It's actually easier than trying to get a co-planer injection on something like a BGA package with a heat spreader.. You design the tooling so the resin doesn't inject into those areas. All you are doing is raising the injection plane up by 3 mils, so presumably the tooling has a flat base with pockets in it to accommodate those raised pads John John Burke (408) 515 4992 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of bob wettermann Sent: Monday, June 02, 2008 9:18 AM To: [log in to unmask] Subject: [TN] QFN "Bumped" Pad Construction Dear Technetters: Since this question could not be raised on "How It's Made" I thought we would pose it here: We have recently come across a few QFN packages where there are raised pads (about 3 mils from the bottom surface of the QFN) on the bottom of the device. Our questions are related to the following: How are these "raised bump" leadless packages fabricated such that these bumps are raised to a different z axis plane then the bottom surface of the device? Regards Bob Wettermann PH 847-767-5745 --------------------------------------------------- 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 -----------------------------------------------------