Yes, It works  without sulfuric acid. Pre-dip removes extra  copper smut and gets contaminated with copper
faster. Then you have to change  PRE-DIP often  otherwise  more copper will be build up in catalyst by
drag. Keep watch on copper  content in catalyst. Change catalyst when copper >/= 1 g/l
Function of sulfuric acid is to minimise copper drag  towards catalyst.
Try  five  to six loads by ommiting sulfuric acid tank  with good rinse and create
confidence in what you are doing. It will be hardly a problem.

Thanks,

 Fulabhai Patel             [log in to unmask]


Eltek Ltd. - Process Engineering wrote:

> Hi !
> We are considering some changes in our vertical ( racks ) PTH line based on
> thin copper electroless . Today microetch section consists of :
> 1 ) microetch at following steady state operating conditions :sodium
> persulfate ( 40g/l) , sulfuric acid ( 60-80 gr/l) , dissolved copper ( 12 g/l )
> 2 ) flowing rinse
> 3 ) sulfuric acid post-dip ( 100 to 200 g/l )
> 4 ) flowing rinse
> 5 ) static catalyst pre-dip
> Due to lack of space in the line for some expansion I am considering
> cancelation of sulfuric acid post dip and the following rinse , since
> microetch solution allready has enough sulfuric acid .
> All opinions ( pro , contra ) will be very appreciated.
> Regards
> Edward Szpruch
> Eltek Ltd - Israel
> Tel  972 3 9395050
> Fax 972 3 9309581
> E-mail :  [log in to unmask]
>
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