The present invention provides a semiconductor memory device and a fabrication method capable of preventing the contact between a dielectric layer of a capacitor and a diffusion barrier. The projection exposure apparatus includes a storing device for storing information related to light intensity distribution on a pupil plane of the projection optical system in a reference state, and a detecting device for detecting a wavefront of the projection optical system in an arbitrary state, on the basis of the stored information. Responsive to the detected freed block being a previously written block in the COW storage, the previously written block in the COW storage is deleted from the COW storage. Predistortion of the input signal results in reception of an output signal at the second location that closely approximates the desired target signal.