Approach to Patterning of Extreme Ultraviolet Lithography Masks using Ru Buffer Layer

Jeong

et al. 2009

jjap

Pattern printability was examined while varying the thickness of a multilayer mask blank by simulation. The variations were related to the total thickness and the monolayer thickness of 40 Si/Mo bilayers. Printability was evaluated by using the pattern edge contrast for a binary mask and an attenuated phase shift mask (att-PSM). The total thickness variation degrades pattern edge contrast with decreasing exposure energy on a wafer. The phase shift between multilayer and absorber on a mask differs depending on the total thickness variation. The phase shift due to the total thickness variation gives rise to the focal position shift as a function of exposure wavelength for both the binary mask and the att-PSM. The phase shift and the focal position shift of the binary mask are different from those of the att-PSM. Monolayer thickness variation did not affect the printability of both the binary mask and the att-PSM.

Section: Optical Conditions For Simulationmentioning

confidence: 99%

(Na_xK_0.98-xLi_0.02)(Nb_0.8Ta_0.2)O₃ Lead-Free Piezoelectric Ceramics

Jeong

et al. 2009

jjap

“…[19][20][21][22] SiO 2 , SiON, C and Ru films are commonly used as repair buffers for a TaN or Cr absorber. [23][24][25] A buffer layer is required to protect the multilayer from damage during the repair of absorber defects with a focused ion beam (FIB). It needs to be patterned along with the EUV absorber layer as a stack to prevent any degradation in the EUV reflectivity of the multilayer.…”

Section: Reflection Maskmentioning

confidence: 99%

“…16), a Mo/Si multilayer (ML) composed of 40 bilayers and an 11-nm-thick Si capping layer are deposited on a ULE r glass substrate. 21,24,25,30 The RMS surface roughness of an as-deposited multilayer is 0. 16 deposited on the Si capping layer by direct current (DC) magnetron sputtering.…”

Section: Reflection Maskmentioning

confidence: 99%

Euv Lithography for Semiconductor Manufacturing and Nanofabrication

Kinoshita

2007

COSMOS

EUV lithography is the exposure technology in which even 15 nm node which is the limit of Si device can be achieved. Unlike the conventional optical lithography, this technology serves as a reflection type optical system, and a multilayer coated mirror is used. Development of manufacturing equipment is accelerated to aim at the utilization starting from 2011. The critical issues of development are the EUV light source which has the power over 115 W and resist with high sensitivity and low line edge roughness (LER).

“…1,[7][8][9][10][11][12][13][14][15] Since the optical index of Ta-based absorbers at EUV wavelengths is not known, we developed an accurate method of determining their optical index.…”

Section: Introductionmentioning

confidence: 99%

“…To solve those problems, we must use a thin absorber with a large extinction coefficient for the EUV mask, such as tantalum (Ta)-based compounds. 1,[7][8][9][10][11][12][13][14][15] Since the optical index of Ta-based absorbers at EUV wavelengths is not known, we developed an accurate method of determining their optical index.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Optical Index of Ta and Ta-Based Absorbers for an Extreme Ultraviolet Mask Using Extreme Ultraviolet Reflectometry

Hosoya¹,

Sakaya²,

Nozawa³

et al. 2008

jjap

We developed an accurate method for determining the optical index of Ta and Ta-based absorber layers with added nitrogen, oxygen, and boron for an extreme ultraviolet (EUV) mask using EUV reflectometry. The optical index at EUV wavelengths was derived from the density and atomic concentration of the composite materials. The atomic concentrations of Ta and Ta-based absorbers were determined using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS) analysis methods when no inconsistency occurred between the results of the XPS and RBS analyses. The volume densities of the Ta and Ta-based absorbers were determined using RBS and EUV reflectivity measurements with the grazing angle (EUVRG) or reflectivity (EUVR) when no inconsistency was observed between results. Deriving the volume density was necessary to establish the layer structure and layer thickness, and the surface oxidation layer was especially important for determining the correct volume density. The layer structure and thickness were derived using a pattern-fitting method for the XRR spectrum. The extinction coefficients of Ta and Ta-based absorbers stacked using conventional sputtering were lower than the extinction coefficient of an ideal Ta crystal.