The invention relates to a method for producing a synthetic
quartz material for a
semiconductor mask plate. The method comprises the following steps: (1) depositing a
silicon source on a guide rod by adopting a
vapor phase axial deposition method to obtain a low-density SiO2 loose body; wherein in the
deposition process, the interior of the deposition cavity is controlled to be in a negative pressure environment, and the temperature is not higher than 500 DEG C; (2) transferring the low-density SiO2 loose body into a
sintering furnace, and heating to 1100-1300 DEG C in a closed environment filled with dehydroxylation
airflow and
oxygen so as to dehydrate the low-density SiO2 loose body; (3) in an
inert gas environment, introducing
fluorine-containing gas into the
sintering furnace, and heating to 1400-1600 DEG C, so that the low-density SiO2 loose body is vitrified to form transparent
quartz glass; in the
dehydration and
vitrification process, the low-density SiO2 loose body is kept not moving in the longitudinal direction, and the longitudinal and radial
temperature gradient in the deposition cavity is smaller than or equal to 2 DEG C; and (4) annealing the transparent
quartz glass to obtain the synthetic quartz material. According to the method disclosed by the invention, the continuity of the production process is high, and T170-193nm of the synthesized quartz product is greater than or equal to 95%.