Hi Waclaw, It sounds like famous "black pad" phenomena and it has nothing with Kapton, but with Nickel layer. Powodzenia Edeward Edward Szpruch Eltek Ltd P.O.Box 159 ; 49101 Petah Tikva Israel Tel ++972 3 9395050 , Fax ++972 3 9309581 e-mail [log in to unmask] > -----Original Message----- > From: karpinski [SMTP:[log in to unmask]] > Sent: ã ôáøåàø 18 2004 23:15 > To: [log in to unmask] > Subject: [TN] Ni/Au solderability on kapton > > Recently we have solderability problems with Ni/Au kapton flex boards > (0,1 µm Au, 3 µm Ni, 35m Cu). > We have produced and assembled large number of boards. > On 10 % of the boards we observe interconnection failures after final > assembly of the pcbs. If the suspected solder joints are lightly > stressed , the connections are easily broken, leaving an open circuits. > It is easy to peel these parts with solder material from the boards. > The pads below the removed parts are discolored dark gray and are sleek . > Some times the handsoldering of the broken joins was successful but > after small strain the joints broke again. > Additional vapor phase soldering did not improved the the strength of > the joints. > This is new problem for us. Does anyone have any experience with this? > How to rework the boards? How to determine when a board should be > reworked or > scrapped? What about reliability issues? Latent failures? > I would appreciate your help very much > regards > > -- > Waclaw Karpinski > I. Physikalisches Institut > RWTH Aachen > D - 52074 Aachen > > --------------------------------------------------- > 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 > 847-509-9700 ext.5315 > ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------