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 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.
• 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.