US 11,789,357 B2
Method of manufacturing reflective mask blank, and reflective mask blank
Yukio Inazuki, Joetsu (JP); Takuro Kosaka, Joetsu (JP); and Tsuneo Terasawa, Joetsu (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Feb. 22, 2021, as Appl. No. 17/181,026.
Claims priority of application No. 2020-035517 (JP), filed on Mar. 3, 2020.
Prior Publication US 2021/0278759 A1, Sep. 9, 2021
Int. Cl. G03F 1/24 (2012.01); C23C 14/34 (2006.01); G03F 1/58 (2012.01); H01L 21/033 (2006.01)
CPC G03F 1/24 (2013.01) [C23C 14/3464 (2013.01); G03F 1/58 (2013.01); H01L 21/0332 (2013.01); H01L 21/0337 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method of manufacturing a reflective mask blank comprising a substrate, a multilayer reflection film formed on one main surface of the substrate, and an absorber film formed on the multilayer reflection film, the multilayer reflection film consisting of at least two first layers and at least two second layers that are laminated alternatively, the first and second layers having different optical properties each other,
the method comprising the step of forming the first and second layers constituting the multilayer reflection film alternatively by a sputtering method, wherein
in the forming step of the first and second layers constituting the multilayer reflection film, each layer is formed by two stages consisting of a first stage applied from when the forming of said each layer is started and until a prescribed thickness is formed, and a second stage applied from when the prescribed thickness is formed and until the forming of said each layer is completed, and
in forming the second layer subsequent to forming the first layer, or in forming the first layer subsequent to forming second layer, a sputtering pressure of the first stage is set to higher than both a sputtering pressure at which the forming of the layer formed just before is completed, and a sputtering pressure of the second stage.