Arrr! -Chris "Whittaker, Dewey (AZ75)" <Dewey.Whittaker@HONEYWELL To: [log in to unmask] .COM> cc: Sent by: TechNet Subject: Re: [TN] Question re Test Probe and blind microvia <[log in to unmask]> 04/19/2006 12:19 PM Please respond to TechNet E-Mail Forum; Please respond to "Whittaker, Dewey (AZ75)" So you're saying the probing of microvias leaves a yacht to be desired. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Rex Waygood Sent: Wednesday, April 19, 2006 9:05 AM To: [log in to unmask] Subject: Re: [TN] Question re Test Probe and blind microvia I think this might be a Werner aeroplane suggestion. Would you want to fly the Atlantic in an aircraft where the boards had microvias probed umpteen times with a great deal of force with spear or blade point probes? I'll go by boat thanks....................... Will your pcb manufacturer fly with you? Rex -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Valerie St.Cyr Sent: 19 April 2006 16:33 To: [log in to unmask] Subject: Re: [TN] Question re Test Probe and blind microvia I don't want to allow it, the Test development engineer doesn't want to allow it. But we have no data at all one way or the other, and it would take some time to make up a DOE, get samples fabricated, make a test fixture for this experiment etc etc... They want an answer and preferably one with some amount of experience informing the decision..... so, just trying to see if anyone has tried it. Valerie Rex Waygood <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 04/19/2006 10:28 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Rex Waygood <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Question re Test Probe and blind microvia I will be interested to read the replies of others. We've never probed microvias but as vias in general are probably the least reliable part of a pcb and pcbs often the least reliable part of an assembly.............do you want to be "hitting it with a LOT of force"???? Our approach is to avoid probe testing on vias, never yet contemplated a microvia. Rex -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Valerie St.Cyr Sent: 19 April 2006 15:10 To: [log in to unmask] Subject: [TN] Question re Test Probe and blind microvia All, I have a question: have any of you first hand experience with allowing blind microvias to be used as test points for In-circuit or Functional Test? The Engineer would like to probe a microvia to eliminate the stub we would normally have from a through hole via used as a test point. I don't know if that should be avoided. The probes we used are either "spear" or "blade" tips; I am talking about probing the loaded board, so this means probing after the board has seen 3 or maybe 4 reflows; the microvia starting laser ablated diameter is typically .006"; if it is a Layer 1 to Layer 2 it is .003" or .004" deep (we used prepreg in that opening, no RCC); if it is Layer 1 to Layer 3, the depth could increase by anywhere from another .0035" to .0055"ish. Our plating specification is IPC6012A Class 3. Our intention would be to drop that blind via in a very large pad, much larger than normal for a blind via; then paste it so it is closed up when we go to probe. That will keep the probe from directly piercing the sidewall plating or the hole knee. Which leaves, I think, the question of how well the plated copper is adhered to the copper foil capture pad - we will be hitting it with a LOT of force - will that mechanical stress cause a de-bonding or weaken that bond ? What if the board needs to be retested and retested if there is a fault and we have to do repetitive debug? So, anyone with experience probing to microvias, your knowledge would help us a lot. Thank you, Valerie --------------------------------------------------- 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 ----------------------------------------------------- ________________________________________________________________________ This email has been scanned for all viruses by the MessageLabs SkyScan service. ________________________________________________________________________ This email has been scanned for all known viruses by the MessageLabs SkyScan service. ================================================================ This email (including any attachments) is confidential and/or may be legally privileged. It is intended for the named recipient (s) only and may not be forwarded, disclosed or otherwise disseminated Although this email has been scanned for viruses, WE DO NOT (to the extent permitted by law) ACCEPT ANY LIABILITY WHATSOEVER for any virus infection, compromise of security or losses resulting from vi NO CONTRACT MAY BE FORMED OR DOCUMENTS SERVED BY THIS EMAIL unless specifically agreed to in writing and signed by a Director of Hansatech. Any views or opinions expressed in this email are those of If you have received this email in error please contact the IT department immediately on (01202) 674 333 or (01553) 691 022 prior to deletion. ================================================================ --------------------------------------------------- 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 ----------------------------------------------------- "This e-mail message is intended only for the use of the intended recipient(s). The information contained therein may be confidential or privileged, and its disclosure or reproduction is strictly prohibited. If you are not the intended recipient, please return it immediately to its sender at the above address and destroy it." --------------------------------------------------- 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 -----------------------------------------------------