Photosensitive novolac resin, positive photosensitive resin composition including same, photosensitive resin film prepared by using the same, and semiconductor device including the photosensitive resin film

A positive photosensitive resin composition comprising:

• (A) a polybenzoxazole precursor including a structural unit represented by the following Chemical Formula 3, a structural unit represented by the following Chemical Formula 4, or a combination thereof;
• (B) a photosensitive novolac resin comprising a structural unit represented by the following Chemical Formula 1 and a structural unit represented by the following Chemical Formula 2;
• and
• (C) a solvent:
• wherein, in Chemical Formulae 3 and 4,
• X1 is independently a substituted or unsubstituted C6 to C30 aromatic organic group or a substituted or unsubstituted C1 to C30 alicyclic organic group,
• X2 is independently a substituted or unsubstituted C6 to C30 aromatic organic group, a substituted or unsubstituted C3 to C30 alicyclic organic group, or a functional group represented by the following Chemical Formula 5,
• Y1 and Y2 are the same or different and are independently a substituted or unsubstituted C6 to C30 aromatic organic group or a substituted or unsubstituted C3 to C30 alicyclic organic group, and
• when the mol % of the structural unit of Chemical Formula 3 is m, and the mol % of the structural unit of Chemical Formula 4 is n in the polybenzoxazole precursor, and m+n is 100 mol %,
• m ranges from about 60 mol % to about 95 mol %, and n ranges from about 5 mol % to about 40 mol %,
• wherein, in Chemical Formula 5,
• R21 to R24 are the same or different and are independently hydrogen, substituted or unsubstituted C1 to C30 alkyl, substituted or unsubstituted C6 to C30 aryl, substituted or unsubstituted C1 to C30 alkoxy, or hydroxy,
• R25 to R26 are the same or different and are independently a single bond, substituted or unsubstituted C1 to C30 alkylene, or substituted or unsubstituted C6 to C30 arylene, and
• k is an integer ranging from 1 to 50,
• wherein, in Chemical Formulae 1 and 2,
• R11 and R12 are the same or different and are independently hydrogen or a quinone diazide sulfonyl group, wherein 50% or more of R11 and R12 in the photosensitive novolac resin is a quinone diazide sulfonyl group,
• R13 and R14 are the same or different and are independently C1 to C7 alkyl, and
• when the number of the structural unit of Chemical Formula 1 is x, and the number of the structural unit of Chemical Formula 2 is y in the photosensitive novolac resin,
• x+y ranges from about 2 to about 30, and x/(x+y) ranges from about 0.6 to about 0.95.