MASK BLANK SUBSTRATE, SUBSTRATE WITH MULTILAYER REFLECTIVE FILM, REFLECTIVE MASK BLANK, REFLECTIVE MASK, METHOD OF MANUFACTURING MASK BLANK SUBSTRATE, METHOD OF MANUFACTURING SUBSTRATE WITH REFLECTIVE FILM AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE

• US 20150331312A1
• Filed: 12/27/2013
• Published: 11/19/2015
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: HAMAMOTO, Kazuhiro, SHOKI, Tsutomu, HORIKAWA, Junichi, ORIHARA, Toshihiko
• Granted Patent: US 9,581,895 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03F 1/24 Reflection masks; Preparation thereof
• CPC Class Codes: G03F 1/60 Substrates
• CPC Class Codes: G03F 1/80 Etching
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/20 Exposure; Apparatus therefor photographic printing apparatus for making copies G03B27/00
• CPC Class Codes: G03F 7/2004 characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light

Abstract

An object of the present invention is to provide a mask blank substrate and the like that enables critical defects to be reliably detected as a result of reducing the number of detected defects, including pseudo defects, even when using highly sensitive defect inspection apparatuses that use light of various wavelengths. The present invention relates to a mask blank substrate that is used in lithography, wherein the power spectral density at a spatial frequency of 1×10⁻² μm⁻¹ to 1 μm⁻¹, obtained by measuring a 0.14 mm×0.1 mm region on a main surface of the mask blank substrate on the side of which a transfer pattern is formed at 640×480 pixels with a white-light interferometer, is not more than 4×10⁶ nm⁴, and the power spectral density at a spatial frequency of not less than 1 μm⁻¹, obtained by measuring a 1 μm×1 μm region on the main surface with an atomic force microscope, is not more than 10 nm⁴.

Claims

1. A mask blank substrate that is used in lithography, wherein

the power spectral density at a spatial frequency of 1×

10<sup>−

2</sup> μ

m<sup>−

1</sup> to 1 μ

m<sup>−

1</sup>, obtained by measuring a 0.14 mm×

0.1 mm region on a main surface of the mask blank substrate on the side of which a transfer pattern is formed at 640×

480 pixels with a white-light interferometer, is not more than 4×

10⁶ nm⁴, and the power spectral density at a spatial frequency of not less than 1 μ

m^{31 1}, obtained by measuring a 1 μ

m×

1 μ

m region on the main surface with an atomic force microscope, is not more than 10 nm⁴.

2. The mask blank substrate according to claim 1, wherein the root mean square roughness (Rms) obtained by measuring a 1 μ

m×

1 μ

m region of the main surface with an atomic force microscope is less than 0.13 nm.

3. The mask blank substrate according to claim 1, wherein the power spectral density at a spatial frequency of 1 μ

m<sup>−

1</sup> to 10 μ

m<sup>−

1</sup> obtained by measuring a 1 μ

m×

1 μ

m region on the main surface with an atomic force microscope is 1 nm⁴ to 10 nm⁴.

4. The mask blank substrate according to claim 1, wherein the substrate is a mask blank substrate used in EUV lithography.

5. A substrate with a multilayer reflective film, comprising:

a multilayer reflective film, in which a high refractive index layer and a low refractive index layer are alternately laminated, on the main surface of the mask blank substrate according to claim 1.

6. The substrate with a multilayer reflective film according to claim 5, further comprising:

a protective film on the multilayer reflective film.

10. A reflective mask blank, comprising:

an absorber film to serve as a transfer pattern on the multilayer reflective film of the substrate with a multilayer reflective film according to claim 5.

11. A reflective mask having an absorber pattern, obtained by patterning the absorber film in the reflective mask blank according to claim 10, on the multilayer reflective film.

19. A method of manufacturing a substrate with a multilayer reflective film, comprising:

forming a multilayer reflective film, in which a high refractive index layer and a low refractive index layer are alternately laminated, on the main surface of the mask blank substrate according to claim 1.

20. The method of manufacturing a substrate with a multilayer reflective film according to claim 19, wherein the multilayer reflective film is formed by alternately depositing the high refractive index layer and the low refractive index layer by ion beam sputtering.

21. The method of manufacturing a substrate with a multilayer reflective film according to claim 20, wherein the multilayer reflective film is formed by making sputtered particles of a high refractive index material and a low refractive index material enter alternately at an incident angle of 0 degree to 30 degrees relative to the normal of the main surface by ion beam sputtering using a target of a high refractive index material and a low refractive index material.

22. The method of manufacturing a substrate with a multilayer reflective film according to claim 19, further comprising:

forming a protective film on the multilayer reflective film.

23. A method of manufacturing a semiconductor device, comprising:

forming a transfer pattern on a workpiece by carrying out a lithography process that uses an exposure apparatus using the reflective mask according to claim 11.

24. A reflective mask blank, comprising:

an absorber film to serve as a transfer pattern on the protective film of the substrate with a multilayer reflective film according to claim 6.

25. A reflective mask having an absorber pattern, obtained by patterning the absorber film in the reflective mask blank according to claim 24, on the protective film.

7. A substrate with a multilayer reflective film, having a multilayer reflective film, in which a high refractive index layer and a low refractive index layer are alternately laminated, on a main surface of a mask blank substrate used in lithography, wherein

the power spectral density at a spatial frequency of 1×

10<sup>−

2</sup> μ

m<sup>−

1</sup> to 1 μ

m<sup>−

1</sup>, obtained by measuring a 0.14 mm×

0.1 mm region on a surface of the substrate with a multilayer reflective film on the side of which the multilayer reflective film is formed at 640×

480 pixels with a white-light interferometer, is not more than 4 ×

10⁷ nm⁴, and the power spectral density at a spatial frequency of 1 μ

m<sup>−

1</sup> to 100 μ

m<sup>−

1</sup>, obtained by measuring a 1 μ

m×

1 μ

m region on the surface of the substrate with a multilayer reflective film with an atomic force microscope, is not more than 20 nm⁴.

8. The substrate with a multilayer reflective film according to claim 7, wherein the root mean square roughness (Rms) obtained by measuring a 1 μ

m×

1 μ

m region of the surface of the substrate with a multilayer reflective film with an atomic force microscope is less than 0.13 nm.

9. The substrate with a multilayer reflective film according to claim 7, further comprising:

a protective film on the multilayer reflective film.

12. A method of manufacturing a mask blank substrate, comprising a step of:

conducting a surface processing for processing a main surface of a mask blank substrate used in lithography on the side of which a transfer pattern is formed so as to obtain a prescribed surface morphology;

wherein,

the surface processing is conducted such that the power spectral density at a spatial frequency of 1×

10<sup>−

2</sup> μ

m<sup>−

1</sup> to 1 μ

m<sup>−

1</sup>, obtained by measuring a 0.14 mm×

0.1 mm region on the main surface at 640×

480 pixels with a white-light interferometer, is not more than 4×

10⁶ nm⁴, and the power spectral density at a spatial frequency of not less than 1 μ

m<sup>−

1</sup>, obtained by measuring a 1μ

m×

1 μ

m region on the main surface with an atomic force microscope, is not more than 10 nm⁴.

13. The method of manufacturing a mask blank substrate according to claim 12, wherein the surface processing is conducted by carrying out an intermediate spatial frequency region roughness-reducing such that the power spectral density at a spatial frequency of 1×

10<sup>−

2</sup> μ

m<sup>−

1</sup> to 1 μ

m<sup>−

1</sup>, obtained by measuring a 0.14 mm×

0.1 mm region on the main surface at 640×

480 pixels with a white-light interferometer, is not more than 4×

10⁶ nm⁴, and a high spatial frequency region roughness-reducing such that the power spectral density at a spatial frequency of not less than 1 μ

m<sup>−

1</sup>, obtained by measuring a 1 μ

m×

1 μ

m region on the main surface with an atomic force microscope, is not more than 10 nm⁴.

14. The method of manufacturing a mask blank substrate according to claim 13, wherein the high spatial frequency region roughness-reducing is carried out after the intermediate spatial frequency region roughness-reducing.

15. The method of manufacturing a mask blank substrate according to claim 12, wherein the surface processing is carried out by elastic emission machining (EEM) and/or catalyst-referred etching (CARE).

16. The method of manufacturing a mask blank substrate according to claim 13, wherein the intermediate spatial frequency region roughness-reducing is carried out by processing the main surface by EEM.

17. The method of manufacturing a mask blank substrate according to claim 13, wherein the high spatial frequency region roughness-reducing is carried out by processing the main surface by catalyst-referred etching.

18. The method of manufacturing a mask blank substrate according to claim 12, wherein the substrate is a mask blank substrate used in EUV lithography.

26. A method of manufacturing a substrate with a multilayer reflective film, comprising:

forming a multilayer reflective film, in which a high refractive index layer and a low refractive index layer are alternately laminated, on the main surface of the mask blank substrate manufactured by the manufacturing method according to claim 12.