Electronics Forum | Fri Nov 08 08:52:54 EST 2002 | dphilbrick
Juan There are many things that cause this and the first thing I would do is request quality records from your board fab facility on that particular lot. If they are unwilling to give them to you this is a good sign they had a processing problem. Th
Electronics Forum | Thu Jun 20 04:49:34 EDT 2002 | scottxiao
according to the ressult of cross-section and removing the component, I find there is no black area in the left pad, and the IMC is also normal, so the black nickle is less impossible. the PCB material is not common FR4, just some thing like ceramic,
Electronics Forum | Wed Sep 03 16:59:13 EDT 2008 | glennster
At a former employer we required HASL thicknes to be a minimum of 0.75 micron (30 microinches), as measured at the thinnest point on any given pad. This would generally assure a minimum 1 year solderability shelf life. Usually when we saw a soldera
Electronics Forum | Wed Sep 10 12:56:09 EDT 2003 | davef
Intermetallic compounds [IMC]: * Form during the alloying process of some metals. In soldering these are Sn, Ni, Ag, Cu, Au. * Do not accept solder. * Increase in depth in logarithmic proportion to both time and temperature. [So during the solder
Electronics Forum | Wed Oct 24 18:08:02 EDT 2001 | davef
1- DF1: WOW!!! How do people get these cool toys? CB: I am with the University at Buffalo Electronic Packaging Lab. http://www.packaging.buffalo.edu We have pretty much everything that is sold on the market as well as Laser inspection technologies we
Electronics Forum | Tue Nov 15 21:06:04 EST 2005 | davef
Is your IMC purple? [The sure way to tell if you have the 'purple plague'.] Where does the failure occur? * At pad / wire bond * Up wire from the bond Tell us about the aluminum pad. * What is the plating specification? Is that what you actually r
Electronics Forum | Mon May 20 21:29:52 EDT 2002 | davef
Q1: Are we saying then that IMC can occur at the solder / Cu pad join on the PCB when finished assembled? A1: Yes, but in a broader context I am saying that when someone solders correctly, they form an IMC. Q2: Will the tin diffuse with the Cu over
Electronics Forum | Mon Jan 22 22:37:27 EST 2001 | davef
50 ppm oxygen was on half joints reflowed in air. 3d Human factors PCB pad cleanliness: Handling of bare board pads creates excessive voiding. Print rejection: Cleaning of OSP pads with acetone or isopropanol increases voiding.
Electronics Forum | Tue Nov 15 09:31:27 EST 2005 | arclightzero
I have been reading a good deal about IMC (purple plague in particular) in gold wire/aluminum pad wire bonds. My company uses ultrasonic wedge bonding, and for the most part all of our bonding is gold/gold, however we have one particulr part that has
Electronics Forum | Fri May 17 15:53:47 EDT 2002 | davef
Based on what you�ve said, comments are: * There is no reason not to expect a trace of Zn in your 85/15 Sn/Pb solderability protection, but Sn/Cu IMC are more prevalent than Zn. * Intermetallic growth and oxidation are very different materials proper
