Electronics Forum | Mon Nov 15 14:40:38 EST 1999 | Bob Smith
Hi, I have a problem I've never seen before so I hope someone here can help. A recent batch of PCBs arrived where the copper lands delaminate with a small pull. Normally you have to pull pretty hard and the whole land comes off the substrate. These
Electronics Forum | Sat May 02 23:31:06 EDT 2009 | kareal
Thanks davef. The defect always occurred during UHAST reliability, but not find in reflow. The key is that there is tin diffuse to copper trace under solder mask. is it a "normal" board defect and what is the potential risk for device? thanks!
Electronics Forum | Thu May 07 20:28:35 EDT 2009 | davef
From our notes, the following is a series of snips from: "Copper Dissolution in Tin" LJ Turbini, PhD, adjunct faculty member, University of Toronto, Materials Science and Engineering, SMT 2/07 As the solder becomes molten, copper from the board diff
Electronics Forum | Mon Jul 18 12:24:53 EDT 2016 | oleksz
Some people involved in PCB assembly process claim that SMD components reflow soldering problems are often caused by traces running under a component. According to this claim, trace (or any copper) covered by solder mask and placed under SMD componen
Electronics Forum | Mon Jul 18 12:25:30 EDT 2016 | oleksz
Some people involved in PCB assembly process claim that SMD components reflow soldering problems are often caused by traces running under a component. According to this claim, trace (or any copper) covered by solder mask and placed under SMD componen
Electronics Forum | Tue Jul 19 11:52:24 EDT 2016 | oleksz
Thank you Pavel. Aleksander
Electronics Forum | Tue Jul 19 08:26:46 EDT 2016 | pavel_murtishev
Aleksander, The answer is no. Solder deposit being printed is 80um-150um in height depending on PCB design what is two times higher than any track covered by solder mask. Molten solder will merely center the component. QFNs are prone to soldering
Electronics Forum | Mon Sep 19 01:57:28 EDT 2016 | shriram
Hi guys, Problem: Mid chip solder balling. Component affected: 0603 caps only Defect is PCB specific (Meaning only one PCB is affected as the aperture is standard for that component). As a containment I'll give a home plate design for the compo
Electronics Forum | Fri May 01 18:01:04 EDT 1998 | Peter Soland
Has anyone experienced profile related microbridging under 0402 capacitors in the past. We use a Sn46Pb46Bi8 paste, 178 degree C L.T.. Double sided board, 2 per panel, 6.5" x 5", convection oven. Profile data; thermalcouples @ components showing 200
Electronics Forum | Wed Aug 04 16:46:40 EDT 2004 | davef
We assume this is different discussion that the discussion about "crystallized flux under BGA". Correct? Milky residue with water washing makes us think "noclean flux res that just got washed". We know what you said, but we can't help ourselves.
