Electronics Forum | Sun Apr 03 10:07:40 EDT 2005 | davef
In 2001, IVF evaluated the reliability of IBM CBGA and CCGA, i.e. packages with "hard" balls and columns, in space applications for the European Space Agency. One clear result was that amount of solder paste printed on the solder lands is very critic
Electronics Forum | Tue Dec 29 08:11:18 EST 1998 | Kelvin Chow
As CSP and BGA packages become more and more popular, I want to know if anyone get problem to assembly CSP packages. Currently, most CSP use 20mil solder ball diameter and it is a trend to go down to 16mil or even 12mil. I wonder if there is a probl
Electronics Forum | Tue Jan 16 14:53:24 EST 2001 | davef
Yanno what's interesting on that topic? A small number of voids make the solder connection of a BGA stronger than no voids. Moral of the story ... don't get too anal about voids. You should check the archives ;-) [har har har] we've discussed this
Electronics Forum | Mon Jan 17 21:01:21 EST 2000 | Dave F
Dennis: On your BGAs: * Never seen voids any place other than the top ... lower density stuff rises. * Our spec on voids says: 1 Voids 1a Voids in soldered balls shall be less than 20% of the diameter of the solder ball. 1b No void shall sho
Electronics Forum | Mon Jun 05 14:17:18 EDT 2000 | C.K.
Dream: Yes, VIA's are connected to actual SMD pads via traces - roughly .030" from the pad. The VIA is .013" in diameter, and the excess solder bleeds out of the actual VIA barrel after the 1st reflow.... -CK
Electronics Forum | Tue May 22 20:27:34 EDT 2007 | davef
What are the area and aspect ratio of the apertures that clog? When you print, you should be able to fit at least 4 of the mean sized solder sphere across the width or diameter of your smallest apertures.
Electronics Forum | Thu Dec 11 07:29:58 EST 2008 | jdumont
I have done a few studies on this issue here. As a result we have increased hole diameter on heavily ground planed pins to a min of .015" over the lead diameter as well as preheating the PCB when hand soldering. I have also had to order the upper pre
Electronics Forum | Thu Apr 27 21:20:38 EDT 2000 | Dean
Here are some pointers to use during your X-ray inspection. Microcracking is virtually impossible to determine with X-ray. However, I suspect you are looking for "hard" opens. Those are much easier to find visually. If using a paste-and-place pro
Electronics Forum | Thu Nov 07 15:06:11 EST 2013 | hegemon
1st X-Ray looks pretty good. One instance of what looks like solder migration in the lower left quadrant. 2nd X-Ray shows a number of locations where the solder has migrated into the vias, shown by the small dark circles between the main spheres.
Electronics Forum | Tue Sep 01 10:16:10 EDT 1998 | Mike Cox
| | We are experiencing shorting on a BGA. The part has a 1mm pitch with a 196 I/O count. The problem seems to pop up without warning & disappear in the same manner. | | Our pad design is .020" diameter pads with .025" solder resist diameter. Th
