Abstract: There is provided a method for forming microlenses in an image sensor having high light transmittance in short wavelength regions of visible lights, the method comprising: depositing a resist film for microlens over a predetermined substrate; selectively first-exposing the resist film to light in a range of exposure wavelengths and developing it to form resist patterns; second-exposing the remaining resist patterns to light photochemically to decompose an active form of sensitisizer remained in the resist patterns into an inactive form; and heating and flowing the resist patterns to form microlenses.