On Tue, 13 Feb 96 14:10:04 PST dhoppe wrote:

> From: dhoppe <[log in to unmask]>
> Date: Tue, 13 Feb 96 14:10:04 PST
> Subject: Fungal contamination
> To: [log in to unmask]
> 
>      Has anyone had any exposure to fungal growths in thier plating line 
>      rinse tanks (especially after the acid cleaner).  This hyphae is quite 
>      hearty and nothing seems to kill it.  It is not an algae.  I've even 
>      tried glutaraldehyde, a common antifoulant used in the metal finishing 
>      industry, to no avail.  What does anybody say?
>      
>      Don Hoppe Jr.
>      ZYCON
>      [log in to unmask]							
									
									
									
	Don:I've seen this same problem with acid cleaners when used in a 
preclean line for dry film resist prior to pattern plate(don't know if this 
is your application).Many acid cleaners contain surfactants and organic acids 
when these combine with resist residue and incoming rinse water these types 
of growths can occur.							
	One thing that has worked for me in the past was to use spent 
microetch.If you are using a persulfate(potassium or sodium)based chemistry 
the combination of the oxidizing potential of the persulfate and the 
anti-fungal properties of the copper can knockout most of this stuff.	
	Fill the tank up with microetch let it sit 6-12hrs. drain and scrub 
with same chemistry rinse and drain thoroughly. Good Luck.		
									
					Regards				
					Michael Barmuta			
					Staff Engineer			
					Fluke corp.			
					Everett Wa.			
					206-356-6076