BGA washing & Surfactant Packs?

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I am starting to use BGAs more and more in our process, whic... - Mar 20, 2002 by

Surfactant. A synthetic detergent made from petrochemicals ... - Mar 20, 2002 by davef

Aaron C

#19200

BGA washing & Surfactant Packs? | 20 March, 2002

I am starting to use BGAs more and more in our process, which is using water soluble paste. Taking to the Paste Rep, he had pointed out that if you add Surfactant Packs to your inline water wash, that it would help get the water underneath the BGA package and clean away any residue.

I think that these surfactant packs reduce the water tension and allows it to "squeeze" under the BGA package.

Perfect world would say I use a "No-Clean" process, but, we are not there just yet in using those pastes.

Has anyone had any experience with these surfactant packages? I am using Reverse Osmosis (RO) water wash, not DI water. Any ideas where I might get this? Com-Kyl perhaps? (Haven't tried them yet)

Thanks, Aaron

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davef

#19212

BGA washing & Surfactant Packs? | 20 March, 2002

Surfactant. A synthetic detergent made from petrochemicals that lowers the surface tension of water and allows better cleaning in small spaces.

Do you have a cleaning issue that requires you to use a surfactant? If so, be aware that you must clean the surfactant in additon to your flux residue. The wetting agents and surfactants are non-ionic materials that are not detected by the Omegameter [or Ionigraph], which only measures the concentration of the ionic materials that are soluble in a alcohol-water solution.

However, these non-ionic residues tend to attract and absorb water onto the surface of the board. As the water is absorbed, it polarizes. When a voltage deferential is applied across two adjacent traces, the water ionizes forming a plating solution and dendrites can grow and develop a short. So, even though your board appears clean according to the Omegameter [or Ionigraph], it is actually a potential problem when it gets to the field.

Your washer and RO suppliers may be good starting points for your search.

[NOTE: The current thread on hand lotions is a nice analog to this thread.]

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