I have worked with Dexter's Autosolver using their proprietary developing
chemistry and also with Surface Tech's AQ-80 controller using Resolve 211
developer.
Both systems use pH to steady-state control the developer.  The initial
pH setting you use very much affects the conveyor speed or breakpoint. 
Once set, the speed becomes very constant.  

pH controllers can be used with generic carbonate to maintain a steady
resist loading and hence a steady speed.  However, both of the
chemistries mentioned contain proprietary ingredients that dramatically
reduce the tendancy for the developer to coat the inside of the machine
with scale.  These also help keep the pH probe from fouling and prevent
drift.


On Wed, 3 Jul 1996 16:45:25 +0400 (EDT) <[log in to unmask]> writes:
>Our process engineer for developing and I have been discussing ways to 
>
>improve that process.  He wants to see if developing solution pH can 
>be 
>used to set developer speed.  Is this possible? Anyone else doing 
>this?  
>We also are looking for ways to use SPC to improve in this process.  
>Anyone want to work with us or discuss this?
>
>Lou Hart    Quality Assurance   Compunetics 412-858-6117>

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