There is disclosed a half-tone type phase shift mask comprising a transparent substrate on which a phase shift pattern and a chrome pattern, both provided with a window, are laminated in sequence, said window exposing a predetermined area of said transparent substrate therethrough, and said chrome pattern having a step near the window which is so thick as to permit penetration of only about 5 to 50% of an incident beam of light illuminated on said half-tone type phase shift mask. Such half-tone type phase shift mask is fabricated by: forming a phase shift layer on a transparent substrate; forming a light screen on the phase shift layer; selectively etching the light screen and the phase shift layer in sequence, to form a light screen pattern and a phase shift pattern, both provided with a window exposing a predetermined area of the transparent substrate; and removing the light screen pattern near said window at a predetermined thickness, to form a step near said window. It is capable of preventing the penetration of light at unintended areas, and thus is capable of providing a photosensitive pattern superior in smooth profile.