SUB-MICRON DEVICE FABRICATION

摘要

Expedient fabrication of phase masks providing for many values of phase delay for exiting pattern delineating radiation depends upon a two-step procedure. Such masks offer improvement in ultimate device fabrication relative to that offered by prior binary-valued masks. In the first step, which may be carried out coincident with introduction of device feature information, apertures of appropriate size and distribution are produced in the relevant mask layer; in the second step material surrounding such apertures is heated to result in backflow-filling. The consequential layer thinning is such as to introduce the desired local change in phase delay.