JOSH,
Attempts to answer your question were written below.


On Oct 4, 11:19am, [log in to unmask] wrote:
> Subject: [TECHNET] Developing question
> Recently, I heard of a dry film photoresist developer system that uses
sodium
> hydroxide as a pH stabilizer.  Apparently, the system doses the
developer
> sump with  carbonate based on a panel counter,  and sodium hydroxide
based on
> solution pH.  The sodium hydroxide is used straight out of the drum,
probably
> at around 40 % strength.    I'm told this controls pH in a very tight
range,
> and reduces consumption of carbonate.
>
> I have some questions regarding a system of this type.
>
> 1.  What would the advantage be of using both chemicals?  Cost savings
don't
> seem to be too likely, since you are replacing one chemical with
another.
ANSWER: YOU CAN MAINTAIN TIGHTER pH CONTROL ON THE DEVELOPER SOLUTION
( CONSISTENT BREAKPOINT), LESS BAIL-OUT ( REDUCED WASTE AND CHEMICAL
COST), INITIAL COST WOULD BE MUCH LESS THAN CONVENTIONAL FEED & BLEED
SYSTEM.
>
> 2.  What are the potential dangers of using sodium hydroxide in a
developer?
ANSWER: AT THIS POINT I HAVEN'T SEEN ANY. WORSE CASE SCENARIO, YOU CAN
FLOOD THE SUMP WITH HYDROXIDE( IF THE pH PROBE OR PUMP IS DEFECTIVE)
WHICH MAY STRIP THE RESIST OR LEAD TO RESIST BREAKDOWN.

>  What effects could it have on photoresist?
ANSWER: SAME AS ABLOVE.
>
> 3.  Does the addition of sodium hydroxide cause bicarbonate to be
converted
> to carbonate?
ANSWER: YES, KOH OR NaOH WHEN ADDED TO THE DEVELOPER SOLUTION WILL
CONVERT BICARBONATE BACK TO ACTIVE CARBONATE.
>
> 4.  How many people are using this type of system in production?
ANSWER: WE HAVE IT IN OUR I/L DEVELOPER & PLANNING TO CONVERT OUR O/L
DEVELOPER INTO THE SYSTEM SOME TIME THIS YEAR.
>
> Thank you in advance for your assistance.
>
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