Thanks for the replies (see below) to my original posting (see below). Seems like several of you are having good luck using flux only vs. solder paste during BGA rework. The thing I wonder about is the reliability of reworked BGA solder joints. I thought that proper BGA solder joint volume was based on the original BGA ball combined with the solder added during the solder paste screen printing process. Thus, what effect does solder volume and solder joint height have on the reliability of a BGA solder joints for plastic BGA components? Thanks again, Jeff Ferry CEO Circuit Technology Center, Inc. Some Replies to prior posting included: --------------------------- My "rule of thumb" is plastic BGA's with eutectic balls - I use stick flux only. For ceramic BGA's with non-eutectic or "hard" balls, I must use a microscreen and apply solder paste. Mark --------------------------- For our eutectic PBGA's, we only flux (no clean). Have only done about 50 or so over the past year with very good (97% yield) results. Have not seen any studies or papers. Just worked closely with our CM to create the profile for each type of BGA. We use Air-Vac. Kerry --------------------------- It's the only way to go. I've been designing, placing, reflowing and reworking BGA's for nearly 8 years now. It took me five minutes to make the discovery and, as I've said far too often, I'd use flux only on initial production if feasible. Regards and respect, Earl Moon --------------------------- We have been working and reworking BGA and Micro BGA for quite sometime. This is a requirement in a prorotye environment. We tried using micro stencil when we first attempt to replace the BGAs and found out that using micro stencil was not a good method. We then tried using no-clean tacky past fux and applied to both the BGA and the PWB substrates. This process has been adopted in our process and has been working well for us. Here are some great benefit of using flux paste only. - No micro stencil cost. - No cleaning is needed (No-clean flux). - No aligning equipment is needed, since we can place the BGA into its footprints without worry about smearing the solder paste, and if the hand alignment if off ( no more than 50%), the liquid tension of the reflowed solder balls will pull it back. - Save time and money. ( stencil cost, cleaning, and aligning). If the solder balls on the BGA are made of non-eutectic, solder paste is required. Tuan Bui Conexant Systems Inc. Prototype Process Dev. Eng. --------------------------- It is my opinion that pasting the board enhances wetting and a superior joint. Jason Gregory --------------------------- On Thu, 31 Jan 2002 10:54:24 -0600, Jeff Ferry <[log in to unmask]> wrote: >Fellow TechNetters, > >We nearly always apply solder paste to the circuit board when we replace >BGA components during rework. Yet, after speaking with a handfull of BGA >equipment companies at APEX, seems like they all recommend using flux only >vs. paste, unless the circuit board is used in a high rel application. > >What do ya'all do/recommend for BAG rework? Can you point me to any >studies/reports on the subject? > >Thanks, > >Jeff Ferry >CEO >Circuit Technology Center, Inc. > >--------------------------------------------------------------------------- ------ >Technet Mail List provided as a free service by IPC using LISTSERV 1.8d >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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL >To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest >Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives >Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional >information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 >--------------------------------------------------------------------------- ------ --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------