| 摘要 |
PURPOSE:To eliminate the waste of time used for frequent replacement of the chemical liquid such as an etchant and the like as well as to prevent the lowering of working efficiency by a method wherein, after the frequency of uses of the chemical liquid reaches the prescribed value, a processing operation is performed by making allowance for the processing period using the chemical liquid in the extent of the period set in advance. CONSTITUTION:When a plurality of the substrates to be processed is etched successively using the same etchant, the difference between the target dimensions and the finished dimensions goes up rectilinearly in proportion to the quantity processed as shown by the curved line 30 in the diagram. When the curved line 30 reaches the first allowable upper limit processing quantity 31, the difference between the target dimension and the finished dimension reaches the upper limit value 32. When the upper limit processing quantity 31 is attained, the correction time with which the difference 33 of the target measurement and the finished measurement at that time becomes zero is added to the initial processing period of time. If an etching process is applied to the substrate to be processed in the above- mentioned added period of time, the difference between the target measurement and the finished measurement started from zero is increased proportionally in accordance with the quantity processed. Thus, if the processing period of time is increased at a fixed rate every time the upper limit processing quantity 31 is attained, the etchant can be used for a plurality of etching processes in excess of the service life.
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