| 摘要 |
PURPOSE: A phosphorous acid processing bath for eliminating a nitride layer for manufacturing a semiconductor device is provided to stably control a process of the high temperature phosphorous acid processing bath, by preventing moisture inside the processing bath from leaking to maintain a uniform etching rate. CONSTITUTION: Mixed water of phosphorous acid and water is stored in an inner bath(1). An outer bath(2) is installed in an upper portion on both sides of the inner bath. A processing bath cover sheet block(3) of a spring driving type always applies winding power to a processing bath cover sheet by restoring force of a spring, installed in one side of the inner and outer baths. A driving motor for unfolding a cover sheet is installed in the other side of the upper portion of the inner and outer baths, facing the processing bath cover sheet block. A processing bath cover sheet is to be wound inside the processing bath cover sheet block. A connection string for unfolding the cover sheet is wound around a revolving axis when the driving motor revolves, to unfold the processing bath cover sheet, connected between both sides of an outer end portion of the processing bath cover sheet and a revolving axis of the driving motor.
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