Electronics Forum | Thu Oct 28 18:14:51 EDT 1999 | John Thorup
Try looking for paste contamination somewhere. Dirty stencil, printer table or fixtures. Placement table/fixtures. Reflow belt/conveyer. Reuseable finger covers, if used. Try covering the fingers with Kapton tape during different stages of the proc
Electronics Forum | Mon Jul 27 17:09:20 EDT 1998 | Rin
| We are trying to reduce the number of units fail at system test due to flux on gold finger. We know so far that the flux is deposited onto the | goldfinger during touch-up or rework and to reduce the contamination we are | planning to imp
Electronics Forum | Mon May 18 17:59:06 EDT 1998 | Richard Jackson
I've tried every thing I can think of. Do you have any Ideas? What I have is micro balls on the gold fingers of panelize boards. These balls only appear on the gold finger. Or at least I can only find them on the gold fingers. What I have tried so
Electronics Forum | Sun Jul 26 22:35:55 EDT 1998 | D.Lange
Masdi, Try board shunts. They are hi-temp rubber strips with grooves cut. They can be popped on and off with ease and are much faster than taping and considerably cheaper. They also work great for masking goldfingers prior to wave soldering. Contac
Electronics Forum | Fri Aug 17 11:55:31 EDT 2001 | davef
5uin. Your nickel thickness is fine. Although if you wanted to trade costs, consider giving-up nickel to 150uin thickness, while increasing the gold thickness. Gold over electroless nickel creates brittle joints because of phosphorous in the nicke
Electronics Forum | Thu Sep 21 17:50:43 EDT 2000 | Bill Boles
Does anyone have a quick reminder for a PCB with immersion gold surface finnish going through a reflow profile: Which of the following statements is more correct? A: In order to minimize gold in the intermetallics of the solder joint, the board temp
Electronics Forum | Mon Aug 27 15:06:29 EDT 2001 | davef
This otta push Wolfgang over the top ... Recommended reading G.G. Harman, Wire Bonding in Microelectronics : Materials, Processes, Reliability, and Yield, 2nd edition, McGraw-Hill Electronic Packaging and Interconnection Series, 1997. G.G. Harman, R
Electronics Forum | Thu Oct 28 09:25:35 EDT 1999 | Dave F
Chris: Typical non-wetting causes are: * Poorly controlled soldering process * Incorrect material * Surface contamination * Insufficient preheat * Misapplied solder mask * Shadowing Without intending to insult you, all of the causes of non-w
Electronics Forum | Thu Oct 28 20:45:38 EDT 1999 | chris
Hi Dave, We suspect that the organic FM causes the non-wetting problem. FTIR analysis confirm that the FM is a flux residue. Dave we only used FTIR to detect organic contaminants, we also used SEM/EDX to determined the elemental composition of the
Electronics Forum | Wed Jan 09 18:17:15 EST 2002 | Chris
I don't have a plasma cleaner either. It will help a lot. Actually I don't clean at all. Our wirebond pads are far enough away so the flux residue does not get on the wirebond pads. That's what we think anyway. I am sure we have some degree of c
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