Mr. Stewart,

A available method of describing the structure of build-up/micro-via
technology boards is;

	A/B/C
	where;
	A = Number of build-up circuit layers on the top of the assembly
	B = Number of circuit (or power/ground) layers on the internal
	standard drilled core
	C = Number of build-up circuit layers on the bottom of the
	assembly

i.e. a 2/4/2 assembly would have 2 layers of build up technology
laminated on each side of a standard 2 layer core.

Phil Yates,
Nextek, Inc.

***********************************
[log in to unmask] wrote:
> 
>     \0
>    TO:         I4235700 IBMMAIL   new address for ipc technet 25.6.96
> 
>    FROM:       DSTEWART EX2       D.Stewart        - Product Development Manager.
> 
>    DATE:       6 February 1997
>    SUBJECT:    High Density Interconnect
>    REFERENCE:  definition?
> 
>     I have been having discussions with customers about how many
>     distribution / high density interconnect layers etc are possible
>     with the new microvia technologies, and we suddenly realised that
>     some of the time we were talking cross purposes, because nobody has
>     really defined what is a high density interconnect/distribution
>     layer. If someone quotes 3 layers of HDI, does this mean 2
>     dielectric seperations with vias linking, or 3 dielectrics?
>     With our laser process linking layer 1-2, I would suggest that this
>     gives 2 layers of HDI or distribution, as the high density is
>     achieved by reducing via pad sizes down to 10 mil or less.
>     Any views or definitions on this?
> 
>     Dougal Stewart
>     Product DEvelopment manager
>     Exacta Circuits
>     Scotland
> 
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