Kitty,
The less "Groups" of blind vias layer there are the cheaper.

Let me explain how it works. When drilling blind/buried vias
the layer(s) that have a via through ONLY them are drilled and
then pressed, then the other half/layers are drilled and pressed with
the first set. This means you attempt to make your blind buried vias
in layer sets.
Ex vias through

Layer 1-2 & layers 3-4 for a 4 layer board. Then there are some from layer
1-4

It's hard to explain very clearly but try to split the layers into groups.
Layer1-3 & Layer4-6 & Layer7-10
or
Layer1-2 & Layer3-4 & Layer5-6 etc.

The board manufacturer can't really drill a via from layer 1-3
and then 2-4. The less of these layer groups the easier and cheaper.
This is also a way to label your drill files.

All layer drill
Layer1-4 drill
layer 5-8 drill

CR




I have a few questions regarding blind vias with controlled depth
drilling.  Is this a reliable process?  I have a board that requires
microvias for a BGA package that will be on the top of the board.  All
the digital parts are on the top and RF parts are on the bottom.  So, I
don't want vias coming all the way from the top to the bottom.  This
will be and 8 layer board and I only want vias to come from the top down
to Layer 2, 3 for signals, and layer 4 for digital power.  I am also
gonna need vias to come from the bottom layer up to layer  7 for signals
and layer 6 for analog power.  Layer 5 is a gnd plane.  Is this
manufacturable?  What is the best way to do this without having an
astronomical cost?  Any help is greatly appreciated.  Also, who can
manufacture these boards?
Thank You,
Kitty

Kitty Hines
SOPHIA Communications, Inc.
8330 S. Madison St., Ste. 15
Burr Ridge, IL  60521
(630) 323-6110 Ext. 336
(630) 323-5173 Fax
[log in to unmask]

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