Spatial period division exposing

A method for producing grids which method includes the steps of exposing a substrate to X-ray radiant energy of wavelength .lambda. through a parent mask having a grid pattern of apertures, the widths of which are less than one half of the local spatial period p defined by X-ray absorbing material with sufficient attenuation to produce with the X-ray energy transmitted through said parent mask a sharp image on said substrate, and spacing said parent mask from said substrate a distance S substantially equal to p.sup.2 /n.lambda. where .lambda. is the wavelength of said X-radiation and n is an integer greater than one, to provide said image with an intensity pattern of period p/n on said substrate.

A method of producing a Fresnel zone pattern which method includes the steps of exposing a substrate to radiant energy of wavelength .lambda. through a parent mask having a pattern of Fresnel-zone concentric circular apertures, the widths of which are less than one half of the local spatial period, p, and spacing said parent mask from said substrate a distance S substantially equal to p.sup.2 /n.lambda. where .lambda. is the wavelength of said radiation and n is an integer greater than one, to provide an intensity pattern on said substrate having the form of a Fresnel zone pattern.

A method for producing gratings, grids and Fresnel-zone patterns which method includes the steps of exposing a substrate to radiant energy of wavelength .lambda. through a parent mask having a pattern of apertures in the form of a grating, a grid or a set of Fresnel zones, wherein the thickness of the material between the parent mask apertures is such that radiation passing through it suffers a differential phase shift that is an odd multiple of .pi. radians relative to radiation passing through the apertures.