Method for creating and preserving alignment marks for aligning mask layers in integrated circuit manufacture

A method for creating and preserving alignment marks used for aligning mask layers in the formation of integrated circuits on semiconductor wafers comprising the steps of:

• a) creating a plurality of alternating parallel lines and spaces in a reference layer to form a basic alignment mark;
• b) creating another plurality of alternating lines and spaces in said reference layer to form a preservation pattern in any layer which functions as a contact layer wherein the preservation pattern is overlapping said basic alignment mark and positioned in a substantially perpendicular direction to said basic alignment mark;
• and
• c) etching said preservation pattern at each contact layer to form a substantially checkerboard pattern with said basic alignment mark such that portions of said basic alignment mark are recessed within said reference layer.

A method for creating and preserving alignment marks for proper alignment of mask layers in integrated circuit manufacture comprising:

• a) forming a first set of marks from at least one of a contact and via formed within an oxide layer deposited on a substrate;
• b) forming a second set of marks in said oxide layer at said at least one of a contact and via wherein said second set of marks a plurality of lines and spaces overlapping said first set of marks in a substantially perpendicular direction;
• c) etching said oxide layer such that said first and second sets of marks together form a checkerboard-type pattern such that segments of said first set of marks remain recessed within said oxide layer;
• d) depositing a first metal layer over said oxide layer thereby filling any open recesses contained within said checkerboard-type pattern;
• e) planarizing said first metal layer;
• f) aligning said recessed segments of said first set of marks with corresponding alignment marks;
• and
• g) depositing a second metal layer over said first metal layer and said oxide layer.