Our etcher have the "fine line" feature build in. But I just have some 
     doubt about this "feature". It works by enabling the adjustment of 
     pressure profile along the perpendicular axis of a panel. Typically, 
     the middle pressure is adjusted to a higher value than the side. 
     Ideally, this should reduce the puddling effect at the center part of 
     a panel. But, please look at the diagram below:
     
                _______________________________________
                |                                     |
                |    a            b               c   |
                |                                     |
                |                                     |
                |                                     |
                |                                     |
                |    d            e               f   |
                |                                     |
                |                                     |
                |                                     |
                |                                     |
                |    g            h               i   |
                ---------------------------------------
     
                        ------------------>
                        conveyor direction
     
     Now, the puddling usually occur at "e". By increasing the middle 
     pressure of the etcher, "d","e","f" is then subjected to high pressure 
     spray, while "a","b","c","g","h","i" are at low pressure spray. So the 
     fine line feature eliminates puddling effect at "e". Good, but how 
     about "d" and "f". This 2 positions do not have puddling under normal 
     condition, but are subjected to high pressure spray.
     
     And in reality, I discover that position "a" and "f" really are the 
     places where overetch usually occur.
     
     If anybody is also using an etcher with the fine line feature, please 
     tell me if you also have this problem. If so, how do you solve it?
     
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