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KR-102962935-B1 - GLASS CERAMIC HAVING SPECIFIC THERMAL EXPANSION CHARACTERISTICS

KR102962935B1KR 102962935 B1KR102962935 B1KR 102962935B1KR-102962935-B1

Abstract

The present invention relates to glass ceramics with improved thermal expansion properties and their use in precision parts.

Inventors

  • 미트라 이나
  • 클라우쎈, 올라프
  • 쿠니쉬 클레멘스
  • 까레 앙투안

Assignees

  • 쇼오트 아게

Dates

Publication Date
20260508
Application Date
20220315
Priority Date
20210316

Claims (20)

  1. As a LAS glass ceramic, Having an average coefficient of thermal expansion CTE of 0 ± 0.1 × 10⁻⁶ /K or less in the range of 0 to 50°C and thermal hysteresis of < 0.1 ppm in a temperature range of at least 10°C to 35°C, and the following components (in mol% based on oxides): SiO2 60 - 71 Li₂O₇ - 9.4 MgO+ZnO 0 - < 0.6 B 2 O 3 0 - 0.1 Fluorine 0 - 0.1 A component selected from the group consisting of P₂O₅ , R₂O , and RO, wherein R₂O may be at least one of Na₂O , K₂O , Cs₂O , and Rb₂O , and RO may be at least one of CaO, BaO, and SrO; and TiO2 , ZrO 2 , A nucleating agent having a content of 1.5 to 6 mol%, which is at least one component selected from the group consisting of Ta₂O₅ , Nb₂O₅ , SnO₂ , MoO₃ , WO₃ , and HfO₂ . LAS glass ceramic comprising, and containing 0.05 mol% or less of As₂O₃ as a purifying agent.
  2. In claim 1, (i) Al₂O₃ with a content of 10 to 22 mol% or 11 to 21 mol % , or (ii) P₂O₅ with a content of 0.1 to 6 mol% or 0.3 to 5 mol%, or (iii) LAS glass ceramic containing both (i) and (ii).
  3. In claim 1 or 2, (i) the total content of ZnO + MgO is ≤ 0.55 mol%, or ≤ 0.5 mol%, or ≤ 0.45 mol%, or ≤ 0.4 mol%, or ≤ 0.3 mol%, or ≤ 0.2 mol%, or (ii) the content of MgO is ≤ 0.35 mol%, or ≤ 0.3 mol%, or ≤ 0.25 mol%, or ≤ 0.2 mol%, or ≤ 0.1 mol%, or (iii) the content of ZnO is ≤ 0.5 mol%, or ≤ 0.45 mol%, or ≤ 0.4 mol%, or ≤ 0.3 mol%, or ≤ 0.2 mol%, or ≤ 0.1 mol%, or (iv) a combination of (i) and (ii), or (v) of (i) and (iii). LAS glass ceramic that is a combination of (vi) (ii) and (iii) or (vii) a combination of (i) to (iii).
  4. LAS glass ceramic according to claim 1 or 2, wherein the SiO2 content is ≤ 70 mol%, or ≤ 69 mol%, or ≤ 68.5 mol%.
  5. LAS glass ceramic according to claim 1 or 2, wherein the total RO (CaO + BaO + SrO) content is (i) ≥ 0.1 mol%, or ≥ 0.2 mol%, or ≥ 0.3 mol%, or ≥ 0.4 mol%, or (ii) ≤ 6 mol%, or ≤ 5 mol%, or ≤ 4.5 mol%, or ≤ 4.0 mol%, or ≤ 3.8 mol%, or ≤ 3.5 mol%, or ≤ 3.2 mol%, or (iii) (i) and (ii).
  6. LAS glass ceramic according to claim 1 or 2, wherein the total R₂O ( Na₂O + K₂O + Cs₂O + Rb₂O ) content is (i) ≥ 0.1 mol%, or ≥ 0.2 mol%, or ≥ 0.3 mol%, or ≥ 0.4 mol%, or (ii) ≤ 6 mol%, or ≤ 5 mol%, or ≤ 4 mol%, or ≤ 3 mol%, or ≤ 2.5 mol%, or (iii) (i) and (ii).
  7. LAS glass ceramic according to claim 1 or 2, wherein the total content of the nucleating agent is (i) ≥ 1.5 mol%, or ≥ 2.5 mol%, or ≥ 3 mol%, or (ii) ≤ 6 mol%, or ≤ 5 mol%, or ≤ 4.5 mol%, or ≤ 4 mol%, or (iii) (i) and (ii).
  8. In claim 1 or 2, (i) the following condition: molar content of SiO₂ + (5-fold molar content of Li₂O ) ≥ 106, or molar content of SiO₂ + (5-fold molar content of Li₂O ) ≥ 107.5 is applicable, or (ii) the following condition: molar content of SiO₂ + (5-fold molar content of Li₂O ) ≤ 115.5, or molar content of SiO₂ + (5-fold molar content of Li₂O ) ≤ 114.5 is applicable, or (iii) both (i) and (ii) are LAS glass ceramics.
  9. LAS glass ceramic according to claim 1 or 2, wherein the processing temperature Va is 1330℃ or lower, or 1320℃ or lower.
  10. A LAS glass ceramic according to claim 1 or 2, wherein (i) the main crystal phase is a high quartz solid solution, or (ii) the main crystal phase is a high quartz solid solution and the average crystallite size of the high quartz solid solution is < 100 nm, or < 80 nm, or < 70 nm, or (iii) the crystal phase content is less than 70 volume%, or (iv) both of (i) and (iii), or (v) both of (ii) and (iii).
  11. LAS glass ceramic according to claim 1 or 2, wherein the exponent F is < 1.2, or < 1.1, or 1.05 or less, and F = TCL (0; 50℃)/|expansion (0; 50℃)|.
  12. LAS glass ceramic according to claim 1 or 2, wherein (i) the replacement index f (20;40) is < 0.024 ppm/K, or (ii) the replacement index f (20;70) is < 0.039 ppm/K, or (iii) the replacement index f (-10;30) is < 0.015 ppm/K, or (iv) a combination of (i) and (ii), or (v) a combination of (i) and (iii), or (vi) a combination of (ii) and (iii), or (vii) a combination of (i) to (iii).
  13. A LAS glass ceramic according to claim 1 or 2, wherein (i) the relative change in length (dl/l 0 ) is ≤ |0.10| ppm, or ≤ |0.09| ppm, or ≤ |0.08| ppm, or ≤ |0.07| ppm within a temperature range of 20°C to 30°C, or (ii) the relative change in length (dl/l 0 ) is ≤ |0.17| ppm, or ≤ |0.15| ppm, or ≤ |0.13| ppm, or ≤ |0.11| ppm within a temperature range of 20°C to 35°C, or (iii) both (i) and (ii).
  14. LAS glass ceramic according to claim 1 or 2, wherein the relative change in length (dl/l 0 ) is ≤ |0.30| ppm, or ≤ |0.25| ppm, or ≤ |0.20| ppm, or ≤ |0.15| ppm within a temperature range of 20°C to 40°C.
  15. LAS glass ceramic according to claim 1 or 2, wherein the CTE-T curve within a temperature interval having a width of at least 30 K has a slope of ≤ 0 ± 2.5 ppb/ K2 , or ≤ 0 ± 2 ppb/ K2 , or ≤ 0 ± 1.5 ppb/K2, or ≤ 0 ± 1 ppb/ K2 .
  16. LAS glass ceramic according to claim 1 or 2, having thermal hysteresis < 0.1 ppm within a temperature range of at least 5°C to 45°C, or at least > 0°C to 45°C, or at least -5°C to 50°C.
  17. LAS glass ceramic according to claim 1 or 2, containing As₂O₃ in a content of ≤ 0.04 mol%, or ≤ 0.03 mol%, or ≤ 0.02 mol%, or ≤ 0.01 mol%, or ≤ 0.005 mol%.
  18. LAS glass ceramic according to claim 1 or 2, wherein, as a purifying agent, instead of As 2 O 3 or in addition to 0.05 mol% or less of As 2 O 3 , (i) at least one alternative redox purifying agent, or (ii) at least one evaporative purifying agent, or (iii) at least one decomposition purifying agent, or (iv) a combination of (i) and (ii), or (v) a combination of (i) and (iii), or (vi) a combination of (ii) and (iii), or (vii) a combination of (i) to (iii).
  19. In claim 18, the LAS glass ceramic is wherein (i) an alternative redox purifying agent is at least one component selected from the group consisting of Sb₂O₃ , SnO₂ , MnO₂ , CeO₂ , and Fe₂O₃ , or (ii) an evaporative purifying agent comprises a halogen having a purifying action, or (iii) a decomposition purifying agent comprises a sulfate component, or (iv) a combination of (i) and (ii), or (v) a combination of (i) and (iii), or (vi) a combination of (ii) and (iii), or (vii) a combination of (i) to (iii).
  20. Precision parts comprising the LAS glass ceramic described in paragraph 1 or 2.

Description

Glass ceramic having specific thermal expansion characteristics The present invention relates to a glass ceramic having specific thermal expansion characteristics, excellent meltability, and more environmentally friendly refining, molding, and ceramizability, and to the use of the glass ceramic according to the present invention in precision parts. Materials and precision components having low thermal expansion or low CTE (coefficient of thermal expansion) are already known in the prior art field. Materials known for precision parts having low thermal expansion in the temperature range near room temperature are ceramics, Ti-doped quartz glass, and glass ceramics. Glass ceramics having low thermal expansion are, in particular, lithium aluminum silicate glass ceramics (LAS glass ceramics), which are described, for example, in US 4,851,372, US 5,591,682, EP 587979 A, US 7,226,881, US 7,645,714, DE 102004008824 A, and DE 102018111144 A. Additional materials for precision parts are cordierite ceramics or cordierite glass ceramics. Such materials are often used in precision components that must meet particularly stringent requirements regarding their properties (e.g., mechanical, physical, and optical properties). They are used particularly in Earth and space-based astronomy and Earth observation, LCD lithography, microlithography and EUV lithography, metrology, spectroscopy, and measurement technologies. In these applications, it is particularly required that the components possess extremely low thermal expansion depending on the specific application. Generally, the thermal expansion of a material is determined by a static method in which the length of a test specimen is determined at the beginning and end of a specific temperature range, and the difference in length is used to calculate the average expansion coefficient α or CTE (coefficient of thermal expansion). Subsequently, the CTE is reported as the average over a temperature range of 0°C to 50°C, for example, as CTE(0;50) or α(0;50). To meet continuously increasing demands, materials have been developed that have a CTE better suited to the application field of parts formed from the material. For example, the average CTE can be optimized not only for standard temperature intervals CTE (0;50), but also for temperature intervals near the actual application temperature, for example, for a specific lithography application, an interval of 19°C to 25°C, i.e., CTE (19;25). Since the thermal expansion of the test specimen, as well as the average CTE, can be determined at very small temperature intervals, they can be represented by a CTE-T curve. Such a CTE-T curve may preferably have a zero crossing at one or more temperatures, preferably the planned application temperature or a temperature close thereto. At the zero crossing of the CTE-T curve, the relative change in length with temperature change is particularly small. In the case of some glass ceramics, such a zero crossing of the CTE-T curve can be shifted to the application temperature of the part by suitable heat treatment. Not only the absolute CTE value, but also the slope of the CTE-T curve near the application temperature must be as low as possible to cause the minimum possible change in the length of the part in the event of slight temperature variations. For these specific zero-expansion glass ceramics, the optimization of CTE or thermal expansion described above is generally influenced by the composition, which remains unchanged by variations in ceramicization conditions. For known precision parts and materials, particularly glass ceramics such as LAS glass ceramics, an adverse effect is "thermal hysteresis," which is referred to as "hysteresis" below. Here, hysteresis means that the change in length of a test specimen when heated at a constant rate differs from the change in length when subsequently cooled at a constant rate, even if the absolute values of the heating and cooling rates are the same. When the change in length is graphed as a function of the temperatures for heating and cooling, the result is a classic hysteresis loop. The range of the hysteresis loop also varies depending on the rate of temperature change. The faster the temperature change, the more pronounced the hysteresis effect becomes. The hysteresis effect demonstrates that the thermal expansion of LAS glass ceramics depends on temperature and time, that is, for example, the rate of temperature change. Regarding this, expert literature, for instance (O. Lindig and W. Pannhorst, "Thermal expansion and length stability of ZERODUR ® in dependence on temperature and time", APPLIED OPTICS, vol. 24, no. 20, Oct. 1985; R. Haug et al., "Length variation in ZERODUR ® M in the temperature range from -60℃ to +100℃", APPLIED OPTICS, vol. 28, no. 19, Oct. 1989; R. Jedamzik et al., "Modeling of the thermal expansion behavior of ZERODUR ® at arbitrary temperature profiles", Proc. SPIE Vol. 7739, 2010; DB Hall, "Dimensional stability tests over