Hi Mike,
        I've been looking into this as well.  My first premonition is, the single
ply of 2313 will have consistent density of glass bundles vs 2 plys of 106.
 The consistent density will yield a more consistent via shape.  Remember,
with 2 plys of 106 you might encounter 2 knuckles on top of each other,
thus requiring you to set the laser power high enough to penetrate both;
however, you will also likely encounter areas that are resin rich, which
does not require as much power.  The excess power in the resin rich areas
will give you an "egg" shaped via.
   My 2 cents....

At 07:05 AM 07/01/1999 -0700, you wrote:
>I have a product that requires a .006 dia. laser ablated via from lyr 1 to
>2.  I'm required to use glass re-inforced FR-4 as a dielectric.  The
>dielectric is approx .0035. I can either use a single ply of 2313 or 2 plies
>of 106 prepreg.  Which would be the most favorable construction in terms of
>laser hole quality and subsequent processing?
>

--
Regis Froats <[log in to unmask]>
Process Engineer - Herco Technology Corp.
13330 Evening Creek Drive North
San Diego, Ca. 92128
Pho:619.679.2800 - Fax:619.679.7565