Heraeus Quarzglas Gmbh & Co Kg

Klaus Becker

Stephan Thomas

Stefan Ochs

Martin Trommer

Walter Lehmann

Jan Vydra

Andreas Langner

Michael Huenermann

Stefan Hengster

Michael Hünermann

Christian Schenk

Achim Hofmann

Andreas Kaske

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

Method for homogenizing glass

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. To enable a radial mixing within the shear zone in addition to the tangential mixing with the lowest possible time and energy input, starting from this method, cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being temporarily non-coaxial with each other.

A known method for homogenizing glass includes the following steps: providing a cylindrical blank composed of the glass, having a cylindrical outer surface which extends between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and moving the shear zone along the longitudinal axis of the blank. To reduce the risk of cracks and fractures during homogenizing, it is proposed that a thermal radiation dissipator is used that at least partially surrounds the shear zone, the lateral dimension of which in the direction of the longitudinal axis of the blank is greater than the shear zone and smaller than the length of the blank, the thermal radiation dissipator being moved synchronously with the shear zone along the longitudinal axis of the blank.

Method and device for homogenizing glass

One aspect relates to a method for producing an optical blank from synthetic quartz glass by vitrifying and shaping a porous, cylindrical SiOsoot body having a longitudinal axis, in a heating zone including a melt mold with bottom plate. The SiOsoot body vitrified in the heating zone at a vitrification temperature so as to form a full cylindrical, completely vitrified, transparent quartz glass body. Subsequently, the vitrified quartz glass body is shaped by softening in the melt mold at a softening temperature so as to form a viscous quartz glass mass which partly fills the volume of the melt mold, and cooling the quartz glass mass and removal from the melt mold so as to form the optical blank. During shaping in the melt mold, the full cylindrical quartz glass body is brought into contact by way of controlled supply with a centering means of the bottom plate.

Method for producing an optical blank from synthetic quartz glass

A substrate for an EUV mirror which contains a zero crossing temperature profile that departs from the statistical distribution is provided. A method for producing a substrate for an EUV mirror is also provided, in which the zero crossing temperature profile in the substrate is adapted to the operating temperature of the mirror. A lithography method using the substrate is also described.

Mirror blank for EUV lithography without expansion under EUV radiation

Common solar radiation receivers are equipped with a chamber for transmission of an operating gas which is directed along to an absorber for solar radiation for thermal absorption. The absorber has a dome-shaped entry window made of quartz glass, wherein the inner side facing the absorber assumes a nominal interior temperature Ti of at least 950&#xb0; C. during proper use, preferably at least 1000&#xb0; C., whereas the outer side facing away from the absorber is exposed to the environment and subject to risk of devitrification. The invention relates to modifying the known solar radiation receiver so that a high absorber temperature can be set and thus a high efficiency of the solar thermal heating is enabled, without increasing the risk of devitrification in the region of the outer side of the entry window.

Solar radiation receiver having an entry window made of quartz glass and method for producing an entry window

A method for producing a mirror substrate blank made from titanium-doped silica glass for EUV lithography, having a thickness of at least 40 millimeters, includes steps of face grinding the surface of the blank and identifying data on defects in a surface layer of the blank. Light penetrates the blank at a predetermined angle of incidence &#x3b1; of less than 90&#xb0; at a location on the flat surface of the blank. The light scatters on a defect in the blank, and the scattered light is detected at a distance x from the penetration location on the surface of the blank by a light detection element arranged perpendicularly thereabove. The method further includes steps of determining the position of the defect in the surface layer based on the obtained data, and partial or complete removal of the surface layer in consideration of the position determination and forming the mirror substrate blank.

Method for producing a mirror substrate blank of titanium-doped silica glass for EUV lithography, and system for determining the position of defects in a blank

The Tiions present in Ti-doped silica glass cause a brown staining of the glass, causing inspection of the lens to become more difficult. Known methods for reducing Tiions in favor of Tiions in Ti-doped silica glass include a sufficiently high proportion of OH-groups and carrying out an oxygen treatment prior to vitrification, which both have disadvantages. In order to provide a cost-efficient production method for Ti-doped silica glass, which at a hydroxyl group content of less than 120 ppm shows an internal transmittance (sample thickness 10 mm) of at least 70% in the wavelength range of 400 nm to 1000 nm, the TiO&#x2014;SiOsoot body is subjected to a conditioning treatment with a nitrogen oxide prior to vitrification. The blank produced in this way from Ti-doped silica glass has the ratio Ti/Ti5&#xd7;10.

Method for producing titanium-doped silica glass for use in EUV lithography and blank produced in accordance therewith

A method for producing a silica glass blank co-doped with titanium and fluorine for use in EUV lithography includes (a) producing a TiO&#x2014;SiOsoot body by flame hydrolysis of silicon- and titanium-containing precursor substances, (b) fluorinating the TiO&#x2014;SiOsoot body to form a fluorine-doped TiO&#x2014;SiOsoot body, (c) treating the fluorine-doped TiO&#x2014;SiOsoot body in a water vapor-containing atmosphere to form a conditioned soot body, and (d) vitrifying the conditioned soot body to form the blank. The blank has an internal transmission of at least 60% in the wavelength range of 400 to 700 nm at a sample thickness of 10 mm, a mean OH content in the range of 10 to 100 wt. ppm and a mean fluorine content in the range of 2,500 to 10,000 wt. ppm. Titanium is present in the blank in the oxidation forms Ti3and Ti.

Method for producing a blank of fluorine-doped and titanium-doped glass having a high silicic-acid content and a blank produced according to the method

A blank made of titanium-doped silica glass for a mirror substrate for use in EUV lithography is provided. The blank includes a surface portion to be provided with a reflective film and having an optically used area (CA) over which a coefficient of thermal expansion (CTE) has a two-dimensional inhomogeneity (dCTE) distribution profile averaged over a thickness of the blank. A maximum inhomogeneity (dCTE) of less than 5 ppb/K is defined as a difference between a CTE maximum value and a CTE minimum value. The dCTEis at least 0.5 ppb/K. The CA forms a non-circular area having a centroid. The dCTE distribution profile is not rotation-symmetrical and is defined over the CA, such that straight profile sections normalized to a unit length and extending through the centroid of the area yield a dCTE family of curves forming a curve band with a bandwidth of less than 0.5&#xd7;dCTE.

Blank made of titanium-doped silica glass and method for the production thereof

A blank of TiO&#x2014;SiOglass for a mirror substrate for use in EUV lithography has a low need for adaptation to optimize the progression of the coefficient of thermal expansion, and consequently also the progression of the zero crossing temperature T. The TiO&#x2014;SiOglass has at a mean value of the fictive temperature Tin the range between 920&#xb0; C. and 970&#xb0; C. a dependence expressed as the differential quotient dT/dTof its zero crossing temperature Ton the fictive temperature Tof less than 0.3.

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Hanau, Germany

Klaus Becker