Method for forming photoresist patterns

A method for forming a photoresist pattern, the method comprising:

• forming a first photoresist pattern on a substrate;
• coating an organic topcoat composition on the photoresist pattern, the organic topcoat composition comprising an acidic compound and an acrylic polymer comprising a structural unit comprising a hydroxy group and a fluorine;
• drying and heating the substrate on which the organic topcoat composition is coated to form a topcoat;
• and
• spraying a rinse solution consisting essentially of an ether-based compound or a combination of the ether-based compound and an alcohol-based compound ether-based compound on the substrate coated with the topcoat to remove the topcoat,
• wherein the acidic compound is a mixture of a sulfonic acidic compound comprising at least one fluorine and a sulfonimide compound comprising at least one fluorine, the sulfonic acidic compound comprising at least one fluorine is represented by Chemical Formula 3, and the sulfonimide compound comprising at least one fluorine is represented by Chemical Formula 4 or Chemical Formula 5:
• and
• wherein in Chemical Formula 3 to Chemical Formula 5,
• R7 to R9 are each independently a fluorine, a C1 to C20 alkyl group substituted with at least one fluorine, a C2 to C20 alkenyl group substituted with at least one fluorine, a C2 to C20 alkynyl group substituted with at least one fluorine, a C3 to C20 cycloalkyl group substituted with at least one fluorine, a C3 to C20 cycloalkenyl group substituted with at least one fluorine, a C3 to C20 cycloalkynyl group substituted with at least one fluorine, a C6 to C20 aryl group substituted with at least one fluorine, or a C1 to C20 heteroaryl group substituted with at least one fluorine, and
• L3 is a C1 to C10 alkylene group substituted with at least one fluorine, a C3 to C20 cycloalkylene group substituted with at least one fluorine, a C6 to C20 arylene group substituted with at least one fluorine, or a C1 to C20 heteroarylene group substituted with at least one fluorine.