Gil, We have been soldering even larger parts for microwave use. There are two alternative ways, if you are lucky to have those possibilites: a) fluxless soldering preform and soldering in a vacuum oven. b) ditto in a nitrogen oven In both cases we cleaned the lands (pads)and the preform in a weak acidous (formic acid) solution immediately before soldering, and cleaned the part in deionised water afterwards. Ingemar Hernefjord Ericsson Microwave Systems -----Ursprungligt meddelande----- Från: TechNet [mailto:[log in to unmask]] För Zilber Gil Skickat: den 23 november 2005 13:01 Till: [log in to unmask] Ämne: Re: [TN] Unusual soldering challenge Hello Jeff, We had similar components short time ago, and we create a grid in the aperture of the stencil, similar to what Ivan suggested. The reflow pass well, but after examine the component with X-ray we saw air trapped in the solder (about 20% of the area). Thus, I suggest designing the pad on the PCB the same way as the grid in the stencil. Regards, Gil Zilber Technologist, Elta system Ltd. Tel. +972-8-8577240 Mobile +972-54-4983222 http://www.iai.co.il/site/en/iai.asp?pi=17887 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeff Brown Sent: Tuesday, November 22, 2005 7:46 AM To: [log in to unmask] Subject: [TN] Unusual soldering challenge Hi Everyone, We have a problem with a fairly unique component that requires soldering to a PCB. I'm really hoping that someone has seen this before as it looking really awkward. The component is mounted on a piece of fiberglass about 25mm x 16mm. The footprint consists of a ground pad which takes up 95% of the area, and four signal pads with 0.5mm clearance from the ground pad. The manufacturer recommends a grid of stenciled paste for the ground pad due to the large area, but we are concerned that if the paste melts from the outside edges in, then it will at a minimum result in flux entrapment, and at worst, the trapped flux will boil and lift the component, or move the molten solder causing shorts to the signal pads. I imagine that even if we used solid paste pattern that this would probably only make the problem worse. Or are we just being overly pessimistic? Any thoughts on options would be gratefully received... Currently wondering about the possibility of applying BGA balls to the package so that there is some clearance between the board and the component. If anyone is interested, I can send the component datasheet to them directly. Thank you all in advance Jeff Brown and Josh Vear EOS Space Systems --------------------------------------------------- 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 message is processed by the PrivaWall Email Security Server. The information contained in this communication is proprietary to Israel Aircraft Industries Ltd. and/or third parties, may contain confidential or privileged information, and is intended only for the use of the intended addressee thereof. If you are not the intended addressee, please be aware that any use, disclosure, distribution and/or copying of this communication is strictly prohibited. If you receive this communication in error, please notify the sender immediately and delete it from your computer. Thank you. This message is processed by the PrivaWall Email Security Server. --------------------------------------------------- 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 -----------------------------------------------------