Abstract: A system, method, and software to form photoresist resin which has a more uniform distribution of polymers are disclosed. In one embodiment, the method includes introducing a first monomer into a reaction vessel; introducing a second monomer into the reaction vessel; and introducing an initiator into the reaction vessel to cause a polymerization of the first and second monomers, wherein the introducing the first and second monomers into the reaction vessel is performed in a manner that a concentration ratio of the first and second monomers is a function of a predetermined inverse relationship to a reactivity ratio of the first and second monomers. In another embodiment, the method includes introducing an initiator into the reaction vessel to cause a living or pseudo-living polymerization of the first and second monomers.