
plane/plane applications.  The challenges are about what you'd expect,
handling, handling and handling.

We also fabricate prepreg openings down to around 3 mils in thickness, too.
Most of these are single-ply applications of 2313 (or similar) style
prepreg.  The challenges here are optimizing both process and design to
avoid low pressure areas which could result in voids and entrapped air.
Cleanliness can also be an issue, at the material supplier and in the board
fabrication process.  We and our suppliers had to invest a lot of effort in
cleaning up our material handling areas to avoid shorts due to contamination
from conductive particles.

The benefits are fairly obvious.  How else are you going to fit 16 layers in
an 0.62" thick board or maintain "reasonable" PTH aspect ratios for 26 layer
boards with BGAs that require .012" drilled holes unless you have dielectric
openings this thin?



> ----------
> From:         Brooks Bill[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Brooks Bill
> Sent:         Thursday, July 13, 2000 8:37 AM
> To:   [log in to unmask]
> Subject:      [TN] Plane Capacitors
>
>
>
>
>
>
>
>
> To: PCB guys and gals...
>
> Plane Capacitors... it was the topic for discussion at PCB West in Santa
> Clara... have any of you had experience with manufacturing boards with a 4
> mil gap between the gnd plane and the signal layer?
> What are the challenges you see... and did you realize any benefits from
> the
> exercise?
>
> Bill Brooks
> Senior PCB Designer -  <mailto:[log in to unmask]> [log in to unmask]
> Zoneworx, Inc.
> 40925 County Center Drive, STE 200
> Temecula, CA 92591
>  <http://www.zoneworx.com/> http://www.zoneworx.com
> Tel: (909) 296-1226 x 1037
> Co-Director / Education Officer / Webmaster
> for the San Diego Chapter of the IPC Designers Council
>  <http://www.ipc.org/SanDiego/index.html>
> http://www.ipc.org/SanDiego/index.html
>
>
>
>
>
>
>
>
>
>
> Thanks,
>
>
>
> Bill Brooks
> Senior PCB Designer - [log in to unmask] <mailto:[log in to unmask]>
> Co-Director / Education Officer / Webmaster
> for the San Diego Chapter of the IPC Designers Council
> http://www.ipc.org/SanDiego/index.html
> <http://www.ipc.org/SanDiego/index.html>
>
>
>
> Expand Your Domain!
>   _____
>
>
>
>
> Zoneworx, Inc.
> 40925 County Center Dr., Suite 200
> Temecula, CA 92591-6037
>
>
> Ph: 909.296.1226 (x1037)
> Fx: 909.296.1227
> Visit us on the Web: zoneworx.com <http://www.zoneworx.com>
>
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