# US 12,111,568 B2 · Mask reticle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,568 B2 - Document ID: US12111568B2 - Status: Granted - Kind: B2 - Application number: 17/449,809 - Filed: 2021-10-02 - Published: 2022-03-24 - Granted: 2024-10-08 - Earliest claimed: 2020-03-23 - Assignees: Changxin Memory Technologies, Inc. - Applicants: Changxin Memory Technologies, Inc. - Inventors: Yunsheng Xia - Web page: https://patentgrep.com/patent/US12111568B2 ## CPC - G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching} - G03F 1/42: Alignment or registration features, e.g. alignment marks on the mask substrates - G03F 9/00: Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically (G03F7/22 takes precedence; preparation of photographic masks G03F1/00; within photographic printing apparatus for making copies G03B27/00) - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract A mask includes a first boundary area and a plurality of exposure pattern areas, the first boundary area including a region surrounding the plurality of exposure pattern areas; in the first boundary area is disposed a plurality of first overlay mark units, each of which includes a plurality of overlay marks; the plurality of overlay marks are sequentially arranged along extension directions of adjacent transversal or longitudinal first boundary lines; a plurality of first overlay mark units are symmetric in pairs with a central line of the mask as a symmetric axis, and two symmetric first overlay mark units form an overlay mark set; arrangement directions of two overlay marks in the first overlay mark units in the same overlay mark set are parallel to and displaced with respect to each other. ## Claims ### Claim 1 A mask, comprising a first boundary area and a plurality of exposure pattern areas, the plurality of exposure pattern areas being arranged in an array, the first boundary area including a region surrounding the plurality of exposure pattern areas; wherein in the first boundary area is disposed a plurality of first overlay mark units, each of which includes a plurality of overlay marks, the first boundary area is provided with transversal and longitudinal first boundary lines corresponding to the plurality of exposure pattern areas arranged in an array, and the plurality of overlay marks are sequentially arranged along extension directions of adjacent transversal or longitudinal first boundary lines; and wherein the plurality of first overlay mark units are symmetric in pairs with a central line of the mask reticle as a symmetric axis, and two mutually symmetric first overlay mark units form an overlay mark set; arrangement direction of the overlay marks in one of the first overlay mark units in the same overlay mark set is parallel to arrangement direction of the overlay marks in another one of the first overlay mark units, and, on the arrangement directions of the overlay marks, one overlay mark in the first overlay mark units is displaced with respect to another overlay mark in the first overlay mark units. ### Claim 2 (depends on 1) The mask according to claim 1, wherein the first overlay mark unit includes at least one overlay mark subunit, each including a plurality of the overlay marks; and wherein on the arrangement directions of the overlay marks, the overlay mark subunit in one of the first overlay mark units in the same overlay mark set is displaced with respect to the overlay mark subunit in another one of the first overlay mark units. ### Claim 3 (depends on 2) The mask according to claim 2, wherein each overlay mark subunit includes three to five overlay marks. ### Claim 4 (depends on 1) The mask according to claim 1, wherein taking the length of the first boundary area perpendicular to the direction of the adjacent transversal or longitudinal first boundary lines as L1, and taking the length of the contour of the overlay mark perpendicular to the direction of the transversal or longitudinal first boundary line as D1, L1 and D1 satisfy the relational expression: D1≤L1≤2D1. ### Claim 5 (depends on 1) The mask according to claim 1, further comprising a second boundary area that includes a region between any two of the exposure pattern areas; wherein in the second boundary area is disposed a plurality of second overlay mark units, each of which includes a plurality of overlay marks; and wherein the second boundary area is provided with transversal and longitudinal second boundary lines corresponding to the plurality of exposure pattern areas arranged in an array, and the plurality of overlay marks are sequentially arranged along extension directions of adjacent transversal or longitudinal second boundary lines. ### Claim 6 (depends on 5) The mask according to claim 5, wherein the plurality of overlay marks in each of the second overlay mark units are sequentially arranged along a straight line, and the straight line is parallel to the second boundary lines. ### Claim 7 (depends on 5) The mask according to claim 5, wherein taking the length of the second boundary area perpendicular to the direction of the adjacent transversal or longitudinal second boundary lines as L2, and taking the length of the contour of the overlay mark perpendicular to the extension direction of the second boundary line as D2, L2 and D2 satisfy the relational expression: 4D2/3≤L2≤2D2. ### Claim 8 (depends on 7) The mask according to claim 7, wherein in the second boundary area, each of the second overlay mark units includes at least two overlay mark subunits, each of which includes a plurality of the overlay marks; and wherein the at least two overlay mark subunits in each second overlay mark unit are sequentially arranged along two straight lines, the two straight lines are parallel to each other, and both are parallel to the second boundary line; on the arrangement directions of the overlay marks, the overlay mark subunits respectively on the two straight lines are displaced with respect to each other. ### Claim 9 (depends on 1) The mask according to claim 1, wherein the first boundary area includes four sides, every two opposite the other, and the first overlay mark units are disposed on at least two end positions of each side. ### Claim 10 (depends on 1) The mask according to claim 1, wherein the number of columns of the plurality of exposure pattern areas arranged in an array are at least two, and the number of rows thereof are at least five.