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] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- -- Virus scanned by Lumison. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------