PREPARATION OF PHASE SHIFT MASK

摘要

PURPOSE: To attain precise etch depth management by detecting a period in which the part of a first unmasked film is completely removed, stopping the etching of the part, and leaving the first masked film on the materials when it is inhibited. CONSTITUTION: A first part of a mask indicated by a bracket 1 is an RIM type phase shifting mask constituted of a 0 degree phase shift area 3 surrounding a 180 degree phase shift area 4. A second part of the mask indicated by a bracket 2 is a Levenson type phase shifting mask in which aπshift area 5 and a 0 shift area 6 are alternately continued. The etching of the masked substrate part of a phase shafting photolithography mask and the masked part of a monitor film are simultaneously carried out. A period in which the etching part of the monitor film is damaged is detected, and an etching stop period is decided. The residual film part remaining after the stop of the etching is arranged on the side wall of the phase shifting mask.