This invention provides novel PF1270A substance, PF1270B substance and PF1270C substance represented by the following formula or pharmaceutically acceptable salts thereof, a method for producing the same and a pharmaceutical composition which comprises at least one of the same as the active ingredient. A first verification may be performed to verify erased states of the memory cells using a first verify voltage different than a second verify voltage. They are favorably used as miscibility improvers for propylene homopolymers and propylene-based copolymers. The method may also include altering at least one parameter of a process module configured to perform a step of the lithography process to reduce within wafer variation of the critical metric.