Reticle with phase-shifters and a method of fabricating the same

A method of fabricating a reticle for projecting a fine pattern onto an object surface, the reticle comprising a transparent substrate having a light transparent area of plural light transmissive regions, the regions producing relative phase differences of incident light transmitted therethrough relative differences in the respective thicknesses of the regions, the method comprising the steps of:

• (a) depositing a transparent layer on said substrate, the thickness of the transparent layer being selected so as to produce a desired phase difference between light transmitted through said substrate in a light transmissive region thereof without said transparent layer and light transmitted through said substrate in a light transmissive region thereof with said transparent layer thereon;
• (b) selectively removing a portion of said transparent layer in accordance with a prescribed pattern and thereby to define, in the light transparent area and in accordance with the prescribed pattern, a first light transmissive region having both said substrate and said transparent layer and a second light transmissive region having said substrate only;
• and
• (c) where an amount of the transparent layer beyond that defined by the prescribed pattern is removed but which was to have been retained, constituting a defective transparent layer area portion, selectively removing a portion of said substrate, corresponding to the defective transparent layer area portion, so as to form a groove of a selected depth in said substrate and thereby define, in the light transparent area, a third light transmissive region corresponding to said groove and wherein light transmitted through said third light transmissive region is in substantially the same phase as light transmitted through said first light transmissive region.

A method of fabricating a reticle for projecting a fine pattern onto an object surface, the reticle comprising a transparent substrate having a light transparent area of plural light transmissive regions, the regions producing relative phase differences of incident light transmitted therethrough as a function of relative differences in the respective thicknesses of the regions, the method comprising the steps of:

• (a) forming a first groove in said substrate in accordance with a prescribed pattern and thereby defining a first light transmissive region of the light transparent area contiguous the first groove, the depth of the first groove being selected so as to produce a desired phase difference between light transmitted through said first light transmissive region and light transmitted through said substrate in the portion thereof defined by said first groove, removal of any amount of the substrate exceeding the prescribed pattern producing a defective substrate portion;
• and
• (b) forming a second groove in said first groove, thereby defining a second transparent region corresponding to the remaining area of said first groove and a third transparent region corresponding to the area of said second groove and thereby to the defective portion of the substrate, the depth of the second groove being selected such that light transmitted through said third transparent region is in the same phase as light transmitted through said first transparent region.