Short-Period Multilayer X-ray Mirrors for “Water” and “Carbon Windows” Wavelengths

Kopylets, I. А.; Devizenko, Oleksander; Zubarev, E. N.; Кондратенко, В. В.; Artyukov, I. A.; Виноградов, А. В.; Penkov, Oleksiy V.

doi:10.1166/jnn.2019.16471

Cited by 22 publications

(10 citation statements)

References 25 publications

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“…The selection is based on the optical properties of materials in the given wavelengths range. For example, Mo/Si PMMs are primarily used for the wavelength of 13.5 nm (EUV), and Mo/B and La/B PMMs are excellent for 6.7 nm (BEUV) because boron has lower absorption in this range compared to silicon [20][21][22][23][24]. Co/C PMMs are the most effective for the shorter wavelength range of 4.4-4.5 nm [25].…”

Section: Materials and Designmentioning

confidence: 99%

Multilayer Reflective Coatings for BEUV Lithography: A Review

Uzoma

Salman

et al. 2021

Nanomaterials

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The development of microelectronics is always driven by reducing transistor size and increasing integration, from the initial micron-scale to the current few nanometers. The photolithography technique for manufacturing the transistor needs to reduce the wavelength of the optical wave, from ultraviolet to the extreme ultraviolet radiation. One approach toward decreasing the working wavelength is using lithography based on beyond extreme ultraviolet radiation (BEUV) with a wavelength around 7 nm. The BEUV lithography relies on advanced reflective optics such as periodic multilayer film X-ray mirrors (PMMs). PMMs are artificial Bragg crystals having alternate layers of “light” and “heavy” materials. The periodicity of such a structure is relatively half of the working wavelength. Because a BEUV lithographical system contains at least 10 mirrors, the optics’ reflectivity becomes a crucial point. The increasing of a single mirror’s reflectivity by 10% will increase the system’s overall throughput six-fold. In this work, the properties and development status of PMMs, particularly for BEUV lithography, were reviewed to gain a better understanding of their advantages and limitations. Emphasis was given to materials, design concepts, structure, deposition method, and optical characteristics of these coatings.

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Section: Materials and Designmentioning

confidence: 99%

Multilayer Reflective Coatings for BEUV Lithography: A Review

Uzoma

Salman

et al. 2021

Nanomaterials

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show abstract

“…The selection is based on the optical properties of materials in the given wavelengths range. For example, Mo/Si PMMs are primarily used for the wavelength of 13.5 nm (EUV), Mo/B and La/B PMMs are excellent for 6.7 nm (BEUV) since Boron has lower absorption in this range compared to silicon [20][21][22][23][24]. Co/C PMMs are the most effective for the shorter wavelength range of 4.4 -4.5 nm [25].…”

Section: Materials and Designmentioning

confidence: 99%

“…Preserving structural uniformity is essential for maintaining Bragg's diffraction condition. The nature of the periodicity is defined mainly by the deposition rate's time stability and maintenance of the substrate temperature [24]. The degree of the uniformity could be quickly evaluated by Low-angle X-ray reflectometry [44]; it manifests itself in the form of broadening of diffraction peaks, as shown in Figure 6.…”

Section: Structure and Optical Characteristics Of Molybdenum-based Beuv Pmmsmentioning

confidence: 99%

Multilayer Reflective Coatings for BEUV Lithography: A Review

Uzhoma¹,

Shabir²,

Hu³

et al. 2021

Preprint

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The development of microelectronics is always driven by reducing transistor size and increasing integration, from the initial micron-scale to the current few nanometers. The photolithography technique for manufacturing the transistor needs to reduce the wavelength of the optical wave, from ultraviolet, deep, to the existing extreme ultraviolet light. One approach toward decreasing the working wavelength is using lithography based on beyond extreme ultraviolet radiation (BEUV) with a wavelength around 7 nm. The BEUV lithography relies on advanced reflective optics such as periodic multilayer film X-ray mirrors (PMMs). PMMs are artificial Bragg crystals having alternate layers of “light” and “heavy” materials. The periodicity of such a structure is relatively half of the working wavelength. Since a BEUV lithographical system contains at least 10 mirrors, optics’ reflectivity becomes a crucial point. The increasing of a single mirror's reflectivity by 10% will increase the system’s overall throughput by 6 times. In this work, the properties and development status of PMMs, particularly for BEUV lithography, were reviewed to gain a better understanding of their advantages and limitations. Emphasis was given to materials, design concepts, structure, deposition method, and optical characteristics of these coatings.

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“…A high-reflective multilayer mirror is a vital component for extreme ultraviolet and soft X-ray based instrumentation used in lithography and microscopy, X-ray lasers, plasma physics, and astrophysics, synchrotron radiation polarimetry etc., and during the last decade this field has experienced significant growth (Kopylets et al, 2019;Qi et al, 2019;Pradhan et al, 2018;Huang et al, 2016Huang et al, , 2017aPanini et al, 2017;Peng et al, 2016;Li et al, 2013;Ferná ndez-Perea et al, 2013;Yi et al, 2017;Harrison et al, 2013). In particular, the development of high-reflective normal-incidence multilayer (ML) optics for the water window region ( ' 2.3-4.4 nm), where water is transmissive but carbon-based organic materials show strong absorption, has acquired great interest.…”

Section: Introductionmentioning

confidence: 99%

Interface modification of Cr/Ti multilayers with C barrier layer for enhanced reflectivity in the water window regime

et al. 2021

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The influence of a carbon barrier layer to improve the reflectivity of Cr/Ti multilayers, intended to be used in the water window wavelength regime, is investigated. Specular grazing-incidence X-ray reflectivity results of Cr/Ti multilayers with 10 bilayers show that interface widths are reduced to ∼0.24 nm upon introduction of a ∼0.3 nm C barrier layer at each Cr-on-Ti interface. As the number of bilayers increases to 75, a multilayer with C barrier layers maintains almost the same interface widths with no cumulative increase in interface imperfections. Using such interface-engineered Cr/C/Ti multilayers, a remarkably high soft X-ray reflectivity of ∼31.6% is achieved at a wavelength of 2.77 nm and at a grazing angle of incidence of 16.2°, which is the highest reflectivity reported so far in the literature in this wavelength regime. Further investigation of the multilayers by diffused grazing-incidence X-ray reflectivity and grazing-incidence extended X-ray absorption fine-structure measurements using synchrotron radiation suggests that the improvement in interface microstructure can be attributed to significant suppression of inter-diffusion at Cr/Ti interfaces by the introduction of C barrier layers and also due to the smoothing effect of the C layer promoting two-dimensional growth of the multilayer.

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Short-Period Multilayer X-ray Mirrors for “Water” and “Carbon Windows” Wavelengths

Cited by 22 publications

References 25 publications

Multilayer Reflective Coatings for BEUV Lithography: A Review

Multilayer Reflective Coatings for BEUV Lithography: A Review

Multilayer Reflective Coatings for BEUV Lithography: A Review

Interface modification of Cr/Ti multilayers with C barrier layer for enhanced reflectivity in the water window regime

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