The photoactive and development parameters of commercially availableg‐line photoresists which are TOKs OFPR800, OFPR5000, TSMR8900, and TSMR‐V3, were measured. From the simulated and experimental linewidth linearity data, it was found that the photoactive parameters have very little effect on the resolution power (linearity limit) of photoresists, while the development parameters (dissolution rate characteristics) greatly affect the resolution power. New indices, which can properly characterize the resolution power of photoresists, were extracted from the dissolution rate characteristics curves. One isCd, which is the contrast of the dissolution rate and the other isRd, which is the range of the dissolution rate. These indices are closely related to the resist resolution power. A largerCdorRdgives a higher resolution power to the photoresist. The necessary value ofCd⋅Rdfor the 0.5‐μm feature size photolithography process was derived from experimental data under the present highest NA(=0.55)g‐line stepper for mass production andCd⋅Rdmust be larger than 39. BothCdandRdare useful parameters for estimation of the photoresist resolution power.