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October 2004

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Subject:
From:
David Greig <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, David Greig <[log in to unmask]>
Date:
Wed, 27 Oct 2004 13:12:38 +0100
Content-Type:
text/plain
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text/plain (114 lines)
On topic - one way of creating resin filled blind vias is in a sequential
build, whereby the resin from the prepreg bonding the separate drilled
sub-boards squeezes thru the via holes. It is then possible to prepare the
outer surfaces and actually plate over the resin plugs. Useful for via in
pad.

Off topic, via inductance can be approximately modelled as being
proportional to ln(1/radius), smaller vias are more inductive, but at least
you can have more of them.

Best Regards

David Greig
_________________________________________
Director
GigaDyne Ltd
Buchan House
Carnegie Campus
Dunfermline KY11 8PL
United Kingdom
Tel. +44 (0) 1383 62 49 75
_________________________________________


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush
Sent: 27 October 2004 12:12
To: [log in to unmask]
Subject: Re: [TN] Filled vias

Smaller vias produce less inductance making low inductance bypass caps more
effective of low inductance no longer needed.  The resin fill is a normal
function of the sub-assembly build up technique for blind vias.




Jeffrey Bush
Director, Quality Assurance and Technical Support

                          76 Technology Drive - POB 1890
                             Brattleboro, Vermont 05302-1890
                                Tel. 802.257.4571.21 Fax. 802.257.0011
                                    [log in to unmask]
                              http://www.vtcircuits.com


-----Original Message-----
From: Steve Kelly [mailto:[log in to unmask]]
Sent: Tuesday, October 26, 2004 3:22 PM
To: [log in to unmask]
Subject: [TN] Filled vias

Good day to all,

We have a customer who wants us to fill some blind vias with pre-preg.
First I have not heard of a pre-preg fill product. Second the via to be
filled will be .003 - .004 . Third - the customer is under the impression
this will improve electrical performance- is this true? Any thoughts or help
would be appreciated. Thanks in advance. Steve Kelly



PFC Flexible Circuits Limited

Ph: (416) 750-8433

Fax: (416) 750-0016

Cell: (416) 577-8433

E-Mail: [log in to unmask]




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