Tim, Since this assembly probably wont last very long, the easiest thing to do is to use Sn-Pb solder to "tin" the ENIG on your PCB, clean your site then place your flip chip on the site and send it into a "peaky" Sn-Pb reflow cycle.... That should form theinterconnects you need without all the other issues that ACF/ACA entail and would probably last as long... Paul Paul Edwards Surface Art Engineering -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Tim Mack Sent: Thursday, May 08, 2008 1:21 PM To: [log in to unmask] Subject: [TN] ACF/ACA Flip Chip Assembly Hello TechNet, Since tomorrow is Friday I thought I better get this out today. I have a bare Si flip chip with plated gold bumps that I need to attach to an ENIG finished FR-4 PCB (the PCB can be changed if ENIG is a bad idea). My plan is to use Anisotropic Conductive Film/Adhesive (ACF/ACA) to produce the interconnects. The chip itself has a 3x4 bump array with a 275 µm pitch. Does anyone here know of vendors for this material? Past experience do's or don'ts? Any info would be appreciated. Thanks, Tim Mack Research Engineer NDSU Center for Nanoscale Science and Engineering <http://www.ndsu.nodak.edu/cnse> www.ndsu.nodak.edu/cnse --------------------------------------------------- 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 ----------------------------------------------------- ============================================================================== This email and any attachments thereto may contain private, confidential, and privileged material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact [log in to unmask] immediately and permanently delete the original and any copies of this email and any attachments thereto. ============================================================================== --------------------------------------------------- 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 -----------------------------------------------------