PURPOSE: To eliminate a possibility of generating pattern defects by residues and to produce the halftone type phase shift mask at a good yield by providing this process with an unnecessary product removing stage for removing the unnecessary products deposited as residues on a transparent substrate at the time of dry etching in a low transmittance layer forming stage before a high- transmittance layer forming stage.

CONSTITUTION: This process is provided with the unnecessary product removing stage for removing the unnecessary products 7a deposited as the residues on the transparent substrate 1 after the low-transmittance layer forming stage (c) by dry etching and before the high-transmittance layer forming stage (e). The reaction products 7a with an etching gas formed at the time of etching in the low-transmittance layer forming stage (c) are removed and, therefore, such a trouble that the dry etching is disturbed by the reaction products acting as a mask and that the residues remain at the time of dry etching of the material for a high-transmittance member (g) is prevented.