Orthogonally separated phase shifted and unphase shifted mask patterns for image improvement
AssigneeInternational Business Machines Corporation
InventorBurn J. Lin
Life of this patent
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Abstract
A structure and fabrication method for an alternating-element phase-shifting mask (Alt PSM) wherein all the mask pattern components extending in a first direction, such as the x direction are formed on a first mask substrate and all the mask pattern components extending in a second direction orthogonal to the first direction, such as the y direction, are formed on a second mask substrate. The two mask substrates are either combined together in a single mask for a single exposure step on a wafer, or separate exposures may be made through each mask and superimposed on a single wafer.
Claims20
A phase-shifting lithographic mask system having a plurality of component materials disposed in a pattern, including x-direction components and y-direction components, wherein said x-direction is orthogonal to said y-direction, and wherein said x-direction components and said y-direction components both include first non-phase-shifting components and second, .pi. radian phase-shifting components, comprising a first mask layer including a first substantially transparent substrate wherein said first transparent substrate contains exclusively;
- only said first x-direction components wherein said first non-phase-shifting x-direction components and said second .pi. radians phase-shifting x-direction components are arranged alternately adjacent on said first transparent substrate;
- a second phase-shifting mask layer including a second substantially transparent substrate wherein said second transparent substrate contains exclusively;
- only said y-direction components wherein said first non-phase-shifting y direction components and said second .pi.-radian phase shifting y-direction components are arranged alternately adjacent on said second transparent substrate.
A method for fabricating a phase-shifting lithographic mask comprising the steps of:
- forming on a first layer of transparent material a first plurality of non-phase-shifting components disposed on said first layer alternately adjacent with a first plurality of .pi. radian phase shifting components, all of said components on said first layer of transparent material being disposed in a first linear direction and forming on a second layer of transparent material a second plurality of non-phase shifting components disposed on said second layer alternately adjacent with a second plurality of .pi. radian phase shifting components, all of said components on said second layer of transparent material being disposed in a second linear direction orthogonal to said first linear direction.
Dependencies are inferred from the claim text.