A method of forming a reticle includes: loading a blank reticle; projecting an electron beam; moving a second aperture plate having a first pattern aperture and a second pattern aperture so that the first pattern aperture is directly overlapped by a first aperture of a first aperture plate, the electron beam passing through the first pattern aperture after passing the first aperture; exposing the blank reticle with the electron beam after the electron beam passes the first pattern aperture, to form a first exposure pattern; moving the second aperture plate so that the second pattern aperture is directly overlapped by the first aperture of the first aperture plate, the electron beam passing through the second pattern aperture after passing the first aperture; exposing the blank reticle with the electron beam after the electron beam passes the second pattern aperture, to form a second exposure pattern; and developing the blank reticle having the first and second exposure patterns to form the reticle having first and second patterns.