| 摘要 |
PROBLEM TO BE SOLVED: To enable a time that grooves located at various positions on the surface of a wafer are all etched to be effectively determined by a method wherein that points located on a moving interface are located out of a matter region where the points are situated before the interface moves is recognized from a per-unit time change of the volume variation of a matter region in time dependence. SOLUTION: An etching volume calculating section which calculates an amountΔA of material etched in a micro timeΔt so as to obtain an amount (ΔA/Δt) of material etched in a unit time. When a BPSG film 405 is etched, boundary points located on a moving surface are shown as points P1 -R0 -P2 . On the other hand, when an etching operation is justly carried out, the point R0 moves to the point P2 , and the point P2 is located out of a region which is corresponding to the BPSG film 405. Therefore, an all etching detecting section detects all etching judging thatΔA/Δt becomes constant (micro variation is below allowable error) afterΔA/Δt becomes zero or an etching operation is justly carried out.
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