Electronics Forum | Wed Feb 20 23:17:34 EST 2002 | surachai
I AM JUST EVALUATION LEAD FREE EVALUATION AND FOUND THE BIG PROBLEM OF SOLDER CRACK BETWEEN TERMINAL OF COMPONENT AND THE INTERMETALLIC LAYER OF LEAD FREE ALLOY BUT DON'T FIND ANY CRACK BETWEEN SOLDER AND SURFACE OF PCB , COULD YOU HELP ME VERIFY T
Electronics Forum | Thu Oct 17 23:25:53 EDT 2002 | redmary
We generally etch the copper back slightly using a 50/50 mix of 3% Hydrogen Peroxide and laboratory grade Ammonium Hydroxide. Swab for about 5 seconds, then rinse. and etch the tin in the solder to further delineate the intermetallic layer that shou
Electronics Forum | Fri Feb 11 01:36:22 EST 2005 | brown
OK I am counting someone knowing this. True or False, if my touch-up operators touch-up the smt solder joints too many times will this make the joint weaker? if yes why? and what happens to my intermetalic layer? I have insisted if it looks good don
Electronics Forum | Thu Dec 12 17:39:14 EST 2019 | davef
When I hear "pinholes" in solder connections, I think of two sources, depending on the situation, which can be either: + Entrapped air and process chemicals develop during reflow soldering to cause the pinholes in and around the intermetallic layer
Electronics Forum | Mon Nov 13 18:36:32 EST 2023 | emeto
Your reflow profile should be designed towards the flux in your solder paste. To form a proper inter-metallic layer, you need to reach 20-30C above your melting point and stay in liquidus state for certain amount of time. SAC 105 has 3C difference fr
Electronics Forum | Wed Aug 19 18:18:02 EDT 2009 | smt_guy
Thanks Sir Dave. Yeah my apologies. To clarify, we built the product PCB whcih has a Lead-Free HASL Finish using a Sn63/Pb37 Solder paste. My major concern regarding reliability is that my profile whish is between 215'C-225'C was insufficient to ref
Electronics Forum | Thu Mar 28 14:04:16 EST 2002 | davef
Intermetalic Layer (IL). A compound formed at the interface of two different metals, whose atoms have an extremely high natural attraction for each other, so high, that they do not bond to other elements by any other means. Also, intermetalic compo
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 | Thu Sep 07 08:50:45 EDT 2006 | Grant
Hi, We have seen a slight rise in failures in a product, and on investigation, the BGA ball has cracked off the PCB. It's below the intermetalic layer in the ball. Reflow otherwise looks good, and the raw components are clean. I am wondering what c
Electronics Forum | Tue Mar 09 22:26:17 EST 2004 | davef
You should to be soldering to the nickel. The intermetallic is Ni3Sn4. "At relatively low temperatures, the tin-nickel layers form about as rapidly as the tin-copper layers do, but at higher temperatures their growth rate is distinctly lower. At 10
