# US 2026/0091402 A1 · Deposition mask and method of manufacturing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0091402 A1 - Document ID: US20260091402A1 - Status: Published application - Kind: A1 - Application number: 19/188,554 - Filed: 2025-04-24 - Published: 2026-04-02 - Earliest claimed: 2024-10-02 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., LTD. - Inventors: Jeong Kuk KIM; Young Jin SONG; Sug Woo JUNG; Ji Hyun JUNG - Web page: https://patentgrep.com/patent/US20260091402A1 ## CPC - B05B 12/20: Masking elements, i.e. elements defining uncoated areas on an object to be coated - H10K 59/1201: {Manufacture or treatment} - H10K 59/12: Active-matrix OLED [AMOLED] displays - H10K 71/166: {using selective deposition, e.g. using a mask} - B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D) - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES ## Abstract Provided is a deposition mask including a mask substrate including a mask opening; a main coating film including a mask pattern overlapping the mask opening; and a pixel opening defined by the mask pattern, the mask pattern spaced apart from each other by the pixel opening, wherein the mask substrate includes: a first surface facing the main coating film; a second surface facing the first surface; a first side surface connected to the first surface; and a second side surface connecting the first side surface and the second surface, wherein the first side surface forms an undercut with the main coating film, and the mask substrate increases as being closer to the main coating film in a perpendicular direction to the mask substrate. ## Claims ### Claim 1 A deposition mask comprising: a mask substrate including a mask opening; a main coating film including a mask pattern overlapping the mask opening; and a pixel opening defined by the mask pattern, the mask pattern spaced apart from each other by the pixel opening, wherein the mask substrate includes: a first surface facing the main coating film; a second surface facing the first surface; a first side surface connected to the first surface; and a second side surface connecting the first side surface and the second surface, the first side surface forms an undercut with the main coating film, and the mask substrate increases as being closer to the main coating film in a perpendicular direction to the mask substrate. ### Claim 2 (depends on 1) The deposition mask of claim 1, wherein the first side surface is recessed toward the main coating film in an opposite direction in which the mask opening is disposed. ### Claim 3 (depends on 2) The deposition mask of claim 2, wherein the main coating film includes a side surface facing the mask opening, and the side surface of the main coating film is protruding toward the mask opening more than the first side surface of the mask substrate. ### Claim 4 (depends on 3) The deposition mask of claim 3, wherein the first surface and the second surface are connected by the first side surface and the second side surface. ### Claim 5 (depends on 4) The deposition mask of claim 4, wherein an inclination angle formed between the second surface and the second side surface includes at least one of an obtuse angle or right-angle. ### Claim 6 (depends on 1) The deposition mask of claim 1, wherein the main coating film is in contact with the first surface, the mask substrate includes silicon, and the mask substrate has a circular shape in a plan view. ### Claim 7 (depends on 1) The deposition mask of claim 1, wherein the mask pattern and the main coating film are disposed on a same line, the mask pattern and the main coating film includes a same material, and the mask pattern and the main coating film include silicon nitride. ### Claim 8 (depends on 1) The deposition mask of claim 1, wherein, in a portion overlapping the first side surface in a direction parallel to the mask substrate, the mask opening increases as being closer to the main coating film. ### Claim 9 (depends on 1) The deposition mask of claim 1, wherein the pixel opening and the mask opening are connected to each other. ### Claim 10 A method of manufacturing a deposition mask, the method comprising: forming a main coating film on a mask substrate and removing a portion of the main coating film to form a pixel opening; forming an auxiliary coating film on the mask substrate in a portion overlapping the pixel opening; removing a portion of the mask substrate to form a mask opening; and removing the auxiliary coating film to allow the pixel opening and the mask opening to be in connection with each other, wherein, in the forming of the auxiliary coating film, the auxiliary coating film is formed in plural numbers, and each of the auxiliary coating films is spaced apart from each other. ### Claim 11 (depends on 10) The method of manufacturing a deposition mask of claim 10, further comprising: forming a mask pattern overlapping the mask opening and defining the pixel opening, wherein the auxiliary coating films are spaced apart from each other with respect to the mask pattern. ### Claim 12 (depends on 11) The method of manufacturing a deposition mask of claim 11, wherein, in the forming of the auxiliary coating film, the auxiliary coating film is in contact with the main coating film and the mask pattern. ### Claim 13 (depends on 12) The method of manufacturing a deposition mask of claim 12, wherein the auxiliary coating film includes silicon oxide. ### Claim 14 (depends on 10) The method of manufacturing a deposition mask of claim 10, wherein, in the forming of the auxiliary coating film, the auxiliary coating film is formed by a thermal oxidation (WTO) process. ### Claim 15 (depends on 10) The method of manufacturing a deposition mask of claim 10, wherein, in the removing of the mask substrate and the auxiliary coating film, an etching process removing the mask substrate and the auxiliary coating film is performed in a rear direction of the mask substrate. ### Claim 16 An electronic device comprising: a display device formed using a deposition mask, the deposition mask comprising: a mask substrate including a mask opening; a main coating film including a mask pattern overlapping the mask opening; and a pixel opening defined by the mask pattern, the mask pattern spaced apart from each other by the pixel opening, wherein the mask substrate includes: a first surface facing the main coating film; a second surface facing the first surface; a first side surface connected to the first surface; and a second side surface connecting the first side surface and the second surface, the first side surface forms an undercut with the main coating film, and the mask substrate increases as being closer to the main coating film in a perpendicular direction to the mask substrate. ### Claim 17 (depends on 16) The electronic device of claim 16, wherein the first side surface is recessed toward the main coating film in an opposite direction in which the mask opening is disposed. ### Claim 18 (depends on 17) The electronic device of claim 17, wherein the main coating film includes a side surface facing the mask opening, and the side surface of the main coating film protrudes toward the mask opening more than the first side surface of the mask substrate. ### Claim 19 (depends on 18) The electronic device of claim 18, wherein the first surface and the second surface are connected by the first side surface and the second side surface. ### Claim 20 (depends on 19) The electronic device of claim 19, wherein an inclination angle formed between the second surface and the second side surface includes at least one of an obtuse angle or right-angle.