Method of forming a mask design having advanced oriented assist features for integrated circuit hole patterns

Abstract

A method of forming a mask for optically transferring a lithographic pattern having a plurality of isolated elements onto a semiconductor substrate, wherein spacing between these isolated elements is controlled according to a given pitch, the method comprising: disposing a plurality of assist features around each of the plurality of isolated elements, each assist feature near to a corner of one isolated element, each assist feature having a width, a length, a first separation parameter defining a distance between individual assist features, and a second separation parameter defining a distance between each of the plurality of assist features and each corresponding adjacent isolated element in the plurality of isolated elements; determining optimized values of the width, the length, the first separation parameter, and the second separation parameter; and setting an assist feature rule according to the given pitch and the optimized values.