Process for improved reflectivity uniformity in extreme-ultraviolet lithography (EUVL) masks

Thiel, Carey W.; Racette, Kenneth C.; Fisch, Emily; Lawliss, Mark; Kindt, Louis; Huang, Chester; Ackel, Robin; Levy, M.

doi:10.1117/12.484988

Cited by 3 publications

(3 citation statements)

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“…In comparison to Cr-based absorber some advantages were exposed towards the TaN-based absorber layers regarding mainly critical dimension (CD) control and inspection capabilities [6]. Deeper investigations related to image placement errors and etch bias pointed out that TaN would be a better material than Cr towards next generation lithography and specifically EUV Lithography [7]. One of the main advantage of the TaN absorber is its higher mass density and its higher stability with respect to chrome binary mask blanks.…”

Section: Progress In Absorber Stack Materialsmentioning

confidence: 99%

EUVL mask blanks: Recent results on substrates, multilayers and the dry-etch process of TaN-absorbers

et al. 2006

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Continuous reduction of feature size in semiconductor industry and manufacturing integrated circuits at low costs requires new and innovative technology to overcome existing limitations of optics. Tremendous progress in key areas like EUVL light source technology and manufacturing technology of EUVL masks with low defect rates have been made recently and EUVL is the leading technology capable to be extended so Moore's law, the shrinkage of IC critical features, can continue to be valid. SCHOTT Lithotec has introduced all relevant technology steps to manufacture EUV mask blanks -ranging from Low Thermal Expansion Material (LTEM) with high quality substrate polishing to low defect blank manufacturing. New polishing and cleaning technologies, improved sputter technology and updated metrology enable us to routinely produce EUVL mask blanks meeting already many of the roadmap requirements. Further R&D is ongoing to path the way to the production of EUV blanks which meet all requirements.An important focus of this paper is to present the recent results on LTEM substrates, which include defect density, roughness and flatness simultaneously, as well as EUVL multilayer properties such as defect density, optical properties like reflectivity and uniformity in the EUV range and optical resistance to cleaning steps. In addition the design of EUVL absorber material will be discussed, including optical performance at EUV wavelength and its contrast behavior.Finally, IMS Chips has developed the dry etch process of these EUV Mask Blanks by optimizing etch selectivities, profiles and etch bias. Results on CD uniformity, linearity and iso/dense bias will be presented.

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Section: Progress In Absorber Stack Materialsmentioning

confidence: 99%

EUVL mask blanks: Recent results on substrates, multilayers and the dry-etch process of TaN-absorbers

et al. 2006

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“…Recently some advantages were exposed towards the TaN based absorber layers regarding mainly CD control and inspection capabilities [6]. Deeper investigations related to image placement errors and etch bias pointed out that TaN would be a better material than Cr towards next generation lithography and specifically EUV Lithography [7]. Even though these result may depend upon the conditions of experiments in terms layer deposition technique and mask processing, We want to come back quickly on to the real natural advantage that can offer TaN material for the EUV absorber system.…”

Section: Definition Of the Absorber Stack For Euv Lithographymentioning

confidence: 99%

Absorber stack optimization toward EUV lithography mask blank pilot production

et al. 2004

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EUV Lithography requires high end quality defect free layers from the backside coating to the absorber stack. Low thermal expansion materials (LTEM) substrates with super flat surfaces are already available with low defect backside coating for E-Chuck technology. The multilayer stack is well developed from a physical point of view and major effort relies nowadays on the layer defectivity. On the other hand, absorber stack becomes one of the main challenges in terms of stress, optical behavior for ultraviolet wavelengths and dry etching behavior.Schott Lithotec is currently developing absorber stack solutions that will fulfill the requirements of next generation lithographies. There are several options for achieving the mechanical, optical and chemical specs for buffer layers and absorber coatings. Some of them are already integrated in our production processes. Buffer layers were evaluated and reach almost the physical and chemical level necessary to fit with the mask processing. TaN based absorber coatings were designed and deposited by an ion beam sputter tool optimized for low defect deposition (LDD-IBS). The chemical composition of our layer and its manufacturing process is already optimized to achieve high quality etching behavior. The current results of defect density for the absorber stack will be presented.

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“…[3][4][5][6] Both stacks are coated on a quartz substrate with 40 Mo/ Si bilayers and a Si capping-layer with 11 nm thickness. While the Cr/ SiO 2 absorber/buffer stack combination has been the initial material choice for EUV masks, the TaN / Cr stack is currently under close investigation due to the superior etch properties of TaN compared to Cr.…”

Section: Euv Mask Fabricationmentioning

confidence: 99%

Characterization of extreme ultraviolet masks by extreme ultraviolet scatterometry

Perlich

Kamm

Rau

et al. 2004

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Process for improved reflectivity uniformity in extreme-ultraviolet lithography (EUVL) masks

Cited by 3 publications

References 0 publications

EUVL mask blanks: Recent results on substrates, multilayers and the dry-etch process of TaN-absorbers

EUVL mask blanks: Recent results on substrates, multilayers and the dry-etch process of TaN-absorbers

Absorber stack optimization toward EUV lithography mask blank pilot production

Characterization of extreme ultraviolet masks by extreme ultraviolet scatterometry

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