You can mask it yourself using a peelable solder mask. <[log in to unmask]> Wrote: | | Date: Tue, 2 Nov 1999 19:17:59 -0500 | From: jong s kadesch <[log in to unmask]> | Subject: CGA attachment on BGA pattern | | Dear TechNetters, | | I have a substrate with BGA pattern where BGA is fanned | out for vias. | Dimensions are following: | | Diameter of the ball: 30 mil | Pitch: 50 mil | via drill size: 6 mil | via with annular ring: 10 mil | | The substrate is solder masked for CGA attachment but | exposing all the vias | (no solder mask on vias) and of course, BGA pattern. CGA | attachment cannot | be done because one BGA pad is too close to the via fanned | out from another | BGA pad (average distance between two is 5 mil) which will | cause short in | the event of solder bridge between the BGA pad and the via | during eutectic | solder reflow process. | | Is there any way that i can fix this problem without | sending these | substrates back to manufacturer for remasking? | Thanks in advance. | | | Jong Kadesch | *************************************** | | Jong, | | You might try "reballing" the devices using "hi-temp" | spheres (Sn90 Pb10) utilizing eutectic | solder paste underprinted by 20%. This will minimize the | probability of encroaching liquidus | material during reflow. If you have interest in persuing | this process on a "test" basis, please | feel free to contact me directly. | | Regards, | | Ed Popielarski | | QTA Machine | 10 McLaren, Ste. D | Irvine, Ca. 92618 | | 949-581-6601 Ph | 949-581-2448 Fx | http://www.qta.net | Ask about our BGA Reballing system! | | ########################################################## | #### | TechNet Mail List provided as a free service by IPC using | LISTSERV 1.8c | ########################################################## | #### | To subscribe/unsubscribe, send a message to | [log in to unmask] with following text in | the body: | To subscribe: SUBSCRIBE TECHNET <your full name> | To unsubscribe: SIGNOFF TECHNET | ########################################################## | #### | Please visit IPC web site | (http://www.ipc.org/html/forum.htm) for additional | information. | If you need assistance - contact Gayatri Sardeshpande at | [log in to unmask] or | 847-509-9700 ext.5365 | ########################################################## | #### | Gus Abu-Hamdeh Maxtek Components Corporation (503)627-2392 ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################