Thanks Mark,
        the only one that I couldn't make a 'reasonable' guess at was the DS
(dimensional stability hadn't occurred to me), but then I would argue this
is a spec and one shouldn't have to guess. DS doesn't make much sense to me
when they talk of tolerance and CTE separately or by other titles (not
necessarily within the tables). The missing X/Y stabilities mystifies me
because I am sure that these various materials, weaves and resin contents
will vary significantly on X/Y stabilities and if those X/Y stabilities are
too mismatched in a stack up, watch out for your bow and twist spec.
        I stopped trying to learn or use the IPC specs for materials a long
time ago because it just confused too many fabricators. I now just work
closely with them to determine which manufacturers materials meet our
requirements from their standard selection using standard required
performance details specific to our designs. I don't really care about the
weave or %RC but do care about the x/y/z stabilities, DK, thickness and loss
tangent.

Brad Velander,
Lead PCB Designer,
Norsat International Inc.,
#300 - 4401 Still Creek Dr.,
Burnaby, B.C., V5C 6G9.
Tel. (604) 292-9089 direct
Fax (604) 292-9010
website www.norsat.com


> -----Original Message-----
> From: Mark E Witherite [mailto:[EMAIL PROTECTED]]
> Sent: Monday, July 09, 2001 12:04 PM
> To: Protel EDA Forum
> Subject: Re: [PEDA] Layer Stackup Info.
> 
> 
> Hi Brad,
>          Your right about the tables they are mislabeled. 
> They were correct 
> in the 9-26-99 document put out by The Copper Connection Inc.
> 
> DS= dimensional Stability
> CHEM= Chemical resistance
> + = better
> - = worse
> %RC = % of resin content
> as for X&Y CTE you got me
> Cheers
> Mark

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