The invention discloses a preparation method of resin for
photoresist. The preparation method is characterized in that the resin is prepared by the steps of dissolving one or more monomers with acid active groups and one or more monomers with polar groups into a
solvent containing a certain amount of
moisture, and carrying out ATRP reaction in the presence of an initiator. The preparation method comprises the following steps: (1) heating the
solvent containing a certain amount of
moisture to 50-80 DEG C, so as to obtain a preheated
organic solvent containing
moisture; (2) dissolving the monomers and an initiator into the
organic solvent containing the same moisture with the
organic solvent in the step (1), so as to obtain a
raw material solution; (3) dropwise adding the
raw material solution into the preheated organic
solvent containing moisture, and carrying out content-temperature
reflux reaction at 50-80 DEG C for 10-30 hours; and (4) cooling to the
room temperature, precipitating resin with a non-polar solvent, filtering, and
drying, so as to obtain the resin for the
photoresist, wherein the moisture content in the solvent is 1ppm-1500ppm. According to the preparation method, the molecular weight of the
polymer resin is regulated through the regulation of the
water content, so that other impurities are not introduced, and the control of the molecular weight is relatively precise.