Lee: Good to know info. ^ current density, ^ brittleness, v plating uniformity and density. Good things take time. Thanks, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Lee parker Sent: Wednesday, April 11, 2007 12:42 PM To: [log in to unmask] Subject: Re: [TN] Via hole plating corner crack Victor You mentioned that the current density is 30 amps per square foot. I consider this to be extremely high and not only will cause brittle copper, but highly non-uniform copper in the barrel. I presented a paper at Apex that mathematically modeled the copper uniformity in the barrel to the plating parameters including current density, you might want to review this paper. The model shows there is an inverse linear dependence between the copper uniformity and the plating density. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 ----- Original Message ----- From: "Victor G. Hernandez" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, April 10, 2007 10:36 AM Subject: Re: [TN] Via hole plating corner crack Can you please post the crack via cross section photo for viewing, "a picture is worth one thousands words". Is this SnPb or LF? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of C J Long Sent: Tuesday, April 10, 2007 9:20 AM To: [log in to unmask] Subject: [TN] Via hole plating corner crack Dear Techneter: I recently experienced customer return of corner crack. The PCB is 50 mil thick, 10 mil via, OSP finish and corner crack is over the 4 corners of top and bottom of hole. Crack is started from the bottom of external foil and crack through the entire plating. You can see the photo (file: crack through) of actual failure. Plating is unusual column type crystal on the surface. In the hole barrel, the plating crystal is regular. We also performed many in-procss WIP cross section (refer to the file "crack 9X IR") and we could only find the crack after 6X IR reflow and its crack is started from external foil top corner. I have sucessfuly duplicated similar failire with very high plating current density of 30ASF with very low brighter (0.15cc/l), but its failure mode is crack on ehe top of external foil not the same as customer return. My questions are: 1. Are these two failre modes with the same root cause? What is the reason one crack is started from the foil top corner and the other is from the bottom? 2.Is there any non-destructive method able screening the cracked plating? http://tw.pg.photos.yahoo.com/ph/minalong2003/album?.dir=/5c32scd Thank you very much. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 15.0 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 15.0 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 -----------------------------------------------------