The invention discloses a preparation method of a
halftone photomask, which comprises the following steps: S1, a binary
mask substrate is subjected to
laser photoetching, and a pattern opening on the substrate comprises a binary
mask area and a
halftone mask area; s2, developing and
etching the substrate, removing the
photoresist, and cleaning the substrate; s3,
coating an
ultraviolet light curing adhesive; s4, carrying out
ultraviolet laser photoetching on a binary mask region; s5, developing and removing the uncured protection area; and S6, depositing a
halftone layer. According to the preparation method disclosed by the invention, the damage to the binary mask
chromium layer in the halftone film layer
deposition process is reduced, the process yield is improved, the halftone mask region is photoetched, and the binary mask region and the mask region are photoetched at the same time, so that the process flow is simplified, and the process does not need to be returned to a factory for secondary
photolithography after being sent out for
coating, thereby shortening the process and improving the production efficiency. The nesting precision and the line precision of the halftone mask plate product are improved, the product quality is improved, and the production efficiency is improved.