Electronics Forum | Tue Feb 17 01:15:26 EST 1998 | J.H Kim
| In solder bumping in flipchip technology by solder printing, | the precise control of solder volume and height is very difficult. | Therefore I'd like to know the solution of this problem. | Thanks
Electronics Forum | Tue Feb 24 01:19:01 EST 1998 | Jon Gruett
You are right !!! The exact volume of solder paste onto flip chips is extremely critical. Only one vendor that I know has taken that part of the process to the next level, whereby they can effectively deposit the right amount onto the flip chip exa
Electronics Forum | Thu Jun 28 09:54:06 EDT 2012 | mosborne1
Dave, They rework fine. All solder joints on the whole board look great especially for lead free sac305. Here are the reflow specs: SAC305 no clean solder paste – Kester EM907 Kic thermal profiling device – 50%process window green light profile. • M
Electronics Forum | Thu Jun 28 15:38:37 EDT 2012 | davef
Matthew: That you can get solder flow when hand soldering, but not when reflow soldering, seems to be telling you that you're not getting the connection warm enough during reflow. You need to have those connections liquidous + 20*C for at least 5 sec
Electronics Forum | Wed Jun 27 21:53:54 EDT 2012 | davef
Questions are: * When you rework these pads, can you get solder to flow on the pads with a soldering iron? * When you profile the board during reflow, what is the temperature on these pads as compared with other similar pads in the vicinity?
Electronics Forum | Fri Jun 29 07:47:16 EDT 2012 | mosborne1
Dave Thanks for the input. The thermocouple read 244 on the pad of the socket. We actually found after extensive investigation that it is the coplanarity of the leads. We were shipped a bad batch of sockets form the manufacture. Go figure!!1
Electronics Forum | Wed Jun 27 11:13:44 EDT 2012 | mosborne1
We are seeing PLCC socket leads not soldered in our SMT process. We are using a KIC thermal profiling device and we are on 50% greem light process window. All other solder joints on the board looks great. The solder flowed what looks like perfect on
Electronics Forum | Sun Sep 10 18:54:12 EDT 2000 | Craig
Does anybody do this? Are there any problems with doing this? Thanks Craig
Electronics Forum | Tue Sep 12 07:59:03 EDT 2000 | Kevin Hussey
I suggest not to. You are also adding the flux of the paste that may cause you trouble in the long run. I suggest setting up a reclaim process with you paste vendor, or someone they reccomend.
Electronics Forum | Mon Sep 11 16:11:50 EDT 2000 | John Thorup
Hello Craig In a nutshell - bad idea Please check the achives as this has come up a number of times John Thorup
