	US 11,987,521 B2
	Substrate for a reflective optical element
Eric Eva, Aalen (DE)
Assigned to CARL ZEISS SMT GMBH, Oberkochen (DE)
Filed by Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed on Dec. 29, 2020, as Appl. No. 17/136,642.
Application 17/136,642 is a continuation of application No. PCT/EP2019/068176, filed on Jul. 5, 2019.
Claims priority of application No. 102018211234.7 (DE), filed on Jul. 6, 2018.
Prior Publication US 2021/0116616 A1, Apr. 22, 2021
Int. Cl. C03C 3/06 (2006.01); G02B 5/08 (2006.01); G02B 7/18 (2021.01); C03C 17/40 (2006.01)

CPC C03C 3/06 (2013.01) [G02B 5/0891 (2013.01); G02B 7/181 (2013.01); C03B 2201/42 (2013.01); C03C 17/40 (2013.01); C03C 2201/21 (2013.01); C03C 2201/23 (2013.01); C03C 2201/42 (2013.01)]

19 Claims

1. A substrate for an optical element configured to reflect extreme ultraviolet wavelength light,

wherein the substrate is made of titanium-doped quartz glass that has a surface region configured to be coated, and

wherein the titanium-doped quartz glass has, at least in a vicinity of the surface region, a proportion of Si—O—O—Si bonds of at least 1*10¹⁶/cm³or a proportion of Si—Si bonds of at least 1*10¹⁶/cm³.